Using Json in Liferay

Introduction:
We have 2 Service tiers..

The Local tier - this tier has no permission checks and is simply a clean cut implementation of the business logic of the service.

i.e. you set local-service="true" when you created the entity.

e.g.
UserLocalServiceUtil.updateActive(long userId, boolean active) (re, no permission check is made, use with caution).

The Remote Tier - this tier is designed to include your permission checks and finally calls the underlying Local service to actually perform the service operation. This tier is also the one on which ALL web-service methods are generated. All the HTTP, JSON, and SOAP are backed by the methods found in this tier.

i.e. you set remote-service="true" when you created the entity AND you implemented methods in [Entity]ServiceImpl.java rather than leaving it blank.

e.g.
UserServiceImpl.updateActive(long userId, boolean active) (i.e., makes a permission check internally):
public User updateActive(long userId, boolean active)
throws PortalException, SystemException {

if ((getUserId() == userId) && !active) {
throw new RequiredUserException();
}

UserPermissionUtil.check(
getPermissionChecker(), userId, ActionKeys.DELETE);

return userLocalService.updateActive(userId, active);
}


SO, all webservice methods which call their implementation of "updateActive" on the UserService are backed by this method. Also, this means that the caller must be authenticated in order to be tested for permissions... otherwise the call will fail. So, you need to be authenticated, AND you need to have permission.

How does a JSON method get authenticated when it's called through and ajax call? All our JSON services are passed through an AutoLogin Filter which handles the authentication based on authorization cookies.

Abstraction for using Json in Liferay:

Step 1. generate service layer for your entity with remote-service="true"
eg.


Step 2. In [entity]ServiceImpl write a method which you want to call using Json.
eg. updateName(userName) throws Exception{//your code goes here}.

Step 3. Do ant build-service -Dservice.file=your_service_xml_path from ext/ext-impl

Step 4. Do ant deploy from ext.

Step 5. Check file ext-web/docroot/html/js/liferay/ext_service_unpacked.js is updated with your method or not.

Note: In liferay version 5.2.x onwards this file is "ext_service.js".

Step 6. Include js like this in file in which you want to call json.

Step 7. Call method like this
eg:
function updateName(userName) {
var params = {
userName: userName
};
Liferay.Service.your_entity_namespace.entity_name.updateName(params);
}