How to use unique validation in laravel?

Question

I have comments table:

My Comment controller where its taking values from form and validating it and storing it in database.

public function store(Request $request, $product_id)
    {
        $this->validate($request, array(
            'name' => 'required',
            'email'=> 'required|email|unique:comments,product_id',
            'comment' => 'required',
            'rating' => 'required|integer'
            ));
        $product = Product::find($product_id);
        $comment = new Comment();
        $comment->name = $request->name;
        $comment->email = $request->email;
        $comment->comment = $request->comment;
        $comment->rating = $request->rating;
        $comment->product()->associate($product);

        $comment->save();
        Session::flash('success','Comment was added');
        return redirect()->route('product.show',[$product->id]);
    }

I am trying to validate such that only unique email id is allowed to comment on every product_id that is if user has already commented on product_id 1 then the same user is not allowed to comment again on that id.

I tried

'email'=> 'required|email|unique:comments,product_id'

But as u can see about same email id data was entered for same product_id.

A user can comment on n number of product_id page but cannot comment again once he has commented on that id.

Is there a way to validate if email data has been entered in database for particular product_id then the same email is not allowed to submit the form.

If different product_id then email can enter.

Thanks.

Answer 1

Write this in your console

php artisan make:provider ValidationServiceProvider

Then replace your App\Providers\ValidationServiceProvider with

namespace App\Providers;

use Validator;
use App\Comment;
use Illuminate\Support\ServiceProvider;

class ValidationServiceProvider extends ServiceProvider
{
  /**
   * Bootstrap any application services.
   *
   * @return void
   */
  public function boot() {
    Validator::extend('unique_email_comment', function($attribute, $value, $parameters, $validator) {
      return !Comment::where('email', $value)->where('product_id', $parameters[0])->exists();
    });
  }

  /**
   * Register the service provider.
   *
   * @return void
   */
  public function register() {
    //
  }
}

Note :- Please ensure the Model App\Comment is replaced with the namespace of the modal you use for your comments system.

Now add it to providers in config/app.php like

App\Providers\ValidationServiceProvider::class,

Now, you can validate the existence of the row by:

'email' => 'unique_email_comment:' . $productId;

// or
// 'email' => 'unique_email_comment:' . request()->get('product_id');

You can also add a custom message like this

return [
  'email.unique_email_comment' => 'A comment has already been made for this product with the email provided';
]

Please note that I haven't tested the code out but this should work if all the data is passed correctly and all namespaces are correctly used.