Part 2: Accessing and Using Liferay JSON Web Services

In previous post, I have worked on introducing all basics about JSON Web Services.
In this post the focus is on accessing and consuming the the services and example

To Restrict a method from being exposed as service, just annotate the method with:
@JSONWebService(mode = JSONWebServiceMode.IGNORE)

To define custom HTTP method name instead of using the default, just annotate the method with:
@JSONWebService(value = "get-user", method = "GET")
public User getUserById( ...

Thus above service will be exposed and accessed as

http://localhost:8080/api/jsonws/user/get-user

instead of 

http://localhost:8080/api/jsonws/user/get-user-by-id

To further customize the URL and remove the serviceClassname, just annotate the method with:
@JSONWebService("/get-user")
public User getUserById(..

Thus above service will be exposed and accessed as

http://localhost:8080/api/jsonws/get-user

instead of 

http://localhost:8080/api/jsonws/user/get-user-by-id

Portal Configuration

JSON Web Services can be enabled or disabled by setting the below portal property:
json.web.service.enabled=true
by default the services are enabled and the property is set to true.

Enabling/Disabling particular HTTP methods
jsonws.web.service.invalid.http.methods=DELETE,POST,PUT
causes portal to accept only GET requests and ignore the HTTP methods specified above.

Below is the comma separated list of public service methods that can be accessed by unauthenticated user:
For all methods as unauthenticated use below
jsonws.web.service.public.methods=*  
For is methods as unauthenticated use below

jsonws.web.service.public.methods=is*

Accessing service via HTML form

<form action="http://localhost:8080/api/jsonws/user/get-user-by-id" method="GET">
        <input type="hidden" name="userId" value="10172"/>
        <input type="submit" value="submit"/>
</form>

When submitted will result in response consisting of User object as JSON string.

Accessing service via Java based Apache HttpClient API 

Below is the example to access the Liferay services using the Apache HTTPClient API

public static void get() throws Exception {
  HttpHost targetHost = new HttpHost("localhost", 8080, "http");
  DefaultHttpClient httpclient = new DefaultHttpClient();
  httpclient.getCredentialsProvider().setCredentials(
    new AuthScope(targetHost.getHostName(), targetHost.getPort()),
    new UsernamePasswordCredentials("test", "test"));

  // Create AuthCache instance
  AuthCache authCache = new BasicAuthCache();
  // Generate BASIC scheme object and add it to the local
  // auth cache
  BasicScheme basicAuth = new BasicScheme();
  authCache.put(targetHost, basicAuth);

  // Add AuthCache to the execution context
  BasicHttpContext ctx = new BasicHttpContext();
  ctx.setAttribute(ClientContext.AUTH_CACHE, authCache);

  HttpPost post = new HttpPost(
    "/api/jsonws/user/get-user-by-id"); 
  List<NameValuePair> params = new ArrayList<NameValuePair>();
  params.add(new BasicNameValuePair("userId", "10172"));
  
  UrlEncodedFormEntity entity = new UrlEncodedFormEntity(params, "UTF-8");
  post.setEntity(entity);
  HttpResponse resp = httpclient.execute(targetHost, post, ctx);
  System.out.println(resp.getStatusLine());
  resp.getEntity().writeTo(System.out);
  httpclient.getConnectionManager().shutdown();
 }

When submitted will result in response consisting of User object as JSON string.

Go to  Next post Part 3: Custom Liferay Plugin JSON Web Services

References:
The article is my summarized view while working on the topic and references have been taken from Liferay community and documentation