php - Laravel validation: Must be a valid JSON string with the "json" rule

Solution:

Well you need to pass an JSON String instead of an JSON Object. This can be done either by json_encode or JSON.stringify.

As an answer on your last comment.:

You could either do this in your frontend application with JSON.stringify or you could implement an Form Request with an prepareForValidation(): https://laravel.com/docs/8.x/validation#prepare-input-for-validation.

Where you would do an json_encode() on the json properties. Like:

protected function prepareForValidation()
{
    $this->merge([
        'colors' => json_encode($this->colors),
        'text_sizes' => json_encode($this->text_sizes)
    ]);
}

Or in your case:

$validator = Validator::make($request->merge([
        'colors' => json_encode($request->colors),
        'text_sizes' => json_encode($request->text_sizes)
    ]), [
    "name" => "required|string",
    "colors" => "json",
     "sizes" => "json"
]);

Solution:

I found a simple solution, just use double quotes to represent a json string, and escape the double quotes inside the json:

{ "name": "Test", "colors": "{\"Man\": \"#0000ff\",\"Second\": \"#FF0000\"}", "sizes": "{\"titles\": \"20px\"}" }

This solve my issue sending json string from Insomnia Api rest.

Solution:

laravel have a convenient way to validate a request please follow these steps to make your own request and response for api 1-php artisan make:request YourRequest

Then customize your request like this

  <?php
    
    namespace App\Http\Requests;
    
    use Illuminate\Contracts\Validation\Validator;
    use Illuminate\Foundation\Http\FormRequest;
    use Illuminate\Http\Exceptions\HttpResponseException;
    use Illuminate\Http\Response;
    
    class OrderRequest extends FormRequest
    {
    
        /**
         * Determine if the user is authorized to make this request.
         *
         * @return bool
         */
        public function authorize(): bool
        {
            return true;
        }
    
        /**
         * Get the validation rules that apply to the request.
         *
         * @return array
         */
        public function rules(): array
        {
    
            $rules = [
                'your filed name' => 'required',
                
            ];
            return $rules;
        }
    
        /**
         * Get the error messages that apply to the request parameters.
         *
         * @return array
         */
        public function messages()
        {
            return [
                'your field name' => 'custom message',
              
            ];
        }
    
        /**
         * Handle a failed validation attempt.
         *
         * @param Validator $validator
         * @return void
         *
         * @throws ValidationException
         */
        protected function failedValidation(Validator $validator)
        {
            $error = collect($validator->errors())->collapse()->toArray();
            $errors = implode(' | ', $error);
            throw new HttpResponseException(response()->json(
                ['response' => ['status' => false, 'message' => $errors]],
                Response::HTTP_UNPROCESSABLE_ENTITY));
        }
    }

this will solve error as recommended by laravel and its a professional way

then use this Request into controller .

if you want to use your own code then

just use json_encode($this->text_sizes)