## Apache Synapse

## Sample 353: Using Ruby Scripts for Mediation

<definitions xmlns="http://ws.apache.org/ns/synapse"> <localEntry key="stockquoteScript" src="file:repository/conf/sample/resources/script/stockquoteTransform.rb"/> <sequence name="main"> <in> <!-- transform the custom quote request into a standard quote request expected by the service --> <script language="rb" key="stockquoteScript" function="transformRequest"/> <!-- send message to real endpoint referenced by name "stockquote" and stop --> <send> <endpoint name="stockquote"> <address uri="http://localhost:9000/services/SimpleStockQuoteService"/> </endpoint> </send> </in> <out> <!-- transform the standard response back into the custom format the client expects --> <script language="rb" key="stockquoteScript" function="transformResponse"/> <send/> </out> </sequence> </definitions>

The external script referenced by the configuration contains the following Ruby scriplet.

<x><![CDATA[ require 'rexml/document' include REXML def transformRequest(mc) newRequest= Document.new '<m:getQuote xmlns:m="http://services.samples">'<< '<m:request><m:symbol></m:symbol></m:request></m:getQuote>' newRequest.root.elements[1].elements[1].text = mc.getPayloadXML().root.elements[1].get_text mc.setPayloadXML(newRequest) end def transformResponse(mc) newResponse = Document.new '<m:CheckPriceResponse xmlns:m="http://www.apache-synapse.org/test"><m:Code>' << '</m:Code><m:Price></m:Price></m:CheckPriceResponse>' newResponse.root.elements[1].text = mc.getPayloadXML().root.elements[1].elements[1].get_text newResponse.root.elements[2].text = mc.getPayloadXML().root.elements[1].elements[2].get_text mc.setPayloadXML(newResponse) end ]]></x>

### Objective

The script mediator of Synapse can be programmed using any BSF compatible programming language. Sample 250 shows how to configure it using JavaScript. This sample shows how to configure the script mediator with Ruby.

### Pre-requisites

- This sample uses Ruby so first setup support for this in Synapse as described at Configuring JRuby
- Deploy the SimpleStockQuoteService in the sample Axis2 server and start Axis2
- Synapse does not ship with a Ruby engine by default. Therefore you should download the Ruby engine from JRuby site and copy the downloaded jar file to the 'lib' directory of Synapse.
- Start Synapse using the configuration numbered 353 (repository/conf/sample/synapse_sample_353.xml)
  Unix/Linux: sh synapse.sh -sample 353
  Windows: synapse.bat -sample 353

### Executing the Client

This sample is identical to sample 350 with the only difference being the use of Ruby instead of JavaScript. Use the stock quote client to send a custom quote request as follows.

ant stockquote -Daddurl=http://localhost:9000/services/SimpleStockQuoteService -Dtrpurl=http://localhost:8280/ -Dmode=customquote

The Ruby scriplets will transform the requests and responses as they flow through the service bus.

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