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
)
public class
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
)
public class
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());
return singletons;
}
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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")
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Example Resource Class
@Path("/employee")
public class 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());
return singletons;
}
|
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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