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ScriptContext Options

The JSR-223 scripting language's ScriptContext is pre-configured with the following attributes all set at ENGINE_SCOPE.

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You can provide additional arguments to the ScriptingEngine using a header on the Camel message with the key CamelScriptArguments.

Example:{snippet:id=e1|lang=java|url=camel/trunk/components/camel-script/src/test/java/org/apache/camel/builder/script/JavaScriptExpressionTest.java}

public void testArgumentsExample() throws Exception {
    getMockEndpoint("mock:result").expectedMessageCount(0);
    getMockEndpoint("mock:unmatched").expectedMessageCount(1);

    // additional arguments to ScriptEngine
    Map<String, Object> arguments = new HashMap<>();
    arguments.put("foo", "bar");
    arguments.put("baz", 7);

    // those additional arguments is provided as a header on the Camel Message
    template.sendBodyAndHeader("direct:start", "hello", ScriptBuilder.ARGUMENTS, arguments);

    assertMockEndpointsSatisfied();


 

Using Properties Function

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If you need to use the Properties component from a script to lookup property placeholders, then its a bit cumbersome to do so. For example, to set a header name myHeader with a value from a property placeholder, whose key is taken from a header named foo.

.setHeader("myHeader").groovy("context.resolvePropertyPlaceholders('{{' + request.headers.get('foo') + '}}')")

From Camel 2.9: you can now use the properties function and the same example is simpler:

.setHeader("myHeader").groovy("properties.resolve(request.headers.get('foo'))")

Loading Script From External Resource

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You can externalize the script and have Camel load it from a resource such as classpath:, file:, or http:. This is done using the following syntax: resource:scheme:location e.g. to refer to a file on the classpath you can do:

.setHeader("myHeader").groovy("resource:classpath:mygroovy.groovy")

How to Get the Result from Multiple Statements Script

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The script engine's eval method returns a null when it runs a multi-statement script. However, Camel can look up the value of a script's result by using the key result from the value set. When writing a multi-statement script set the value of the result variable as the script return value.

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textbar = "baz"; # some other statements ... # camel take the result value as the script evaluation result result = body * 2 + 1

Dependencies

To use scripting languages in your camel routes you need to add the a dependency on camel-script which integrates the JSR-223 scripting engine.

If you use maven you could just add the following to your pom.xml, substituting the version number for the latest & greatest release (see the download page for the latest versions).

<dependency>
 <groupId>org.apache.camel</groupId>
 <artifactId>camel-script</artifactId>
 <version>x.x.x</version>
</dependency>