How to call python script file from wso2 proxy services

Question

How to call python script file from wso2 proxy service.

We tried with send mediator to call the python script file which is located in my local machine.

<?xml version="1.0" encoding="UTF-8"?>
<proxy xmlns="http://ws.apache.org/ns/synapse"
       name="FilepythonTest"
       transports="http https"
       startOnLoad="true">
   <description/>
   <target >
      <inSequence>
         <send>
            <endpoint>
               <address uri="local:///Users/vikashsaharan/Desktop/python/testpy.py"/>
            </endpoint>
         </send>
      </inSequence>
      <outSequence>
         <log level="full"/>
      </outSequence>
   </target>
</proxy>

We are unable to call with this call. Please guide me how can i call python script from wso2

Answer 1

You can use a class mediator and execute a python script from there. Following is a sample class mediator that would do this.

public boolean mediate(MessageContext context) { 
        String command = "python /path/to/script.py";
        try {
            Process p = Runtime.getRuntime().exec(command);
            BufferedReader in = new BufferedReader(new InputStreamReader(p.getInputStream()));
            String ret = in.readLine();
            System.out.println("value is : "+ret);
        } catch (IOException e) {
            // handle exception
        }
        return true;
    }

You can refer Running a .py file from Java

Answer 2

WSO2 EI has the inbuilt capability to execute a python script using the Script mediator. Following is a sample configuration.

**sample api configuration** 

<api xmlns="http://ws.apache.org/ns/synapse" name="api" context="/api-context">
   <resource methods="POST GET">
      <inSequence>
         <log level="full">
            <property name="Message" value="Before transformation"/>
         </log>
         <script language="py" key="conf:/repository/script/stockquoteTransformResponse.py" function="transformRequest"/>
         <log level="full">
            <property name="Message" value="After transformation"/>
         </log>
         <respond/>
      </inSequence>
   </resource>
</api>

**stockquoteTransformResponse.py file saved in carbon registry.**

from org.apache.synapse.util.xpath import SynapseXPath

def transformRequest(mc):
    symbolXPath = SynapseXPath("//*[local-name()='Code']/text()")
    symbol = symbolXPath.stringValueOf(mc)
    mc.setPayloadXML('''
	<m:getQuote xmlns:m="http://services.samples">
		<m:request>
			<m:symbol>''' + symbol + '''</m:symbol>
		</m:request>
	</m:getQuote>''')

We need to add the jython jar to WSO2EI_HOME/lib directory. This was tested with jython-2.2.1.jar from http://central.maven.org/maven2/org/python/jython/2.2.1/jython-2.2.1.jar

Following output can be seen once we invoke the above api.