How to use attach method for an API Laravel project?

Hi evereyone,

My project is an API on Laravel. I've got two tables (users & projects) who have a relationship many to many, so I've a pivot table (user_project). So I would like to assign users to projects by giving the id in the route.

I tried by myself with attach method, it works when I give an id to findOrFail method in the code

ProjectController.php

public function affect(Request $request, Project $project, User $user){
        $pjt= Project::findOrFail(1);
        $pjt->users()->attach($user);
    }

But when I don't want to give an id and i put $project in findOrFail(), I've got an error "BadMethodCallException Method users does not exist" when I'm testing the route. Sorry, I'm only starting in Laravel.

I put my code to you:

ProjectController.php

public function affect(Request $request, Project $project, User $user){
        $pjt= Project::findOrFail($project);
        $pjt->users()->attach($user);
    }

Project.php (Model)

    public function users()
    {
        return $this->belongsToMany(User::class, 'user_project', 'project_id', 'user_id')->select( 'email', 'date_of_birth', 'firstname', 'lastname');
    }

    public function status()
    {
        return $this->belongsTo(Status::class);
    }
}

User.php (Model)

public function projects()
    {
        return $this->belongsToMany(Project::class, 'user_project', 'user_id', 'project_id');
    }

my api route:

api.php

Route::post('projects/{project}/users/{user}', 'ProjectController@affect');

And my migrations table

create_users_table.php

public function up()
    {
        Schema::create('users', function (Blueprint $table) {
            $table->increments('id');
            $table->string('firstname');
            $table->string('lastname');
            $table->string('email')->unique();
            $table->string('password');
            $table->date('date_of_birth');
            $table->rememberToken();
            $table->timestamps();
        });
}

create_projects_table.php

public function up()
    {
        Schema::create('projects', function(Blueprint $table) {
            $table->increments('id');
            $table->string('name');
            $table->integer('creator_id')->default(1);
            $table->foreign('creator_id')->references('id')->on('users')
                ->onDelete('restrict')
                ->onUpdate('restrict');
            $table->integer('status_id')->default(1);
            $table->foreign('status_id')->references('id')->on('status')
                ->onDelete('restrict')
                ->onUpdate('restrict');
            $table->timestamps();
            $table->softDeletes();

        });
    }

create_user_projects_table.php

public function up()
    {
        Schema::create('user_project', function(Blueprint $table) {
            $table->increments('id');
            $table->timestamps();
            $table->integer('user_id')->unsigned();
            $table->integer('project_id')->unsigned();
            $table->foreign('user_id')->references('id')->on('users')
                ->onDelete('restrict')
                ->onUpdate('restrict');
            $table->foreign('project_id')->references('id')->on('projects')
                ->onDelete('restrict')
                ->onUpdate('restrict');
        });
    }

Thank you in advance for your help

automica

5 years ago

Best Answer

Level 54

@kramas not answering your question but some suggestions:

convention for join tables is to use tables in alphabetical order so 'user_project' would be 'project_user'.

if you do this, you should be able to replace

$this->belongsToMany(User::class, 'user_project', 'project_id', 'user_id')

with

$this->belongsToMany(User::class)

for here:

public function affect(Request $request, Project $project, User $user){
        $pjt= Project::findOrFail($project);
        $pjt->users()->attach($user);
    }

as you are using Route Model Binding (and passing in the Project $project) you can do the following

public function affect(Request $request, Project $project, User $user)
   {       
        $project->users()->attach($user);
    }

I cant see any specific reason why your attach doesn't work but switching to using Laravel conventions may make it easier to diagnose.

1 like

Snapey

5 years ago

Level 122

You are type hinting the project so you should not need the findOrFail at all

public function affect(Request $request, Project $project, User $user)
{
    $project->users()->attach($user);
}

Also, I noticed your select in the relationship. Always make sure you include the primary key (id) in the select otherwise the records cannot be linked up.

1 like

Kramas

5 years ago

Level 1

It works, thank you so much for your help !

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