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Chapter 28. Ruby

Overview

Ruby is a dynamic, open source programming language with a focus on simplicity and productivity. It has an elegant syntax that is natural to read and easy to write. The Ruby support is part of the camel-script module.

Adding the script module

To use Ruby in your routes you need to add a dependency on camel-script to your project as shown in Example 28.1, “Adding the camel-script dependency”.

Example 28.1. Adding the camel-script dependency

<!-- Maven POM File -->
...
<dependencies>
  ...
  <dependency>
    <groupId>org.apache.camel</groupId>
    <artifactId>camel-script</artifactId>
    <version>${camel-version}</version>
  </dependency>
  ...
</dependencies>

Static import

To use the ruby() static method in your application code, include the following import statement in your Java source files: 
import static org.apache.camel.builder.camel.script.ScriptBuilder.*;

Built-in attributes

Table 28.1, “Ruby attributes” lists the built-in attributes that are accessible when using Ruby.

Table 28.1. Ruby attributes

AttributeTypeValue
contextorg.apache.camel.CamelContextThe Camel Context
exchangeorg.apache.camel.ExchangeThe current Exchange
requestorg.apache.camel.MessageThe IN message
responseorg.apache.camel.MessageThe OUT message
propertiesorg.apache.camel.builder.script.PropertiesFunctionFunction with a resolve method to make it easier to use the properties component inside scripts.
The attributes all set at ENGINE_SCOPE.

Example

Example 28.2, “Route using Ruby” shows a route that uses Ruby.

Example 28.2. Route using Ruby

<camelContext>
  <route>
    <from uri="direct:start"/>
    <choice>
      <when>
        <langauge langauge="ruby">$request.headers['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").ruby("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 chapter "Properties" in "Apache Camel Component Reference".