"interface" - Interface Definition Element

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∟"interface" - Interface Definition Element

This section describes 'interface', a definition element that defines an interface type with one or multiple operations. An operation is defined with an input-output pattern. An input or output is defined use a given data element.

"interface" is a top level element of a WSDL 2.0 document. "interface" is used to define an interface with one or multiple operations with "operation" sub elements. An operation is defined with a sequence of input and output messages to form an input-output pattern.

WSDL 2.0 supports 3 predefined input-output patterns:

in-only - input only: The endpoint receives a message and sends no responses.
robust-in-only - input only: The endpoint receives a message and sends no responses.
in-out - input followed by output: The endpoint receives a message and sends back a response.

The syntax of "interface" looks like this:

  <wsdl:interface name="nmtoken0" extends="qname_list"
    styleDefault="uri_list">

    <wsdl:fault name="nmtoken1" element="qname1"/>
    ...

    <-- in-only operation -->
    <wsdl:operation name="nmtoken2" pattern="uri" style="uri_list">
      <wsdl:input messageLabel="name" element="qname1"/>
      <wsdl:infault ref="qname2" messageLabel="In"/>
    </wsdl:operation>

    <-- in-out operation -->
    <wsdl:operation name="nmtoken2" pattern="uri" style="uri_list">
      <wsdl:input messageLabel="name" element="qname1"/>
      <wsdl:output messageLabel="name" element="qname1"/>
      <wsdl:infault ref="qname2" messageLabel="name"/>
      <wsdl:outfault ref="qname2" messageLabel="name"/>
    </wsdl:operation>

    ...
  </wsdl:interface >

Notes on the "interface" element:

name="nmtoken0" - Provides a reference name to this interface.
extends="qname_list" - Provides a list base interfaces.
styleDefault="uri_list" - Provides a list of default styles for this interface.
name="nmtoken1" - Provides a reference name to this fault message.
element="qname1" - Specifies the data element for this fault, in or out message.
name="nmtoken2" - Provides a reference name to this operation.
pattern="uri" - Specifies the message pattern for this this operation. You can use one of the predefined patterns: In-Only, Robust In-Only, and In-Out.
style="uri_list" - Provides a list of styles for this operation. "style" is optional, so you don't have to use any predefined styles.
messageLabel="name" - Specifies the message label, which should match a message placeholder name in the message exchange pattern.
ref="qname2" - Specifies the fault message to be used in this operation.

Here is an example of "interface" element:

  <wsdl:interface name="helloInterface">
    <wsdl:operation name="Hello"
      pattern="http://www.w3.org/ns/wsdl/in-out">
      <wsdl:input messageLabel="In" element="hy:Hello"/>
      <wsdl:output messageLabel="Out" element="hy:HelloResponse"/>
    </wsdl:operation>
  </wsdl:interface>

In this example,

Interface, helloInterface, is defined with one operation, Hello.
Operation, Hello, is defined as an "in-out" operation with no style messages.
The input is defined to use data element, Hello.
The output is defined to use data element, HelloResponse.
No fault message is defined for Hello operation. I can add it later. Let's hope that the operation will not fail.