Laravel API JSON customization and table relationship

问题

I'm developing a social media project using Laravel. I need to provide a customized API for Follows and Followers. Accordingly, I want to establish a relationship between the user table and the followers and followed tables. I have looked at a lot of resources but get confused. Can anyone help me with relationships?

Models

Users: id, username, email, password

Follows: id, user_id, follow_id(user_id)

Followers: id, user_id, follower_id(user_id)

API Url: http://localhost/api/follows/user_id/1

FollowController

public function user_follow($user_id)
{
    $user_find = Follows::where("user_id", "=", $user_id)->get();
    
    return response()->json($user_find, 201);
}

Output

[
  {
    "id": 4,
    "user_id": 1,
    "follow_id": 4,
    "created_at": "2020-03-23T15:11:48.000000Z",
    "updated_at": "2020-12-11T11:10:10.000000Z"
  },
  {
    "id": 5,
    "user_id": 1,
    "follow_id": 1,
    "created_at": "2012-08-30T20:16:51.000000Z",
    "updated_at": "2020-12-11T11:10:10.000000Z"
  }
]

API that brings relevant followed people according to user request. But here, I want to give additional user information of the relevant users, how do I do this?

回答1:

The most right implementation for me looks like this:

First you do not need two separate tables for tracking follow actions. With one table you can have both.

users
*id
*username
*email
*password

user_followers
*id
*user_id
*follower_id

Then in the model you can do something like:

public function followers()
{
    return UserFollower::where('user_id', $this->id)->get();
}

public function following()
{
    return UserFollower::where('follower_id', $this->id)->get();
}

public function followUser($userId)
{
    // create & insert new row as a follower to the other user
    $follower = new UserFollower();
    $follower->user_id = $userId;
    $follower->follower_id = $this->id;
    $follower->save();
}

And in the API you can do:

domain/api/users/{user_id}/followers/
domain/api/users/{user_id}/following/

• To get additional information from the related model, I think you could do a 'leftJoin'.

Something like that

public function followers()
{
    return DB::table('user_followers')
        ->select('user_followers.*', 'users.email', 'users.name')
        ->where('user_followers.user_id', '=', $this->id)
        ->leftJoin('users', 'user_followers.follower_id', '=', 'users.id')
        ->get();
}

Edit: Another approach for the followers method is to use the 'hasManyThrough' method of the base Model's class.

public function followers()
{
    return $this->hasManyThrough(UserFollower::class, User::class);
}

This way this method returns User models

回答2:

As it is evident from your model, define a one to many relationship for user in the Follow model as below:

Follow

public function user(){
    return $this->belongsTo('App\Models\User');
}

Then, get the related user from the Follow in your controller:

$user_find = Follows::where("user_id", "=", $user_id)->get();
$related_user = $user_find->pluck('user');

来源：https://stackoverflow.com/questions/65327577/laravel-api-json-customization-and-table-relationship