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h2. UrlRewrite Component
*Available as of Camel 2.11*

The {{camel-urlrewrite}} component allows to plugin url rewrite functionality to [HTTP], [HTTP4], [Jetty], or [AHC] components. This component integrates the [UrlRewriteFilter|http://code.google.com/p/urlrewritefilter/] project with Apache Camel. This allows you to use the capabilities from the url rewrite project with your Camel routes.

This component *requires* that your Camel routes starts from a servlet based endpoint such as [Jetty] or [Servlet].

h3. Options

The {{camel-urlrewrite}} component offers the following options

{div:class=confluenceTableSmall}
|| Name || Default Value || Description ||
| {{conf}} | {{null}} | To use a custom {{org.tuckey.web.filters.urlrewrite.Conf}} as the configuration for the url rewrite filter. |
| {{configFile}} | {{null}} | Refers to a file name to load as the configuration file. The file should be XML file. |
| {{modRewriteConfFile}} | {{null}} | Refers to a file name to load as the Apache mod_rewrite style based configuration file. This file should be a plain text file. |
| {{modRewriteConfText}} | {{null}} | Is used to quickly configure a Apache mod_rewrite style based configuration without using a file. |
| {{useQueryString}} | {{false}} | Whether to use query strings in the url rewrite rules. |
| {{useContext}} | {{false}} | Whether to include context-path or not in the matching. Will be default remove the context-path. |
| {{defaultMatchType}} | {{"regex"}} | Which match type to use. Can be either "wildcard" or "regex". |
| {{decodeUsing}} | {{null}} | To use a specific encoding such as "utf-8" or "iso-8859-1". |
{div}

h3. Usage

The following component producers supports using together with the {{camel-urlrewrite}} component: [Http], [Http4] [Jetty].

{div:class=confluenceTableSmall}
|| Component || Class ||
| {{camel-http}} | {{org.apache.camel.component.urlrewrite.http.HttpUrlRewrite}} |
| {{camel-jetty}} | {{org.apache.camel.component.urlrewrite.http.HttpUrlRewrite}} |
| {{camel-http4}} | {{org.apache.camel.component.urlrewrite.http4.HttpUrlRewrite}} |
{div}

You setup the url rewrite as a bean of the type {{org.apache.camel.component.urlrewrite.http.HttpUrlRewrite}} (when using [Http] component) as shown below:
{snippet:id=e1|lang=java|url=camel/trunk/components/camel-urlrewrite/src/test/java/org/apache/camel/component/urlrewrite/jetty/JettyUrlRewriteTest.java}

And in XML DSL you can do:
{code:xml}
<bean id="myRewrite" class="org.apache.camel.component.urlrewrite.HttpUrlRewrite">
  <property name="configFile" value="example/urlrewrite2.xml"/>
</bean>
{code}

In the bean above we configure it with the {{configFile}} option which is a XML [UrlRewriteFilter|http://code.google.com/p/urlrewritefilter/] configuration file.
{snippet:id=e1|lang=xml|url=camel/trunk/components/camel-urlrewrite/src/test/resources/example/urlrewrite2.xml}

{tip}
See more details at [UrlRewriteFilter|http://code.google.com/p/urlrewritefilter/] for how to configure the XML rules file.
{tip}

In the Camel routes, you bridge the endpoints, and refer to the url rewrite on the producer endpoint as shown below. Notice how we refer to our url rewrite filter using the {{urlRewrite}} option in the endpoint uri.
{snippet:id=e2|lang=java|url=camel/trunk/components/camel-urlrewrite/src/test/java/org/apache/camel/component/urlrewrite/jetty/JettyUrlRewriteTest.java}

h4. Using Apache mod_rewrite style configuration

The [UrlRewriteFilter|http://code.google.com/p/urlrewritefilter/] project also supports Apache mod_rewrite style configuration. 

For example to configure the bean using the modRewriteConfFile property to refer to a mod configuration file:
{code:xml}
<bean id="myRewrite" class="org.apache.camel.component.urlrewrite.HttpUrlRewrite">
  <property name="modRewriteConfFile" value="example/modrewrite.cxf"/>
</bean>
{code}

Which then can contain mod rewrite rules and the likes:
{snippet:e1|lang=none|url=camel/trunk/components/camel-urlrewrite/src/test/resources/example/modrewrite.cfg}

You can have multiple RewriteRule rules and other configurations. See more details at [UrlRewriteFilter|http://code.google.com/p/urlrewritefilter/] project.


h3. Writing custom url rewriters

You can implement your custom url rewriters by implementing either of the following interfaces from the component of choice:

Component(s): camel-http / camel-jetty
- {{org.apache.camel.component.http.UrlRewrite}}
- {{org.apache.camel.component.http.HttpServletUrlRewrite}}

Component(s): camel-http4
- {{org.apache.camel.component.http4.UrlRewrite}}
- {{org.apache.camel.component.http4.HttpServletUrlRewrite}}

The former is a simple and generic interface, which is not dependent on the Servlet API.
The later is servlet based which requires the Camel route to start from a servlet based component such as [Jetty] or [Servlet]. The servlet based is more feature rich and that's the API we use to integrate with the [UrlRewriteFilter|http://code.google.com/p/urlrewritefilter/] project in this {{camel-urlrewrite}} component.

h4. A simple url rewrite filter

In this example we implement a custom {{org.apache.camel.component.http.UrlRewrite}} that just replaces yahoo with google. Mind this example is based on a unit test, and only for demonstration purposes. As its java code you have full power to implement more complex logic.

The url parameter contains the full url including scheme://hostname:port/path?query. The relativeUrl parameter is the url without the endpoint configured path. Notice this option may be null if the url doesn't start with the endpoint configured path. 

{snippet:id=e1|lang=java|url=camel/trunk/components/camel-http/src/test/java/org/apache/camel/component/http/GoogleUrlRewrite.java}


{include:Endpoint See Also}
- [Jetty]
- [Http4]
- [Http]
- [AHC]