Laravel5 Eloquent default date mutator fails with JSON date input - php

Question

I've a model with date mutators, such as created_at. Let's say a generic timestamp property.
When passing data from the client in JSON format, i'll get
{
timestamp: "2016-06-07T22:00:00.000Z"
}
That property will be used to set some model like so:
$model = new Foo();
$model->timestamp = Input::get('timestamp');
Since this will trigger the date mutator, php Carbon gets called and fails with
InvalidArgumentException in Carbon.php line 425
Unexpected data found.
Trailing data
Now, that's not an issue with Carbon itself, that is able to handle JSON formats. If you'll try
new Carbon('2016-06-07T22:00:00.000Z');
you'd infact get the expected result.
From what i see, the problem origins from a weird Eloquent behaviour. See this trace from the above mentioned InvalidArgumentException in Carbon.php line 425:
in Carbon.php line 425
at Carbon::createFromFormat('Y-m-d H:i:s', '2016-06-07T22:00:00.000Z') in Model.php line 2915
at Model->asDateTime('2016-06-07T22:00:00.000Z') in Model.php line 2871
at Model->fromDateTime('2016-06-07T22:00:00.000Z') in Model.php line 2826
at Model->setAttribute('timestamp', '2016-06-07T22:00:00.000Z') in Model.php line 3351
Eloquent is trying to createFromFormat passing a bad format which doesnt mirror the actual JSON format, that is causing the Carbon exception.
On the other hand, a simple call like the above mentioned new Carbon($jsonDate) would work fine in this case.
How should i approach to solve this?
Isn't this supposed to be an Eloquent bug?
== EDIT ==
I didn't code any mutator myself. I'm using default date mutators like so:
public function getDates() {
return ['timestamp'];
}

Answer 1

Eloquent analyses the date you give it, when the attribute is set in the getDates function.
In it's analyses it has four steps: (see Modal.php asDateTime method for clarification, the code is pretty well commented: https://github.com/illuminate/database/blob/master/Eloquent/Model.php#L2898)
If it is already a Carbon instance, use that
If it is an instance implementing DateTimeInterface, use that
If it is numeric, parse as a Unix timestamp
If it is a simple year month day format (tried by regex) use that
If none of the above, create a Carbon instance with the format you specify as default
In you case, 1-4 don't match, so it tries 5.
You have no custom dateFormat specified on the model, so it uses the default date format applicable to the type of database connection you are using. You can override this by adding a $dateFormat variable to the model:
protected $dateFormat = 'U';
But your normal timestamps are probably in the correct format already. So this solution would not work for you.
In your case I would just do:
$model->timestamp = Carbon::parse(Input::get('timestamp'));
Or use Carbon::createFromFormat() with the appropriate format.
I don't exactly know why they don't just parse it with Carbon directly. I guess it is more error prone and less controllable. With different international formats you might get an unexpected outcome (month and day switched etc). It might also be slower than their current approach.