Invoking Mashups using JSON

Mashups running on the WSO2 Mashup Server can be invoked in using various message formats. They are SOAP 1.1, SOAP 1.2, POX (Plain Old XML), REST, JSON, SOAP/POX over JMS, SOAP/POX over SMTP.

Here is how you can use JSON to invoke a simple Mashup. In this example I will be invoking the RESTSample running on mooshup.com. This simple sample sends the payload as JSON and receives the response as JSON as well.

// Providing optional annotations
invokePOSTWeather.inputTypes={"city" : "string", "weatherDetails" : "string"};
invokePOSTWeather.outputType="#raw";
function invokePOSTWeather(city, weatherDetails){
     var request = new WSRequest();
     var options = new Array();
     // Instracts the server that my request needs to be formatted as JSON
     options.HTTPInputSerialization = "application/json/badgerfish";
     var payload = <POSTWeather><city>{city}</city><weatherDetails>{weatherDetails}
</weatherDetails></POSTWeather>;
     var result;
     try {
             request.open(options,"http://mooshup.com/services/samples/RESTSample/", false);
             request.send(payload);
             result = request.responseE4X;
     } catch (e) {
             result =  e.toString();
     }
     return result
}

If you were to use TCPMonitor to trace the messages you will be able to see the messages sent and received by the Server.

Here is the request sent out by this Mashup

{"POSTWeather":{"city":{"$":"col"},"weatherDetails":{"$":"10"}}}

And the response it received

{"ws:POSTWeatherResponse":{"@xmlns":{"ws":"http:\/\/services.mashup.wso2.org\/RESTSample?xsd"},"return":{"$":"col"}}}

Note : There are three main ways that you can get the response from WSRequest. There are response.responseText, response.responseXML and response.responseE4X. If you were to use these variants when the response if JSON they will act as follows,

response.responseText - Would return the JSON string as the response
response.responseXML - Would return the XML representation of the JSON string
response.responseE4X - Would return the E4X representation of the JSON string