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2 Universal Worker Service WD
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19 <table><tr><td rowspan="1" colspan="1"><a href="http://www.ivoa.net/" shape="rect"><img alt="IVOA" src="http://www.ivoa.net/icons/ivoa_logo_small.jpg"/></a></td></tr></table>
20 <h1>Universal Worker Service<br clear="none"/>
21 Version 0.9</h1>
22 <h2>IVOA Working Draft @RELEASEDATE@</h2>
23 <dl><dt>Working Group</dt><dd><a href="http://www.ivoa.net/twiki/bin/view/IVOA/IvoaGridAndWebServices" shape="rect">http://www.ivoa.net/twiki/bin/view/IVOA/IvoaGridAndWebServices</a></dd><dt><b>This version:</b></dt><dd> 0.9</dd><dt><b>Latest version:</b></dt><dd> not issued outside
24 GWS-WG</dd><dt><b>Previous version(s):</b></dt><dd> Internal Working Draft
25 v0.1, 2005-01-24
26 Internal Working Draft
27 v0.2, 2006-05-11 Internal
28 Working Draft v.0.3, 2007-04-26 Internal
29 Working Draft v.04 2008-05-10, Internal Working draft 0.5 </dd><dt><b>Author(s):</b></dt><dd> P.
30 Harrison, G. Rixon</dd>
31 </dl>
32
33 <h2>Abstract</h2>
34 <p>The Universal Worker Service pattern
35 (UWS) defines how to manage asynchronous execution of jobs on a
36 service. Any application of the pattern defines a family of related
37 services with a common service contract. Four possible applications
38 are described.</p>
39 <h2> Status of This Document</h2>
40 <p>This is an working draft of
41 the GWS-WG. The first release of this document was on 2005-01-24
42 within the working group; This version is the first public WD.</p>
43 <p><em>This
44 is an IVOA Working Draft for review by IVOA members and other
45 interested parties. It is a draft document and may be updated,
46 replaced, or made obsolete by other documents at any time. It is
47 inappropriate to use IVOA Working Drafts as reference materials or to
48 cite them as other than &#8220;work in progress&#8221;.</em></p>
49 <p> <em>A list of </em><span style="background: transparent"><a href="http://www.ivoa.net/Documents/" shape="rect"><i>current
50 IVOA Recommendations and other technical documents</i></a></span><em> can be found at http://www.ivoa.net/Documents/.</em></p>
51 <h2 class="prologue-heading-western">Acknowledgements</h2>
52 <p>The need for the UWS pattern was
53 inspired by AstroGrid&#8217;s Common Execution Architecture and
54 particularly by discussions with Noel Winstanley. The ideas about
55 statefulness are distilled from debates in the Global Grid Forum in
56 respect of the Open Grid Services Infrastructure that was the
57 fore-runner of Web Services Resource Framework. The REST binding came
58 initially from suggestions by Norman Gray.</p>
59 </div>
60 <h2>Contents</h2>
61 <div><copy xmlns:h="http://www.w3.org/1999/xhtml" xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:dcterms="http://purl.org/dc/terms/"><div id="toc" class="toc"><ul><li><a href="#Introduction"><span class="secnum">1. </span>Introduction</a><ul><li><a href="#SynchronousStateless"><span class="secnum">1.1. </span> Synchronous, stateless services</a></li><li><a href="#IVOOutGrow"><span class="secnum">1.2. </span> Some IVO activities that outgrow synchronous, stateless services</a></li><li><a href="#AsynchronousServices"><span class="secnum">1.3. </span> Asynchronous and stateful services</a></li><li><a href="#JDL"><span class="secnum">1.4. </span> Job description language, service contracts and universality</a></li></ul></li><li><a href="#UWSpattern"><span class="secnum">2. </span> Universal Worker Service Pattern</a><ul><li><a href="#UWSObjects"><span class="secnum">2.1. </span> Objects within a UWS</a><ul><li><a href="#Joblist"><span class="secnum">2.1.1. </span>
62 Job list </a></li><li><a href="#Job"><span class="secnum">2.1.2. </span>Job</a></li><li><a href="#ExecutionPhase"><span class="secnum">2.1.3. </span> Execution Phase</a></li><li><a href="#ExecutionDuration"><span class="secnum">2.1.4. </span> Execution Duration</a></li><li><a href="#DestructionTime"><span class="secnum">2.1.5. </span> Destruction Time</a></li><li><a href="#Quote"><span class="secnum">2.1.6. </span>Quote</a></li><li><a href="#Error"><span class="secnum">2.1.7. </span>Error</a></li><li><a href="#Error2"><span class="secnum">2.1.8. </span>Owner</a></li><li><a href="#Error3"><span class="secnum">2.1.9. </span>RunId</a></li><li><a href="#ResultsList"><span class="secnum">2.1.10. </span>Results List</a></li><li><a href="#ResultsList2"><span class="secnum">2.1.11. </span>Parameter List</a></li></ul></li><li><a href="#RESTbinding"><span class="secnum">2.2. </span>The REST Binding</a><ul><li><a href="#d1e834"><span class="secnum">2.2.1. </span>Resources and URIs</a></li><li><a href="#d1e603"><span class="secnum">2.2.2. </span>Representations of resources</a><ul><li><a href="#d1e1030"><span class="secnum">2.2.2.1. </span>Job List</a></li><li><a href="#d1e1040"><span class="secnum">2.2.2.2. </span>Job</a></li><li><a href="#d1e1344"><span class="secnum">2.2.2.3. </span>Results List</a></li><li><a href="#d1e1353"><span class="secnum">2.2.2.4. </span>Parameters List</a></li></ul></li><li><a href="#d1e634"><span class="secnum">2.2.3. </span>State changing requests</a><ul><li><a href="#d1e1375"><span class="secnum">2.2.3.1. </span>Creating a Job</a></li><li><a href="#d1e1390"><span class="secnum">2.2.3.2. </span>Deleting a Job</a></li><li><a href="#d1e1402"><span class="secnum">2.2.3.3. </span>Changing the Destruction
63 Time</a></li><li><a href="#d1e1420"><span class="secnum">2.2.3.4. </span>Changing the Execution
64 Duration</a></li><li><a href="#d1e1439"><span class="secnum">2.2.3.5. </span> Starting a Job</a></li><li><a href="#d1e1448"><span class="secnum">2.2.3.6. </span>Aborting a Job</a></li></ul></li><li><a href="#d1e708"><span class="secnum">2.2.4. </span>Message pattern</a></li></ul></li></ul></li><li><a href="#security"><span class="secnum">3. </span>Security Considerations</a></li><li><a href="#ApplicationsOfUWS"><span class="secnum">4. </span> Applications of UWS (informative)</a><ul><li><a href="#Imageservice"><span class="secnum">4.1. </span> Image service with data staging</a></li><li><a href="#ADQLservice"><span class="secnum">4.2. </span> ADQL service with cursor</a></li><li><a href="#ParameterizedApplications"><span class="secnum">4.3. </span> Parameterized applications</a></li></ul></li><li><a href="#SynchronousService"><span class="secnum">5. </span> Implementing a Synchronous Service on top of UWS (informative)</a></li><li><a href="#Updates"><span class="secnum">Appendix A. </span> Updates from previous versions</a><ul><li><a href="#d1e1112"><span class="secnum">Appendix A.1. </span>At Version 0.5</a></li><li><a href="#d1e1775"><span class="secnum">Appendix A.2. </span>At Version 1.0</a></li></ul></li><li><a href="#UWSSchema"><span class="secnum">Appendix B. </span> UWS Schema</a></li></ul></div></copy></div>
65 <div class="body">
66 <div class="section"><h2><a name="Introduction" id="Introduction" shape="rect"/><span class="secnum">1. </span>Introduction</h2>
67 <p>The Universal Worker Service (UWS)
68 pattern defines how to build <i>asynchronous</i>, <i>stateful</i>, <i>job-oriented</i> services<i> </i>(the italicized terms are defined
69 in sub-sections of this introduction). It does so in a way that
70 allows for wide-scale reuse of software and support from software
71 toolkits.</p>
72 <p>Section <h:span xmlns:h="http://www.w3.org/1999/xhtml" xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:dcterms="http://purl.org/dc/terms/" class="xref"><a href="#UWSpattern">2. </a></h:span> of this document describes
73 the pattern and lists the aspects that are common to all its
74 applications. Any such application would involve a service contract
75 that embodies the pattern and fixes the issues left undefined in the
76 pattern itself. The contract would include the XML schemata (XSD and
77 WSDL) for the application. It is intended that each such contract
78 cover a family of related applications, such that the implementations
79 may be widely reused.</p>
80 <p>Section 3 outlines several possible
81 applications of the pattern. These use-cases may be expanded into
82 full IVOA standards that are siblings of the current document.</p>
83 <p>Section 4 describes the preferred
84 method of creating a synchronous facade to a UWS system.</p>
85 <div class="section"><h3><a name="SynchronousStateless" id="SynchronousStateless" shape="rect"/><span class="secnum">1.1. </span> Synchronous, stateless services</h3>
86 <p>Simple web services are <i>synchronous</i> and <i>stateless</i>. Synchronous means that the client waits for
87 each request to be fulfilled; if the client disconnects from the
88 service then the activity is abandoned. <i>Stateless</i> means that
89 the service does not remember results of a previous activity (or, at
90 least, the client cannot ask the service about them).</p>
91 <p>Synchronous, stateless services work
92 well when two criteria apply.</p>
93 <ol><li>
94 <p>The length of each activity is
95 less than the &#8220;attention span&#8221; of the connection.</p>
96 </li><li>
97 <p>The results of each activity are
98 compact enough to be easily passed back to the client via the
99 connection on which the request was made (and possibly pushed back
100 to the service as parameters of the next activity).</p>
101 </li></ol>
102 <p>There are various limits to the
103 attention span.</p>
104 <ul><li>
105 <p>HTTP assumes that the start of a
106 reply quickly follows its request, even if the body of the reply
107 takes a long time to stream. If the service takes too long to
108 compute the results and to start the reply, then HTTP times out at
109 the request is lost.</p>
110 </li><li>
111 <p>A client runs computer which
112 will not stay on-line indefinitely.</p>
113 </li><li>
114 <p>A network with finite
115 reliability will eventually break communications during an activity.</p>
116 </li><li>
117 <p>A service is sometimes shut down
118 for maintenance.</p>
119 </li></ul>
120 <p>Synchronous, stateless services, in
121 short, do not scale well.</p>
122 </div>
123 <div class="section"><h3><a name="IVOOutGrow" id="IVOOutGrow" shape="rect"/><span class="secnum">1.2. </span> Some IVO activities that outgrow synchronous, stateless services</h3>
124 <p>These cases are examples. They are
125 not a complete list!</p>
126 <ol><li>
127 <p>An ADQL <cite>
128 [<a xmlns:h="http://www.w3.org/1999/xhtml" xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:dcterms="http://purl.org/dc/terms/" href="#ref:std:adql">std:adql</a>]
129 </cite> service gives access
130 to a large object-catalogue. Most queries run in less than a minute,
131 but some legitimate queries involve a full-table traverse and take
132 hours or days. The service needs to run these special cases in a
133 low-priority queue.</p>
134 </li><li>
135 <p>An object-finding service runs
136 the SExtractor <cite>
137 [<a xmlns:h="http://www.w3.org/1999/xhtml" xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:dcterms="http://purl.org/dc/terms/" href="#ref:sextractor">sextractor</a>]
138 </cite> application on a list of images. Normally, the list
139 is short and the request is quickly satisfied. Occasionally, a list
140 of 10,000 images is sent in the expectation that the work will be
141 finished over the weekend.</p>
142 </li><li>
143 <p>A cone-search <cite>
144 [<a xmlns:h="http://www.w3.org/1999/xhtml" xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:dcterms="http://purl.org/dc/terms/" href="#ref:std:scs">std:scs</a>]
145 </cite> request on a
146 rich catalogue raises 10,000,000 rows of results, but the client is
147 connected via a slow link and cannot read all the results in a
148 reasonable time. The client needs the service to send the results
149 into storage over a faster link. This could mean sending them to
150 VOSpace, or simply holding them temporarily until the user can
151 retrieve them on a fast link.</p>
152 </li><li>
153 <p>An ADQL service allows users to
154 save query results into new tables such that they can be the target
155 of later queries. However, space is limited and the results tables
156 can only be kept for a short time. The client and service negotiate
157 the lifetime of the results tables.</p>
158 </li><li>
159 <p>A service performs image
160 stacking on a list of fields. Each field can be processed by a
161 synchronous service but the list is long and the user wants to
162 retrieve the results of the early fields before the last fields are
163 processed.</p>
164 </li></ol>
165 </div>
166 <div class="section"><h3><a name="AsynchronousServices" id="AsynchronousServices" shape="rect"/><span class="secnum">1.3. </span> Asynchronous and stateful services</h3>
167 <p>Services can be made to scale better
168 by making them <i>asynchronous</i> and <i>stateful</i>. Asynchronous
169 means that a client makes two or more separate requests to the
170 service in the course of one activity, and that the client and
171 service may be disconnected, possibly for days or more, in between
172 those requests. Stateful means that the service stores state
173 information about the activity and the client addresses requests to
174 this state.</p>
175 <p>Web services that are asynchronous
176 are almost always stateful. Most of special extra arrangements for
177 asynchronous activities are actually managing the state of the
178 activity.</p>
179 <p>There is an important class of
180 stateful services where the state is peculiar to one job or session
181 and the job is &#8220;owned&#8221; by one user. These, for the purpose of
182 this document, are called <i>job-oriented</i> services. There are
183 stateful services that are not job-oriented (e.g. a service managing
184 a shared, client-writeable DB table), but UWS does not apply to
185 these.</p>
186 <p>For the purpose of this discussion,
187 let the term <i>job</i> refer to the work specified by the JDL
188 instructions and the term <i>resource</i> refer to the state of the
189 job as recorded by the service. Both have a finite duration. The <i>lifetime</i> of the resource &#8211; i.e. the time from inception
190 until the service forgets the state &#8211; is generally finite and must
191 be at least as long the duration of the job.</p>
192 </div>
193 <div class="section"><h3><a name="JDL" id="JDL" shape="rect"/><span class="secnum">1.4. </span> Job description language, service contracts and universality</h3>
194 <p>Consider the web-service operation
195 that starts off a job. This operation must express what is to be done
196 in the activity: it must carry parameters in some form.</p>
197 <p>The parameters may be expressed as a
198 list. E.g., a cone search service takes a list of three parameters:
199 RA, DEC, RADIUS. Alternatively, the parameters may be arranged as an
200 XML document (e.g. ADQL, CEA). The rules for setting and arranging
201 the parameters for a job are called the<i> Job-Description Language </i>(JDL).</p>
202 <p>The combination of the UWS pattern, a
203 JDL and details of the job state visible to the client defines a
204 service contract; for a SOAP service, this contract can be captured
205 in WSDL. Changing the JDL changes the contract. Thus, it is not
206 meaningful to &#8220;implement UWS&#8221; in isolation; any implementation
207 standard must specify the rest of the contract.</p>
208 <p>If the JDL is very general, a single
209 service-contract can be reused for many kinds of service. AstroGrid&#8217;s
210 CEA <cite>
211 [<a xmlns:h="http://www.w3.org/1999/xhtml" xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:dcterms="http://purl.org/dc/terms/" href="#ref:harrison05">harrison05</a>]
212 </cite>exploits this: one JDL covers all services offering parameterized
213 applications and even ADQL services. In the limit, a
214 sufficiently-general JDL turns a specialized worker service into a
215 universal worker service.</p>
216 </div>
217 </div>
218 <div class="section"><h2><a name="UWSpattern" id="UWSpattern" shape="rect"/><span class="secnum">2. </span> Universal Worker Service Pattern</h2>
219 <div class="section"><h3><a name="UWSObjects" id="UWSObjects" shape="rect"/><span class="secnum">2.1. </span> Objects within a UWS</h3>
220 <p>A UWS consists logically in a set of
221 objects that may be read and written to in order to control jobs.</p>
222 <p>In a SOAP binding of UWS, these
223 components are exposed as properties of the object that lives at the
224 endpoint registered for the service. In a REST binding, the
225 components are distinct web-resources each with its own URI.</p>
226 <p> The following sub-sections explain the semantics of the objects. The
227 UML diagram below shows the relationships more succinctly.</p>
228 <p><img src="Class_Diagram__UWS__UWSObjects.png" alt="UWS Objects Class Diagram" name="graphics2" width="460" height="390" border="0" align="top" id="graphics2"/></p>
229 <div class="section"><h4><a name="Joblist" id="Joblist" shape="rect"/><span class="secnum">2.1.1. </span>
230 Job list </h4>
231 <p>The Job List is the outermost object:
232 it contains all the other objects in the UWS. The immediate children
233 of the job list are Job objects (see next sub-section).</p>
234 <p>The job list may be read to find the
235 extant jobs.</p>
236 <p>The job list may be updated to add a
237 new job.</p>
238 <p>The job list itself does not allow
239 jobs to be deleted. Instead, when a job is destroyed by an action on
240 its job object, then the list updates itself accordingly.</p>
241 </div>
242 <div class="section"><h4><a name="Job" id="Job" shape="rect"/><span class="secnum">2.1.2. </span>Job</h4>
243 <p>A Job object contains the state of
244 one job. The state is a collection of other objects. Each Job
245 aggregates</p>
246 <ul><li>
247 <p>Exactly one Execution Phase.</p>
248 </li><li>
249 <p>Exactly one Execution Duration.</p>
250 </li><li>
251 <p>Exactly one Deletion Time</p>
252 </li><li>
253 <p>Exactly one Quote.</p>
254 </li><li>
255 <p>Exactly one Results List.</p>
256 </li><li>
257 <p>Zero or one Error.</p>
258 </li></ul>
259 </div>
260 <div class="section"><h4><a name="ExecutionPhase" id="ExecutionPhase" shape="rect"/><span class="secnum">2.1.3. </span> Execution Phase</h4>
261 <p>The job is treated as a state machine
262 with the Execution Phase naming the state. The phases are;</p>
263 <ul><li>
264 <p>PENDING: the job is accepted by
265 the service but not yet committed for execution by the client. In
266 this state, the job quote can be read and evaluated. This is the
267 state into which a job enters when it is first created.</p>
268 </li><li>
269 <p>QUEUED: the job is committed for
270 execution by the client but the service has not yet assigned it to a
271 processor. No Results are produced in this phase.</p>
272 </li><li>
273 <p>EXECUTING: the job has been
274 assigned to a processor. Results may be produced at any time during
275 this phase.</p>
276 </li><li>
277 <p>COMPLETED: the execution of the
278 job is over. The Results may be collected.</p>
279 </li><li>
280 <p>ERROR: the job failed to
281 complete. No further work will be done nor Results produced. Results
282 may be unavailable or available but invalid; either way the Results
283 should not be trusted.</p>
284 </li><li>
285 <p>ABORTED: the job has been
286 manually aborted by the user, or the system has aborted the job due
287 to lack of or overuse of resources.</p>
288 </li></ul>
289 </div>
290 <div class="section"><h4><a name="ExecutionDuration" id="ExecutionDuration" shape="rect"/><span class="secnum">2.1.4. </span> Execution Duration</h4>
291 <p>An Execution Duration object defines
292 the duration for which a job shall run. This represents the
293 &#8220;computation time&#8221; that a job is to be allowed, although because
294 a specific measure of CPU time may not be available in all
295 environments, this duration is defined in real clock seconds. An
296 execution duration of 0 implies unlimited execution duration.</p>
297 <p>When the execution duration has been
298 exceeded the service will automatically abort the job, which has the
299 same effect as when a manual &#8220;Abort&#8221; is requested.</p>
300 <p>Specifically, when a job is aborted:</p>
301 <ul><li>
302 <p>if the job is still executing,
303 the execution is aborted.</p>
304 </li><li>
305 <p>any previously generated results
306 of the job are retained.</p>
307 </li></ul>
308 <p>When a job is created, the service
309 sets the initial execution duration. The client may write to an
310 Execution Duration to try to change the job's cpu time allocation.
311 The service may forbid changes, or may set limits on the allowed
312 execution duration.</p>
313 </div>
314 <div class="section"><h4><a name="DestructionTime" id="DestructionTime" shape="rect"/><span class="secnum">2.1.5. </span> Destruction Time</h4>
315 <p>The Destruction Time object
316 represents the instant when the job shall be destroyed. The
317 Destruction Time is an absolute time.</p>
318 <p>Destroying a job implies;</p>
319 <ul><li>
320 <p>if the job is still executing,
321 the execution is aborted.</p>
322 </li><li>
323 <p>any results from the job are
324 destroyed and storage reclaimed.</p>
325 </li>
326 <li>
327 <p>the service forgets that
328 the job existed.</p>
329 </li></ul>
330 <p>The Destruction Time may be viewed as
331 a measure of the amount of time that a service is prepared to
332 allocate storage for a job &#8211; typically this will be a longer
333 duration that the amount of CPU time that a service would allocate.</p>
334 <p>When a job is created the service
335 sets the initial Destruction Time. The client may write to the
336 Destruction Time to try to change the life expectancy of the job. The
337 service may forbid changes, or may set limits on the allowed
338 destruction time.</p>
339 </div>
340 <div class="section"><h4><a name="Quote" id="Quote" shape="rect"/><span class="secnum">2.1.6. </span>Quote</h4>
341 <p>A Quote object predicts when the job
342 is likely to complete. The intention is that a client creates the
343 same job on several services, compares the quotes and then accepts
344 the best quote.</p>
345 <p>Quoting for a computational job is
346 notoriously difficult. A UWS implementation must always provide a
347 quote object, in order that the two-phase committal of jobs be
348 uniform across all UWS, but it may supply a &#8220;don't know&#8221; answer
349 for the completion time.</p>
350 </div>
351 <div class="section"><h4><a name="Error" id="Error" shape="rect"/><span class="secnum">2.1.7. </span>Error</h4>
352 <p>The error object gives a human
353 readable error message (if any) for the underlying job. This object
354 is intended to be a detailed error message, and consequently might be
355 a large piece of text such as a stack trace. When there is an error
356 running a job a summary of the error should be given using the
357 optional errorSummary element of the JobSummary type.</p>
358 </div>
359 <div class="section"><h4><a name="Error" id="Error2" shape="rect"/><span class="secnum">2.1.8. </span>Owner</h4>
360 <p>The owner object represents the identifier for the creator of the job. This object will not exist for all invocations of a UWS conformant protocol, but only in cases where the access to the service is authenticated as discussed more thoroughly in <h:span xmlns:h="http://www.w3.org/1999/xhtml" xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:dcterms="http://purl.org/dc/terms/" class="xref"><a href="#security">3. </a></h:span>. </p>
361 </div>
362 <div class="section"><h4><a name="Error" id="Error3" shape="rect"/><span class="secnum">2.1.9. </span>RunId</h4>
363 <p>The RunId object represents an identifier that the job creator uses to identify the job. Note that this is distinct from the Job Identifier that the UWS system itself assigns to each job. The UWS system should do no parsing or processing of the RunId, but merely pass back the value (if it exists) as it was passed to the UWS at job creation time. In particular it may be the case that multiple jobs have the same RunId, as this is a mechanism by which the calling process can identifiy jobs that belong to a particular group. The exact mechanism of setting the RunId is not specified here, but will be part of the specification of the protocol using the UWS pattern.</p>
364 </div>
365 <div class="section"><h4><a name="ResultsList" id="ResultsList" shape="rect"/><span class="secnum">2.1.10. </span>Results List</h4>
366 <p>The Results List object is a
367 container for formal results of the job. Its children may be any
368 objects resulting from the computation that may be fetched from the
369 service when the job has completed.</p>
370 <p>Reading the Results List itself
371 enumerates the available or expected result objects.</p>
372 <p>The children of the Results List may
373 be read but not updated or deleted. The client may not add anything
374 to the Results List.</p>
375 </div>
376 <div class="section"><h4><a name="ResultsList" id="ResultsList2" shape="rect"/><span class="secnum">2.1.11. </span>Parameter List</h4>
377 <p>The Parameter List</p>
378 <p>Reading the Results List itself
379 enumerates the available or expected result objects.</p>
380 <p>A particular imlementation of UWS may choose to allow the parameters to be updated after the initial job creation step, before the Phase is set to the executing state. It is up to the individual implementation to specify exactly how these parameters may be updated, but good practice would be to choose one of the following options.</p>
381 <ol>
382 <li>HTTP POST an <i>application/x-www-form-urlencoded</i><b> </b>parameter name, value pair to either
383 <ol>
384 <li>/{jobs}/{job-id)</li>
385 <li>/{jobs}/{job-id)/parameters</li>
386 </ol>
387 </li>
388 <li>HTTP PUT the parameter value to /{jobs}/{job-id)/parameters/(parameter-name)</li>
389 </ol>
390 </div>
391 </div>
392 <div class="section"><h3><a name="RESTbinding" id="RESTbinding" shape="rect"/><span class="secnum">2.2. </span>The REST Binding</h3>
393 <p>In order to create a usable service the objects discussed in the section above must be exposed in a particular interface which can be addressed over a particular transport mechanism - this combination is known as a "binding". In this first version of the UWS pattern only a REST (Representational State
394 Transfer) binding <cite>
395 [<a xmlns:h="http://www.w3.org/1999/xhtml" xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:dcterms="http://purl.org/dc/terms/" href="#ref:fielding00">fielding00</a>]
396 </cite>is presented, however, future versions of this document will add other bindings such as SOAP. <cite>
397 [<a xmlns:h="http://www.w3.org/1999/xhtml" xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:dcterms="http://purl.org/dc/terms/" href="#ref:std:soap">std:soap</a>]
398 </cite></p>
399
400 <div class="section"><h4><a name="d1e834"/><span class="secnum">2.2.1. </span>Resources and URIs</h4>
401 <p>In a REST (Representational State
402 Transfer) binding of UWS, each of the objects defined above is
403 available as a web resource with its own URI. These URIs must form a
404 hierarchy as shown in the rable below:</p>
405 <table border="1" cellpadding="2" cellspacing="0">
406 <tr>
407 <th scope="col">URI</th>
408 <th scope="col">Description</th>
409 <th scope="col">Representation</th>
410 </tr>
411 <tr>
412 <td>/{jobs}</td>
413 <td>the Job List</td>
414 <td> the <span class="xmlelement">&lt;jobs&gt;</span> element in the UWS schema</td>
415 </tr>
416 <tr>
417 <td>/{jobs}/(job-id)</td>
418 <td>a Job</td>
419 <td><p>the <span class="xmlelement">&lt;job&gt;</span> element in the UWS schema<br/>
420 </p></td>
421 </tr>
422 <tr>
423 <td>/{jobs}/(job-id)/phase</td>
424 <td> the Phase of job
425 (job-id)</td>
426 <td>one of the fixed strings</td>
427 </tr>
428 <tr>
429 <td>/{jobs}/(job-id)/executionduration</td>
430 <td>the
431 maximum execution duration of (job-id)</td>
432 <td>Integer number of seconds</td>
433 </tr>
434 <tr>
435 <td>/{jobs}/(job-id)/destruction</td>
436 <td> the
437 destruction instant for (job-id)</td>
438 <td><cite>
439 [<a xmlns:h="http://www.w3.org/1999/xhtml" xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:dcterms="http://purl.org/dc/terms/" href="#ref:std:iso8601">std:iso8601</a>]
440 </cite></td>
441 </tr>
442 <tr>
443 <td>/{jobs}/(job-id)/error</td>
444 <td>any error
445 message associated with (job-id)</td>
446 <td>any representation appropriate to the implementing service</td>
447 </tr>
448 <tr>
449 <td>/{jobs}/(job-id)/quote </td>
450 <td>the Quote for
451 (job-id)</td>
452 <td>Integer number of seconds</td>
453 </tr>
454 <tr>
455 <td>/{jobs}/(job-id)/results</td>
456 <td>any parameters for the job
457 (job-id)</td>
458 <td>the <span class="xmlelement">&lt;results&gt;</span> element in the UWS schema</td>
459 </tr>
460 <tr>
461 <td>/{jobs}/(job-id)/parameters</td>
462 <td>any parameters for the job
463 (job-id)</td>
464 <td>the <span class="xmlelement">&lt;parameters&gt;</span> element in the UWS schema</td>
465 </tr>
466 <tr>
467 <td>/{jobs}/(job-id)/owner</td>
468 <td>the owner of the job (job-id)</td>
469 <td>and appropriate identifier as discussed in <h:span xmlns:h="http://www.w3.org/1999/xhtml" xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:dcterms="http://purl.org/dc/terms/" class="xref"><a href="#security">3. </a></h:span></td>
470 </tr>
471 </table>
472 <p>The service implementor is free to
473 choose the names given in parentheses above, i.e. the root of the URI tree, and the form that the job identifider takes (though note that it should be a legal URI path element) - the other names are part
474 of the UWS standard.</p>
475 <p>The URI for the Job List, in its
476 absolute form is the root URI for the whole UWS. This URI should be
477 given as the access URL in the UWS registration.</p>
478 </div>
479 <div class="section"><h4><a name="d1e603" id="d1e603" shape="rect"/><span class="secnum">2.2.2. </span>Representations of resources</h4>
480 <p>For each of the resources HTTP GET
481 fetches a representation. In general where an object is a container for other objects then an XML representation of the object is returned, otherwise for simple atomic types a textual representation is returned. The XML schema for the various objects described above is
482 detailed in <h:span xmlns:h="http://www.w3.org/1999/xhtml" xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:dcterms="http://purl.org/dc/terms/" class="xref"><a href="#UWSSchema">Appendix B. </a></h:span> of this specification. This schema is the definitive description of the exact form of the XML returned by a UWS and should not vary between implementations.</p>
483 <p>HTTP allows multiple representations
484 of a resource distinguished by their MIME types and selected by the
485 HTTP "Accept" headers of a GET request. UWS exploits this to support both web
486 browsers and rich clients in the same tree of resources. Although the default behaviour is to return XML, a UWS should return HTML or XHTML to
487 clients that accept these types. These clients are assumed to be web
488 browsers and the UWS is generating its own user interface. The HTML
489 interface generated should allow full control of the UWS via the use
490 of HTML forms and appropriate links.</p>
491 <p>Clients which are assumed to be part
492 of remote applications that drive UWS without showing the details to
493 their users should accept only "application/xml". A UWS must therefore
494 return XML representations of the resources in preference to the HTML representation. A technique that may be used to always return XML that modern browsers can transform on the client-side to HTML is via the <span class="xmlelement">&lt;?xml-stylesheet ?&gt;</span> processing instruction, which can be used to point to a suitable XSL resource to perform the transformation.</p>
495 <p> More detail for some of the UWS objects is provided below;</p>
496 <div class="section"><h4><a name="d1e1030"/><span class="secnum">2.2.2.1. </span>Job List</h4>
497 <p>The representation of the Job List is
498 a list of links to extant jobs. The list may be empty if the UWS is
499 idle.</p>
500 </div>
501 <div class="section"><h4><a name="d1e1040"/><span class="secnum">2.2.2.2. </span>Job</h4>
502 <p>The representation of a Job is as specified by the <span class="xmlelement">&lt;job&gt;</span> element in the UWS schema as detailed in <h:span xmlns:h="http://www.w3.org/1999/xhtml" xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:dcterms="http://purl.org/dc/terms/" class="xref"><a href="#UWSSchema, "/></h:span>an example or such a job instance is shown below</p>
503 <div><?incxml href="../UWSJobInstance.xml" ?><div xmlns:h="http://www.w3.org/1999/xhtml" xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:dcterms="http://purl.org/dc/terms/" class="viewxml"><div class="element"><span class="markup">&lt;</span><span class="start-tag">uws:job</span> <span class="attribute-name">xsi:schemaLocation</span><span class="markup">=</span><span class="attribute-value">"http://www.ivoa.net/xml/UWS/v1.0rc3 UWS.xsd "</span> <span class="attribute-name">xlmns:xml</span><span class="markup">=</span><span class="attribute-value">"http://www.w3.org/XML/1998/namespace"</span> <span class="attribute-name">xlmns:uws</span><span class="markup">=</span><span class="attribute-value">"http://www.ivoa.net/xml/UWS/v1.0rc3"</span> <span class="attribute-name">xlmns:xlink</span><span class="markup">=</span><span class="attribute-value">"http://www.w3.org/1999/xlink"</span> <span class="attribute-name">xlmns:xsi</span><span class="markup">=</span><span class="attribute-value">"http://www.w3.org/2001/XMLSchema-instance"</span><span class="markup">&gt;</span><div class="indent"><span class="markup">&lt;</span><span class="start-tag">uws:jobId</span><span class="markup">&gt;</span><span class="text">cea-agdevel.jb.man.ac.uk-130.88.24.18-1242749568029-508182314</span><span class="markup">&lt;/</span><span class="end-tag">uws:jobId</span><span class="markup">&gt;</span></div><div class="indent"><span class="markup">&lt;</span><span class="start-tag">uws:ownerId</span> <span class="attribute-name">xsi:nil</span><span class="markup">=</span><span class="attribute-value">"true"</span><span class="markup">/&gt;</span></div><div class="indent"><span class="markup">&lt;</span><span class="start-tag">uws:phase</span><span class="markup">&gt;</span><span class="text">COMPLETED</span><span class="markup">&lt;/</span><span class="end-tag">uws:phase</span><span class="markup">&gt;</span></div><div class="indent"><span class="markup">&lt;</span><span class="start-tag">uws:startTime</span><span class="markup">&gt;</span><span class="text">2009-05-19T17:12:48.038+01:00</span><span class="markup">&lt;/</span><span class="end-tag">uws:startTime</span><span class="markup">&gt;</span></div><div class="indent"><span class="markup">&lt;</span><span class="start-tag">uws:endTime</span><span class="markup">&gt;</span><span class="text">2009-05-19T17:12:48.041+01:00</span><span class="markup">&lt;/</span><span class="end-tag">uws:endTime</span><span class="markup">&gt;</span></div><div class="indent"><span class="markup">&lt;</span><span class="start-tag">uws:executionDuration</span><span class="markup">&gt;</span><span class="text">86400</span><span class="markup">&lt;/</span><span class="end-tag">uws:executionDuration</span><span class="markup">&gt;</span></div><div class="indent"><span class="markup">&lt;</span><span class="start-tag">uws:destruction</span><span class="markup">&gt;</span><span class="text">2009-05-29T17:12:48.035+01:00</span><span class="markup">&lt;/</span><span class="end-tag">uws:destruction</span><span class="markup">&gt;</span></div><div class="element"><span class="markup">&lt;</span><span class="start-tag">uws:parameters</span><span class="markup">&gt;</span><div class="indent"><span class="markup">&lt;</span><span class="start-tag">uws:parameter</span> <span class="attribute-name">id</span><span class="markup">=</span><span class="attribute-value">"scaleFactor"</span><span class="markup">&gt;</span><span class="text">1.8</span><span class="markup">&lt;/</span><span class="end-tag">uws:parameter</span><span class="markup">&gt;</span></div><div class="indent"><span class="markup">&lt;</span><span class="start-tag">uws:parameter</span> <span class="attribute-name">id</span><span class="markup">=</span><span class="attribute-value">"image"</span> <span class="attribute-name">byReference</span><span class="markup">=</span><span class="attribute-value">"true"</span><span class="markup">&gt;</span><span class="text">
504 http://myserver.org/uws/jobs/jobid123/param/image</span><span class="markup">&lt;/</span><span class="end-tag">uws:parameter</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">uws:parameters</span><span class="markup">&gt;</span></div><div class="element"><span class="markup">&lt;</span><span class="start-tag">uws:results</span><span class="markup">&gt;</span><div class="indent"><span class="markup">&lt;</span><span class="start-tag">uws:result</span> <span class="attribute-name">id</span><span class="markup">=</span><span class="attribute-value">"correctedImage"</span> <span class="attribute-name">xlink:href</span><span class="markup">=</span><span class="attribute-value">"http://myserver.org/uws/jobs/jobid123/result/image"</span><span class="markup">/&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">uws:results</span><span class="markup">&gt;</span></div><div class="element"><span class="markup">&lt;</span><span class="start-tag">uws:errorSummary</span> <span class="attribute-name">type</span><span class="markup">=</span><span class="attribute-value">"transient"</span><span class="markup">&gt;</span><div class="indent"><span class="markup">&lt;</span><span class="start-tag">uws:message</span><span class="markup">&gt;</span><span class="text">we have problem</span><span class="markup">&lt;/</span><span class="end-tag">uws:message</span><span class="markup">&gt;</span></div><div class="indent"><span class="markup">&lt;</span><span class="start-tag">uws:detail</span> <span class="attribute-name">xlink:href</span><span class="markup">=</span><span class="attribute-value">"http://myserver.org/uws/jobs/jobid123/error"</span><span class="markup">/&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">uws:errorSummary</span><span class="markup">&gt;</span></div><div class="element"><span class="markup">&lt;</span><span class="start-tag">uws:jobInfo</span><span class="markup">&gt;</span><div class="element"><span class="markup">&lt;</span><span class="start-tag">any</span><span class="markup">&gt;</span><div class="element"><span class="markup">&lt;</span><span class="start-tag">xml</span><span class="markup">&gt;</span><div class="indent"><span class="markup">&lt;</span><span class="start-tag">thatyouwant</span><span class="markup">/&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xml</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">any</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">uws:jobInfo</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">uws:job</span><span class="markup">&gt;</span></div></div></div>
505 <p>The <span class="xmlelement">&lt;job&gt;</span> element has placeholders of all of the standard UWS objects, and in addition there is a <span class="xmlelement">&lt;uws:jobinfo&gt;</span> element which can be used by implementations to include any extra information within the job description.</p>
506 </div>
507 <div class="section"><h4><a name="d1e1344"/><span class="secnum">2.2.2.3. </span>Results List</h4>
508 <p>The representation of a Results List
509 is a list of links to the resources representing the results. These
510 resources may have any URI and any MIME type. A sensible default for
511 their URIs is to make them children of /{jobs}/(job-id)/results, but
512 this is not required. It may sometimes be easier for a service
513 implementer to point to a resource on some web server separate from
514 that running the UWS. Therefore, a client must always parse the
515 Results List to find the results. Where a protocol applying UWS
516 specifies standard results it must do so by naming those results; the
517 names then appear in the Results List in addition to the URIs. Not
518 all results need to be named; sometimes the meaning of the result is
519 obvious from the context and the name is omitted.</p>
520 </div>
521 <div class="section"><h4><a name="d1e1353"/><span class="secnum">2.2.2.4. </span>Parameters List</h4>
522 The representation of the parameters list is a list of
523 <span class="xmlelement">&lt;parameter&gt;</span> elements. Each of these elements can either represent the value of the parameter directly, where the content of the element is a textual representation of the parameter, or in the case where the parameter value cannot be represented legally within XML (e.g. the parameter is a binary type such as a FITS file) then the content of the parameter is a URL to the parameter value - to indicate this case the attribute byReference is set to "true".</div>
524 </div>
525 <div class="section"><h4><a name="d1e634" id="d1e634" shape="rect"/><span class="secnum">2.2.3. </span>State changing requests</h4>
526 <p>Certain of the UWS' resources accept
527 HTTP POST and DELETE messages to change the state of the service &#8211;
528 This is the fundamental way that a client controls the execution of a
529 job. In most of the cases where a job subobject is set the response
530 will have a http 303 &#8220;See other&#8221; status and a Location header
531 that points back to the main job summary obtained at the <span style="font-weight: medium">/{jobs}/(job-id)
532 URI. The job summary contains the values of (or links to) all the UWS objects
533 within the returned XML (or XHTML). This mode of operation was chosen
534 (as opposed to returning only the sub-object being altered) as it
535 makes for a more natural user interface &#8211; especially in the case of
536 the XHMTL interface. A client that wants to obtain only the value of
537 a particular sub-object can at any time request that sub-object with
538 a HTTP GET.</span></p>
539 <div class="section"><h4><a name="d1e1375"/><span class="secnum">2.2.3.1. </span>Creating a Job</h4>
540 <p>POSTing a request to the Job List
541 creates a new job (unless the service rejects the request). The
542 response when a job is accepted must have code 303 &#8220;See other&#8221;
543 and the Location header of the response must point to the created
544 job.</p>
545 <p>This initial POST will in most cases
546 carry parameters for the protocol that is using the UWS pattern, as
547 detailed in <h:span xmlns:h="http://www.w3.org/1999/xhtml" xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:dcterms="http://purl.org/dc/terms/" class="xref"><a href="#ApplicationsOfUWS">4. </a></h:span>.</p>
548 </div>
549 <div class="section"><h4><a name="d1e1390"/><span class="secnum">2.2.3.2. </span>Deleting a Job</h4>
550 <p>Sending a HTTP DELETE to a Job
551 resource destroys that job, with the meaning noted in the definition
552 of the Job object, above. No other resource of the UWS may be
553 directly deleted by the client. The response to this request must
554 have code 303 &#8220;See other&#8221; and the Location header of the response
555 must point to the Job List at the /{jobs} URI.</p>
556 <p>Posting a request with a parameter
557 ACTION=DELETE to the Job also destroys the job, the response being as
558 for a deletion. This action supports web browsers which typically
559 cannot send DELETE requests.</p>
560 </div>
561 <div class="section"><h4><a name="d1e1402"/><span class="secnum">2.2.3.3. </span>Changing the Destruction
562 Time</h4>
563 <p>The Destruction Time may be changed
564 by POSTing to /{jobs}/(job-id)/destruction. In this case, the body
565 of the posted request is of type <i>application/x-www-form-urlencoded</i><b> </b><span style="font-weight: medium">and
566 contains the parameter named DESTRUCTION whose value is the new
567 destruction time in ISO8601 format; i.e. this request is what an HTML
568 form sends.</span></p>
569 <p style="font-weight: medium">The
570 response to this request must have code 303 &#8220;See other&#8221; and the
571 Location header of the response must point to the /{jobs}/(job-id)
572 URI so that the client receives the value that the service has
573 actually set the Destruction Time to within the Job summary response.</p>
574 </div>
575 <div class="section"><h4><a name="d1e1420"/><span class="secnum">2.2.3.4. </span>Changing the Execution
576 Duration</h4>
577 <p>The Execution Duration may be changed
578 by POSTing to /{jobs}/(job-id)/executionduration. In this case, the body
579 of the posted request is of type <i>application/x-www-form-urlencoded</i><b> </b><span style="font-weight: medium">and
580 contains the parameter named EXECUTIONDURATION whose value is the new
581 executionduration in seconds.</span></p>
582 <p style="font-weight: medium">The
583 response to this request must have code 303 &#8220;See other&#8221; and the
584 Location header of the response must point to the
585 /{jobs}/(job-id) so that the client receives the value that the
586 service has actually set the Execution Duration to &#8211; the service is
587 free to override the request if it needs.</p>
588 </div>
589 <div class="section"><h4><a name="d1e1439"/><span class="secnum">2.2.3.5. </span> Starting a Job</h4>
590 <p style="font-weight: medium">A
591 job may be started by POSTing to the /{jobs}/(job-id)/phase URI. The
592 POST contains a single parameter PHASE=RUN which instructs the UWS to
593 attempt to start the job. The response to this request must have code
594 303 &#8220;See other&#8221; and the Location header of the response must
595 point to the /{jobs}/(job-id) URI so that the client receives the
596 phase that the job has been set to. Typically a UWS will put a job
597 into a QUEUED state on receipt of this command, but depending on how
598 busy the server is, the job might be put almost immediately (and
599 without client intervention) into an EXECUTING state.</p>
600 </div>
601 <div class="section"><h4><a name="d1e1448"/><span class="secnum">2.2.3.6. </span>Aborting a Job</h4>
602 <p style="font-weight: medium">A
603 job may be aborted by POSTing to the /{jobs}/(job-id)/phase URI. The
604 POST contains a single parameter PHASE=ABORT which instructs the UWS
605 to attempt to abort the job. The response to this request must have
606 code 303 &#8220;See other&#8221; and the Location header of the response must
607 point to the /{jobs}/(job-id) URI so that the client receives the
608 phase that the job has been set to.</p>
609 </div>
610 </div>
611 <div class="section"><h4><a name="d1e708" id="d1e708" shape="rect"/><span class="secnum">2.2.4. </span>Message pattern</h4>
612 <p>The REST binding results in the
613 message pattern shown in figure 2.</p>
614 <p><i>Illustration 2:
615 Typical calling sequence for the REST binding of UWS</i></p>
616 <p><img src="Sequence_Diagram__UWS__Rest_Message_Pattern__Rest_Message_Pattern__Rest_Message_Pattern.png" name="graphics3" width="1970" height="1024" border="0" align="left" id="graphics3" alt="rest message pattern"/>
617 </p>
618 </div>
619 </div>
620
621 </div>
622 <div class="section"><h2><a name="security" id="security" shape="rect"/><span class="secnum">3. </span>Security Considerations</h2>
623 <p>A UWS should follow IVOA standards for security <cite>
624 [<a xmlns:h="http://www.w3.org/1999/xhtml" xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:dcterms="http://purl.org/dc/terms/" href="#ref:std:ssoauth">std:ssoauth</a>]
625 </cite> if it is desired that a non-public UWS be created. It is possible to imagine many different authorization policies that might be employed in an authenticated UWS, where particular groups of users have different permissions to create and view different types of jobs. A full discussion of such authorization policies is beyond the scope of this document, but a UWS should behave as described in section <h:span xmlns:h="http://www.w3.org/1999/xhtml" xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:dcterms="http://purl.org/dc/terms/" class="xref"><a href="#RESTbinding">2.2. </a></h:span> for any individual authenticated user, although it is clear that a user without sufficient privileges might only obtain a restricted list of jobs withing the joblist at /{jobs}. Any attempt to retrieve a job for which the user does not have sufficient privilege should result in a 403 Forbiden HTTP status being returned.</p>
626 <p>When an authentication mechanism is used in the UWS then the implementation should set the owner object to the identity obtained by the authentication. </p>
627 </div>
628 <div class="section"><h2><a name="ApplicationsOfUWS" id="ApplicationsOfUWS" shape="rect"/><span class="secnum">4. </span> Applications of UWS (informative)</h2>
629 <p>The UWS pattern leaves undefined two
630 essential parts of the service contract: the content that must be
631 posted to create a job; and the pattern of results made available by
632 a completed job. An application of UWS completes a service contract
633 by defining these matters.</p>
634 <p>There follow some use cases applying
635 the UWS pattern. The descriptions are neither formal nor complete.
636 The intention is to show a range of ways that the pattern can be
637 applied without burdening the reader with the level of detail needed
638 for a standard implementation.</p>
639 <p>Any of these cases could be worked up
640 into a full IVOA standard by formalizing the description, adding
641 detail (schemata, WSDL) and generally making the specification more
642 exact and complete.</p>
643 <div class="section"><h3><a name="Imageservice" id="Imageservice" shape="rect"/><span class="secnum">4.1. </span> Image service with data staging</h3>
644 <p>Consider a service that computes
645 images from archive data. The computation takes significant time, so
646 the service is asynchronous. The service keeps the computed images in
647 its own storage until the user downloads them; this is essentially
648 the model of SIAP <cite>
649 [<a xmlns:h="http://www.w3.org/1999/xhtml" xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:dcterms="http://purl.org/dc/terms/" href="#ref:std:siap">std:siap</a>]
650 </cite>.</p>
651 <p>The asynchronous image-service is a
652 logical extension of a synchronous SIA service. Therefore it uses the
653 REST binding of UWS.</p>
654 <p>The parameters for posting a new job
655 are as for SIAP 1.0:</p>
656 <ul><li>
657 <p>POS, the position on the sky to
658 be searched;</p>
659 </li><li>
660 <p>SIZE, the size of the search
661 box;</p>
662 </li><li>
663 <p>FORMAT: the type of images to be
664 computed.</p>
665 </li></ul>
666 <p>Particular implementations are free
667 to add extra parameters.</p>
668 <p>These parameters are posted in a
669 document of type <i>application/x-www-form-urlencoded</i><span style="font-style: normal">:
670 i.e. they can be sent from an HTML form.</span></p>
671 <p style="font-style: normal">The
672 images generated by the job are accessible as unnamed results. Each
673 image has its own URI and can be downloaded over HTTP at any time
674 until the destruction time of the job. The URIs for the images may be
675 discovered from the Results List in the normal UWS way.</p>
676 <p style="font-style: normal">SIAP
677 1.0 produces, for each query, a table of metadata describing the
678 images. The asynchronous image-service produces a table to the same
679 schema as a named result, called &#8220;table&#8221;.</p>
680 <p><span style="font-style: normal">Image
681 results are added to the results list, and to the &#8220;table&#8221; result,
682 as they are generated. Hence, a client that polls the service can
683 discover, download and use some of the images before the job is
684 finished. </span>If the client is satisfied with
685 these early images, the client can cancel the rest of the job by
686 destroying the job. However, destroying the job deletes the cached
687 images so the client has to download them <i>first</i>.</p>
688 </div>
689 <div class="section"><h3><a name="ADQLservice" id="ADQLservice" shape="rect"/><span class="secnum">4.2. </span> ADQL service with cursor</h3>
690 <p>ADQL [1] can serve as a JDL. Consider
691 an ADQL service that supports long-running queries as asynchronous
692 operations. In general, the results of the query may be a large set
693 of data. They may be too large to download comfortably. We might like
694 to cache these results on the service and to operate a cursor,
695 drawing down from the resource a few rows of the table at a time.</p>
696 <p>The parameters of a job are as
697 follows:</p>
698 <ul><li>
699 <p>ADQL: the query text</p>
700 </li><li>
701 <p>FORMAT: the format for the
702 results</p>
703 </li></ul>
704 <p>These parameters are posted in a
705 document of type <i>application/x-www-form-urlencoded</i><span style="font-style: normal">:
706 i.e. they can be sent from an HTML form.</span></p>
707 <p style="font-style: normal">A
708 successful query generates the following, named results.</p>
709 <ul><li>
710 <p style="font-style: normal"><i>table</i>:
711 the whole result set as one file resource.</p>
712 </li><li>
713 <p style="font-style: normal"><i>header</i>:
714 the metadata for the output table.</p>
715 </li><li>
716 <p style="font-style: normal"><i>cursor</i>:
717 a selection of rows of output.</p>
718 </li></ul>
719 <p>The <i>cursor</i> result is
720 parameterized by the query parameters FIRST and LAST in the query
721 string of its URI: these parameters state the index of the first and
722 last row to be returned; e.g.</p>
723 <p> http://whatever.org/adlqService/results/cursor?FIRST=1&amp;LAST=100</p>
724 <p>If the parameters are missing, the
725 service decides which rows to emit.</p>
726 </div>
727 <div class="section"><h3><a name="ParameterizedApplications" id="ParameterizedApplications" shape="rect"/><span class="secnum">4.3. </span> Parameterized applications</h3>
728 <p>There is a class of applications on
729 which a job may be defined by a list of simple parameters. &#8220;Simple&#8221;
730 here means unstructured: a scalar value such as a number, a string of
731 text or a Boolean value. If the parameters are allowed to name files,
732 so that structured data are passed indirectly, then the class of
733 applications is very large indeed: almost any non-interactive
734 application can be driven in this way.</p>
735 <p>Turning each application of choice
736 into a service (with or without UWS semantics) would be onerous.
737 However, if the application&#8217;s interface is entirely characterized,
738 through the JDL, in terms of typed input and output parameters, then
739 one service contract will work for all the applications and a single
740 implementation of the contract can be reused for all cases.</p>
741 <p>AstroGrid&#8217;s Common Execution
742 Architecture (CEA) <cite>
743 [<a xmlns:h="http://www.w3.org/1999/xhtml" xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:dcterms="http://purl.org/dc/terms/" href="#ref:harrison05">harrison05</a>]
744 </cite> works in this way. It has just one service
745 contract for all applications (including ADQL services; the ADQL
746 query is passed in the list of parameters). It has four
747 implementations, one for each of the possible interfaces between the
748 service and a kind of job (jobs can be implemented with Java classes,
749 command-line applications, HTTP-get services or JDBC databases). CEA
750 also specifies stateful, asynchronous services and makes use of
751 VOSpace.</p>
752 <p>Consider a CEA reworked to use the
753 UWS pattern for consistency with other (future) IVOA standards. Call
754 it CEA v2 to distinguish it from CEA v1 as currently maintained by
755 AstroGrid. For this example, consider the particular kind of CEA
756 service that runs applications supplied as executable binaries.</p>
757 <p>A binary application-server has a
758 library of applications co-located with its service and defined in
759 the service configuration set by the service provider. It does not
760 accept code from the client for local execution.</p>
761 <p>The JDL in CEA v2 is similar to that
762 in CEA v1 It is a formal, XML vocabulary for expressing choice
763 of application and parameter lists <cite>
764 [<a xmlns:h="http://www.w3.org/1999/xhtml" xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:dcterms="http://purl.org/dc/terms/" href="#ref:std:vocea">std:vocea</a>]
765 </cite>. Parameters may be inputs or
766 outputs of the job.</p>
767 <p>To start a job, a document in this
768 JDL is posted to the UWS. The document is sent in its native
769 MIME-type, application/xml, so this is not an interface that can be
770 driven directly from an HTML form, although it can be driven from the
771 emerging XForms technology<cite>
772 [<a xmlns:h="http://www.w3.org/1999/xhtml" xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:dcterms="http://purl.org/dc/terms/" href="#ref:std:xform">std:xform</a>]
773 </cite>.</p>
774 <p>The results of the job depend on the
775 choice of application. They are all named results and the names and
776 types are defined in the definition of the application. That
777 application-definition is registered, so the client knows before
778 running the job what results to expect.</p>
779 <p>CEA input-parameters may be indirect:
780 i.e. they may refer to data in on-line storage. In this case, the JDL
781 document contains the URIs for those data objects Alternatively, the
782 parameters may be direct, in which case the JDL contains the actual
783 value of the parameters.</p>
784 <p>Similarly, CEA results may be made
785 indirect. In this case, the results are named as parameters in the
786 JDL where the values are the URIs to which the results are delivered.
787 The application server can then stream the results to the specified
788 destination as they become available and need not cache them locally.
789 If a job result is indirect, then the server can choose whether or
790 not to keep a local copy. If it chooses not to cache locally, then
791 the result URI in the UWS is set to the external location named in
792 the URI.</p>
793 </div>
794 </div>
795 <div class="section"><h2><a name="SynchronousService" id="SynchronousService" shape="rect"/><span class="secnum">5. </span> Implementing a Synchronous Service on top of UWS (informative)</h2>
796 <p>Whilst the provision of synchronous
797 services is not one of the design aims of the UWS pattern, there is
798 clearly a desire in second generation IVOA services to still allow a
799 simple synchronous calling pattern to be available to simple clients.
800 What follows is a recommended recipe for putting a synchronous facade
801 on UWS;</p>
802 <p>It is assumed that the core of the
803 service does provide a true UWS compliant set of endpoints rooted at
804 /async (equivalent to the /{jobs} endpoint in the nomenclature used
805 above). The desired synchronous service is to be rooted at /sync.</p>
806 <ol><li>
807 <p>The job is started by either a
808 GET (for compatibility with existing IVOA standards) or a POST
809 (preferably) of form encoded parameters to the /sync endpoint.</p>
810 </li><li>
811 <p>Internally the service creates a
812 job in the standard UWS system with the given parameters and sets
813 the PHASE to RUN, noting the returned job identifier which we will
814 call {job-id}. The /sync endpoint then responds with a STATUS 303
815 (redirection) response to the URL /sync/{job-id}.</p>
816 </li><li>
817 <p>The /sync/{job-id} endpoint then
818 blocks until it detects that the underlying job has finished at
819 which point it responds with a STATUS 303 (redirection) to the
820 /{jobs}/{job-id}/results/mainresult URL, where &#8220;mainresult&#8221; is
821 the name of the primary result of the job.</p>
822 </li></ol>
823 <p>In this way the service appears to be
824 a synchronous to the original client &#8211; assuming it obeys standard
825 HTTP redirection semantics, so a simple client like a web browser
826 could obtain the result with a single &#8220;click&#8221;. At the same time a
827 more sophisticated, UWS aware, client could control the same job from
828 the standard /{jobs} endpoint &#8211; indeed if the synchronous call
829 timed out for some reason, then it would be possible for the original
830 client to retrieve the results by looking at the /{jobs}/{job-id} URL
831 tree, because it could make the association of the job-Id from the
832 URL it receives in step 2 above.</p>
833 <p>The purely synchronous client is
834 restricted compared with the full UWS pattern in that there can only
835 be one result directly returned to the client, as noted in stage 3
836 above. This is usually not a problem for compatibility with existing
837 version 1.0 DAL services as they typically return a single VOTable
838 containing references to the desired data.</p>
839 </div>
840
841 <div class="appendices"><h2>Appendices</h2>
842
843 <div class="section"><h2><a name="Updates" id="Updates"/><span class="secnum">Appendix A. </span> Updates from previous versions</h2>
844 <div class="section"><h3><a name="d1e1112" id="d1e1112"/><span class="secnum">Appendix A.1. </span>At Version 0.5</h3>
845 <ul><li>
846 <p>changed the POST parameter names
847 to be the same as the resource paths.</p>
848 </li><li>
849 <p>added synchronous section.</p>
850 </li><li>
851 <p>updated SOAP binding section</p>
852 </li></ul>
853 </div>
854 <div class="section"><h3><a name="d1e1775"/><span class="secnum">Appendix A.2. </span>At Version 1.0</h3>
855 <ul>
856 <li>Removed all SOAP binding - deferred to later version.</li>
857 <li>Added parameterList</li>
858 <li>Added ownerId and jobId as subsidiary job object</li>
859 </ul>
860 </div>
861 </div>
862
863 <div class="section"><h2><a name="UWSSchema" id="UWSSchema"/><span class="secnum">Appendix B. </span> UWS Schema</h2>
864 <p>Note that this schema can be found on-line at <a href="http://www.ivoa.net/xml/UWS/1.0" shape="rect">http://www.ivoa.net/xml/UWS/v1.0</a> (i.e. the target namespace
865 can also be used as a URL for the schema.) This location should
866 represent the definitive source, the schema is reproduced below only for
867 completeness of this document.</p>
868 <div><?incxml href="../UWS.xsd"?><div xmlns:h="http://www.w3.org/1999/xhtml" xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:dcterms="http://purl.org/dc/terms/" class="viewxml"><div class="comment">&lt;!-- $Id: UWS.xsd,v 1.1 2009/06/15 15:30:32 pah Exp $ --&gt;</div><div class="comment">&lt;!-- proposal for basic UWS schema - Paul Harrison May 2008 --&gt;</div><div class="comment">&lt;!--
869 $Log: UWS.xsd,v $
870 Revision 1.1 2009/06/15 15:30:32 pah
871 made some of the global element defintions for job subobjects just local again
872 added runid, ownerid
873 added ParamList
874 changed some element names to be consistent with the uris
875 Revision 1.6 2008/10/01 11:54:02 pah fix up cvs
876 header Revision 1.5 2008/09/25 00:22:35 pah change termination
877 time to execution duration
878 --&gt;</div><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:schema</span> <span class="attribute-name">targetNamespace</span><span class="markup">=</span><span class="attribute-value">"http://www.ivoa.net/xml/UWS/v1.0rc3"</span> <span class="attribute-name">elementFormDefault</span><span class="markup">=</span><span class="attribute-value">"qualified"</span> <span class="attribute-name">attributeFormDefault</span><span class="markup">=</span><span class="attribute-value">"unqualified"</span> <span class="attribute-name">xlmns:xml</span><span class="markup">=</span><span class="attribute-value">"http://www.w3.org/XML/1998/namespace"</span> <span class="attribute-name">xlmns:xs</span><span class="markup">=</span><span class="attribute-value">"http://www.w3.org/2001/XMLSchema"</span> <span class="attribute-name">xlmns:uws</span><span class="markup">=</span><span class="attribute-value">"http://www.ivoa.net/xml/UWS/v1.0rc3"</span> <span class="attribute-name">xlmns:xlink</span><span class="markup">=</span><span class="attribute-value">"http://www.w3.org/1999/xlink"</span><span class="markup">&gt;</span><div class="indent"><span class="markup">&lt;</span><span class="start-tag">xs:import</span> <span class="attribute-name">namespace</span><span class="markup">=</span><span class="attribute-value">"http://www.w3.org/1999/xlink"</span> <span class="attribute-name">schemaLocation</span><span class="markup">=</span><span class="attribute-value">"http://software.astrogrid.org/schema/stc/STC/v1.30/XLINK.xsd"</span><span class="markup">/&gt;</span></div><div class="comment">&lt;!--
879 &lt;xs:import namespace="http://www.w3.org/1999/xlink"
880 schemaLocation="http://www.ivoa.net/xml/Xlink/xlink.xsd"/&gt;
881 --&gt;</div><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:complexType</span> <span class="attribute-name">name</span><span class="markup">=</span><span class="attribute-value">"ShortJobDescription"</span><span class="markup">&gt;</span><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:sequence</span><span class="markup">&gt;</span><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:element</span> <span class="attribute-name">name</span><span class="markup">=</span><span class="attribute-value">"phase"</span> <span class="attribute-name">type</span><span class="markup">=</span><span class="attribute-value">"uws:ExecutionPhase"</span><span class="markup">&gt;</span><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:annotation</span><span class="markup">&gt;</span><div class="indent"><span class="markup">&lt;</span><span class="start-tag">xs:documentation</span><span class="markup">&gt;</span><span class="text"> the execution phase - returned at
882 /(jobs)/(jobid)/phase</span><span class="markup">&lt;/</span><span class="end-tag">xs:documentation</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:annotation</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:element</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:sequence</span><span class="markup">&gt;</span></div><div class="indent"><span class="markup">&lt;</span><span class="start-tag">xs:attribute</span> <span class="attribute-name">name</span><span class="markup">=</span><span class="attribute-value">"id"</span> <span class="attribute-name">type</span><span class="markup">=</span><span class="attribute-value">"uws:JobIdentifier"</span> <span class="attribute-name">use</span><span class="markup">=</span><span class="attribute-value">"required"</span><span class="markup">/&gt;</span></div><div class="indent"><span class="markup">&lt;</span><span class="start-tag">xs:attributeGroup</span> <span class="attribute-name">ref</span><span class="markup">=</span><span class="attribute-value">"uws:reference"</span><span class="markup">/&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:complexType</span><span class="markup">&gt;</span></div><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:attributeGroup</span> <span class="attribute-name">name</span><span class="markup">=</span><span class="attribute-value">"reference"</span><span class="markup">&gt;</span><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:annotation</span><span class="markup">&gt;</span><div class="indent"><span class="markup">&lt;</span><span class="start-tag">xs:documentation</span><span class="markup">&gt;</span><span class="text">standard xlink references
883 </span><span class="markup">&lt;/</span><span class="end-tag">xs:documentation</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:annotation</span><span class="markup">&gt;</span></div><div class="indent"><span class="markup">&lt;</span><span class="start-tag">xs:attribute</span> <span class="attribute-name">ref</span><span class="markup">=</span><span class="attribute-value">"xlink:type"</span> <span class="attribute-name">use</span><span class="markup">=</span><span class="attribute-value">"optional"</span> <span class="attribute-name">default</span><span class="markup">=</span><span class="attribute-value">"simple"</span><span class="markup">/&gt;</span></div><div class="indent"><span class="markup">&lt;</span><span class="start-tag">xs:attribute</span> <span class="attribute-name">ref</span><span class="markup">=</span><span class="attribute-value">"xlink:href"</span> <span class="attribute-name">use</span><span class="markup">=</span><span class="attribute-value">"optional"</span><span class="markup">/&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:attributeGroup</span><span class="markup">&gt;</span></div><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:simpleType</span> <span class="attribute-name">name</span><span class="markup">=</span><span class="attribute-value">"ExecutionPhase"</span><span class="markup">&gt;</span><div class="comment">&lt;!--
884 need to think a little here about the implication of allowing a
885 "re-entrant" application that is capable of running
886 mini-jobs...probably this is indicated with a different state
887 varible entirely
888 --&gt;</div><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:annotation</span><span class="markup">&gt;</span><div class="indent"><span class="markup">&lt;</span><span class="start-tag">xs:documentation</span><span class="markup">&gt;</span><span class="text"> Enumeration of possible phases of job
889 execution</span><span class="markup">&lt;/</span><span class="end-tag">xs:documentation</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:annotation</span><span class="markup">&gt;</span></div><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:restriction</span> <span class="attribute-name">base</span><span class="markup">=</span><span class="attribute-value">"xs:string"</span><span class="markup">&gt;</span><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:enumeration</span> <span class="attribute-name">value</span><span class="markup">=</span><span class="attribute-value">"PENDING"</span><span class="markup">&gt;</span><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:annotation</span><span class="markup">&gt;</span><div class="indent"><span class="markup">&lt;</span><span class="start-tag">xs:documentation</span><span class="markup">&gt;</span><span class="text"> The first phase a job is entered into
890 - this is where a job is being set up but no request
891 to run has occurred.</span><span class="markup">&lt;/</span><span class="end-tag">xs:documentation</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:annotation</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:enumeration</span><span class="markup">&gt;</span></div><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:enumeration</span> <span class="attribute-name">value</span><span class="markup">=</span><span class="attribute-value">"QUEUED"</span><span class="markup">&gt;</span><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:annotation</span><span class="markup">&gt;</span><div class="indent"><span class="markup">&lt;</span><span class="start-tag">xs:documentation</span><span class="markup">&gt;</span><span class="text"> An job has been accepted for execution
892 but is waiting in a queue</span><span class="markup">&lt;/</span><span class="end-tag">xs:documentation</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:annotation</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:enumeration</span><span class="markup">&gt;</span></div><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:enumeration</span> <span class="attribute-name">value</span><span class="markup">=</span><span class="attribute-value">"EXECUTING"</span><span class="markup">&gt;</span><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:annotation</span><span class="markup">&gt;</span><div class="indent"><span class="markup">&lt;</span><span class="start-tag">xs:documentation</span><span class="markup">&gt;</span><span class="text">An job is running</span><span class="markup">&lt;/</span><span class="end-tag">xs:documentation</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:annotation</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:enumeration</span><span class="markup">&gt;</span></div><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:enumeration</span> <span class="attribute-name">value</span><span class="markup">=</span><span class="attribute-value">"COMPLETED"</span><span class="markup">&gt;</span><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:annotation</span><span class="markup">&gt;</span><div class="indent"><span class="markup">&lt;</span><span class="start-tag">xs:documentation</span><span class="markup">&gt;</span><span class="text"> An job has completed successfully
893 </span><span class="markup">&lt;/</span><span class="end-tag">xs:documentation</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:annotation</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:enumeration</span><span class="markup">&gt;</span></div><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:enumeration</span> <span class="attribute-name">value</span><span class="markup">=</span><span class="attribute-value">"ERROR"</span><span class="markup">&gt;</span><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:annotation</span><span class="markup">&gt;</span><div class="indent"><span class="markup">&lt;</span><span class="start-tag">xs:documentation</span><span class="markup">&gt;</span><span class="text"> Some form of error has occurred
894 </span><span class="markup">&lt;/</span><span class="end-tag">xs:documentation</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:annotation</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:enumeration</span><span class="markup">&gt;</span></div><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:enumeration</span> <span class="attribute-name">value</span><span class="markup">=</span><span class="attribute-value">"UNKNOWN"</span><span class="markup">&gt;</span><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:annotation</span><span class="markup">&gt;</span><div class="indent"><span class="markup">&lt;</span><span class="start-tag">xs:documentation</span><span class="markup">&gt;</span><span class="text"> The job is in an unknown state
895 </span><span class="markup">&lt;/</span><span class="end-tag">xs:documentation</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:annotation</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:enumeration</span><span class="markup">&gt;</span></div><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:enumeration</span> <span class="attribute-name">value</span><span class="markup">=</span><span class="attribute-value">"HELD"</span><span class="markup">&gt;</span><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:annotation</span><span class="markup">&gt;</span><div class="indent"><span class="markup">&lt;</span><span class="start-tag">xs:documentation</span><span class="markup">&gt;</span><span class="text"> The job is HELD pending execution and
896 will not automatically be executed (cf pending)
897 </span><span class="markup">&lt;/</span><span class="end-tag">xs:documentation</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:annotation</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:enumeration</span><span class="markup">&gt;</span></div><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:enumeration</span> <span class="attribute-name">value</span><span class="markup">=</span><span class="attribute-value">"SUSPENDED"</span><span class="markup">&gt;</span><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:annotation</span><span class="markup">&gt;</span><div class="indent"><span class="markup">&lt;</span><span class="start-tag">xs:documentation</span><span class="markup">&gt;</span><span class="text"> The job has been suspended by the
898 system during execution</span><span class="markup">&lt;/</span><span class="end-tag">xs:documentation</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:annotation</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:enumeration</span><span class="markup">&gt;</span></div><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:enumeration</span> <span class="attribute-name">value</span><span class="markup">=</span><span class="attribute-value">"ABORTED"</span><span class="markup">&gt;</span><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:annotation</span><span class="markup">&gt;</span><div class="indent"><span class="markup">&lt;</span><span class="start-tag">xs:documentation</span><span class="markup">&gt;</span><span class="text"> The job has been aborted, either by
899 user request or by the server because of lack or
900 overuse of resources.</span><span class="markup">&lt;/</span><span class="end-tag">xs:documentation</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:annotation</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:enumeration</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:restriction</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:simpleType</span><span class="markup">&gt;</span></div><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:complexType</span> <span class="attribute-name">name</span><span class="markup">=</span><span class="attribute-value">"JobSummary"</span><span class="markup">&gt;</span><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:annotation</span><span class="markup">&gt;</span><div class="indent"><span class="markup">&lt;</span><span class="start-tag">xs:documentation</span><span class="markup">&gt;</span><span class="text">The complete representation of the state
901 of a job</span><span class="markup">&lt;/</span><span class="end-tag">xs:documentation</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:annotation</span><span class="markup">&gt;</span></div><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:sequence</span><span class="markup">&gt;</span><div class="indent"><span class="markup">&lt;</span><span class="start-tag">xs:element</span> <span class="attribute-name">name</span><span class="markup">=</span><span class="attribute-value">"jobId"</span> <span class="attribute-name">type</span><span class="markup">=</span><span class="attribute-value">"uws:JobIdentifier"</span><span class="markup">/&gt;</span></div><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:element</span> <span class="attribute-name">name</span><span class="markup">=</span><span class="attribute-value">"runId"</span> <span class="attribute-name">type</span><span class="markup">=</span><span class="attribute-value">"xs:string"</span> <span class="attribute-name">maxOccurs</span><span class="markup">=</span><span class="attribute-value">"1"</span> <span class="attribute-name">minOccurs</span><span class="markup">=</span><span class="attribute-value">"0"</span><span class="markup">&gt;</span><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:annotation</span><span class="markup">&gt;</span><div class="indent"><span class="markup">&lt;</span><span class="start-tag">xs:documentation</span><span class="markup">&gt;</span><span class="text"> this is a client supplied identifier -
902 the UWS system does nothing other than to return it as
903 part of the description of the job</span><span class="markup">&lt;/</span><span class="end-tag">xs:documentation</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:annotation</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:element</span><span class="markup">&gt;</span></div><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:element</span> <span class="attribute-name">name</span><span class="markup">=</span><span class="attribute-value">"ownerId"</span> <span class="attribute-name">type</span><span class="markup">=</span><span class="attribute-value">"xs:string"</span> <span class="attribute-name">nillable</span><span class="markup">=</span><span class="attribute-value">"true"</span><span class="markup">&gt;</span><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:annotation</span><span class="markup">&gt;</span><div class="indent"><span class="markup">&lt;</span><span class="start-tag">xs:documentation</span><span class="markup">&gt;</span><span class="text">the owner (creator) of the job -
904 this should be expressed as a string that can be
905 parsed in accordance with IVOA security standards. If
906 there was no authenticated job creator then this
907 should be set to NULL.</span><span class="markup">&lt;/</span><span class="end-tag">xs:documentation</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:annotation</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:element</span><span class="markup">&gt;</span></div><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:element</span> <span class="attribute-name">name</span><span class="markup">=</span><span class="attribute-value">"phase"</span> <span class="attribute-name">type</span><span class="markup">=</span><span class="attribute-value">"uws:ExecutionPhase"</span><span class="markup">&gt;</span><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:annotation</span><span class="markup">&gt;</span><div class="indent"><span class="markup">&lt;</span><span class="start-tag">xs:documentation</span><span class="markup">&gt;</span><span class="text"> the execution phase - returned at
908 /(jobs)/(jobid)/phase</span><span class="markup">&lt;/</span><span class="end-tag">xs:documentation</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:annotation</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:element</span><span class="markup">&gt;</span></div><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:element</span> <span class="attribute-name">name</span><span class="markup">=</span><span class="attribute-value">"quote"</span> <span class="attribute-name">type</span><span class="markup">=</span><span class="attribute-value">"xs:dateTime"</span> <span class="attribute-name">nillable</span><span class="markup">=</span><span class="attribute-value">"true"</span> <span class="attribute-name">maxOccurs</span><span class="markup">=</span><span class="attribute-value">"1"</span> <span class="attribute-name">minOccurs</span><span class="markup">=</span><span class="attribute-value">"0"</span><span class="markup">&gt;</span><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:annotation</span><span class="markup">&gt;</span><div class="indent"><span class="markup">&lt;</span><span class="start-tag">xs:documentation</span><span class="markup">&gt;</span><span class="text"> A Quote predicts when the job is likely to complete - returned at /(jobs)/(jobid)/quote
909 "don't know" is encoded by setting to the XML null value xsi:nil="true"</span><span class="markup">&lt;/</span><span class="end-tag">xs:documentation</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:annotation</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:element</span><span class="markup">&gt;</span></div><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:element</span> <span class="attribute-name">name</span><span class="markup">=</span><span class="attribute-value">"startTime"</span> <span class="attribute-name">type</span><span class="markup">=</span><span class="attribute-value">"xs:dateTime"</span> <span class="attribute-name">nillable</span><span class="markup">=</span><span class="attribute-value">"true"</span><span class="markup">&gt;</span><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:annotation</span><span class="markup">&gt;</span><div class="indent"><span class="markup">&lt;</span><span class="start-tag">xs:documentation</span><span class="markup">&gt;</span><span class="text">The instant at which the job started execution.</span><span class="markup">&lt;/</span><span class="end-tag">xs:documentation</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:annotation</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:element</span><span class="markup">&gt;</span></div><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:element</span> <span class="attribute-name">name</span><span class="markup">=</span><span class="attribute-value">"endTime"</span> <span class="attribute-name">type</span><span class="markup">=</span><span class="attribute-value">"xs:dateTime"</span> <span class="attribute-name">nillable</span><span class="markup">=</span><span class="attribute-value">"true"</span><span class="markup">&gt;</span><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:annotation</span><span class="markup">&gt;</span><div class="indent"><span class="markup">&lt;</span><span class="start-tag">xs:documentation</span><span class="markup">&gt;</span><span class="text">The instant at which the job finished execution</span><span class="markup">&lt;/</span><span class="end-tag">xs:documentation</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:annotation</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:element</span><span class="markup">&gt;</span></div><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:element</span> <span class="attribute-name">name</span><span class="markup">=</span><span class="attribute-value">"executionDuration"</span> <span class="attribute-name">type</span><span class="markup">=</span><span class="attribute-value">"xs:int"</span> <span class="attribute-name">nillable</span><span class="markup">=</span><span class="attribute-value">"false"</span><span class="markup">&gt;</span><div class="comment">&lt;!-- TODO look if xs:duration here has any benefits --&gt;</div><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:annotation</span><span class="markup">&gt;</span><div class="indent"><span class="markup">&lt;</span><span class="start-tag">xs:documentation</span><span class="markup">&gt;</span><span class="text"> The duration (in seconds) for which
910 the job should be allowed to run - a value of 0 is
911 intended to mean unlimited - returned at
912 /(jobs)/(jobid)/executionduration</span><span class="markup">&lt;/</span><span class="end-tag">xs:documentation</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:annotation</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:element</span><span class="markup">&gt;</span></div><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:element</span> <span class="attribute-name">name</span><span class="markup">=</span><span class="attribute-value">"destruction"</span> <span class="attribute-name">type</span><span class="markup">=</span><span class="attribute-value">"xs:dateTime"</span> <span class="attribute-name">nillable</span><span class="markup">=</span><span class="attribute-value">"true"</span><span class="markup">&gt;</span><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:annotation</span><span class="markup">&gt;</span><div class="indent"><span class="markup">&lt;</span><span class="start-tag">xs:documentation</span><span class="markup">&gt;</span><span class="text"> The time at which the whole job +
913 records + results will be destroyed. returned at
914 /(jobs)/(jobid)/destruction</span><span class="markup">&lt;/</span><span class="end-tag">xs:documentation</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:annotation</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:element</span><span class="markup">&gt;</span></div><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:element</span> <span class="attribute-name">ref</span><span class="markup">=</span><span class="attribute-value">"uws:parameters"</span> <span class="attribute-name">maxOccurs</span><span class="markup">=</span><span class="attribute-value">"1"</span> <span class="attribute-name">minOccurs</span><span class="markup">=</span><span class="attribute-value">"0"</span><span class="markup">&gt;</span><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:annotation</span><span class="markup">&gt;</span><div class="indent"><span class="markup">&lt;</span><span class="start-tag">xs:documentation</span><span class="markup">&gt;</span><span class="text">The parameters to the job (where appropriate)
915 can also be retrieved at /(jobs)/(jobid)/parameters</span><span class="markup">&lt;/</span><span class="end-tag">xs:documentation</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:annotation</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:element</span><span class="markup">&gt;</span></div><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:element</span> <span class="attribute-name">ref</span><span class="markup">=</span><span class="attribute-value">"uws:results"</span><span class="markup">&gt;</span><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:annotation</span><span class="markup">&gt;</span><div class="indent"><span class="markup">&lt;</span><span class="start-tag">xs:documentation</span><span class="markup">&gt;</span><span class="text">The results for the job - can also be retrieved at /(jobs)/(jobid)/results</span><span class="markup">&lt;/</span><span class="end-tag">xs:documentation</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:annotation</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:element</span><span class="markup">&gt;</span></div><div class="indent"><span class="markup">&lt;</span><span class="start-tag">xs:element</span> <span class="attribute-name">name</span><span class="markup">=</span><span class="attribute-value">"errorSummary"</span> <span class="attribute-name">type</span><span class="markup">=</span><span class="attribute-value">"uws:ErrorSummary"</span> <span class="attribute-name">maxOccurs</span><span class="markup">=</span><span class="attribute-value">"1"</span> <span class="attribute-name">minOccurs</span><span class="markup">=</span><span class="attribute-value">"0"</span><span class="markup">&gt;</span><span class="text">
916 </span><span class="markup">&lt;/</span><span class="end-tag">xs:element</span><span class="markup">&gt;</span></div><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:element</span> <span class="attribute-name">name</span><span class="markup">=</span><span class="attribute-value">"jobInfo"</span> <span class="attribute-name">maxOccurs</span><span class="markup">=</span><span class="attribute-value">"1"</span> <span class="attribute-name">minOccurs</span><span class="markup">=</span><span class="attribute-value">"0"</span><span class="markup">&gt;</span><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:annotation</span><span class="markup">&gt;</span><div class="indent"><span class="markup">&lt;</span><span class="start-tag">xs:documentation</span><span class="markup">&gt;</span><span class="text"> This is arbitrary information that can
917 be added to the job description by the UWS
918 implementation.</span><span class="markup">&lt;/</span><span class="end-tag">xs:documentation</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:annotation</span><span class="markup">&gt;</span></div><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:complexType</span><span class="markup">&gt;</span><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:sequence</span><span class="markup">&gt;</span><div class="indent"><span class="markup">&lt;</span><span class="start-tag">xs:any</span> <span class="attribute-name">namespace</span><span class="markup">=</span><span class="attribute-value">"##any"</span> <span class="attribute-name">processContents</span><span class="markup">=</span><span class="attribute-value">"lax"</span> <span class="attribute-name">minOccurs</span><span class="markup">=</span><span class="attribute-value">"0"</span> <span class="attribute-name">maxOccurs</span><span class="markup">=</span><span class="attribute-value">"unbounded"</span><span class="markup">/&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:sequence</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:complexType</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:element</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:sequence</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:complexType</span><span class="markup">&gt;</span></div><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:simpleType</span> <span class="attribute-name">name</span><span class="markup">=</span><span class="attribute-value">"JobIdentifier"</span><span class="markup">&gt;</span><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:annotation</span><span class="markup">&gt;</span><div class="indent"><span class="markup">&lt;</span><span class="start-tag">xs:documentation</span><span class="markup">&gt;</span><span class="text"> The identifier for the job
919 </span><span class="markup">&lt;/</span><span class="end-tag">xs:documentation</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:annotation</span><span class="markup">&gt;</span></div><div class="indent"><span class="markup">&lt;</span><span class="start-tag">xs:restriction</span> <span class="attribute-name">base</span><span class="markup">=</span><span class="attribute-value">"xs:string"</span><span class="markup">/&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:simpleType</span><span class="markup">&gt;</span></div><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:element</span> <span class="attribute-name">name</span><span class="markup">=</span><span class="attribute-value">"job"</span> <span class="attribute-name">type</span><span class="markup">=</span><span class="attribute-value">"uws:JobSummary"</span><span class="markup">&gt;</span><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:annotation</span><span class="markup">&gt;</span><div class="indent"><span class="markup">&lt;</span><span class="start-tag">xs:documentation</span><span class="markup">&gt;</span><span class="text"> This is the information that is returned
920 when a GET is made for a single job resource - i.e.
921 /(jobs)/(jobid)</span><span class="markup">&lt;/</span><span class="end-tag">xs:documentation</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:annotation</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:element</span><span class="markup">&gt;</span></div><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:element</span> <span class="attribute-name">name</span><span class="markup">=</span><span class="attribute-value">"jobs"</span><span class="markup">&gt;</span><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:annotation</span><span class="markup">&gt;</span><div class="indent"><span class="markup">&lt;</span><span class="start-tag">xs:documentation</span><span class="markup">&gt;</span><span class="text"> The list of job references returned at
922 /(jobs)</span><span class="markup">&lt;/</span><span class="end-tag">xs:documentation</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:annotation</span><span class="markup">&gt;</span></div><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:complexType</span><span class="markup">&gt;</span><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:annotation</span><span class="markup">&gt;</span><div class="indent"><span class="markup">&lt;</span><span class="start-tag">xs:documentation</span><span class="markup">&gt;</span><span class="text"> ISSUE - do we want to have any sort of
923 paging or selection mechanism in case the job list gets
924 very large? Or is that an unnecessary complication...
925 </span><span class="markup">&lt;/</span><span class="end-tag">xs:documentation</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:annotation</span><span class="markup">&gt;</span></div><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:sequence</span><span class="markup">&gt;</span><div class="indent"><span class="markup">&lt;</span><span class="start-tag">xs:element</span> <span class="attribute-name">name</span><span class="markup">=</span><span class="attribute-value">"jobref"</span> <span class="attribute-name">type</span><span class="markup">=</span><span class="attribute-value">"uws:ShortJobDescription"</span> <span class="attribute-name">maxOccurs</span><span class="markup">=</span><span class="attribute-value">"unbounded"</span> <span class="attribute-name">minOccurs</span><span class="markup">=</span><span class="attribute-value">"0"</span><span class="markup">/&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:sequence</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:complexType</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:element</span><span class="markup">&gt;</span></div><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:complexType</span> <span class="attribute-name">name</span><span class="markup">=</span><span class="attribute-value">"ResultReference"</span><span class="markup">&gt;</span><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:annotation</span><span class="markup">&gt;</span><div class="indent"><span class="markup">&lt;</span><span class="start-tag">xs:documentation</span><span class="markup">&gt;</span><span class="text"> A reference to a UWS result
926 </span><span class="markup">&lt;/</span><span class="end-tag">xs:documentation</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:annotation</span><span class="markup">&gt;</span></div><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:sequence</span><span class="markup">&gt;</span><div class="indent"><span class="markup">&lt;</span><span class="start-tag">xs:element</span> <span class="attribute-name">name</span><span class="markup">=</span><span class="attribute-value">"phase"</span> <span class="attribute-name">maxOccurs</span><span class="markup">=</span><span class="attribute-value">"1"</span> <span class="attribute-name">minOccurs</span><span class="markup">=</span><span class="attribute-value">"0"</span> <span class="attribute-name">type</span><span class="markup">=</span><span class="attribute-value">"uws:ExecutionPhase"</span><span class="markup">/&gt;</span></div><div class="comment">&lt;!--
927 pah - TODO why is this here - there was a use case to do
928 with picking up results of partially finished jobs ?
929 --&gt;</div><span class="markup">&lt;/</span><span class="end-tag">xs:sequence</span><span class="markup">&gt;</span></div><div class="indent"><span class="markup">&lt;</span><span class="start-tag">xs:attribute</span> <span class="attribute-name">name</span><span class="markup">=</span><span class="attribute-value">"id"</span> <span class="attribute-name">type</span><span class="markup">=</span><span class="attribute-value">"xs:string"</span> <span class="attribute-name">use</span><span class="markup">=</span><span class="attribute-value">"required"</span><span class="markup">/&gt;</span></div><div class="indent"><span class="markup">&lt;</span><span class="start-tag">xs:attributeGroup</span> <span class="attribute-name">ref</span><span class="markup">=</span><span class="attribute-value">"uws:reference"</span><span class="markup">/&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:complexType</span><span class="markup">&gt;</span></div><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:element</span> <span class="attribute-name">name</span><span class="markup">=</span><span class="attribute-value">"results"</span><span class="markup">&gt;</span><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:annotation</span><span class="markup">&gt;</span><div class="indent"><span class="markup">&lt;</span><span class="start-tag">xs:documentation</span><span class="markup">&gt;</span><span class="text"> The element returned for
930 /(jobs)/(jobid)/results</span><span class="markup">&lt;/</span><span class="end-tag">xs:documentation</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:annotation</span><span class="markup">&gt;</span></div><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:complexType</span><span class="markup">&gt;</span><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:sequence</span><span class="markup">&gt;</span><div class="indent"><span class="markup">&lt;</span><span class="start-tag">xs:element</span> <span class="attribute-name">name</span><span class="markup">=</span><span class="attribute-value">"result"</span> <span class="attribute-name">type</span><span class="markup">=</span><span class="attribute-value">"uws:ResultReference"</span> <span class="attribute-name">maxOccurs</span><span class="markup">=</span><span class="attribute-value">"unbounded"</span> <span class="attribute-name">minOccurs</span><span class="markup">=</span><span class="attribute-value">"0"</span><span class="markup">/&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:sequence</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:complexType</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:element</span><span class="markup">&gt;</span></div><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:complexType</span> <span class="attribute-name">name</span><span class="markup">=</span><span class="attribute-value">"ErrorSummary"</span><span class="markup">&gt;</span><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:annotation</span><span class="markup">&gt;</span><div class="indent"><span class="markup">&lt;</span><span class="start-tag">xs:documentation</span><span class="markup">&gt;</span><span class="text"> A short summary of an error - a fuller representation of the error may be retrieved from /(jobs)/(jobid)/error
931 </span><span class="markup">&lt;/</span><span class="end-tag">xs:documentation</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:annotation</span><span class="markup">&gt;</span></div><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:sequence</span><span class="markup">&gt;</span><div class="indent"><span class="markup">&lt;</span><span class="start-tag">xs:element</span> <span class="attribute-name">name</span><span class="markup">=</span><span class="attribute-value">"message"</span> <span class="attribute-name">type</span><span class="markup">=</span><span class="attribute-value">"xs:string"</span><span class="markup">/&gt;</span></div><div class="comment">&lt;!-- is this detail redundant if we say that the "detailed message" is always available from /(jobs)/(jobid)/error--&gt;</div><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:element</span> <span class="attribute-name">name</span><span class="markup">=</span><span class="attribute-value">"detail"</span> <span class="attribute-name">maxOccurs</span><span class="markup">=</span><span class="attribute-value">"1"</span> <span class="attribute-name">minOccurs</span><span class="markup">=</span><span class="attribute-value">"0"</span><span class="markup">&gt;</span><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:complexType</span><span class="markup">&gt;</span><div class="indent"><span class="markup">&lt;</span><span class="start-tag">xs:attributeGroup</span> <span class="attribute-name">ref</span><span class="markup">=</span><span class="attribute-value">"uws:reference"</span><span class="markup">/&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:complexType</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:element</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:sequence</span><span class="markup">&gt;</span></div><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:attribute</span> <span class="attribute-name">name</span><span class="markup">=</span><span class="attribute-value">"type"</span> <span class="attribute-name">type</span><span class="markup">=</span><span class="attribute-value">"uws:ErrorType"</span><span class="markup">&gt;</span><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:annotation</span><span class="markup">&gt;</span><div class="indent"><span class="markup">&lt;</span><span class="start-tag">xs:documentation</span><span class="markup">&gt;</span><span class="text">characterization of the
932 type of the error</span><span class="markup">&lt;/</span><span class="end-tag">xs:documentation</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:annotation</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:attribute</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:complexType</span><span class="markup">&gt;</span></div><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:simpleType</span> <span class="attribute-name">name</span><span class="markup">=</span><span class="attribute-value">"ErrorType"</span><span class="markup">&gt;</span><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:restriction</span> <span class="attribute-name">base</span><span class="markup">=</span><span class="attribute-value">"xs:string"</span><span class="markup">&gt;</span><div class="indent"><span class="markup">&lt;</span><span class="start-tag">xs:enumeration</span> <span class="attribute-name">value</span><span class="markup">=</span><span class="attribute-value">"transient"</span><span class="markup">/&gt;</span></div><div class="indent"><span class="markup">&lt;</span><span class="start-tag">xs:enumeration</span> <span class="attribute-name">value</span><span class="markup">=</span><span class="attribute-value">"fatal"</span><span class="markup">/&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:restriction</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:simpleType</span><span class="markup">&gt;</span></div><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:complexType</span> <span class="attribute-name">name</span><span class="markup">=</span><span class="attribute-value">"Parameter"</span> <span class="attribute-name">mixed</span><span class="markup">=</span><span class="attribute-value">"true"</span><span class="markup">&gt;</span><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:annotation</span><span class="markup">&gt;</span><div class="indent"><span class="markup">&lt;</span><span class="start-tag">xs:documentation</span><span class="markup">&gt;</span><span class="text"> the list of input parameters to the job - if
933 the job description language does not naturally have
934 parameters, then this list should contain one element which
935 is the content of the original POST that created the job.
936 </span><span class="markup">&lt;/</span><span class="end-tag">xs:documentation</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:annotation</span><span class="markup">&gt;</span></div><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:attribute</span> <span class="attribute-name">name</span><span class="markup">=</span><span class="attribute-value">"byReference"</span> <span class="attribute-name">type</span><span class="markup">=</span><span class="attribute-value">"xs:boolean"</span> <span class="attribute-name">default</span><span class="markup">=</span><span class="attribute-value">"false"</span><span class="markup">&gt;</span><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:annotation</span><span class="markup">&gt;</span><div class="indent"><span class="markup">&lt;</span><span class="start-tag">xs:documentation</span><span class="markup">&gt;</span><span class="text"> if this attribute is true then the
937 content of the parameter represents a URL to retrieve the
938 actual parameter value.</span><span class="markup">&lt;/</span><span class="end-tag">xs:documentation</span><span class="markup">&gt;</span></div><div class="indent"><span class="markup">&lt;</span><span class="start-tag">xs:documentation</span><span class="markup">&gt;</span><span class="text"> It is up to the implementation to decide
939 if a parameter value cannot be returned directly as the
940 content - the basic rule is that the representation of
941 the parameter must allow the whole job element to be
942 valid XML. If this cannot be achieved then the parameter
943 value must be returned by reference.</span><span class="markup">&lt;/</span><span class="end-tag">xs:documentation</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:annotation</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:attribute</span><span class="markup">&gt;</span></div><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:attribute</span> <span class="attribute-name">name</span><span class="markup">=</span><span class="attribute-value">"id"</span> <span class="attribute-name">type</span><span class="markup">=</span><span class="attribute-value">"xs:string"</span> <span class="attribute-name">use</span><span class="markup">=</span><span class="attribute-value">"required"</span><span class="markup">&gt;</span><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:annotation</span><span class="markup">&gt;</span><div class="indent"><span class="markup">&lt;</span><span class="start-tag">xs:documentation</span><span class="markup">&gt;</span><span class="text"> the identifier for the parameter
944 </span><span class="markup">&lt;/</span><span class="end-tag">xs:documentation</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:annotation</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:attribute</span><span class="markup">&gt;</span></div><div class="indent"><span class="markup">&lt;</span><span class="start-tag">xs:attribute</span> <span class="attribute-name">name</span><span class="markup">=</span><span class="attribute-value">"isPost"</span> <span class="attribute-name">type</span><span class="markup">=</span><span class="attribute-value">"xs:boolean"</span><span class="markup">/&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:complexType</span><span class="markup">&gt;</span></div><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:element</span> <span class="attribute-name">name</span><span class="markup">=</span><span class="attribute-value">"parameters"</span><span class="markup">&gt;</span><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:complexType</span><span class="markup">&gt;</span><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:sequence</span><span class="markup">&gt;</span><div class="indent"><span class="markup">&lt;</span><span class="start-tag">xs:element</span> <span class="attribute-name">name</span><span class="markup">=</span><span class="attribute-value">"parameter"</span> <span class="attribute-name">type</span><span class="markup">=</span><span class="attribute-value">"uws:Parameter"</span> <span class="attribute-name">maxOccurs</span><span class="markup">=</span><span class="attribute-value">"unbounded"</span> <span class="attribute-name">minOccurs</span><span class="markup">=</span><span class="attribute-value">"0"</span><span class="markup">/&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:sequence</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:complexType</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:element</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:schema</span><span class="markup">&gt;</span></div><div class="comment">&lt;!--
945
946 --&gt;</div></div></div>
947
948 </div>
949 </div>
950 <div class="section-nonum'"><h2><a name="References" id="References"/>References</h2>
951 <div>
952 <?bibliography ivoadoc/refs.bib ?>
953 <dl>
954
955 <dt><a name="std:xform">[std:xform] John~M. Boyer, editor.</a></dt> <dd>
956 <a href="http://www.w3.org/TR/xforms11/" >Xforms 1.1</a>, 2007.
957 </dd>
958
959 <dt><a name="std:soap">[std:soap] Don Box, David Ehnebuske, Gopal Kakivaya,
960 Andrew Layman, Noah Mendelsohn, Henrik~Frystyk Nielsen, Satish Thatte, and
961 Dave Winer.</a></dt> <dd>
962 <a href="http://www.w3.org/TR/2000/NOTE-SOAP-20000508/" >Simple object access
963 protocol (soap) 1.1</a>, 2000.
964 </dd>
965
966 <dt><a name="fielding00">[fielding00] Roy~Thomas Fielding.</a></dt> <dd>
967 <a href="http://www.ics.uci.edu/~fielding/pubs/dissertation/top.htm"
968 ><em>Architectural Styles and the Design of Network-based Software
969 Architectures</em></a>.
970 PhD thesis, University of California, Irvine, 2000.
971 </dd>
972
973 <dt><a name="std:iso8601">[std:iso8601] {Grid and Web Services Working Group},
974 Guy Rixon and Matthew Graham, editors.</a></dt> <dd>
975 <a href="http://www.ivoa.net/Documents/latest/SSOAuthMech.html" >Ivoa
976 single-sign-on profile: Authentication mechanisms version 1.01</a>, 2008.
977 </dd>
978
979 <dt><a name="std:ssoauth">[std:ssoauth] {Grid and Web Services Working Group},
980 Guy Rixon and Matthew Graham, editors.</a></dt> <dd>
981 <a href="http://www.ivoa.net/Documents/latest/SSOAuthMech.html" >Ivoa
982 single-sign-on profile: Authentication mechanisms version 1.01</a>, 2008.
983 </dd>
984
985 <dt><a name="harrison05">[harrison05] P.~Harrison.</a></dt> <dd>
986 <a href="http://www.ivoa.net/Documents/latest/CEA.html" >A proposal for a
987 common execution architecture</a>.
988 {IVOA Note}, May 2005.
989 </dd>
990
991 <dt><a name="std:vocea">[std:vocea] Paul Harrison.</a></dt> <dd>
992 Vocea - an xml schema for registering cea.
993 </dd>
994
995 <dt><a name="sextractor">[sextractor]
996 http://astromatic.iap.fr/software/sextractor/.</a></dt> <dd>
997 <a href="http://astromatic.iap.fr/software/sextractor/" >Sextractor</a>.
998 [Online].
999 </dd>
1000
1001 <dt><a name="std:adql">[std:adql] Iñaki Ortiz, Jeff Lusted, Pat Dowler,
1002 Alexander Szalay, Yuji Shirasaki, Maria~A. Nieto-Santisteba, Masatoshi
1003 Ohishi, William OÕMullane, Pedro Osuna, the VOQL-TEG, and the VOQL
1004 Working~Group, Pedro Osuna and Iñaki Ortiz, editors.</a></dt> <dd>
1005 <a href="http://www.ivoa.net/Documents/latest/ConeSearch.html" >Ivoa
1006 astronomical data query language</a>.
1007 {IVOA Recommendation}, 2008.
1008 </dd>
1009
1010 <dt><a name="std:siap">[std:siap] Doug Tody and Ray Plant, Paul Harrison,
1011 editor.</a></dt> <dd>
1012 <a href="http://www.ivoa.net/Documents/latest/SIA.html" >Simple image access
1013 specification</a>.
1014 {IVOA Recommendation}, 2009.
1015 </dd>
1016
1017 <dt><a name="std:scs">[std:scs] Roy Williams, Robert Hanisch, Alex Szalay, and
1018 Raymond Plante, Raymond Plante, editor.</a></dt> <dd>
1019 <a href="http://www.ivoa.net/Documents/latest/ConeSearch.html" >Simple cone
1020 search</a>.
1021 {IVOA Recommendation}, 2008.
1022 </dd>
1023
1024 </dl></div>
1025 </div>
1026 </div>
1027 <p style="text-align: right; font-size: x-small; color: #888;">
1028 $Revision: 847 $ $Date: 2008-10-29 14:33:57 +0000 (Wed, 29. Oct 2008) $
1029 </p>
1030
1031 </body></html>

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