Generate REST API from SOAP Backend

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. Log in to the API Publisher and click ADD NEW API
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.
   • Generate REST APIs – This option is used to generate REST API definitions from the given WSDL URL.

3. Provide the WSDL URL for the SOAP backend and click Start Creating. The default option is Pass Through.
   

4. Select the Generate REST APIs option and go to the Design tab. Click on Edit Source to edit the Swagger specification of the API.
   
5. Click Apply Changes to save your API.
   

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

   The definition properties are mapped with a Swagger vendor-specific field x-xpath, which is used to map the SOAP binding operation parameters with the REST parameters. If a parameter does not have this field it is not mapped with a backend operation. To ensure the mapping functions smoothly, do not make any changes to the properties.

7. Go to the Implement tab and view the SOAP Mapping section. Click on a resource to view the In and Out sequences of the API.
   

8. The following sample shows the generated API In-sequence for a GET method with query parameters.

   GET https://<host_name>:8243/weather/1.0.0/weather?CityName=xxxxx&CountryName=xxxxx

   <property name="HTTP_METHOD" value="POST" scope="axis2" type="STRING"/>
            <header name="SOAPAction"
                    scope="transport"
                    value="http://www.webserviceX.NET/GetWeather"
                    description="SOAPAction"/>
            <property name="REST_URL_POSTFIX" scope="axis2" action="remove"/>
            <property name="req.var.CityName" expression="$url:CityName"/>
            <property name="req.var.CountryName" expression="$url:CountryName"/>
            <payloadFactory media-type="xml" description="transform">
               <format>
                  <soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/"
                                    xmlns:web="http://www.webserviceX.NET">
                     <soapenv:Header/>
                     <soapenv:Body>
                        <web:GetWeather>
                           <web:CityName>$1</web:CityName>
                           <web:CountryName>$2</web:CountryName>
                        </web:GetWeather>
                     </soapenv:Body>
                  </soapenv:Envelope>
               </format>
               <args>
                  <arg evaluator="xml" expression="get-property('req.var.CityName')"/>
                  <arg evaluator="xml" expression="get-property('req.var.CountryName')"/>
               </args>
            </payloadFactory>
            <property name="messageType"
                      value="application/soap+xml"
                      scope="axis2"
                      type="STRING"
                      description="messageProperty"/>

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

9. Enter the SOAP endpoint URL. The endpoint type should be the HTTP/SOAP Endpoint as shown below.
   
10. Go to the Manage tab and the relevant configuration. Click Publish to publish the API to the API Store. For instructions, see Create and Publish an API.
11. Navigate to the API Store and invoke the API.