[TYPO3-mvc] relations with metadata

[Franz Koch]

Hi,

> I'm currently working on tx_community for the Google Summer of Code and, starting with profiles, I have a question about relations. In particular it's about the friendship (yes, that's the common term in social networks) between users.
> When one user wants to add another user as a friend, the other one gets notified and has to confirm the friendship. My question is how to technically implement those relations. Ingo and I have had several ideas:

I'd say I'd use a intermediate object called 'friend' or 'friendship'.

USER1 -> FRIENDSHIP <- USER2

The friendship model could look like this:
----------------------------------------------------
class Tx_Community_Domain_Model_Friendship {

	/**
	 * the user who initiated the friendship
	 */
	protected $initiator;

	/**
	 * the friend that got invited/added
	 */
	protected $friend;

	protected $dateOfRequest;

	protected $dateOfAcceptance;

	/**
	 * a comment/message the initiator wrote in his friendship request
	 */
	protected $comment;
	# some other
}
----------------------------------------------------


Then, a user model could look like:
----------------------------------------------------
class Tx_Community_Domain_Model_User extends 
Tx_ExtBase_Domain_Model_FeUser {

	/**
	 * the friendships this user has initiated
	 * @var 
Tx_Extbase_Persistence_ObjectStorage<Tx_Community_Domain_Model_Frienship>
	 * @lazy
	 */
	protected $friendships;

	
	/**
	 * method that's returning all friends, that get fetched by a userService
	 * the service itself is calling a special method in the userRepository
	 * like $this->userRepository->getFriendsByUser($user);
	 * @return 
Tx_Extbase_Persistence_ObjectStorage<Tx_Community_Domain_Model_User>
	 */
	public function getFriends() {
		// the service can/should maybe initiated in the constructor
		return $this->userService->getFriendsByUser($this);
	}

	/**
	 * Is returning all related friendships, not only the ones initiated by 
this user
	 * @return 
Tx_Extbase_Persistence_ObjectStorage<Tx_Community_Domain_Model_Frienship>
	 */
	public function getAllFriendships() {
		$this->userService->getAllFriendshipsByUser($this);
	}
	
	/**
	 * only returning friendships initiated by this user
	 * @return 
Tx_Extbase_Persistence_ObjectStorage<Tx_Community_Domain_Model_Frienship>
	 */
	public function getFriendships() {
		return $this->friendships;
	}

}
----------------------------------------------------


Something like that I think. As you will always need a intermediate 
table, simply make it a intermediate object and use it to also store 
meta data. You won't get a direct relation between the two persons - 
there's always a friendship/relation inbetween.

-- 
kind regards,
Franz Koch