Sample 451: Conditional URL Rewriting

Objective: Demonstrate the ability of the URL Rewrite mediator to evaluate conditions on messages and perform rewrites based on the results.

<definitions xmlns="http://ws.apache.org/ns/synapse">

    <sequence name="main">
        <in>
            <rewrite>
                <rewriterule>
                    <condition>
                        <and>
                            <equal type="url" source="host" value="localhost"/>
                            <not>
                                <equal type="url" source="protocol" value="https"/>
                            </not>
                        </and>
                    </condition>
                    <action fragment="protocol" value="https"/>
                    <action fragment="port" value="9002"/>
                </rewriterule>
            </rewrite>
            <send/>
        </in>
        <out>
            <send/>
        </out>
    </sequence>

</definitions>

Prerequisites:

• Deploy the SimpleStockQuoteService in sample Axis2 server and start it on port 9000.
• Start ESB with the sample configuration 451 (i.e. wso2esb-samples -sn 451).

Invoke the Axis2 client and send some requests to ESB with different address URL values. If the address URL value contains localhost as the hostname and https as the protocol prefix, ESB will route the message as it is. But if the hostname is localhost and the protocol is not https, Synapse will rewrite the URL by setting https as the protocol. The port number will also be set to the HTTPS port of the Axis2 server.

The condition evaluation feature is provided by the Synapse evaluator framework. Currently one can evaluate expressions on URL values, query parameters, transport headers, properties and SOAP envelope content using this framework. Hence URL rewriting can be done based on any of these aspects.