Friendship system with Laravel : Many to Many relationship - php

Question

I'm trying to create a Friendship system with Laravel (I'm starting with it) but I'm blocked with relationships. Here's the thing : there is one table Users and one table Friends which contains the following columns :
friends: id, user_id, friend_id, accepted.
It looks like a Many to Many so here's what I set on User class :
class User extends Eloquent {
function friends()
{
return $this->belongsToMany('User');
}
}
But when I try a :
$friends = User::find($id)->friends()->get()
I have this error :
Base table or view not found: 1146 Table 'base.user_user' doesn't exist
I would like to get a list of the Friends of a user, no matters if the user sent the invitation or received it. So the user can ba on user_id or on friend_id and then I retrieve the data of the other user depending of that column.
Any idea? Thank's!
EDIT : Here's the code I use :
$usersWithFriends = User::with('friendsOfMine', 'friendOf')->get();
$user = User::find(Auth::id())->friends;
foreach($user as $item) {
echo $item->first()->pivot->accepted;
}

Answer 1

tldr; you need 2 inverted relationships to make it work, check SETUP and USAGE below
First off the error - this is how your relation should look like:
function friends()
{
return $this->belongsToMany('User', 'friends', 'user_id', 'friend_id')
// if you want to rely on accepted field, then add this:
->wherePivot('accepted', '=', 1);
}
Then it will work without errors:
$user->friends; // collection of User models, returns the same as:
$user->friends()->get();
SETUP
However you would like the relation to work in both ways. Eloquent doesn't provide a relation of that kind, so you can instead use 2 inverted relationships and merge the results:
// friendship that I started
function friendsOfMine()
{
return $this->belongsToMany('User', 'friends', 'user_id', 'friend_id')
->wherePivot('accepted', '=', 1) // to filter only accepted
->withPivot('accepted'); // or to fetch accepted value
}
// friendship that I was invited to
function friendOf()
{
return $this->belongsToMany('User', 'friends', 'friend_id', 'user_id')
->wherePivot('accepted', '=', 1)
->withPivot('accepted');
}
// accessor allowing you call $user->friends
public function getFriendsAttribute()
{
if ( ! array_key_exists('friends', $this->relations)) $this->loadFriends();
return $this->getRelation('friends');
}
protected function loadFriends()
{
if ( ! array_key_exists('friends', $this->relations))
{
$friends = $this->mergeFriends();
$this->setRelation('friends', $friends);
}
}
protected function mergeFriends()
{
return $this->friendsOfMine->merge($this->friendOf);
}
USAGE
With such setup you can do this:
// access all friends
$user->friends; // collection of unique User model instances
// access friends a user invited
$user->friendsOfMine; // collection
// access friends that a user was invited by
$user->friendOf; // collection
// and eager load all friends with 2 queries
$usersWithFriends = User::with('friendsOfMine', 'friendOf')->get();
// then
$users->first()->friends; // collection
// Check the accepted value:
$user->friends->first()->pivot->accepted;

Answer 2

It's oviously a problem in your DB and also definition of the relation. Many-to-Many relation type expects you to use and intermediate table. Here's what you have to do :
Create a user_friend (id, user_id, friend_id) table in your schema.
Remove unnecessary fields from user and friend tables.
Create proper foreign keys . user.id-> user_friend.user_id , friend.id -> user_friend.friend_id
Better define full relation on the User and Friend models,
for example :
class User extends Eloquent {
function friends()
{
return $this->belongsToMany('User', 'user_friend', 'user_id', 'friend_id');
}
}
You can read much more in Laravel docs, HERE