頻率限制

• 簡介

  • 快取設定

• 基礎用法

  • 手動增加嘗試次數
  • 清除嘗試次數

簡介

Laravel includes a simple to use rate limiting abstraction which, in conjunction with your application's cache, provides an easy way to limit any action during a specified window of time.

快取設定

一般來說，Rate Limiter 會使用專案中 cache 設定檔 default 索引鍵上所定義的預設快取。不過，我們可以在專案的 cache 設定檔中定義 limiter 索引鍵來指定 Rate Limiter 要使用哪個快取 Driver：

1'default' => 'memcached',
2 
3'limiter' => 'redis',
1'default' => 'memcached',
2 
3'limiter' => 'redis',

基礎用法

可通過 Illuminate\Support\Facades\RateLimiter Facade 來使用 Rate Limiter。Rate Limiter 所提供的最簡單的方法是 attempt 方法，該方法會對給定閉包以給定秒數來做頻率限制。

若該回呼已無法再嘗試，則 attempt 方法會回傳 false。若還能繼續嘗試，則 attempt 會回傳該回呼的執行結果或 true。attempt 方法的第一個引數為 Rate Limiter 的「索引鍵」，索引鍵可以是任意字串，用來表示要被頻率限制的動作：

 1use Illuminate\Support\Facades\RateLimiter;
 2 
 3$executed = RateLimiter::attempt(
 4    'send-message:'.$user->id,
 5    $perMinute = 5,
 6    function() {
 7        // Send message...
 8    }
 9);
10 
11if (! $executed) {
12  return 'Too many messages sent!';
13}
 1use Illuminate\Support\Facades\RateLimiter;
 2 
 3$executed = RateLimiter::attempt(
 4    'send-message:'.$user->id,
 5    $perMinute = 5,
 6    function() {
 7        // Send message...
 8    }
 9);
10 
11if (! $executed) {
12  return 'Too many messages sent!';
13}

如有需要，可以為 attempt 方法提供第四個「Decay Rate」引數，或是直到頻率限制被重設前的秒數。例如，我們可以將上面的範例改為每 2 分鐘允許 5 次嘗試：

1$executed = RateLimiter::attempt(
2    'send-message:'.$user->id,
3    $perTwoMinutes = 5,
4    function() {
5        // Send message...
6    },
7    $decayRate = 120,
8);
1$executed = RateLimiter::attempt(
2    'send-message:'.$user->id,
3    $perTwoMinutes = 5,
4    function() {
5        // Send message...
6    },
7    $decayRate = 120,
8);

手動增加嘗試次數

若想手動使用 Rate Limiter，則還有其他許多能使用的方法。舉例來說，我們可以叫用 tooManyAttempts 方法來判斷給定的 Rate Limiter 索引鍵是否已遇到其每分鐘所允許的最大嘗試次數：

1use Illuminate\Support\Facades\RateLimiter;
2 
3if (RateLimiter::tooManyAttempts('send-message:'.$user->id, $perMinute = 5)) {
4    return 'Too many attempts!';
5}
6 
7RateLimiter::increment('send-message:'.$user->id);
8 
9// Send message...
1use Illuminate\Support\Facades\RateLimiter;
2 
3if (RateLimiter::tooManyAttempts('send-message:'.$user->id, $perMinute = 5)) {
4    return 'Too many attempts!';
5}
6 
7RateLimiter::increment('send-message:'.$user->id);
8 
9// Send message...

Alternatively, you may use the remaining method to retrieve the number of attempts remaining for a given key. If a given key has retries remaining, you may invoke the increment method to increment the number of total attempts:

1use Illuminate\Support\Facades\RateLimiter;
2 
3if (RateLimiter::remaining('send-message:'.$user->id, $perMinute = 5)) {
4    RateLimiter::increment('send-message:'.$user->id);
5 
6    // Send message...
7}
1use Illuminate\Support\Facades\RateLimiter;
2 
3if (RateLimiter::remaining('send-message:'.$user->id, $perMinute = 5)) {
4    RateLimiter::increment('send-message:'.$user->id);
5 
6    // Send message...
7}

If you would like to increment the value for a given rate limiter key by more than one, you may provide the desired amount to the increment method:

1RateLimiter::increment('send-message:'.$user->id, amount: 5);
1RateLimiter::increment('send-message:'.$user->id, amount: 5);

判斷 Limiter 是否可用

若某個索引鍵已無可用的嘗試次數，則 availableIn 方法會回傳距離下次可獲得嘗試次數的剩餘秒數：

 1use Illuminate\Support\Facades\RateLimiter;
 2 
 3if (RateLimiter::tooManyAttempts('send-message:'.$user->id, $perMinute = 5)) {
 4    $seconds = RateLimiter::availableIn('send-message:'.$user->id);
 5 
 6    return 'You may try again in '.$seconds.' seconds.';
 7}
 8 
 9RateLimiter::increment('send-message:'.$user->id);
10 
11// Send message...
 1use Illuminate\Support\Facades\RateLimiter;
 2 
 3if (RateLimiter::tooManyAttempts('send-message:'.$user->id, $perMinute = 5)) {
 4    $seconds = RateLimiter::availableIn('send-message:'.$user->id);
 5 
 6    return 'You may try again in '.$seconds.' seconds.';
 7}
 8 
 9RateLimiter::increment('send-message:'.$user->id);
10 
11// Send message...

清除嘗試次數

可使用 clear 方法來重設給定 Rate Limiter 索引鍵的嘗試次數。舉例來說，我們可以在收件人已閱讀某個訊息後重設嘗試次數：

 1use App\Models\Message;
 2use Illuminate\Support\Facades\RateLimiter;
 3 
 4/**
 5 * Mark the message as read.
 6 */
 7public function read(Message $message): Message
 8{
 9    $message->markAsRead();
10 
11    RateLimiter::clear('send-message:'.$message->user_id);
12 
13    return $message;
14}
 1use App\Models\Message;
 2use Illuminate\Support\Facades\RateLimiter;
 3 
 4/**
 5 * Mark the message as read.
 6 */
 7public function read(Message $message): Message
 8{
 9    $message->markAsRead();
10 
11    RateLimiter::clear('send-message:'.$message->user_id);
12 
13    return $message;
14}