Redis是一個開源的使用ANSI C語言編寫、支持網絡、可基於內存亦可持久化的日誌型、Key-Value數據庫，並提供多種語言的API。
本文將使用其incr(自增)，get(獲取)，delete(清除)方法來實現計數器類。
1.Redis計數器類代碼及演示實例
RedisCounter.class.php
<?php
/**
* PHP基於Redis計數器類
* Date: 2017-10-28
* Author: fdipzone
* Version: 1.0
*
* Descripton:
* php基於Redis實現自增計數，主要使用redis的incr方法，併發執行時保證計數自增唯一。
*
* Func:
* public incr 執行自增計數並獲取自增後的數值
* public get 獲取當前計數
* public reset 重置計數
* private connect 創建redis連接
*/
class RedisCounter{ // class start
private $_config;
private $_redis;
/**
* 初始化
* @param Array $config redis連接設定
*/
public function __construct($config){
$this->_config = $config;
$this->_redis = $this->connect();
}
/**
* 執行自增計數並獲取自增後的數值
* @param String $key 保存計數的鍵值
* @param Int $incr 自增數量，默認爲1
* @return Int
*/
public function incr($key, $incr=1){
return intval($this->_redis->incr($key, $incr));
}
/**
* 獲取當前計數
* @param String $key 保存計數的健值
* @return Int
*/
public function get($key){
return intval($this->_redis->get($key));
}
/**
* 重置計數
* @param String $key 保存計數的健值
* @return Int
*/
public function reset($key){
return $this->_redis->delete($key);
}
/**
* 創建redis連接
* @return Link
*/
private function connect(){
try{
$redis = new Redis();
$redis->connect($this->_config['host'],$this->_config['port'],$this->_config['timeout'],$this->_config['reserved'],$this->_config['retry_interval']);
if(empty($this->_config['auth'])){
$redis->auth($this->_config['auth']);
}
$redis->select($this->_config['index']);
}catch(RedisException $e){
throw new Exception($e->getMessage());
return false;
}
return $redis;
}
} // class end
?>demo.php
<?php
Require 'RedisCounter.class.php';
// redis連接設定
$config = array(
'host' => 'localhost',
'port' => 6379,
'index' => 0,
'auth' => '',
'timeout' => 1,
'reserved' => NULL,
'retry_interval' => 100,
);
// 創建RedisCounter對象
$oRedisCounter = new RedisCounter($config);
// 定義保存計數的健值
$key = 'mycounter';
// 執行自增計數，獲取當前計數，重置計數
echo $oRedisCounter->get($key).PHP_EOL; // 0
echo $oRedisCounter->incr($key).PHP_EOL; // 1
echo $oRedisCounter->incr($key, 10).PHP_EOL; // 11
echo $oRedisCounter->reset($key).PHP_EOL; // 1
echo $oRedisCounter->get($key).PHP_EOL; // 0
?>輸出：
0
1
11
1
02.併發調用計數器，檢查計數唯一性
測試代碼如下：
<?php
Require 'RedisCounter.class.php';
// redis連接設定
$config = array(
'host' => 'localhost',
'port' => 6379,
'index' => 0,
'auth' => '',
'timeout' => 1,
'reserved' => NULL,
'retry_interval' => 100,
);
// 創建RedisCounter對象
$oRedisCounter = new RedisCounter($config);
// 定義保存計數的健值
$key = 'mytestcounter';
// 執行自增計數並返回自增後的計數，記錄入臨時文件
file_put_contents('/tmp/mytest_result.log', $oRedisCounter->incr($key).PHP_EOL, FILE_APPEND);
?>測試併發執行，我們使用ab工具進行測試，設置執行150次，15個併發。
ab -c 15 -n 150 http://localhost/test.php執行結果：
ab -c 15 -n 150 http://localhost/test.php
This is ApacheBench, Version 2.3 <$Revision: 1554214 $>
Copyright 1996 Adam Twiss, Zeus Technology Ltd, http://www.zeustech.net/
Licensed to The Apache Software Foundation, http://www.apache.org/
Benchmarking home.rabbit.km.com (be patient).....done
Server Software: nginx/1.6.3
Server Hostname: localhost
Server Port: 80
Document Path: /test.php
Document Length: 0 bytes
Concurrency Level: 15
Time taken for tests: 0.173 seconds
Complete requests: 150
Failed requests: 0
Total transferred: 24150 bytes
HTML transferred: 0 bytes
Requests per second: 864.86 [#/sec] (mean)
Time per request: 17.344 [ms] (mean)
Time per request: 1.156 [ms] (mean, across all concurrent requests)
Transfer rate: 135.98 [Kbytes/sec] received
Connection Times (ms)
min mean[+/-sd] median max
Connect: 0 0 0.2 0 1
Processing: 3 16 3.2 16 23
Waiting: 3 16 3.2 16 23
Total: 4 16 3.1 17 23
Percentage of the requests served within a certain time (ms)
50% 17
66% 18
75% 18
80% 19
90% 20
95% 21
98% 22
99% 22
100% 23 (longest request)檢查計數是否唯一
生成的總計數
wc -l /tmp/mytest_result.log
150 /tmp/mytest_result.log
生成的唯一計數
sort -u /tmp/mytest_result.log | wc -l
150可以看到在併發調用的情況下，生成的計數也保證唯一。
源碼下載地址：點擊查看
