Laravel 5: Handle exceptions when request wants JSON

Question

I'm doing file uploads via AJAX on Laravel 5. I've got pretty much everything working except one thing.

When I try to upload a file that is too big (Bigger than upload_max_filesize and post_max_size I get a TokenMismatchException thrown.

This is to be expected however, because I know that my input will be empty if these limits are being exceeded. Empty input, means no _token is received hence why the middleware responsible for verifying CSRF tokens is kicking up a fuss.

My issue however is not that this exception is being thrown, it is how it is being rendered. When this exception is being caught by Laravel it's spitting out the HTML for the generic Whoops page (With a load of stack tracing since I'm in debug mode).

What's the best way to handle this exception so that JSON is returned over AJAX (Or when JSON is requested) while keeping the default behaviour otherwise?

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Edit: This seems to happen regardless of the exception thrown. I've just tried making a request via AJAX (Datatype: JSON) to a 'page' that doesn't exist in an attempt to get a 404 and the same thing happens - HTML is returned, nothing JSON friendly.

Answer 1

I'm going to take a shot at this one myself taking into account the answer given by @Wader and the comments from @Tyler Crompton:

app/Exceptions/Handler.php

/**
 * Render an exception into an HTTP response.
 *
 * @param  \Illuminate\Http\Request  $request
 * @param  \Exception $e
 * @return \Illuminate\Http\Response
 */
public function render($request, Exception $e)
{
    // If the request wants JSON (AJAX doesn't always want JSON)
    if ($request->wantsJson()) {
        // Define the response
        $response = [
            'errors' => 'Sorry, something went wrong.'
        ];

        // If the app is in debug mode
        if (config('app.debug')) {
            // Add the exception class name, message and stack trace to response
            $response['exception'] = get_class($e); // Reflection might be better here
            $response['message'] = $e->getMessage();
            $response['trace'] = $e->getTrace();
        }

        // Default response of 400
        $status = 400;

        // If this exception is an instance of HttpException
        if ($this->isHttpException($e)) {
            // Grab the HTTP status code from the Exception
            $status = $e->getStatusCode();
        }

        // Return a JSON response with the response array and status code
        return response()->json($response, $status);
    }

    // Default to the parent class' implementation of handler
    return parent::render($request, $e);
}