Set the default __toString() format per Carbon instance? - php-carbon

Question

I retrieve dates from a database and have the option to pre-process them (via the Laravel framework (v5.2)). The dates or times can come in any particular format but for this example let's say Y-m-d.
I want to be able to access the date as a Carbon instance in the view — this would give me the flexibility to format the date however I please or do nothing with it and print as-is (with the default toString being the same as its original string format).
The issue is maintaining the default expected toString format at the top-level Carbon toString format.
According to the docs, you can use the ::setToStringFormat() method to change the default format of toString. It is possible to set it with the static method Carbon::setToStringFormat() but it also works as an instance method e.g. ($date = Carbon::now())->setToStringFormat('Y-m-d') - albeit this seems to behave identically to the static method.
So, is it possible to set the individual __toString() format for a date instance?
It would allow me to do the following:
public function getDateAttribute($value)
{
$date = Carbon::createFromFormat('Y-m-d', $value);
// $date->setToStringFormat('Y-m-d');
return $date; // prints in 'Y-m-d' format
}
In a view, I would then chain methods on the date, or print it as-is.

Answer 1

I had the same sort of issue and worked my way around it
First create a global serialization method for carbon dates (e.g. in the boot of the Laravel AppServiceProvider)
<?php
namespace App\Providers;
use Illuminate\Support\Carbon;
use Illuminate\Support\ServiceProvider;
class AppServiceProvider extends ServiceProvider {
/**
* Bootstrap any application services.
*
* #return void
*/
public function boot() {
// ...
Carbon::serializeUsing(function (Carbon $carbon):string {
$format = $carbon->getSettings()['toStringFormat'] ?? 'Y-m-d\TH:i:s';
return $carbon->format($format);
});
// ...
}
// ...
}
Then set the 'toStringFormat' setting to the format you need
$someCarbonDate->settings([ 'toStringFormat' => 'Y-m-d' ]);
Carbon::serializeUsing will now check if the carbon being serialized has a toStringFormat and use that or it will fall back to some other format you define.
You could probably also create your own Carbon class and extend Carbon\Carbon or Illuminate\Support\Carbon (used by Laravel) and override the __toString method, but that creates some new challenges when used in combination with the casting Laravel does internally.

Answer 2

If you just want to set the default format for when rendering Blade templates you can use the Blade::stringable method.
<?php
namespace App\Providers;
use Illuminate\Support\Facades\Blade;
use Illuminate\Support\ServiceProvider;
class AppServiceProvider extends ServiceProvider
{
// ...
/**
* Bootstrap any application services.
*
* #return void
*/
public function boot() {
// ...
Blade::stringable(function(\Illuminate\Support\Carbon $dateTime) {
return $dateTime->format('d/m/Y H:i:s');
});
// ...
}
// ...
}
Any Illuminate\Support\Carbon instances should automatically be rendered with this format unless you choose otherwise.
For example...
{{ $user->created_at }} would now render as 23/07/2021 10:16:24 by default
{{ $user->created_at->toDateString() }} still works and would render as 23/07/2021
NOTE: You might need to run php artisan view:clear to clear any compiled views before this takes effect 🙂