Laravel 输入数组为什么我在 $request->quantity 中得到 null

Question

After searching similar questions I still didn't get the error

The thing is that I have a form that usually works, but the 10% of the users have this error

array_sum() expects parameter 1 to be array, null given

Form

<select name="quantity[]" class="form-control option-quantity" data-price="100">
   <option data-price="100" value="0">0</option>
   <option data-price="101" value="1" selected="selected">1</option>
   <option data-price="102" value="2">2</option>
</select>

Controller

$validator = Validator::make($request->all(), [
   'quantity.*' => 'required|integer',
]); 

if ($validator->fails()) { 
   abort(500);
}

if(count($request->quantity) == 0 || array_sum($request->quantity) < 1)){
   //message to select at least a quatity
}

They always put an amount because I did't restrictions, js to avoid nulls or 0 and from the server side not to allow 0

So, as it happens just sometimes, I'm wondering if some explorers do something weird changing the quantity[] to quantity or null or something, I'm driving a bit crazy here and I can't reproduce the error myself and it wouldn't be a good idea to wait the error to happen to a user (:

BTW of course I can add if($request->quantity) to avoid the error, but that not solves the question of why I get a null just sometimes, rest is fine.

As per suggestion after doing dd($request->quantity); I get:

array:1 [
  0 => "1"
]

But again, for me its working good, not for the 10%.

Answer 1

You can simply avoid this error by checking quantity.It

 if($request->quantity){
  if(count($request->quantity) == 0 || array_sum($request->quantity) < 1)){
   //message to select at least a quatity
  }
}

It is throwing this error because $request->quantity is null;

Hope this helps

Answer 2

Since you have not tagged the version of Laravel, I'll make an assumption that you are using latest version.

why I get a null

Check your validation rule..

When a user submits the data with empty strings, Laravel makes it nullable. Checkout the middleware ConvertEmptyStringsToNull which is located inside Illuminate\\Foundation\\Http\\Middleware folder.

So, if you want it to be always present at the time of submitting the user data, make it required like so.

return [
    'quantity' => 'required',
    // .. other validation rules..
];

Answer 3

Try removing "[]" from the name on the select, so you will have this:

<select name="quantity" class="form-control option-quantity" data-price="100">
   <option data-price="100" value="0">0</option>
   <option data-price="101" value="1" selected="selected">1</option>
   <option data-price="102" value="2">2</option>
</select>