Base64 validation

[MrShnaider]

Is there any way in Laravel to validate base64 encoded files? For example, check that the parameter is base64 encoded, that it is png encoded, or that its maximum size is no more than a few MB? It looks like a common use case, but I didn't find it in the documentation.

[ghost]

https://laravel.com/docs/10.x/validation#rule-mimes
https://laravel.com/docs/10.x/validation#rule-max
https://laravel.com/docs/10.x/validation#custom-validation-rules and build your custom validation with base64_decode

[Raza9798]

https://laravel.com/docs/10.x/validation#rule-mimes https://laravel.com/docs/10.x/validation#rule-max https://laravel.com/docs/10.x/validation#custom-validation-rules and build your custom validation with base64_decode

To make a custom validation run the command php artisan make:rule Base64Image and implement the function as below

<?php

namespace App\Rules;

use Illuminate\Contracts\Validation\Rule;

class Base64Image implements Rule
{
    public function passes($attribute, $value)
    {
        if (!preg_match('/^data:image\/(\w+);base64,/', $value)) {
            return false;
        }

        list($type, $data) = explode(';', $value);
        list(, $data)      = explode(',', $data);

        if (!in_array($type, ['image/png', 'image/jpeg', 'image/gif'])) {
            return false;
        }

        if (strlen(base64_decode($data)) > 2 * 1024 * 1024) {
            return false;
        }

        return true;
    }

    public function message()
    {
        return 'The :attribute must be a valid base64 encoded image (PNG, JPEG, GIF) with a maximum size of 2MB.';
    }
}

to call the validation you can try as follows

use App\Rules\Base64Image;

public function store(Request $request)
{
    $request->validate([
        'image' => ['required', new Base64Image],
    ]);
 
}

[SolankiJignashu]

Before

list($type, $data) = explode(';', $value);

we should remove the data: prefix from the base64 string (if present) to avoid incorrect parsing.

if (str_starts_with($value, 'data:')) {
      $value = substr($value, 5);
}
list($type, $data) = explode(';', $value);
list(, $data)      = explode(',', $data);

This ensures the base64 data is correctly split into $type and $data

[shaedrich]

Instead of specifically images, we should make a general base64 rule where mimes can be applied

[SolankiJignashu]

Yes. That can be good solution.

[Raza9798]

<?php

namespace App\Rules;

use Illuminate\Contracts\Validation\Rule;

class Base64Image implements Rule
{
    public function passes($attribute, $value)
    {
        return preg_match('#^data:image/(png|jpeg|gif);base64,#', $value)
            && ($data = base64_decode(substr($value, strpos($value, ',') + 1), true))
            && strlen($data) <= 2 * 1024 * 1024
            && @getimagesizefromstring($data);
    }

    public function message()
    {
        return 'The :attribute must be a valid base64 encoded PNG, JPEG, or GIF image under 2MB.';
    }
}

try me latest validation @shaedrich @SolankiJignashu

[shaedrich]

So no jpg (just jpeg) and no other image formats (looking at you webp)?