Etags middleware for Laravel

Etags.php

<?php

namespace App\Http\Middleware;

use Closure;

class ETags
{
    /**
     * Implement Etag support.
     *
     * @param \Illuminate\Http\Request $request
     * @param \Closure                 $next
     *
     * @return mixed
     */
    public function handle($request, Closure $next)
    {
        // Get response
        $response = $next($request);

        // If this was a GET request...
        if ($request->isMethod('get')) {

            // Generate Etag
            $etag = md5($response->getContent());
            $requestEtag = str_replace('"', '', $request->getETags());
            $requestEtag = str_replace('W/', '', $requestEtag);

            // Check to see if Etag has changed
            if ($requestEtag && $requestEtag[0] == $etag) {
                $response->setNotModified();
            }

            // Set Etag
            $response->setEtag($etag);
        }

        // Send response
        return $response;
    }
}