XML to JSON conversion when multiple attributes and elements exists

There are situations that we need to convert xml payloads into JSON. WSO2 ESB provides this support and refer http://docs.wso2.org/display/ESB481/JSON+Support for more details.

To convert an XML payload into JSON, we have to set the messageType property to application/json in synapse configuration.

Here I discuss about XML to JSON conversion when multiple attributes and elements available in the payload.

You may receive a soap request as follows:

SOAP Request:

 <soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/" xmlns:m0="http://services.samples" xmlns:xsd="http://services.samples/xsd">  
 <soapenv:Header/>  
 <soapenv:Body>  
 <m0:getQuote xmlns:m0="http://services.samples" id="12345">  
 <person sex="female" fn:target="urn:getQuote" xmlns:fn="abcdef" id="12345">  
 <firstname>Anna</firstname>  
 <lastname id="12345678">Smith</lastname>  
 </person>  
 <m0:request>  
 <m0:symbol>A</m0:symbol>  
 </m0:request>  
 </m0:getQuote>  
 </soapenv:Body>  
 </soapenv:Envelope>   

Person element contains multiple attributes sex, target, namespace and id.

i.e:  <person sex="female" fn:target="urn:getQuote" xmlns:fn="abcdef" id="12345">  

Also, lastnname is a sub element of person and it contains attribute as id and text content as "Smith"

i.e: <lastname id="12345678">Smith</lastname>

We will see how to covert such payload into json and its how the response looks like.

In ESB create a proxy service with SimpleStockQuote endpoint.

Proxy Service Configuration:

 <?xml version="1.0" encoding="UTF-8"?>  
 <proxy xmlns="http://ws.apache.org/ns/synapse"  
 name="XMLtoJSON"  
 transports="https,http"  
 statistics="disable"  
 trace="disable"  
 startOnLoad="true">  
 <target>  
 <inSequence>  
 <property name="messageType" value="application/json" scope="axis2"/>  
 <log level="full"/>  
 <respond/>  
 </inSequence>  
 <outSequence>  
 <send/>  
 </outSequence>  
 <endpoint>  
 <address uri="http://localhost:9000/services/SimpleStockQuoteService/"/>  
 </endpoint>  
 </target>  
 <description/>  
 </proxy>   

Note: 
For conversion, use "<property name="messageType" value="application/json" scope="axis2"/>" in the configuration as discussed above.

1. You have to start sample backend to receove response which is provided with WSO2 ESB. (Start axis2Service @ESB_HOME/samples/axis2Server)

2. Built SimpleStockQuote Service @ESB_HOME/samples/axis2Server/src/SimpleStockQuoteService by running "ant" command.

3. Send the SOAP request to proxy service using SOAP UI.

Response should be as follows:

 HTTP/1.1 200 OK  
 Host: shashi-ThinkPad-T530:8280  
 SOAPAction: "urn:getQuote"  
 Accept-Encoding: gzip,deflate  
 Content-Type: application/json  
 Date: Fri, 24 Jan 2014 06:00:54 GMT  
 Server: WSO2-PassThrough-HTTP  
 Transfer-Encoding: chunked  
 Connection: Keep-Alive  
 {"getQuote":{"@id":"12345","person":{"@id":"12345","@sex":"female","@target":"urn:getQuote","firstname":"Anna","lastname":{"@id":"12345678","$":"Smith"}},"request":{"symbol":"A"}}}  

Points to focus in response:

1. Content-Type should be 'application/json'

2. XML: 

<person sex="female" fn:target="urn:getQuote" xmlns:fn="abcdef" id="12345">  

JSON:

"person":{"@id":"12345","@sex":"female","@target":"urn:getQuote"

*** Attributes displayed with prefix '@' in JSON conversion. ("@id":"12345")

When nodes has text content as well as attributes, that text content is stored in a key with “$”

XML:

 <lastname id="12345678">Smith</lastname>  

JSON:

"lastname":{"@id":"12345678","$":"Smith"}

If a node has multiple children with the same tag name, they are converted into a numerically indexed array e.g. “person”
XML

 <person>Anvar</person>  
 <person>Porter</person>  
 <person>Raj</person>  

JSON

"person":["Anvar","Porter","Raj"]

SOAP request:

 <soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/" xmlns:m0="http://services.samples" xmlns:xsd="http://services.samples/xsd">  
 <soapenv:Header/>  
 <soapenv:Body>  
 <m0:getQuote xmlns:m0="http://services.samples" id="12345">  
 <person>Anvar</person>  
 <person>Porter</person>  
 <person>Raj</person>  
 <m0:request>  
 <m0:symbol>A</m0:symbol>  
 </m0:request>  
 </m0:getQuote>  
 </soapenv:Body>  
 </soapenv:Envelope>  

Response:

 HTTP/1.1 200 OK  
 Host: shashi-ThinkPad-T530:8280  
 SOAPAction: "urn:mediate"  
 Accept-Encoding: gzip,deflate  
 Content-Type: application/json  
 Date: Sun, 09 Feb 2014 02:49:07 GMT  
 Server: WSO2-PassThrough-HTTP  
 Transfer-Encoding: chunked  
 Connection: Keep-Alive  
 {"getQuote":{"@id":"12345","person":["Anvar","Porter","Raj"],"request":{"symbol":"A"}}}