URLRewrite Mediator

The URLRewrite Mediator is used to modify and transform the URL values available in messages. This can be done by defining a rewrite action for each fragment of a selected property value. Alternatively, you can rewrite the entire URL string at once.

The URLRewrite mediator is a content aware mediator.

Syntax

<rewrite [inProperty="string"] [outProperty="string"]>
    <rewriterule>
        <condition>
        ...
        </condition>?
        <action [type="append|prepend|replace|remove|set"] [value="string"]
          [xpath="xpath"] [fragment="protocol|host|port|path|query|ref|user|full"] [regex="regex"]>+
    </rewriterule>+
</rewrite>

UI Configuration

The parameters available to configure the URL Rewrite mediator are as follows.

Parameter Name	Description
In Property	This parameter is used to enter property of which the value should be considered the input URL. The rewrite rules are applied to the value of the property entered in this parameter to generate the result URL. If no property is entered, the rewrite rules will be applied to the `To` header of the message.
Out Property	This parameter is used to enter the property to which the transformations done via the rewrite rules should be applied. If no property is entered, the transformations will be applied to the `To` header of the message.

The Rewrite mediator applies the URL transformations by evaluating a set of rules on the message. To add a rule to the mediator, click Add Rule. The rewrite rule will be added to the mediator tree as a child of the URLRewrite mediator (see the image below).

Click URLRewriteRule in the mediator tree to configure the rewrite rule you added. The following section will be displayed.

A rule can consist of one or more rewrite actions and an optional condition. The Condition parameter is used to enter the optional condition. If a condition is specified, it will be evaluated before the rewrite actions, and the rewrite actions will be executed only if the condition evaluates to true.

A rewrite action is added by clicking Add Action which would display the following row.

The parameters available to configure a rewrite action are as follows.

Parameter Name	Description
Action	This parameter is used to specify the action to be performed by the rewrite action. Each rewrite action is performed on a fragment entered in the Fragment parameter. Possible values are as follows. Replace: If this is selected, the existing in property value fragment will be replaced by the result value. Remove: If this is selected, the result value will be removed from the in property value fragment. Append: If this is selected, the result value will be added to the end of the in property value fragment. Prepend: If this is selected, the result value will be added to the beginning of the in property value fragment. Set: If this is selected, the result value will be set as the in property value fragment.
Fragment	The fragment of the in property (i.e. input URL) for which the rewrite action should be performed. The available fragments are as follows. Protocol: Host Port Path Query Ref User Full Note that this breakdown is inline with the URI specification (RFC2396). URL rewrite mediator enables rewriting each of the above segments separately and finally combining them to get the final URL value. It also supports rewriting the entire URL string at once.
Option	This parameter is used to define the result value of the rewrite action. Select one of the following. Value: If this is selected, the result value would be a static value. Expression: If this is selected, the result value will be evaluated using an expression.
Value/Expression	This parameter is used to enter the result value of the URLRewrite mediator as a static value or an expression, depending on what you selected for the Option parameter.
Namespace Editor	You can click this link to add namespaces when you are providing an expression. Then the Namespace Editor panel would appear where you can provide any number of namespace prefixes and URLs used in the XPath expression.
Regex	This parameter is used to specify which part of the in property value fragment should be replaced by the result value if you selected `Replace` for the Action parameter.
Delete	Click Delete in the relevant row to remove a rewrite action.

Note

You can configure the mediator using XML. Click switch to source view in the Mediator window.

Example

In this example, the URLRewrite mediator has a rewrite action which replaces the value soap with value services in the fragment path of the input URL. Since no in property or an out property is specified, the To header of the request is both the input to which the rewrite rule is applied and the target where the result URL is set. This configuration is typically used when the address URL of a request contains the context soap which needs to be converted since all the services are deployed under a context named services in the ESB server. Thus, the URL http://localhost:8280/soap/StockQuoteProxy1 is rewritten as http://localhost:8280/services/StockQuoteProxy1 to ensure that the requests are successfully delivered to the server.

<rewrite>
	<rewriterule>
		<action type="replace" regex="soap" value="services" fragment="path" />
	</rewriterule>
</rewrite>

Samples

For more examples, see: