php - Laravel middleware to format keys of response array

Solution:

Due to the answer of AnsellC I solved it by using Response Macros (https://laravel.com/docs/5.8/responses#response-macros). My solution looks as follows:

<?php

namespace App\Providers;

use Illuminate\Contracts\Support\Arrayable;
use Illuminate\Support\Arr;
use Illuminate\Support\Facades\Response;
use Illuminate\Support\ServiceProvider;
use Illuminate\Support\Str;

class ApiResponseMacroServiceProvider extends ServiceProvider
{
    /**
     * Bootstrap services.
     *
     * @return void
     */
    public function boot()
    {
        Arr::macro('renameKeysCamel', function($array){
            $newArray = array();
            foreach($array as $key => $value) {
                if(is_string($key)) $key = Str::camel($key);
                if(is_array($value)) $value = static::renameKeysCamel($value);
                $newArray[$key] = $value;
            }
            return $newArray;
        });

        // API Response macros
        Response::macro('success', function ($data, $message = '') {

            // If collection change it to associative array
            if($data instanceof Arrayable) $data = $data->toArray();
            if(is_object($data)) $data = (array) $data;

            // Change to camelCase key names
            if(is_array($data)) $data = Arr::renameKeysCamel($data);

            return Response::json([
              'success'  => true,
              'message' => $message,
              'data' => $data,
            ]);
        });

        Response::macro('error', function ($message, $error_code = null, $status = 400) {
            return Response::json([
              'success'  => false,
              'errorCode' => $error_code,
              'message' => $message,
            ], $status);
        });
    }    
}

Copy code

It registers two macros for the REST API responses:success($data, $message) anderror($message, $error_code, $status). There is a third macro extendingIlluminate\Support\Arr to recursive changing the keys to camelCaserenameKeysCamel.

As completion here is the code to handle incoming request by a middleware and change the JSON keys to snake_case:

<?php

namespace App\Http\Middleware;

use Closure;
use Illuminate\Support\Str;

class ProcessIncomingJsonMiddleware
{
    /**
     * Handle an incoming request and change json data keys to snake_case.
     *
     * @param  \Illuminate\Http\Request  $request
     * @param  \Closure  $next
     * @return mixed
     */
    public function handle($request, Closure $next)
    {
        if ($request->isJson())
        {
            // Fetch json data
            $json_array = $this->renameKeysSnake($request->json()->all());
            // Create changed response
            $request->json()->replace($json_array);
        }

        return $next($request);
    }

    protected function renameKeysSnake($array) {
        $newArray = array();
        foreach($array as $key => $value) {
            if(is_string($key)) $key = Str::snake($key);
            if(is_array($value)) $value = $this->renameKeysSnake($value);

            $newArray[$key] = $value;
        }
        return $newArray;
    }
}

Copy code