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Chapter 27. Python
Overview
Python is a remarkably powerful dynamic programming language that is used in a wide variety of application domains. Python is often compared to Tcl, Perl, Ruby, Scheme or Java. The Python support is part of the
camel-script module.
Adding the script module
To use Python in your routes you need to add a dependency on
camel-script to your project as shown in Example 27.1, “Adding the camel-script dependency”.
Example 27.1. 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
python() 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 27.1, “Python attributes” lists the built-in attributes that are accessible when using Python.
| Attribute | Type | Value |
|---|---|---|
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 27.2, “Route using Python” shows a route that uses Python.
Example 27.2. Route using Python
<camelContext>
<route>
<from uri="direct:start"/>
<choice>
<when>
<langauge langauge="python">if request.headers.get('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").python("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".
