Liferay is leveraging JAX-RS implementation to generate portal services to outside world. Liferay 7/DXP provided inbuilt capability to use JAX-RS implementation in OSGi modules with simple configuration in code level. Rest of the code and services implementation will follow the same as JAX-RS compliance.
Liferay implemented OAtuh2 Authorization to secure JAX-RS services which is exposed from Liferay Portal Modules and its inbuilt capability provided by Liferay 7/DXP Portal.
Liferay 7/DXP used the JAX-RS Whiteboard design pattern implementation to make use of JAX-RS in Liferay OSGi Module Framework.
Liferay Rest Module Application Component have following two properties.
Rest Service Base Path
Service name that is available in OAuth portal configuration
Example
@Component( property = { JaxrsWhiteboardConstants.JAX_RS_APPLICATION_BASE + "=/liferaysavvy", JaxrsWhiteboardConstants.JAX_RS_NAME + "=LiferaySavvy.Rest" }, service = Application.class ) publicclass Liferay72EmployeeRestApplication extends Application { } |
We can use all JAX-RS annotation in the Application component class to expose services
Example
@Component( property = { JaxrsWhiteboardConstants.JAX_RS_APPLICATION_BASE + "=/liferaysavvy", JaxrsWhiteboardConstants.JAX_RS_NAME + "=LiferaySavvy.Rest" }, service = Application.class ) publicclass Liferay72EmployeeRestApplication extends Application { @GET @Produces("text/plain") public String working() { return"It works!"; } @GET @Path("/morning") @Produces("text/plain") public String hello() { return"Good morning!"; } } |
Instead of writing all service implementation methods in one component class we can use JAX-RS Resources to provide services implementation.
JAX-RS resources is a java class which will handle the all incoming requests based on URL. Resource class have methods which distinguish each request with help of JAX-RS annotations like @Path and each method will fulfill specific requirement.
We have to add these JAX-RS resources to Application singleton set, for this we need to override getSingletons method in Application Component class. We can add as many as resources to the set.
Example:
@Override public Set<Object> getSingletons() { Set<Object> singletons = new HashSet<Object>(); //add the automated Jackson marshaller for JSON. singletons.add(new JacksonJsonProvider()); // add Employee REST endpoints (resources) singletons.add(new EmployeeResource()); returnsingletons; } |
JAX-RS Resource some of the important annotations
@Path("<RESOURCE/METHOD-PATH>/<PAT") @GET @POST @PUT @DELETE @Produces("<Media-Type>") @Consumes("<Media-Type>") |
Example Usage
@Path("/employee") @GET @POST @PUT @DELETE @Path("{id}") @Produces("application/json") @Consumes("application/json") |
Example Resource Class
@Path("/employee") publicclass EmployeeResource { @GET @Produces("application/json") public List<Employee> getAllPeople() { // Implementation } @GET @Path("{id}") @Produces("application/json") public Response getEmployee(@PathParam("id") String id) { // Implementation } @POST @Consumes("application/json") @Produces("application/json") public Employee addEmployee(Employee newEmployee) { // Implementation } @PUT @Path("{id}") @Consumes("application/json") @Produces("application/json") public Response updateEmployee(Employee newEmployee, @PathParam("id") String id) { // Implementation } @DELETE @Path("{id}") public Response deleteEmployee(@PathParam("id") String id) { // Implementation } } |
Example Rest Endpoints as follows
Add Employee --> Request Type: POST GET All Employees --> Request Type: GET Get Employee --> Request Type: GET Delete Employee --> Request Type: DELETE UPDATE Employee --> Request Type: PUT |
To provide Automated Object Marshaling and Un-Marshaling feature we have to use Jackson libraries. JacksonJsonProvider will provide these capabilities and we have to add JacksonJsonProvider in singleton set.
Example:
@Override public Set<Object> getSingletons() { Set<Object> singletons = new HashSet<Object>(); //add the automated Jackson marshaller for JSON. singletons.add(new JacksonJsonProvider()); // add Employee REST endpoints (resources) singletons.add(new EmployeeResource()); returnsingletons; } |
Before use Jackson features in modules, we have to deploy Jackson OSGi modules in Liferay Module Framework. Deploy following Jackson OSGi module jar files in Liferay Portal “osgi/modules” directory.
jackson-core-2.10.3.jar jackson-databind-2.10.3.jar jackson-jaxrs-base-2.10.3.jar jackson-module-jaxb-annotations-2.10.3.jar jackson-annotations-2.10.3.jar jackson-jaxrs-json-provider-2.10.3.jar |
Gradle Module we have add above dependencies in buld.gradle file with CompileOnly scope.
compileOnly group: 'com.fasterxml.jackson.jaxrs', name: 'jackson-jaxrs-json-provider', version: '2.10.3' compileOnly group: 'com.fasterxml.jackson.core', name: 'jackson-annotations', version: '2.10.3' compileOnly group: 'com.fasterxml.jackson.core', name: 'jackson-core', version: '2.10.3' compileOnly group: 'com.fasterxml.jackson.core', name: 'jackson-databind', version: '2.10.3' compileOnly group: 'com.fasterxml.jackson.jaxrs', name: 'jackson-jaxrs-base', version: '2.10.3' compileOnly group: 'com.fasterxml.jackson.module', name: 'jackson-module-jaxb-annotations', version: '2.10.3' |
Maven module add same dependencies with provided scope
<dependency> <groupId>com.fasterxml.jackson.jaxrs</groupId> <artifactId>jackson-jaxrs-json-provider</artifactId> <version>2.10.3</version> <scope>provided</scope> </dependency> <dependency> <groupId>com.fasterxml.jackson.core</groupId> <artifactId>jackson-annotations</artifactId> <version>2.10.3</version> <scope>provided</scope> </dependency> <dependency> <groupId>com.fasterxml.jackson.core</groupId> <artifactId>jackson-core</artifactId> <version>2.10.3</version> <scope>provided</scope> </dependency> <dependency> <groupId>com.fasterxml.jackson.core</groupId> <artifactId>jackson-databind</artifactId> <version>2.10.3</version> <scope>provided</scope> </dependency> <dependency> <groupId>com.fasterxml.jackson.jaxrs</groupId> <artifactId>jackson-jaxrs-base</artifactId> <version>2.10.3</version> <scope>provided</scope> </dependency> <dependency> <groupId>com.fasterxml.jackson.module</groupId> <artifactId>jackson-module-jaxb-annotations</artifactId> <version>2.10.3</version> <scope>provided</scope> </dependency> |
Liferay JAX-RS OSGi Module Development
- Create Liferay OSGi Rest Module
- Create JAX-RS Resource Class
- Implement Required Rest Services with JAX-RS Annotations
- Override getSingletons method in Application component to add Resources and Providers to set Collection.
- Add Required Dependencies (Jackson libraries)
- Build and Deploy
Example to Access API End points
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