禁用给定请求的翻译（laravel）

Question

I'm currently building a Vue.js SPA with laravel as the backend where I need to support multiple locales. I'm therefore considering using Lang.js alongside laravel's built-in translation system to manage the translated stings. I basicly want to manage all the strings in laravel (on the backend) but let the frontend handle the actual translations, to allow the user to switch language dynamicly with a language switcher ui component.

The problem is that when I submit a form request that is validated on the server, the error messages are already translated, thus not allowing the frontend to pick a language on-the-fly.

My question is how I can disable the translation for a given request (preferably using headers in middleware or something like that) and instead print the raw translation keys

For example for the given validation

<?php
function store() {
    request()->validate(['test' => 'required'])
}

The server returns

{
    'message': 'The given data was invalid',
    'errors': {
        'test': 'The test field is required'
    }
}

instead of

{
    'message': 'The given data was invalid',
    'errors': {
        'test': 'validation.required',
    }
}

I have already tried using \App::setLocale('somethinginvalidandrandom') which should technically try to translate the key into a language that doesn't exist, thus returning the key, but besides feeling wrong and hacky, this approach won't work if I want to preserve the fallback language funcionality of laravel, since the key would be found in the fallback language (en).

Answer 1

I actually just solved it myself, and thought to reply here in case others where trying to solve the same problem as me in the future.

Solution

I added an invalidJson method to my App\Exceptions\Handler class, that Laravel will automaticly call whenever an ValidationException is thrown and $request->wantsJson() is true.

In that method i just checked if my custom header (X-WITH-UNTRANSLATED-VALIDATION) is present in the request with the value of "yes". If that is the case i get the validator instance from the exception, and grab all the rules.

However laravel represent these rules internally in "studly caps case" (StartsWith) and we want to get them in a snake case format ("starts_with"). To fix this I used the laravel collection helpers to map over the nested array and convert the rule keys to snake case.

Code

Here is the code from app\Exceptions\Handler.php.

/**
 * Convert a validation exception into a JSON response.
 *
 * @param  \Illuminate\Http\Request  $request
 * @param  \Illuminate\Validation\ValidationException  $exception
 * @return \Illuminate\Http\Response
 */
protected function invalidJson($request, ValidationException $exception)
{
    //If the header is not present in the request 'no' wil be provided as the fallback value, thus not being equal with "yes"
    if($request->header('X-WITH-UNTRANSLATED-VALIDATION', 'no') === "yes") {
        $failed = $this->makeUntranslatedMessagesIntoSnakeCase($exception);

        return response([
            // Get the original exception message
            'message' => $exception->getMessage(),
            'errors' => $failed,
            // Add the original translated error messages under a diffrent key to help with debugging
            'translated_errors' => $exception->errors(),
        ], $exception->status);
    }

    //If the header is not present (with the right value) we return the default JSON response instead
    return parent::invalidJson($request, $exception);
}

/**
 * Convert the untranslated rule names of a validation exception into snake case.
 * 
 * @param \Illuminate\Validation\ValidationException  $exception
 * @return array
 */
protected function makeUntranslatedMessagesIntoSnakeCase(ValidationException $exception) : array
{
    return collect($exception->validator->failed())->map(function ($item) {
        return collect($item)->mapWithKeys(function ($values, $rule) {
            return [Str::snake($rule) => $values];
        });
    })->toArray();
}

Further improvements

If you need to disable translation for normal "non-json" requests, you can also override the invalid method in the Handler.php and do a similar thing, but just add the messages to the session instead. Likewise you could also add the translated messages alongside the untranslated messages.

Edit

I also added 'translated_errors' => $exception->errors(), to the response to help with debugging