4.5. Swagger Integration

Overview

Integrated with the REST DSL, the camel-swagger component enables users to create API docs for any REST-defined routes and endpoints in a CamelContext file. The camel-swagger component creates a servlet integrated with the CamelContext that pulls the information from each REST endpoint to generate the API docs (JSON file).
If using Maven, you need to add the camel-swagger component to your pom.xml file: 
<dependency>
   <groupId>org.apache.camel</groupId>
   <artifactId>camel-swagger</artifactId>
   <version>x.x.x</version>
   <!-- Use the same version as your Camel core version --> 
</dependency>

Configuring the camelContext

To enable Swagger, add to the CamelContext file:
  • The service element, which exposes the camel-swagger servlet and initializes its parameters.
    In the service element, add the servlet (org.apache.camel.component.swagger.DefaultCamelSwaggerServlet) and the service-properties that configure the servlet's parameters.
    For details on servlet parameters, see chapter "Swagger" in "Apache Camel Component Reference".
  • Configure the REST implementation
    Define the REST service within the camelContext element using the restConfiguration and rest elements.
    For details on configuring REST services in the CamelContext, see Section 4.2, “Defining Services with REST DSL”.
For OSGi deployments, you need to configure the servlet options
 and REST configuration in the blueprint.xml file; for example: 
<?xml version="1.0" encoding="UTF-8"?>
<blueprint xmlns="http://www.osgi.org/xmlns/blueprint/v1.0.0"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="
             http://www.osgi.org/xmlns/blueprint/v1.0.0 
             http://www.osgi.org/xmlns/blueprint/v1.0.0/blueprint.xsd
             http://camel.apache.org/schema/blueprint 
             http://camel.apache.org/schema/blueprint/camel-blueprint.xsd">

    <service interface="javax.servlet.http.HttpServlet">
        <service-properties>
            <entry key="alias" value="/api-docs/*"/>
            <entry key="init-prefix" value="init."/>
            <entry key="init.base.path" value="//localhost:8080/"/>
            <entry key="init.api.path" value="//localhost:8181/api-docs"/>
            <entry key="init.api.title" value="Camel Rest Example API"/>
            <entry key="init.api.version" value="1.2"/>
            <entry key="init.api.description"
                value="Camel Rest Example with Swagger that provides an User REST service"/>
        </service-properties>
        <bean class="org.apache.camel.component.swagger.DefaultCamelSwaggerServlet" />
    </service>

    
    <camelContext id="log-example-context"
        xmlns="http://camel.apache.org/schema/blueprint">

        <restConfiguration component="jetty" port="8080"/>
        <rest path="/say">
            <get uri="/hello">
                <to uri="direct:hello"/>
            </get>
            <get uri="/bye" consumes="application/json">
                <to uri="direct:bye"/>
            </get>
            <post uri="/bye">
                <to uri="mock:update"/>
            </post>
        </rest>
        <route id="rte1-log-example">
            <from uri="direct:hello"/>
            <transform>
                <constant>Hello World</constant>
            </transform>
        </route>
        <route id="rte2-log-example">
            <from uri="direct:bye"/>
            <transform>
                <constant>Bye World</constant>
            </transform>
        </route>

    </camelContext>

</blueprint>
The following parameters are used in the above example as described here:
service
The service element exposes the camel swagger servlet (<bean class="org.apache.camel.component.swagger.DefaultCamelSwaggerServlet"/>) and initializes several servlet properties.
alias
The alias property binds the camel swagger servlet to /api-docs/*.
init-prefix
The init-prefix property sets the prefix for all camel swagger servlet properties to init.. This is analogous to using init-param elements in the web.xml configuration for WAR implementations (see chapter "Swagger" in "Apache Camel Component Reference").
restConfiguration
In the camelContext element, the restConfiguration element specifies the REST implementation to use. In this case, it is Jetty web servlet on port 8080.
rest
In the camelContext element, the rest element defines a REST service and provides the base path (/say) to it. In this case, the service consists of two REST endpoints, hello and bye, which are routed to their corresponding camel endpoints defined in the route elements.