If you are using laravel as api only, you might want to return JSON on every request, even on errors/exceptions. The easiest way to do so is using this middleware globally.

JsonMiddleware.php

<?php 

namespace App\Http\Middleware;

use Closure;
use Illuminate\Http\Request;

class JsonMiddleware 
{
    public function handle(Request $request, Closure $next) 
    {
        $request->headers->set('Accept', 'application/json');
        
        return $next($request);
    }
}
    

Originally shared by Alexander Lichter
https://twitter.com/TheAlexLichter/status/969879256271597568

Hi, thank you so much!
I noticed something. When a NotFoundHttpException happens because of sending a model id that doesn't exist via path parameter, the error is not displayed in JSON (unless you manually add the header). In the next code you can see how I solved it:

app/Exceptions/Handler.php

    public function render($request, Exception $exception)
    {
        if (in_array('api', $request->route()->middleware())) {
            $request->headers->set('Accept', 'application/json');
        }

        return parent::render($request, $exception);
    }

My workaround doesn't work in Laravel 5.4.
Yours works in Laravel 5.4 only when the validation is not using a Form Request.

It seems this middleware only works when it is a global middleware. When moved into the web or api routes, it does not seem to work.

It seems this middleware only works when it is a global middleware. When moved into the web or api routes, it does not seem to work.

You have to add it as first middleware in the api group

thanks!

You can place that middleware wherever you want in your middleware groups, just make sure that it's defined first in the $middlewarePriority array.

    protected $middlewarePriority = [
        \App\Http\Middleware\JsonOnlyMiddleware::class, // <- Make it the top priority middleware
        \Illuminate\Session\Middleware\StartSession::class,
        \Illuminate\View\Middleware\ShareErrorsFromSession::class,
        \Illuminate\Contracts\Auth\Middleware\AuthenticatesRequests::class,
        \Illuminate\Routing\Middleware\ThrottleRequests::class,
        \Illuminate\Session\Middleware\AuthenticateSession::class,
        \Illuminate\Routing\Middleware\SubstituteBindings::class,
        \Illuminate\Auth\Middleware\Authorize::class,
    ];

If you cannot see that array in your Http Kernel, copy/paste it from the parent class: Illuminate\Foundation\Http\Kernel. (I think it's been removed from 7.x by default).

Hi, thank you so much!
I noticed something. When a NotFoundHttpException happens because of sending a model id that doesn't exist via path parameter, the error is not displayed in JSON (unless you manually add the header). In the next code you can see how I solved it:

app/Exceptions/Handler.php

    public function render($request, Exception $exception)
    {
        if (in_array('api', $request->route()->middleware())) {
            $request->headers->set('Accept', 'application/json');
        }

        return parent::render($request, $exception);
    }

When it's a 404 error (route not found) there will be an exception, because $request->route() will return null.
I just change it a little:

if ($request->route() !== null && in_array('api', $request->route()->middleware())) {
    $request->headers->set('Accept', 'application/json');
}

But with this fix you'll get an HTML response as default in case when it's 404 error.

If you need 404 also in JSON, update the render function as follows. This solved for me in Laravel 6

app/Exceptions/Handler.php

public function render($request, Exception $exception)
{
        if (substr($request->server()['REQUEST_URI'],1,3) =='api') {
            $request->headers->set('Accept', 'application/json');
        }
        return parent::render($request, $exception);
}

Returns "text/html; charset=UTF-8"

Route::get('/foo', function () {
    return 'hello world';
});