Chapter 54. Extending JAX-RS Endpoints with OpenAPI Support Abstract The CXF OpenApiFeature ( org.apache.cxf.jaxrs.openapi.OpenApiFeature ) allows you to generate OpenAPI documents by extending published JAX-RS service endpoints with a simple configuration. The OpenApiFeature is supported in both Spring Boot and Karaf implementations. 54.1. OpenApiFeature options You can use the following options in OpenApiFeature. Table 54.1. OpenApiFeature operations Name Description Default configLocation The OpenAPI configuration location null contactEmail The contact email+ null contactName The contact name+ null contactUrl The contact link+ null customizer The customizer class instance null description The description+ null filterClass A security filter++ null ignoredRoutes Excludes specific paths when scanning all resources (see scanAllResources )++ null license The license+ null licenseUrl The license URL+ null prettyPrint When generating openapi.json, pretty-print the JSON document++ true propertiesLocation The properties file location /swagger.properties readAllResources Read all operations also with no @Operation++ true resourceClasses A list of resource classes which must be scanned++ null resourcePackages A list of package names where resources must be scanned++ null runAsFilter Runs the feature as a filter false scan Scan all JAX-RS resources automatically true scanKnownConfigLocations Scan known OpenAPI configuration location (classpath or filesystem), which are: true scannerClass The name of the JAX-RS API scanner class, used to scope the application, resource packages, resource classes and classpath scanning, please refer to Resource Scanning section null securityDefinitions A list of security definitions+ null supportSwaggerUi Turns on/off SwaggerUI support null (== true) swaggerUiConfig Swagger UI configuration null swaggerUiMavenGroupAndArtifact The Maven artifacts to pinpoint SwaggerUI null swaggerUiVersion The version of SwaggerUI null termsOfServiceUrl The terms of service URL+ null title The title+ null useContextBasedConfig If set, the unique Context Id is going to be generated for each OpenApiContext instance (please see Using Multiple Server Endpoints ). Also, you may want to set scan property to false. false version The version+ null + The option is defined in the OpenAPI class ++ The option is defined in the SwaggerConfiguration class 54.2. Karaf Implementations This section describes how to use the OpenApiFeature in which REST services are defined inside JAR files and deployed to a Fuse on Karaf container. 54.2.1. Quickstart example You can download Red Hat Fuse quickstarts from the Fuse Software Downloads page. The Quickstart zip file contains a /cxf/rest/ directory for a quickstart that demonstrates how to create a RESTful (JAX-RS) web service using CXF and how to enable OpenAPI and annotate the JAX-RS endpoints. 54.2.2. Enabling OpenAPI Enabling OpenAPI involves: Modifying the XML file that defines the CXF service by adding the CXF class ( org.apache.cxf.jaxrs.openapi.OpenApiFeature ) to the <jaxrs:server> definition. For an example, see Example 55.4 Example XML file . In the REST resource class: Importing the OpenAPI annotations for each annotation required by the service: where * = Api , ApiOperation , ApiParam , ApiResponse , ApiResponses , and so on. For details, go to https://github.com/swagger-api/swagger-core/wiki/Annotations-1.5.X . For an example, see Example 55.5 Example Resource class . Adding OpenAPI annotations to the JAX-RS annotated endpoints ( @PATH , @PUT , @POST , @GET , @Produces , @Consumes , @DELETE , @PathParam , and so on). For an example, see Example 55.5 Example Resource class . Example 55.4 Example XML file Example 55.5 Example Resource class 54.3. Spring Boot Implementations This section describes how to use the Swagger2Feature in Spring Boot. Note that for OpenAPI 3 implementations, use the OpenApiFeature( org.apache.cxf.jaxrs.openapi.OpenApiFeature ). 54.3.1. Quickstart example The Quickstart example ( https://github.com/fabric8-quickstarts/spring-boot-cxf-jaxrs ) demonstrates how you can use Apache CXF with Spring Boot. The Quickstart uses Spring Boot to configure an application that includes a CXF JAX-RS endpoint with Swagger enabled. 54.3.2. Enabling Swagger Enabling Swagger involves: In the REST application: Importing Swagger2Feature: Adding Swagger2Feature to a CXF endpoint: For an example, see Example 55.1 Example REST application . In the Java implementation file, importing the Swagger API annotations for each annotation required by the service: where * = Api , ApiOperation , ApiParam , ApiResponse , ApiResponses , and so on. For details, see https://github.com/swagger-api/swagger-core/wiki/Annotations . For an example, see Example 55.2 Example Java implementation file . In the Java file, adding Swagger annotations to the JAX-RS annotated endpoints ( @PATH , @PUT , @POST , @GET , @Produces , @Consumes , @DELETE , @PathParam , and so on). For an example, see Example 55.3 Example Java file . Example 55.1 Example REST application Example 55.2 Example Java implementation file Example 55.3 Example Java file 54.4. Accessing OpenAPI Documents When OpenAPI is enabled by OpenApiFeature, the OpenAPI documents are available at the location URL constructed of the service endpoint location followed by /openapi.json or /openapi.yaml . For example, for a JAX-RS endpoint that is published at http://host:port/context/services/ where context is a web application context and /services is a servlet URL, its OpenAPI documents are available at http://host:port/context/services/openapi.json and http://host:port/context/services/openapi.yaml . If OpenApiFeature is active, the CXF Services page links to OpenAPI documents. In the above example, you would go to http://host:port/context/services/services and then follow a link which returns an OpenAPI JSON document. If CORS support is needed to access the definition from an OpenAPI UI on another host, you can add the CrossOriginResourceSharingFilter from cxf-rt-rs-security-cors . 54.5. Accessing OpenAPI through a reverse proxy If you want to access an OpenAPI JSON document or an OpenAPI UI through a reverse proxy, set the following options: Set the CXFServlet use-x-forwarded-headers init parameter to true . In Spring Boot, prefix the parameter name with cxf.servlet.init : In Karaf, add the following line to the installDir/etc/org.apache.cxf.osgi.cfg configuration file: Note: If you do not already have an org.apache.cxf.osgi.cfg file in your etc directory, you can create one. If you specify a value for the OpenApiFeature basePath option and you want to prevent OpenAPI from caching the basePath value, set the OpenApiFeature usePathBasedConfig option to TRUE :

Commands:
openapi-configuration.yaml openapi-configuration.json openapi.yaml openapi.json
import io.swagger.annotations.*
<blueprint xmlns="http://www.osgi.org/xmlns/blueprint/v1.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:jaxrs="http://cxf.apache.org/blueprint/jaxrs" xmlns:cxf="http://cxf.apache.org/blueprint/core" xsi:schemaLocation=" http://www.osgi.org/xmlns/blueprint/v1.0.0 https://www.osgi.org/xmlns/blueprint/v1.0.0/blueprint.xsd http://cxf.apache.org/blueprint/jaxrs http://cxf.apache.org/schemas/blueprint/jaxrs.xsd http://cxf.apache.org/blueprint/core http://cxf.apache.org/schemas/blueprint/core.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> <bean class="org.apache.cxf.jaxrs.openapi.OpenApiFeature"> <property name="title" value="Fuse:CXF:Quickstarts - Customer Service" /> <property name="description" value="Sample REST-based Customer Service" /> <property name="version" value="USD{project.version}" /> </bean> </jaxrs:features> </jaxrs:server> <cxf:bus> <cxf:features> <cxf:logging /> </cxf:features> <cxf:properties> <entry key="skip.default.json.provider.registration" value="true" /> </cxf:properties> </cxf:bus> <bean id="customerSvc" class="org.jboss.fuse.quickstarts.cxf.rest.CustomerService"/> </blueprint>
. . . 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.Context; import javax.ws.rs.core.Response; import io.swagger.annotations.Api; import io.swagger.annotations.ApiOperation; import io.swagger.annotations.ApiParam; import io.swagger.annotations.ApiResponse; import io.swagger.annotations.ApiResponses; . . . @Path("/customerservice/") @Api(value = "/customerservice", description = "Operations about customerservice") public class CustomerService { private static final Logger LOG = LoggerFactory.getLogger(CustomerService.class); private MessageContext jaxrsContext; private long currentId = 123; private Map<Long, Customer> customers = new HashMap<>(); private Map<Long, Order> orders = new HashMap<>(); 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); return customers.get(idNumber); } @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); Response r; if (c != null) { r = Response.ok().build(); customers.remove(idNumber); } else { r = Response.notModified().build(); } return r; } . . . }
import org.apache.cxf.jaxrs.swagger.Swagger2Feature;
endpoint.setFeatures(Arrays.asList(new Swagger2Feature()));
import io.swagger.annotations.*
package io.fabric8.quickstarts.cxf.jaxrs; import java.util.Arrays; import org.apache.cxf.Bus; import org.apache.cxf.endpoint.Server; import org.apache.cxf.jaxrs.JAXRSServerFactoryBean; import org.apache.cxf.jaxrs.swagger.Swagger2Feature; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.boot.SpringApplication; import org.springframework.boot.autoconfigure.SpringBootApplication; import org.springframework.context.annotation.Bean; @SpringBootApplication public class SampleRestApplication { @Autowired private Bus bus; public static void main(String[] args) { SpringApplication.run(SampleRestApplication.class, args); } @Bean public Server rsServer() { // setup CXF-RS JAXRSServerFactoryBean endpoint = new JAXRSServerFactoryBean(); endpoint.setBus(bus); endpoint.setServiceBeans(Arrays.<Object>asList(new HelloServiceImpl())); endpoint.setAddress("/"); endpoint.setFeatures(Arrays.asList(new Swagger2Feature())); return endpoint.create(); } }
import io.swagger.annotations.Api; @Api("/sayHello") public class HelloServiceImpl implements HelloService { public String welcome() { return "Welcome to the CXF RS Spring Boot application, append /{name} to call the hello service"; } public String sayHello(String a) { return "Hello " + a + ", Welcome to CXF RS Spring Boot World!!!"; } }
package io.fabric8.quickstarts.cxf.jaxrs; import javax.ws.rs.GET; import javax.ws.rs.Path; import javax.ws.rs.PathParam; import javax.ws.rs.Produces; import javax.ws.rs.core.MediaType; import org.springframework.stereotype.Service; @Path("/sayHello") @Service public interface HelloService { @GET @Path("") @Produces(MediaType.TEXT_PLAIN) String welcome(); @GET @Path("/{a}") @Produces(MediaType.TEXT_PLAIN) String sayHello(@PathParam("a") String a); }
cxf.servlet.init.use-x-forwarded-headers=true
cxf.servlet.init.use-x-forwarded-headers=true
<bean class="org.apache.cxf.jaxrs.openapi.OpenApiFeature"> <property name="usePathBasedConfig" value="TRUE" /> </bean>