Chapter 19. JavaScript
Overview
JavaScript, also known as ECMAScript is a Java-based scripting language that allows quick parsing of object. The JavaScript support is part of the
camel-script module.
Adding the script module
To use JavaScript in your routes you need to add a dependency on
camel-script to your project as shown in Example 19.1, “Adding the camel-script dependency”.
Example 19.1. Adding the camel-script dependency
<!-- Maven POM File -->
<properties>
<camel-version>2.17.0.redhat-630xxx</camel-version>
...
</properties>
<dependencies>
...
<dependency>
<groupId>org.apache.camel</groupId>
<artifactId>camel-script</artifactId>
<version>${camel-version}</version>
</dependency>
...
</dependencies>Static import
To use the
javaScript() static method in your application code, include the following import statement in your Java source files:
import static org.apache.camel.builder.script.ScriptBuilder.*;
Built-in attributes
Table 19.1, “JavaScript attributes” lists the built-in attributes that are accessible when using JavaScript.
| Attribute | Type | Value |
|---|---|---|
context | org.apache.camel.CamelContext | The Camel Context |
exchange | org.apache.camel.Exchange | The current Exchange |
request | org.apache.camel.Message | The IN message |
response | org.apache.camel.Message | The OUT message |
properties | org.apache.camel.builder.script.PropertiesFunction | Function with a resolve method to make it easier to use the properties component inside scripts. |
The attributes all set at
ENGINE_SCOPE.
Example
Example 19.2, “Route using JavaScript” shows a route that uses JavaScript.
Example 19.2. Route using JavaScript
<camelContext>
<route>
<from uri="direct:start"/>
<choice>
<when>
<langauge langauge="javaScript">request.headers.get('user') == 'admin'</langauge>
<to uri="seda:adminQueue"/>
</when>
<otherwise>
<to uri="seda:regularQueue"/>
</otherwise>
</choice>
</route>
</camelContext>Using the properties component
To access a property value from the properties component, invoke the
resolve method on the built-in properties attribute, as follows:
.setHeader("myHeader").javaScript("properties.resolve(PropKey)")
Where PropKey is the key of the property you want to resolve, where the key value is of
String type.
For more details about the properties component, see Properties in the Apache Camel Component Reference Guide.
