Chapter 51. Extending JAX-RS Endpoints with Swagger Support

Abstract

CXF includes a SwaggerFeature (org.apache.cxf.jaxrs.swagger.SwaggerFeature), which extends published JAX-RS endpoints with support for Swagger. Swagger is fundamentally a JSON-based format used to describe RESTful services, like its predecessors WSDL and WADL, but much easier to use. For a detailed description, see Swagger.
The SwaggerFeature is supported in both standalone CXF and in JBoss Fuse implementations.

51.1. Standalone CXF Implementations

Overview

This section describes how to use the SwaggerFeature in a standalone CXF implementation, in which REST services are defined inside WAR files and deployed to a standalone web server, such as Tomcat.
Note
The project should be a Maven WAR project. After building and packaging it, you can deploy it to Tomcat by dropping the WAR file into the $TOMCAT_HOME/webapps directory.

Enabling Swagger

Enabling Swagger involves:
  • Modifying the XML file that defines the CXF service by adding the CXF class org.apache.cxf.jaxrs.swagger.SwaggerFeature to the <jaxrs:server> definition:
    <jaxrs:server id="xx" address="/address" />
        <jaxrs:features>
            <bean class="org.apache.cxf.jaxrs.swagger.SwaggerFeature"/>
        </jaxrs:features>
    </jaxrs:server>
    
    See Example 51.1, “Example Swagger-enabled Spring configuration ” for an example of a Spring XML file for a Swagger-enabled CXF service.
  • In the REST resource class:
    • Importing the Swagger API annotations for each annotation required by the service:
      import com.wordnik.swgger.annotations.Api*
      where * = Api, ApiOperation, ApiParam, ApiResponse, ApiResponses, and so on.
    • Adding Swagger annotations to the JAX-RS annotated endpoints (@PATH, @PUT, @POST, @GET, @Produces, @Consumes, @DELETE, @PathParam, and so on).
      See Example 51.2, “Example REST resource with Swagger annotations” for an example of a Swagger-annotated REST resource class.

Configuration examples

Example 51.1. Example Swagger-enabled Spring configuration

<beans
xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:jaxrs="http://cxf.apache.org/jaxrs"
xsi:schemaLocation="
	http://www.springframework.org/schema/beans  
	http://www.springframework.org/schema/beans/spring-beans.xsd
	http://cxf.apache.org/jaxrs http://cxf.apache.org/schemas/jaxrs.xsd">

        <jaxrs:server id="customerService" address="/crm">
           <jaxrs:serviceBeans>
               <ref component-id="customerSvc"/>
           </jaxrs:serviceBeans>
           <jaxrs:providers>
               <bean class="com.fasterxml.jackson.jaxrs.json.JacksonJsonProvider" />
           </jaxrs:providers>
           <jaxrs:features>
               <!-- include Swagger Feature -->
               <bean class=“org.apache.cxf.jaxrs.swagger.SwaggerFeature” />
           </jaxrs:features>
       </jaxrs:server>

	</beans>
This example shows only the relevant parts of a Swagger-annotated REST resource class.

Example 51.2. Example REST resource with Swagger annotations

...
                
import javax.annotation.Resource;
import javax.ws.rs.core.Context;
import javax.ws.rs.Consumes;
import javax.ws.rs.DELETE;
import javax.ws.rs.GET;
import javax.ws.rs.POST;
import javax.ws.rs.PUT;
import javax.ws.rs.Path;
import javax.ws.rs.PathParam;
import javax.ws.rs.Produces;
import javax.ws.rs.core.Response;

import com.wordnik.swagger.annotations.Api;
import com.wordnik.swagger.annotations.ApiOperation;
import com.wordnik.swagger.annotations.ApiParam;
import com.wordnik.swagger.annotations.ApiResponses;
import com.wordnik.swagger.annotations.ApiResponse;

…

@Path("/customerservice/")
@Api(value = "/customerservice", description = "Operations about customerservice")
public class CustomerService {

    private static final Logger LOG = LoggerFactory.getLogger(CustomerService.class);

    long currentId = 123;
    Map<Long, Customer> = customers = new HashMap<Long, Customer>();
    Map<Long, Order> orders = new HashMap<Long, Order>();
    private MessageContext jaxrsContext;

    public CustomerService() {
        init();
    }

   @GET
    @Path("/customers/{id}/")
    @Produces("application/xml")
    @ApiOperation(value = "Find Customer by ID", notes = "More notes about this method", response = Customer.class)
    @ApiResponses(value = {
            @ApiResponse(code = 500, message = "Invalid ID supplied"),
            @ApiResponse(code = 204, message = "Customer not found")
            })
    public Customer getCustomer(@ApiParam(value = "ID of Customer to fetch", required = true) @PathParam("id") String id) {
        LOG.info("Invoking getCustomer, Customer id is: {}", id);
        long idNumber = Long.parseLong(id);
        Customer c = customers.get(idNumber);
        return c;
    }

    @PUT
    @Path("/customers/")
    @Consumes({ "application/xml", "application/json" })
    @ApiOperation(value = "Update an existing Customer")
    @ApiResponses(value = {
            @ApiResponse(code = 500, message = "Invalid ID supplied"),
            @ApiResponse(code = 204, message = "Customer not found")
            })
    public Response updateCustomer(@ApiParam(value = "Customer object that needs to be updated", required = true) Customer customer) {
        LOG.info("Invoking updateCustomer, Customer name is: {}", customer.getName());
        Customer c = customers.get(customer.getId());
        Response r;
        if (c != null) {
            customers.put(customer.getId(), customer);
            r = Response.ok().build();
        } else {
            r = Response.notModified().build();
        }

        return r;
    }

    @POST
    @Path("/customers/")
    @Consumes({ "application/xml", "application/json" })
    @ApiOperation(value = "Add a new Customer")
    @ApiResponses(value = { @ApiResponse(code = 500, message = "Invalid ID supplied"), })
    public Response addCustomer(@ApiParam(value = "Customer object that needs to be updated", required = true) Customer customer) {
        LOG.info("Invoking addCustomer, Customer name is: {}", customer.getName());
        customer.setId(++currentId);

        customers.put(customer.getId(), customer);
        if (jaxrsContext.getHttpHeaders().getMediaType().getSubtype().equals("json")) {
            return Response.ok().type("application/json").entity(customer).build();
        } else {
            return Response.ok().type("application/xml").entity(customer).build();
        }
    }
   
    @DELETE
    @Path("/customers/{id}/")
    @ApiOperation(value = "Delete Customer")
    @ApiResponses(value = {
            @ApiResponse(code = 500, message = "Invalid ID supplied"),
            @ApiResponse(code = 204, message = "Customer not found")
            })
    public Response deleteCustomer(@ApiParam(value = "ID of Customer to delete", required = true) @PathParam("id") String id) {
        LOG.info("Invoking deleteCustomer, Customer id is: {}", id);
        long idNumber = Long.parseLong(id);
        Customer c = customers.get(idNumber);

     …   
}