Chapter 29. 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 29.1, “Adding the camel-script dependency”.

Example 29.1. 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.script.ScriptBuilder.*;

Built-in attributes

Table 29.1, “Ruby attributes” lists the built-in attributes that are accessible when using Ruby.

Table 29.1. Ruby attributes

AttributeTypeValue

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

Example 29.2. 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 Properties in the Apache Camel Component Reference Guide.