Generate a file using the request payload and send to a backend via WSO2 ESB

Let's say WSO2 ESB receives an request with a payload, and we need to create a file using that payload content and send that file to a endpoint.

Here's the required proxy cofiguration.

	<proxy name="testProxy" transports="https http" startOnLoad="true" trace="disable">
	<description/>
	<target inSequence="testProxy_in" outSequence="testProxy_out"/>
	</proxy>

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This sequence builds the message as a multipart/form-data and send it to the endpoint.

	<sequence xmlns="http://ws.apache.org/ns/synapse" name="testProxy_in">
	<property name="HTTP_METHOD" value="POST" scope="axis2" type="STRING"></property>
	<property name="messageType" value="multipart/form-data" scope="axis2" type="STRING"></property>
	<payloadFactory media-type="xml">
	<format>
	<text xmlns="http://ws.apache.org/commons/ns/payload">$1</text>
	</format>
	<args>
	<arg xmlns:ns="http://org.apache.synapse/xsd" expression="$body/*" evaluator="xml"></arg>
	</args>
	</payloadFactory>
	<log level="full" separator="testProxy In Sequence, "></log>
	<send>
	<endpoint key="fileUploadEndpoint"></endpoint>
	</send>
	</sequence>

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If you want to customise MultipartFormDataFormatter, write your own class extending MultipartFormDataFormatter.

Configure it in WSO2_ESB/repository/conf/axis2/axis2.xml file as follows.

	<messageFormatters>
	<messageFormatter contentType="application/x-www-form-urlencoded"
	class="org.apache.axis2.transport.http.XFormURLEncodedFormatter"/>
	<messageFormatter contentType="multipart/form-data"
	class="org.wso2.custom.CustomMultipartFormDataFormatter"/>

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This org.wso2.custom.CustomMultipartFormDataFormatter sets the file name as filename.xml, Content-Type as text/xml and payload as the content of the file

	package com.wso2.custom;
	import org.apache.axiom.om.OMAbstractFactory;
	import org.apache.axiom.om.OMElement;
	import org.apache.axiom.om.OMFactory;
	import org.apache.axiom.om.OMOutputFormat;
	import org.apache.axis2.AxisFault;
	import org.apache.axis2.context.MessageContext;
	import org.apache.axis2.transport.http.MultipartFormDataFormatter;
	import org.apache.commons.httpclient.methods.multipart.FilePart;
	import org.apache.commons.httpclient.methods.multipart.FilePartSource;
	import org.apache.commons.httpclient.methods.multipart.Part;
	import org.apache.commons.httpclient.methods.multipart.StringPart;
	import org.apache.commons.io.FileUtils;
	import java.io.ByteArrayOutputStream;
	import java.io.File;
	import java.io.IOException;
	import java.util.ArrayList;
	import java.util.Iterator;
	public class CustomMultipartFormDataFormatter extends MultipartFormDataFormatter {
	@Override
	public byte[] getBytes(MessageContext messageContext, OMOutputFormat format) throws AxisFault {
	OMElement omElement = messageContext.getEnvelope().getBody().getFirstElement();
	Part[] parts = createMultipatFormDataRequest(omElement);
	if (parts.length > 0) {
	ByteArrayOutputStream bytesOut = new ByteArrayOutputStream();
	try {
	// This is accessing a class of Commons-FlieUpload
	Part.sendParts(bytesOut, parts, format.getMimeBoundary().getBytes());
	} catch (IOException e) {
	throw AxisFault.makeFault(e);
	}
	return bytesOut.toByteArray();
	}
	return new byte[0]; //To change body of implemented methods use File | Settings | File Templates.
	}
	private Part[] createMultipatFormDataRequest(OMElement dataOut) {
	ArrayList parts = new ArrayList();
	if (dataOut != null) {
	Iterator iter1 = dataOut.getChildElements();
	OMFactory omFactory = OMAbstractFactory.getOMFactory();
	while (iter1.hasNext()) {
	OMElement ele = (OMElement) iter1.next();
	Iterator iter2 = ele.getChildElements();
	// check whether the element is a complex type
	if (iter2.hasNext()) {
	OMElement omElement = ele.cloneOMElement();
	try {
	File file = new File("filename.xml");
	FileUtils.writeStringToFile(file, omElement.toString());
	parts.add(new FilePart("xmlfile", new FilePartSource(file), "text/xml", "UTF-8"));
	} catch (IOException ex) {
	}
	} else {
	parts.add(new StringPart(ele.getQName().getLocalPart(), ele.getText()));
	}
	}
	}
	Part[] partsArray = new Part[parts.size()];
	return (Part[]) parts.toArray(partsArray);
	}
	}

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