This is an IVOA Working Draft for review by IVOA members and other interested parties. It is a draft document and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use IVOA Working Drafts as reference materials or to cite them as other than "work in progress."
Parts that the editor considers should be removed from the document are marked in red with a strike through line, and parts to be expanded are in green
Comments on this document are now welcome for consideration in the next version of this document. They should be sent to registry@ivoa.net, a mailing list with a public archive or on the UWSRegExt twiki discussion page. General discussion of related technology is also welcome on the Registry WG wiki site.
A list of current IVOA Recommendations and other technical documents can be found at http://www.ivoa.net/Documents/.
This document has been developed with support from the STFC, and from the European Commission's Sixth Framework Program via the Optical Infrared Coordination Network (OPTICON).
The eXtensible Markup Language, or XML, is document syntax for marking textual information with named tags and is defined by the World Wide Web Consortium (W3C) Recommendation, XML 1.0 [XML]. The set of XML tag names and the syntax rules for their use is referred to as the document schema. One way to formally define a schema for XML documents is using the W3C standard known as XML Schema [Schema].
XML document validation is a software process that checks that an XML document is not only well-formed XML but also conforms to the syntax rules defined by the applicable schema. Typically, when the schema is defined by one or more XML Schema [Schema] documents (see next section), validation refers to checking for conformance to the syntax described in those Schema documents. This document describes additional syntax constraints that cannot be enforced solely by the rules of XML Schema; thus, in this document, use of the term validation includes the extra checks that goes beyond common Schema-aware parsers which ensure conformance with this document.
The Universal Worker Service (UWS) [UWS] specification has intentionally been written to accomodate a wide variety of requirements. Although it is used as part of other standards e.g. [TAP] which will have their own specific schema to describe them [TAPRegExt], there is an additional demand to implement 'pure' UWS services (referred to as paramerized applications in the original UWS specification) where there is no other applicable IVOA standard service. In consequence, implementors have to make a number of choices relevant to remote clients -- here understood to be software agents -- or their users. In order to communicate these choices in a standardized way, UWS services support querying for their capabilities, either by using HTTP GET on the capabilities child of the service's root resource (cf. [VOSI]).
The capability element defined here is also used when registering UWS
services at an IVOA registry (see [REGWG]). As
such it is analogous to the capability definitions contained in the
extension schemas for SIA, SCS, SSA, and so on (available at [SCHEMA]). It is therefore defined as
an XML Schema type derived from vr:Capability by first fixing the standardID attribute to ivo://ivoa.net/std/UWS and then extending it to give UWS-specific
properties and interface as described below.
This specification relies directly on other IVOA standards in the following ways:
This standard also relates to other IVOA standards:
capabilities endpoint described by VOSI.
The concept of an application in the context of this standard can cover almost any computer program or process than can consume and/or emit data. e.g.
Note that although this is a very wide ranging definition, forms of "application" e.g. web services which are specifically covered by other IVOA standards, should normally be described in terms of those standards, rather than as a general UWSRegExt.
<xs:complexType name="UWSInterface" >
<xs:complexContent >
<xs:extension base="vr:Interface" >
<xs:sequence >
<xs:element name="testQuery" type="xs:string" maxOccurs="1" minOccurs="0" />
</sequence>
</extension>
</complexContent>
</complexType>
| uwsr:UWSInterface Extension Metadata Elements | |||||||
|---|---|---|---|---|---|---|---|
| Element | Definition | ||||||
| testQuery |
| ||||||
<xs:complexType name="UWSCapability" >
<xs:complexContent >
<xs:extension base="UWSCapRestriction" >
<xs:sequence >
<xs:element name="retentionPeriod" type="TimeLimits" minOccurs="0"
maxOccurs="1" />
<xs:element name="executionDuration" type="TimeLimits" minOccurs="0"
maxOccurs="1" />
</sequence>
</extension>
</complexContent>
</complexType>
| uwsr:UWSCapability Extension Metadata Elements | |||||||
|---|---|---|---|---|---|---|---|
| Element | Definition | ||||||
| retentionPeriod |
| ||||||
| executionDuration |
| ||||||
Note that this schema can be found on-line at http://www.ivoa.net/xml/UWSRegExt/v1.0 (i.e. the target namespace can also be used as a URL for the schema.) This location should represent the definitive source, the schema is only copied below for completeness of this document.
http://www.ietf.org/rfc/rfc2119.txt http://www.ivoa.net/Documents/REC/ResMetadata/RM-20040426.htm http://www.ivoa.net/Documents/latest/VOResource.htmlhttp://www.ivoa.net/Documents/latest/VOResource.htmlhttp://www.ivoa.net/Documents/latest/VOCEA.htmlhttp://www.ivoa.net/Documents/latest/CEADM.htmlhttp://www.w3.org/TR/REC-xml
http://www.w3.org/TR/xmlschema-0/
http://www.ivoa.net/Documents/REC/Identifiers/Identifiers-200505XX.html.
$Revision: 847 $ $Date: 2008-10-29 14:33:57 +0000 (Wed, 29. Oct 2008) $ $HeadURL: $