ScriptContext
Options
The The JSR-223
scripting languages language's ScriptContext
is pre-configured with the following attributes all set at ENGINE_SCOPE
:.
Attribute | Type | Value |
---|---|---|
|
| The Camel Context. |
|
| The Camel Context (cannot be used in groovy). |
|
| The current Exchange. |
|
| Camel 2.9: Function with a |
|
| The The |
|
| The OUT message |
You can add your own attributes with the attribute(name, value)
DSL method, such as:
Example
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.
Deprecated: The |
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:
Code Block | ||
---|---|---|
| ||
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 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 myHeader
with a value from a property placeholder, whose key is taken from a header named foo
.
Code Block | ||
---|---|---|
| ||
.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:
Code Block | ||
---|---|---|
| ||
.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:
Code Block | ||
---|---|---|
| ||
.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).
Code Block | ||
---|---|---|
| ||
<dependency>
<groupId>org.apache.camel</groupId>
<artifactId>camel-script</artifactId>
<version>x.x.x</version>
</dependency> | ||
Code Block | ||
java | java |
from("direct:in").setHeader("name").groovy("'$user.firstName $user.lastName'").attribute("user", myUser").to("seda:users");
|