Web Services Description Language (WSDL) Version 1.2: Bindings

1.1 Notational Conventions

The keywords "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in RFC2119 [IETF RFC 2119].

This specification uses a number of namespace prefixes throughout; they are listed in Table 1. Note that the choice of any namespace prefix is arbitrary and not semantically significant (see [XML Information Set]).

Namespace names of the general form "http://example.org/..." and "http://example.com/..." represent application or context-dependent URIs [IETF RFC 2396].

This specification uses the Extended Backus-Naur Form (EBNF) as described in XML 1.0 [XML 1.0].

With the exception of examples and sections explicitly marked as "Non-Normative", all parts of this specification are normative.

2.1 Pseudo Schema (Non-Normative)

The WSDL SOAP binding described in this section extends WSDL[WSDL 1.2] by adding element information items and attribute information items to the Infoset of the WSDL binding element information item in the "http://www.w3.org/2003/01/wsdl" namespace. The following pseudo schema depicts each of these extensions.

<definitions ...>
  <binding ...>
   <soap:binding transport="uri" 
                  styleDefault="document|rpc"?
                  namespaceDefault="uri"? 
                  encodingStyleDefault="uri"? />
   <soap:module uri="uri"
                 required="boolean"? >
      <soap:propertyConstraint uri="uri"
                               type="qname"? />*
    </soap:module>*
    <operation ...>
     <soap:operation style="document|rpc"? 
                      soapAction="uri"? /> ?
      <input>
       <soap:body namespace="uri"?
                   encodingStyle="uri"? /> ?
       <soap:header element="qname"?
                     type="qname"?
                     localname="nmtoken"?
                     namespace="uri"?
                     encodingStyle="uri"?
                     role="uri"? />*
       <soap:headerfault message="qname"
                          part="nmtoken"
                          namespace="uri"?
                          encodingStyle="uri"? />*
      </input>?
      <output>
       // same as input
      </output>?
      <fault>
       <soap:fault name="nmtoken"
                    namespace="uri"?
                    encodingStyle="uri"? />
      </fault>*
    </operation>*
  </binding>

  <service ...>
    <port ...>
     <soap:address location="uri" /> 
    </port>
  </service>
</definitions>

2.2 binding Element with binding [parent]

The mandatory binding element information item indicates that messages are SOAP Envelopes [SOAP 1.2 Part 1: Messaging Framework].

The binding element information item has the following Infoset properties:

• A [local name] of binding

• A [namespace name] of "http://www.w3.org/2003/01/wsdl/soap12"

• A [parent] of binding in the namespace named "http://www.w3.org/2003/01/wsdl"

• One or more attribute information items amongst its [attributes] as follows:

  • A required transport attribute information item as described below

  • An optional styleDefault attribute information item as described below

  • An optional namespaceDefault attribute information item as described below

  • An optional encodingStyleDefault attribute information item as described below

The binding element information item has no [children].

2.3 module Element with binding [parent]

The optional module element information item indicates SOAP module(s) supported by a binding element information item. A SOAP module[SOAP 1.2 Part 1: Messaging Framework] realizes zero or more SOAP features implemented as one or more SOAP header blocks.

The module element information item has the following Infoset properties:

• A [local name] of module

• A [namespace name] of "http://www.w3.org/2003/01/wsdl/soap12"

• A [parent] of binding in the namespace named "http://www.w3.org/2003/01/wsdl"

• One or more attribute information items amongst its [attributes] as follows:

  • A required uri attribute information item as described below

  • An optional required attribute information item as described below

2.4 propertyConstraint Element with module [parent]

The optional propertyConstraint element information item indicates SOAP module(s) supported by a module element information item.

The propertyConstraint element information item has the following Infoset properties:

• A [local name] of propertyConstraint

• A [namespace name] of "http://www.w3.org/2003/01/wsdl/soap12"

• A [parent] of module in the namespace named "http://www.w3.org/2003/01/wsdl"

• One or more attribute information items amongst its [attributes] as follows:

  • A required uri attribute information item as described below

  • An optional type attribute information item as described below

The value of the propertyConstraint element information item is the value that is required for the SOAP property of the [parent] module .

The propertyConstraint element information item has no [children].

2.5 operation Element with operation [parent]

The optional operation element information item provides binding information for the [parent] operation. The operation element information item has the following Infoset properties:

• A [local name] of operation

• A [namespace name] of "http://www.w3.org/2003/01/wsdl/soap12"

• A [parent] of operation in the namespace named "http://www.w3.org/2003/01/wsdl"

• Zero or more attribute information items amongst its [attributes] as follows:

  • An optional style attribute information item as described below

  • An optional soapAction attribute information item as described below

The operation element information item has no [children].

If the operation element information item has no [attributes], it MAY be omitted.

2.6 body Element with input or output [parent]

The optional body element information item specifies properties of the SOAP Envelope body block(s) for the [parent] operation. The body element information item has the following Infoset properties:

• A [local name] of body

• A [namespace name] of "http://www.w3.org/2003/01/wsdl/soap12"

• A [parent] of input or output in the namespace named "http://www.w3.org/2003/01/wsdl"

• Zero or more attribute information items amongst its [attributes] as follows:

  • An optional namespace attribute information item as described below

  • An optional encodingStyle attribute information item as described below

The body element information item has no [children].

If the body element information item has no [attributes], it MAY be omitted.

The body element information item provides information on how to assemble the different message parts inside the Fault element of the SOAP Envelope. The body element information item is used in both RPC-oriented and document-oriented messages, but the style of the enclosing operation has important effects on how the Fault section is structured:

• If the operation style is rpc each part is a parameter or a return value and appears inside a wrapper element within the body. The wrapper element is named identically to the operation name and its namespace is the value of the namespace attribute. Each message part (parameter) appears under the wrapper, represented by an accessor named identically to the corresponding parameter of the call. Parts are arranged in the same order as the parameters of the call.

• If the operation style is document there are no additional wrappers, and the message parts appear directly under the SOAP Fault element.

The same mechanisms are used to define the content of the Fault and parameter accessor elements.

Each part references a concrete schema definition using either the element or type attribute information item. In the first case, the element referenced by the part will appear directly under the Body SOAP Envelope element (for document style bindings) or under an accessor element named after the message part (in rpc style). In the second, the type referenced by the part becomes the schema type of the enclosing element (Body for document style or part accessor element for rpc style).

2.7 header Element with input or output [parent]

The optional header element information item specifies SOAP header block(s) for the [ancestor] operation. The header element information item has the following Infoset properties:

• A [local name] of header

• A [namespace name] of "http://www.w3.org/2003/01/wsdl/soap12"

• A [parent] of input or output in the namespace named "http://www.w3.org/2003/01/wsdl"

• One or more attribute information items amongst its [attributes] as follows:

  • An optional element attribute information item as described below

  • An optional type attribute information item as described below

  • An optional localname attribute information item as described below

  • An optional namespace attribute information item as described below

  • An optional encodingStyle attribute information item as described below

  • An optional role attribute information item as described below

The header element information item has no [children].

The header element information item allow headers to be defined that are transmitted as SOAP header blocks. It is not necessary to exhaustively list all header blocks that appear in the SOAP Envelope using header element information items. For example, extensions (see Language Extensibility and Binding, [WSDL 1.2], section 4) to WSDL may imply specific headers should be added to the actual payload, and it is not required to list those headers here.

Exactly one of the element and type attribute information items MUST be specified. The localname and namespace attribute information items MUST be specified if and only if the type attribute information item is specified.

2.8 headerfault Element with input or output [parent]

The soap:header and soap:headerfault elements allows header to be defined that are transmitted inside the Header element of the SOAP Envelope. It is patterned after the soap:body element (see section 2.6 body Element with input or output [parent] ).

It is not necessary to exhaustively list all headers that appear in the SOAP Envelope using soap:header . For example, extensions (see Language Extensibility and Binding, [WSDL 1.2], section 4) to WSDL may imply specific headers should be added to the actual payload and it is not required to list those headers here.

The namespace attribute is used in the same way as with soap:body (see section 2.6 body Element with input or output [parent] ), only style ="document" is assumed since headers do not contain parameters.

Together, the message attribute (of type QName ) and the part attribute (of type nmtoken ) reference the message part that defines the header type. The schema referenced by the part MAY include definitions for the soap:actor and soap:mustUnderstand attributes.

The referenced message need not be the same as the message that defines the SOAP Body .

The optional headerfault elements which appear inside soap:header and have the same syntax as soap:header allows specification of the header type(s) that are used to transmit error information pertaining to the header defined by the soap:header . The SOAP specification states that errors pertaining to headers must be returned in headers, and this mechanism allows specification of the format of such headers.

2.9 fault Element with operation [parent]

The soap:fault element specifies the contents of the SOAP Fault Details element. It is patterned after the soap:body element (see section 2.6 body Element with input or output [parent] ).

The name attribute relates the soap:fault to the wsdl:fault defined for the operation.

The fault message MUST have a single part. The namespace attribute is used in the same way as with soap:body (see section 2.6 body Element with input or output [parent] ), only style ="document" is assumed since faults do not contain parameters.

2.10 address Element with port [parent]

The mandatory address element information item contains the endpoint address of a port . The address element information item has the following Infoset properties:

• A [local name] of address

• A [namespace name] of "http://www.w3.org/2003/01/wsdl/soap12"

• A [parent] of port in the namespace named "http://www.w3.org/2003/01/wsdl"

• One attribute information item amongst its [attributes] as follows:

  • A required location attribute information item as described below

  
  
  

The address element information item has no [children].

3.1 HTTP GET/POST Examples

The following example shows three ports that are bound differently for a given port type.

If the values being passed are "part1=1", "part2=2", "part3=3", the request format would be as follows for each port:

port1: GET, URL="http://example.com/o1/A1B2/3"
port2: GET, URL="http://example.com/o1?p1=1&p2=2&p3=3
port3: POST, URL="http://example.com/o1", PAYLOAD="p1=1&p2=2&p3=3"

For each port, the response is either a GIF or a JPEG image.

<definitions .... >
    <message name="m1">
        <part name="part1" type="xsd:string"/>
        <part name="part2" type="xsd:int"/>
        <part name="part3" type="xsd:string"/>
    </message>

    <message name="m2">
        <part name="image" type="xsd:binary"/>
    </message>

    <portType name="pt1">
        <operation name="o1">
           <input message="tns:m1"/>
           <output message="tns:m2"/>
        </operation>
    </portType>

    <service name="service1">
        <port name="port1" binding="tns:b1">
           <http:address location="http://example.com/"/>
        </port>
        <port name="port2" binding="tns:b2">
           <http:address location="http://example.com/"/>
        </port>
        <port name="port3" binding="tns:b3">
             <http:address location="http://example.com/"/>
        </port>
    </service>

    <binding name="b1" type="pt1">
       <http:binding verb="GET"/>
        <operation name="o1">
          <http:operation location="o1/A(part1)B(part2)/(part3)"/>
           <input>
              <http:urlReplacement/>
           </input>
           <output>
              <mime:content type="image/gif"/>
              <mime:content type="image/jpeg"/>
           </output>
        </operation>
    </binding>

    <binding name="b2" type="pt1">
       <http:binding verb="GET"/>
        <operation name="o1">
          <http:operation location="o1"/>
          <input>
              <http:urlEncoded/>
          </input>
           <output>
              <mime:content type="image/gif"/>
              <mime:content type="image/jpeg"/>
           </output>
        </operation>
    </binding>

    <binding name="b3" type="pt1">
       <http:binding verb="POST"/>
        <operation name="o1">
          <http:operation location="o1"/>
           <input>
              <mime:content type="application/x-www-form-urlencoded"/>
           </input>
           <output>
              <mime:content type="image/gif"/>
              <mime:content type="image/jpeg"/>
           </output>
        </operation>
    </binding>
</definitions>

3.2 How the HTTP GET/POST Binding Extends WSDL

The HTTP GET/POST Binding extends WSDL with the following extension elements:

<definitions .... >
    <binding .... >
       <http:binding verb="nmtoken"/>
        <operation .... >
          <http:operation location="uri"/>
           <input .... >
              <-- mime elements -->
           </input>
           <output .... >
              <-- mime elements -->
           </output>
        </operation>
    </binding>

    <port .... >
       <http:address location="uri"/>
    </port>
</definitions>

These elements are covered in the subsequent sections.

3.3 http:address

The location attribute specifies the base URI for the port. The value of the attribute is combined with the values of the location attribute of the http:operation binding element. See section 3.5 http:operation for more details.

3.4 http:binding

The http:binding element indicates that this binding uses the HTTP protocol.

<definitions .... >
    <binding .... >
       <http:binding verb="nmtoken"/>
    </binding>
</definitions>

The value of the required verb attribute indicates the HTTP verb. Common values are GET or POST, but others may be used. Note that HTTP verbs are case sensitive.

3.5 http:operation

The location attribute specifies a relative URI for the operation. This URI is combined with the URI specified in the http:address element to form the full URI for the HTTP request. The URI value MUST be a relative URI.

<definitions .... >
    <binding .... >
        <operation .... >
          <http:operation location="uri"/>
        </operation>
    </binding>
</definitions>

3.6 http:urlEncoded

The urlEncoded element indicates that all the message parts are encoded into the HTTP request URI using the standard URI- encoding rules ("name1=value&name2=value…"). The names of the parameters correspond to the names of the message parts. Each value contributed by the part is encoded using a "name=value" pair. This may be used with GET to specify URL encoding, or with POST to specify a FORM-POST. For GET, the "?" character is automatically appended as necessary.

<http:urlEncoded/>

For more information on the rules for URI-encoding parameters, see Form submission ([HTML 4.01], section 17.13), Ampersands in URI ([HTML 4.01], section B.2.2), and Form content types ([HTML 4.01], section 17.13.4).

3.7 http:urlReplacement

The http:urlReplacement element indicates that all the message parts are encoded into the HTTP request URI using a replacement algorithm:

• The relative URI value of http:operation is searched for a set of search patterns.

• The search occurs before the value of the http:operation is combined with the value of the location attribute from http:address .

• There is one search pattern for each message part. The search pattern string is the name of the message part surrounded with parenthesis "(" and ")".

• For each match, the value of the corresponding message part is substituted for the match at the location of the match.

• Matches are performed before any values are replaced (replaced values do not trigger additional matches).

Message parts MUST NOT have repeating values.

<http:urlReplacement/>

4.1 MIME Binding example

This example describes that a GetCompanyInfo SOAP request may be sent to a StockQuote service via the SOAP HTTP binding. The request takes a ticker symbol of type string. The response contains multiple parts encoded in the MIME format multipart/related: a SOAP Envelope containing the current stock price as a float, zero or more marketing literature documents in HTML format, and an optional company logo in either GIF or JPEG format.

<definitions .... >

    <types>
        <schema .... >
           <element name="GetCompanyInfo">
               <complexType>
                   <all>
                       <element name="tickerSymbol " type="string"/>
                   </all>
               </complexType>
           </element>
           <element name="GetCompanyInfoResult">
               <complexType>
                   <all>
                       <element name="result" type="float"/>
                   </all>
               </complexType>
           </element>
           <complexType name="ArrayOfBinary">
               <complexContent>
                   <restriction base="soapenc:Array">
                      <attribute ref="soapenc:arrayType" wsdl:arrayType="xsd:binary[]"/>
                   </restriction>
               <complexContent>
           </complexType>
        </schema>
    </types>

    <message name="m1">
        <part name="body" element="tns:GetCompanyInfo"/>
    </message>

    <message name="m2">
        <part name="body" element="tns:GetCompanyInfoResult"/>
        <part name="docs" type="xsd:string"/>
        <part name="logo" type="tns:ArrayOfBinary"/>
    </message>

    <portType name="pt1">
        <operation name="GetCompanyInfo">
           <input message="m1"/>
           <output message="m2"/>
        </operation>
    </portType>

    <binding name="b1" type="tns:pt1">
        <operation name="GetCompanyInfo">
          <soap:operation soapAction="http://example.com/GetCompanyInfo"/>
           <input>
              <soap:body use="literal"/>
           </input>
           <output>
              <mime:multipartRelated>
                  <mime:part>
                      <soap:body parts="body" use="literal"/>
                  </mime:part>
                  <mime:part>
                      <mime:content part="docs" type="text/html"/>
                  </mime:part>
                  <mime:part>
                      <mime:content part="logo" type="image/gif"/>
                      <mime:content part="logo" type="image/jpeg"/>
                  </mime:part>
              </mime:multipartRelated>
           </output>
        </operation>
    </binding>

    <service name="CompanyInfoService">
        <port name="CompanyInfoPort"binding="tns:b1">
          <soap:address location="http://example.com/companyinfo"/>
        </port>
    </service>
</definitions>

4.2 How the MIME Binding extends WSDL

The MIME Binding extends WSDL with the following extension elements:

<mime:content part="nmtoken"? type="string"?/>

<mime:multipartRelated>
    <mime:part> *
        <-- mime element -->
    </mime:part>
</mime:multipartRelated>
<mime:mimeXml part="nmtoken"?/>

They are used at the following locations in WSDL:

<definitions .... >
    <binding .... >
        <operation .... >
           <input .... >
              <-- mime elements -->
           </input>
           <output .... >
              <-- mime elements -->
           </output>
        </operation>
    </binding>
</definitions>

MIME elements appear under input and output to specify the MIME format. If multiple appear, they are considered to be alternatives.

4.3 mime:content

To avoid having to define a new element for every MIME format, the mime:content element may be used if there is no additional information to convey about the format other than its MIME type string.

<mime:content part="nmtoken"? type="string"?/>

The part attribute is used to specify the name of the message part. If the message has a single part, then the part attribute is optional. The type attribute contains the MIME type string. A type value has two portions, separated by a slash (/), either of which may be a wildcard (*). Not specifying the type attribute indicates that all MIME types are acceptable.

If the return format is XML [XML 1.0], but the schema is not known ahead of time, the generic mime element can be used indicating "text/xml" [IETF RFC 3023]:

<mime:content type="text/xml"/>

A wildcard (*) can be used to specify a family of mime types, for example all text types.

<mime:content type="text/*"/>

The following two examples both specify all mime types:

<mime:content type="*/*"/>
<mime:content/>

4.4 mime:multipartRelated

The "multipart/related" MIME type aggregates an arbitrary set of MIME formatted parts into one message using the MIME type "multipart/related". The mime:multipartRelated element describes the concrete format of such a message:

<mime:multipartRelated>
    <mime:part> *
        <-- mime element -->
    </mime:part>
</mime:multipartRelated>

The mime:part element describes each part of a "multipart/related" message [IETF RFC 2387]. MIME elements appear within mime:part to specify the concrete MIME type for the part. If more than one MIME element appears inside a mime:part , they are alternatives.

4.5 soap:body

When using the MIME binding with SOAP requests [SOAP 1.2 Part 1: Messaging Framework], it is legal to use the soap:body element as a MIME element. It indicates the content type is "text/xml", and there is an enclosing SOAP Envelope.

4.6 mime:mimeXml

To specify XML payloads that are not SOAP compliant (do not have a SOAP Envelope), but do have a particular schema, the mime:mimeXml element may be used to specify that concrete schema. The part attribute refers to a message part defining the concrete schema of the root XML element. The part attribute MAY be omitted if the message has only a single part. The part references a concrete schema using the element attribute for simple parts or type attribute for composite parts .

<mime:mimeXml part="nmtoken"?/>

5.1 Normative References

[HTML 4.01]

HTML 4.01 Specification, D. Raggett, A. Le Hors, I. Jacobs, Editors. World Wide Web Consortium, 24 December 1999. This version of the HTML 4.01 Recommendation is http://www.w3.org/TR/1999/REC-html401-19991224. The latest version of HTML 4.01 is available at http://www.w3.org/TR/html401.

[IETF RFC 2045]

Multipurpose Internet Mail Extensions (MIME) Part One: Format of Internet Message Bodies, N. Freed, N. Borenstein, Authors. Internet Engineering Task Force, November 1996. Available at http://www.ietf.org/rfc/rfc2045.txt.

[IETF RFC 2119]

Key words for use in RFCs to Indicate Requirement Levels, S. Bradner, Author. Internet Engineering Task Force, June 1999. Available at http://www.ietf.org/rfc/rfc2119.txt.

[IETF RFC 2387]

The MIME Multipart/Related Content-type, E. Levinson, Authors. Internet Engineering Task Force, August 1998. Available at http://www.ietf.org/rfc/rfc2387.txt.

[IETF RFC 2396]

Uniform Resource Identifiers (URI): Generic Syntax, T. Berners-Lee, R. Fielding, L. Masinter, Authors. Internet Engineering Task Force, August 1998. Available at http://www.ietf.org/rfc/rfc2396.txt.

[IETF RFC 2616]

Hypertext Transfer Protocol -- HTTP/1.1, R. Fielding, J. Gettys, J. Mogul, H. Frystyk, L. Masinter, P. Leach, T. Berners-Lee, Authors. Internet Engineering Task Force, June 1999. Available at http://www.ietf.org/rfc/rfc2616.txt.

[IETF RFC 3023]

XML Media Types, M. Murata, S. St. Laurent, D. Kohn, Authors. Internet Engineering Task Force, January 2001. Available at http://www.ietf.org/rfc/rfc3023.txt.

[SOAP 1.2 Part 1: Messaging Framework]

SOAP Version 1.2 Part 1: Messaging Framework, M. Gudgin, M. Hadley, N. Mendelsohn, J-J. Moreau, H. Frystyk Nielsen, Editors. World Wide Web Consortium, 19 December 2002. This version of the SOAP Version 1.2 Part 1 Specification is http://www.w3.org/TR/2002/CR-soap12-part1-20021219/. The latest version of SOAP Version 1.2 Part 1 is available at http://www.w3.org/TR/soap12-part1/.

[SOAP 1.2 Part 2: Adjuncts]

SOAP Version 1.2 Part 2: Adjuncts, M. Gudgin, M. Hadley, N. Mendelsohn, J-J. Moreau, and H. Frystyk Nielsen, Editors. World Wide Web Consortium, 19 December 2002. This version of the SOAP Version 1.2 Part 2 Specification is http://www.w3.org/TR/2002/CR-soap12-part2-20021219/. The latest version of SOAP Version 1.2 Part 2 is available at http://www.w3.org/TR/soap12-part2/.

[XML 1.0]

Extensible Markup Language (XML) 1.0 (Second Edition), T. Bray, J. Paoli, C. M. Sperberg-McQueen, and E. Maler, Editors. World Wide Web Consortium, 10 February 1998, revised 6 October 2000. This version of the XML 1.0 Recommendation is http://www.w3.org/TR/2000/REC-xml-20001006. The latest version of XML 1.0 is available at http://www.w3.org/TR/REC-xml.

[XML Information Set]

XML Information Set, J. Cowan and R. Tobin, Editors. World Wide Web Consortium, 24 October 2001. This version of the XML Information Set Recommendation is http://www.w3.org/TR/2001/REC-xml-infoset-20011024. The latest version of XML Information Set is available at http://www.w3.org/TR/xml-infoset.

[XML Schema Structures]

XML Schema Part 1: Structures, H. Thompson, D. Beech, M. Maloney, and N. Mendelsohn, Editors. World Wide Web Consortium, 2 May 2001. This version of the XML Schema Part 1 Recommendation is http://www.w3.org/TR/2001/REC-xmlschema-1-20010502. The latest version of XML Schema Part 1 is available at http://www.w3.org/TR/xmlschema-1.

[XML Schema Datatypes]

XML Schema Part 2: Datatypes, P. Byron and A. Malhotra, Editors. World Wide Web Consortium, 2 May 2001. This version of the XML Schema Part 2 Recommendation is http://www.w3.org/TR/2001/REC-xmlschema-2-20010502. The latest version of XML Schema Part 2 is available at http://www.w3.org/TR/xmlschema-2.

[WSDL 1.2]

Web Services Description Language (WSDL) Version 1.2, R. Chinnici, M. Gudgin, J-J. Moreau, S. Weerawarana, Editors. World Wide Web Consortium, 24 January 2003. This version of the Web Services Description Version 1.2 Specification is available is available at http://www.w3.org/TR/2003/WD-wsdl12-20030124. The latest version of Web Services Description Version 1.2 is available at http://www.w3.org/TR/wsdl12.

5.2 Informative References

[WSDL 1.2 Primer]

Web Services Description (WSDL) Version 1.2: Primer, K. Sankar, K. Liu, D. Booth, Editors. World Wide Web Consortium, 24 January 2003. The editors' version of the Web Services Description Version 1.2: Primer document is available from http://www.w3.org/2002/ws/desc/.