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ScriptContext Options

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

Attributes

You can add your own attributes with the attribute(name, value) DSL method, such as:

In the sample below we add an attribute user that is an object we already have instantiated as myUser. This object has a getFirstName() method that we want to set as header on the message. We use the groovy language to concat the first and last name into a single string that is returned.

...

from("direct:in").setHeader("name").groovy("'$user.firstName $user.lastName'").attribute("user", myUser).to("seda:users");

Any scripting language

Camel can run any JSR-223 scripting languages using the script DSL method such as:

...

from("direct:in").setHeader("firstName").script("jaskel", "user.firstName").attribute("user", myUser).to("seda:users");

This is a bit different using the Spring DSL where you use the expression element that doesn't support setting attributes (yet):

...

    <from uri="direct:in"/>
    <setHeader headerName="firstName">
        <expression language="jaskel">user.firstName</expression>
    </setHeader>
    <to uri="seda:users"/>

See Scripting Languages for the list of languages with explicit DSL support.

Passing Additional Arguments to the ScriptingEngine

Available from Camel 2.8

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

Example:

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

Available from

You can also use predicates e.g. in a Filter:

...

    <filter>
        <language language="beanshell">request.getHeaders().get("Foo").equals("Bar")</language>
        <to uri="direct:next" />
    </filter>

See Scripting Languages for the list of languages with explicit DSL support.

Some languages without specific DSL support but known to work with these generic methods include:

Additional arguments to ScriptingEngine

Available as of Camel 2.8

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

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

Using properties function

Available as of Camel 2.9

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 name myHeader with a value from a property placeholder, which whose key is provided in taken from a header named "foo".

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

From Camel 2.9 onwards : 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

Available from Camel 2.11

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

Available from Camel 2.14

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.

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>