My back port to Laravel 5.1 of the Laravel 5.2 middleware feature to have the ability to throttle request coming in.

ThrottleRequest.php

<?php

namespace App\Http\Middleware;

use Closure;
use Illuminate\Http\Response;
use Illuminate\Cache\RateLimiter;

class ThrottleRequests
{
    /**
     * The rate limiter instance.
     * Add to you middleware and then you can implement on a
     * a route such as 
     * Route::get('search/{location}','SearchController@search')->middleware('throttle');
     *
     * @var \Illuminate\Cache\RateLimiter
     */
    protected $limiter;

    /**
     * Create a new request throttler.
     *
     * @param  \Illuminate\Cache\RateLimiter $limiter
     * @return void
     */
    public function __construct(RateLimiter $limiter)
    {
        $this->limiter = $limiter;
    }

    /**
     * Handle an incoming request.
     *
     * @param  \Closure $next
     * @param  int $maxAttempts
     * @param  int $decayMinutes
     * @return mixed
     */
    public function handle($request, Closure $next, $maxAttempts = 60, $decayMinutes = 1)
    {
        $key = $this->resolveRequestSignature($request);

        if ($this->limiter->tooManyAttempts($key, $maxAttempts, $decayMinutes)) {
            return new Response('Too Many Attempts.', 429, [
                'Retry-After' => $this->limiter->availableIn($key),
                'X-RateLimit-Limit' => $maxAttempts,
                'X-RateLimit-Remaining' => 0,
            ]);
        }

        $this->limiter->hit($key, $decayMinutes);

        $response = $next($request);

        $response->headers->add([
            'X-RateLimit-Limit' => $maxAttempts,
            'X-RateLimit-Remaining' => $maxAttempts - $this->limiter->attempts($key) + 1,
        ]);

        return $response;
    }

    /**
     * Resolve request signature.
     *
     * @param  \Illuminate\Http\Request $request
     * @return string
     */
    protected function resolveRequestSignature($request)
    {
        return $this->fingerprint($request);
    }

    protected function fingerprint($request)
    {
        if (!$request->route()) {
            throw new RuntimeException('Unable to generate fingerprint. Route unavailable.');
        }

        return sha1(
            implode('|', $request->route()->methods()) .
            '|' . $request->route()->domain() .
            '|' . $request->route()->uri() .
            '|' . $request->ip()
        );
    }
}