Generate REST APIs from SOAP Backends

This feature allows users to expose their legacy SOAP backends as REST APIs through WSO2 API Manager. WSO2 API Manager supports WSDL 1.1 based SOAP backends.

The following instructions explain how to generate REST APIs in WSO2 API Manager for an existing SOAP backend.

1. Sign in to the API Publisher and click ADD NEW API, which is under the API menu.
2. Select I Have a SOAP Endpoint. You see the following two options to create APIs for SOAP backend.
   • Pass Through – Create a pass through proxy for SOAP requests coming to the API Gateway. You can either select a WSDL URL to provide a URL for your API or you can upload a WSDL archive/file.
   • Generate REST APIs – This option is used to generate REST API definitions from the given WSDL URL. Therefore, select a WSDL URL to provide a URL for your API. 

3. Select Generate REST APIs (The default option is Pass Through). Provide the WSDL URL given below for the SOAP backend and click Start Creating. 

   Sample WSDL URL

   http://ws.cdyne.com/phoneverify/phoneverify.asmx?wsdl

   The WSDL URL and WSDL Archive/File options that are shown in the following screenshot, which allow you to modify API resources, are only available as a WUM update and is effective from 11th January 2019 (11-01-2019). For more information, see Updating WSO2 API Manager.

   

4. Click on Edit Source to edit the Swagger specification of the API.
   
   The automatically generated REST resources of the API appears.
   You can describe your REST API better by modifying the Open API Specification that you see on this page. The following is a sample of how this particular API has been described.

   

5. Optionally, update the Swagger definition of your API and click Apply Changes to save your API.
   Let's update the API by replacing the existing Swagger definition with the following Swagger definition.

    Expand to see the edited Swagger definition...

   swagger: "2.0"
   paths:
     /checkPhoneNumber:
       get:
         operationId: CheckPhoneNumber
         parameters:
           - in: query
             name: PhoneNumber
             required: true
             type: string
           - in: query
             name: LicenceKey
             required: true
             type: string
         responses:
           default:
             description: ""
             schema:
               $ref: "#/definitions/checkPhoneNumberOutput"
         x-wso2-soap:
           soap-action: "http://ws.cdyne.com/PhoneVerify/query/CheckPhoneNumber"
           soap-operation: CheckPhoneNumber
           namespace: "http://ws.cdyne.com/PhoneVerify/query"
           x-soap-version: "1.2"
     /checkPhoneNumbers:
       post:
         operationId: CheckPhoneNumbers
         parameters:
           - in: body
             name: Payload
             required: true
             schema:
               $ref: "#/definitions/checkPhoneNumbersInput"
         responses:
           default:
             description: ""
             schema:
               $ref: "#/definitions/checkPhoneNumbersOutput"
         x-wso2-soap:
           soap-action: "http://ws.cdyne.com/PhoneVerify/query/CheckPhoneNumbers"
           soap-operation: CheckPhoneNumbers
           namespace: "http://ws.cdyne.com/PhoneVerify/query"
           x-soap-version: "1.2"
   info:
     title: PhoneVerificationAPI
     version: 1.0.0
   definitions:
     checkPhoneNumberInput:
       type: object
       properties:
         CheckPhoneNumber:
           $ref: "#/definitions/CheckPhoneNumber"
     checkPhoneNumberOutput:
       type: object
       properties:
         CheckPhoneNumberResponse:
           $ref: "#/definitions/CheckPhoneNumberResponse"
     checkPhoneNumbersInput:
       type: object
       properties:
         CheckPhoneNumbers:
           $ref: "#/definitions/CheckPhoneNumbers"
     checkPhoneNumbersOutput:
       type: object
       properties:
         CheckPhoneNumbersResponse:
           $ref: "#/definitions/CheckPhoneNumbersResponse"
     StringArray:
       type: string
       properties:
         String:
           type: array
           items:
             type: string
       xml:
         namespace: "http://www.w3.org/2001/XMLSchema"
         prefix: s
     CheckPhoneNumber:
       type: object
       properties:
         PhoneNumber:
           type: string
         LicenseKey:
           type: string
       xml:
         namespace: "http://www.w3.org/2001/XMLSchema"
         prefix: s
     CheckPhoneNumbersResponse:
       type: object
       properties:
         CheckPhoneNumbersResult:
           $ref: "#/definitions/ArrayOfPhoneReturn"
       xml:
         namespace: "http://www.w3.org/2001/XMLSchema"
         prefix: s
     ArrayOfString:
       type: object
       properties:
         string:
           type: array
           items:
             type: string
       xml:
         namespace: "http://www.w3.org/2001/XMLSchema"
         prefix: s
     ArrayOfPhoneReturn:
       type: object
       xml:
         namespace: "http://www.w3.org/2001/XMLSchema"
         prefix: s
     CheckPhoneNumbers:
       type: object
       properties:
         PhoneNumbers:
           $ref: "#/definitions/ArrayOfString"
         LicenseKey:
           type: string
       xml:
         namespace: "http://www.w3.org/2001/XMLSchema"
         prefix: s
     PhoneReturn:
       type: object
       xml:
         namespace: "http://www.w3.org/2001/XMLSchema"
         prefix: s
     CheckPhoneNumberResponse:
       type: object
       properties:
         CheckPhoneNumberResult:
           $ref: "#/definitions/PhoneReturn"
       xml:
         namespace: "http://www.w3.org/2001/XMLSchema"
         prefix: s

   

6. The generated API definitions are added to the API as shown below.
   

   A REST API method is mapped with the corresponding SOAP operation through a Swagger, vendor-specific field - x-wso2-soap. Note that this should not be edited. A parameter without this field cannot be mapped with a SOAP backend operation.

   See the sample REST operation given below.

     /checkPhoneNumber:
       post:
         operationId: CheckPhoneNumber
         parameters:
       ...
         x-wso2-soap:
           soap-action: "http://ws.cdyne.com/PhoneVerify/query/CheckPhoneNumber"
           soap-operation: CheckPhoneNumber
           namespace: "http://ws.cdyne.com/PhoneVerify/query"
           x-soap-version: "1.2"

   The operationId parameter is used to map the REST resource with the corresponding SOAP operation.

7. Edit the details of the API as shown below.

   Field		Sample value
   Name		PhoneVerification
   Context		/phoneverify
   Version		1.0.0
   Access Control		All
   Visibility on Store		Public
   Tags		phone

   For more information on the meanings of the latter mentioned fields, see Create and Publish an API.

   

8. Go to the Implement tab. Click on Managed API. 

9. Select the Endpoint Type as the HTTP/SOAP Endpoint. Enter the SOAP endpoint URL given below.

   SOAP Endpoint URL

   http://ws.cdyne.com/phoneverify/phoneverify.asmx

   

10. Navigate to the SOAP to REST Mapping section. Click on a resource to view the In and Out sequences of the API.
    
    The following is a sample Synapse based XML configuration which reads some parameters from the request path and constructs the SOAP payload required for the backend (target) services.

    <header description="SOAPAction" name="SOAPAction" scope="transport" value="http://ws.cdyne.com/PhoneVerify/query/CheckPhoneNumber"/>
    <property name="REST_URL_POSTFIX" scope="axis2" action="remove"/>
    <property expression="$url:PhoneNumber" name="req.var.PhoneNumber"/>
    <property expression="$url:LicenceKey" name="req.var.LicenceKey"/>
    
    
    <payloadFactory description="transform" media-type="xml">
      <format>
      <soapenv:Envelope xmlns:soapenv="http://www.w3.org/2003/05/soap-envelope" xmlns:web="http://ws.cdyne.com/PhoneVerify/query">
      <soapenv:Header/>
      <soapenv:Body>
      	<web:CheckPhoneNumber xmlns:web="http://ws.cdyne.com/PhoneVerify/query">
       <web:PhoneNumber>$1</web:PhoneNumber>
       <web:LicenceKey>$2</web:LicenceKey>
    </web:CheckPhoneNumber>
    
      </soapenv:Body>
      </soapenv:Envelope>
      </format>
      <args>
     	<arg evaluator="xml" expression="get-property('req.var.PhoneNumber')"/>
    <arg evaluator="xml" expression="get-property('req.var.LicenceKey')"/>
    
      </args>
    </payloadFactory>
    <property description="messageProperty" name="messageType" scope="axis2" type="STRING" value="application/soap+xml"/>

    The incoming JSON message parameters are stored using properties. The SOAP payload needed for the backend is generated using a payload factory mediator.

11. Go to the Manage tab and select the throttling tiers for the API. Click Publish to publish the API to the API Store.
    For instructions, see Create and Publish an API.

12. Navigate to the API Store and subscribe to an API.
    After generating the production and sandbox keys you receive a valid access token to access the API.

    https://localhost:9443/store

13. Run the following HTTP request to invoke the API.
    You receive the actual backend response.

    Related Links

    • Create and Publish a SOAP API.
    • You can also invoke this API using a third-party tool such as SOAP UI. For more information on how to invoke an API using a SOAP client, see Invoke an API using a SOAP Client.