laravel如何实现一个关注/粉丝系统_Laravel关注与粉丝系统实现教程

public function up()
{
    Schema::create('followers', function (Blueprint $table) {
        $table->id();
        $table->unsignedBigInteger('follower_id'); // 关注者 ID
        $table->unsignedBigInteger('following_id'); // 被关注者 ID
        $table->timestamps();

        // 确保不能重复关注
        $table->unique(['follower_id', 'following_id']);

        // 可选：添加外键约束
        $table->foreign('follower_id')->references('id')->on('users')->onDelete('cascade');
        $table->foreign('following_id')->references('id')->on('users')->onDelete('cascade');
    });
}

class User extends Authenticatable
{
    // 当前用户关注了哪些人（我关注的人）
    public function following()
    {
        return $this->belongsToMany(User::class, 'followers', 'follower_id', 'following_id');
    }

    // 哪些用户关注了当前用户（我的粉丝）
    public function followers()
    {
        return $this->belongsToMany(User::class, 'followers', 'following_id', 'follower_id');
    }
}

use Illuminate\Http\Request;
use App\Models\User;

class FollowController extends Controller
{
    // 关注用户
    public function follow(User $user)
    {
        $follower = auth()->user();

        if ($follower->id === $user->id) {
            return back()->with('error', '不能关注自己。');
        }

        $follower->following()->attach($user->id);

        return back()->with('success', '已成功关注该用户。');
    }

    // 取消关注
    public function unfollow(User $user)
    {
        $follower = auth()->user();
        $follower->following()->detach($user->id);

        return back()->with('success', '已取消关注。');
    }
}

Route::middleware(['auth'])->group(function () {
    Route::post('/follow/{user}', [FollowController::class, 'follow'])->name('follow');
    Route::delete('/unfollow/{user}', [FollowController::class, 'unfollow'])->name('unfollow');
});

@if(auth()->user()->isFollowing($targetUser->id))
    <form action="{{ route('unfollow', $targetUser) }}" method="POST">
        @csrf
        @method('DELETE')
        <button type="submit">取消关注</button>
    </form>
@else
    <form action="{{ route('follow', $targetUser) }}" method="POST">
        @csrf
        <button type="submit">关注</button>
    </form>
@endif

public function isFollowing($userId)
{
    return $this->following()->where('following_id', $userId)->exists();
}

$user = auth()->user();
$followers = $user->followers; // 所有粉丝

$following = $user->following;

// 是否互相关注
$mutual = $user->following->contains($otherUserId) && $otherUser->following->contains($user->id);