unique validation is in not working in laravel 5.4 - php

Question

I am making a todo list with validation using laravel 5.4.
When I click on the submit button, only the required validation is working but not the unique.
What am I doing wrong and how do I fix it so as to get it working as desired?
Below is my form (located at home.blade.php):
<div class="panel-body">
<form class="form form-control" action="/todo" method="post">
{{csrf_field()}}
<fieldset class="form-group">
<textarea class="form-control" name="textbox" id="textArea"></textarea>
<button type="submit" class="btn btn-primary">Submit</button>
</fieldset>
</form>
{{-- for dispaying the error --}}
#if (count($errors) >0)
{{-- expr --}}
#foreach ($errors->all() as $error)
<h3 class="text-danger">{{$error}}</h3>
#endforeach
#endif
</div>
Here, the content of my Todo controller (in my todocontroller.php file):
use Illuminate\Http\Request;
use App\todo;
public function store(Request $request)
{
$todo = new todo;
$todo->body = $request->textbox;
$this->validate($request,[
"body" => "required|unique:todos"
]);
$todo->save();
return redirect('/todo');
}

Answer 1

You should simply use the name of the field; you don't need to stress yourself.
Take a look at the snippet below:
<?php
namespace App\Http\Controllers;
use App\Todo;// following Laravel's standards, your model name should be Todo; not todo
use Illuminate\Http\Request;
class NameOfYourTodoController extends Controller
{
public function store(Request $request)
{
$todo = new Todo();
// use the name of the field directly (here, textbox)
$this->validate($request, [
'textbox' => 'required|unique:todos'
]);
// other code logics here.
}
}