本文實(shí)例講述了PHP+redis實(shí)現(xiàn)的限制搶購(gòu)防止商品超發(fā)功能。分享給大家供大家參考，具體如下：
- redis不僅僅是單純的緩存，它還有一些特殊的功能，在一些特殊場(chǎng)景上很好用。redis中key的原子自增incrby和判斷key不存在再寫入的setnx方法，可以有效的防止超發(fā)。
- 下面使用兩個(gè)不同的方式來(lái)說(shuō)明利用redis做商品購(gòu)買庫(kù)存數(shù)量限制。
- 業(yè)務(wù)場(chǎng)景很簡(jiǎn)單，就是限制搶購(gòu)5個(gè)商品，模擬并發(fā)請(qǐng)求搶購(gòu)商品，每搶購(gòu)一次對(duì)應(yīng)redis中的key值增加一次，通過(guò)判斷限購(gòu)的數(shù)量來(lái)限制搶購(gòu)，搶購(gòu)成功寫入成功日志，失敗寫入失敗的信息記錄，通過(guò)記錄的數(shù)量來(lái)判斷是否超發(fā)。
文件index.php
?php
require_once './myRedis.php';
require_once './function.php';
class sendAward{
public $conf = [];
const V1 = 'way1';//版本一
const V2 = 'way2';//版本二
const AMOUNTLIMIT = 5;//搶購(gòu)數(shù)量限制
const INCRAMOUNT = 1;//redis遞增數(shù)量值
//初始化調(diào)用對(duì)應(yīng)方法執(zhí)行商品發(fā)放
public function __construct($conf,$type){
$this->conf = $conf;
if(empty($type))
return '';
if($type==self::V1){
$this->way1(self::V1);
}elseif($type==self::V2){
$this->way2(self::V2);
}else{
return '';
}
}
//搶購(gòu)商品方式一
protected function way1($v){
$redis = new myRedis($this->conf);
$keyNmae = getKeyName($v);
if(!$redis->exists($keyNmae)){
$redis->set($keyNmae,0);
}
$currAmount = $redis->get($keyNmae);
if(($currAmount+self::INCRAMOUNT)>self::AMOUNTLIMIT){
writeLog("沒(méi)有搶到商品",$v);
return;
}
$redis->incrby($keyNmae,self::INCRAMOUNT);
writeLog("搶到商品",$v);
}
//搶購(gòu)商品方式二
protected function way2($v){
$redis = new myRedis($this->conf);
$keyNmae = getKeyName($v);
if(!$redis->exists($keyNmae)){
$redis->setnx($keyNmae,0);
}
if($redis->incrby($keyNmae,self::INCRAMOUNT) > self::AMOUNTLIMIT){
writeLog("沒(méi)有搶到商品",$v);
return;
}
writeLog("搶到商品",$v);
}
}
//實(shí)例化調(diào)用對(duì)應(yīng)執(zhí)行方法
$type = isset($_GET['v'])?$_GET['v']:'way1';
$conf = [
'host'=>'192.168.0.214','port'=>'6379',
'auth'=>'test','db'=>2,
];
new sendAward($conf,$type);
文件myRedis.php
?php
/**
* @desc 自定義redis操作類
* **/
class myRedis{
public $handler = NULL;
public function __construct($conf){
$this->handler = new Redis();
$this->handler->connect($conf['host'], $conf['port']); //連接Redis
//設(shè)置密碼
if(isset($conf['auth'])){
$this->handler->auth($conf['auth']); //密碼驗(yàn)證
}
//選擇數(shù)據(jù)庫(kù)
if(isset($conf['db'])){
$this->handler->select($conf['db']);//選擇數(shù)據(jù)庫(kù)2
}else{
$this->handler->select(0);//默認(rèn)選擇0庫(kù)
}
}
//獲取key的值
public function get($name){
return $this->handler->get($name);
}
//設(shè)置key的值
public function set($name,$value){
return $this->handler->set($name,$value);
}
//判斷key是否存在
public function exists($key){
if($this->handler->exists($key)){
return true;
}
return false;
}
//當(dāng)key不存在的設(shè)置key的值，存在則不設(shè)置
public function setnx($key,$value){
return $this->handler->setnx($key,$value);
}
//將key的數(shù)值增加指定數(shù)值
public function incrby($key,$value){
return $this->handler->incrBy($key,$value);
}
}
文件function.php
?php
//獲取商品key名稱
function getKeyName($v)
{
return "send_goods_".$v;
}
//日志寫入方法
function writeLog($msg,$v)
{
$log = $msg.PHP_EOL;
file_put_contents("log/$v.log",$log,FILE_APPEND);
}
1.ab工具并發(fā)測(cè)試way1方法
[root@localhost oversend]# ab -c 100 -n 200 http://192.168.0.213:8083/index.php?v=way1
This is ApacheBench, Version 2.3 $Revision: 655654 $>
Copyright 1996 Adam Twiss, Zeus Technology Ltd, http://www.zeustech.net/
Licensed to The Apache Software Foundation, http://www.apache.org/
Benchmarking 192.168.0.213 (be patient)
Completed 100 requests
Completed 200 requests
Finished 200 requests
Server Software: nginx
Server Hostname: 192.168.0.213
Server Port: 8083
Document Path: /index.php?v=way1
Document Length: 0 bytes
Concurrency Level: 100
Time taken for tests: 0.089 seconds
Complete requests: 200
Failed requests: 0
Write errors: 0
Total transferred: 30600 bytes
HTML transferred: 0 bytes
Requests per second: 2243.13 [#/sec] (mean)
Time per request: 44.581 [ms] (mean)
Time per request: 0.446 [ms] (mean, across all concurrent requests)
Transfer rate: 335.16 [Kbytes/sec] received
Connection Times (ms)
min mean[+/-sd] median max
Connect: 0 6 2.2 5 17
Processing: 2 28 16.3 25 55
Waiting: 1 26 15.2 24 50
Total: 5 34 16.3 30 60
Percentage of the requests served within a certain time (ms)
50% 30
66% 35
75% 54
80% 56
90% 57
95% 60
98% 60
99% 60
100% 60 (longest request)
v1方法日志分析
[root@localhost log]# less -N way1.log
1 搶到商品
2 搶到商品
3 搶到商品
4 搶到商品
5 搶到商品
6 搶到商品
7 沒(méi)有搶到商品
8 沒(méi)有搶到商品
9 沒(méi)有搶到商品
10 沒(méi)有搶到商品
11 沒(méi)有搶到商品
12 沒(méi)有搶到商品
觀察日志發(fā)現(xiàn) 搶到商品的記錄有6條超過(guò)正常的5條，說(shuō)明超發(fā)了
2.ab工具并發(fā)測(cè)試way2方法
[root@localhost oversend]# ab -c 100 -n 200 http://192.168.0.213:8083/index.php?v=way2
This is ApacheBench, Version 2.3 $Revision: 655654 $>
Copyright 1996 Adam Twiss, Zeus Technology Ltd, http://www.zeustech.net/
Licensed to The Apache Software Foundation, http://www.apache.org/
Benchmarking 192.168.0.213 (be patient)
Completed 100 requests
Completed 200 requests
Finished 200 requests
Server Software: nginx
Server Hostname: 192.168.0.213
Server Port: 8083
Document Path: /index.php?v=way2
Document Length: 0 bytes
Concurrency Level: 100
Time taken for tests: 0.087 seconds
Complete requests: 200
Failed requests: 0
Write errors: 0
Total transferred: 31059 bytes
HTML transferred: 0 bytes
Requests per second: 2311.68 [#/sec] (mean)
Time per request: 43.259 [ms] (mean)
Time per request: 0.433 [ms] (mean, across all concurrent requests)
Transfer rate: 350.58 [Kbytes/sec] received
Connection Times (ms)
min mean[+/-sd] median max
Connect: 0 6 5.4 5 13
Processing: 3 31 16.6 30 70
Waiting: 1 30 16.6 30 70
Total: 5 37 18.5 32 82
Percentage of the requests served within a certain time (ms)
50% 32
66% 41
75% 45
80% 50
90% 68
95% 80
98% 81
99% 82
100% 82 (longest request)
v2方法日志分析
[root@localhost log]# less -N v2.log
[root@localhost log]# less -N way2.log
1 搶到商品
2 搶到商品
3 搶到商品
4 搶到商品
5 沒(méi)有搶到商品
6 搶到商品
7 沒(méi)有搶到商品
8 沒(méi)有搶到商品
9 沒(méi)有搶到商品
10 沒(méi)有搶到商品
總結(jié)：觀察日志可知搶到商品的日志記錄是5條并沒(méi)有超發(fā)，說(shuō)明利用這種方式可以限制住庫(kù)存的數(shù)量。之所以超發(fā)是因?yàn)榉椒ㄒ恢型ㄟ^(guò)加法來(lái)判斷限制條件的同時(shí)，并發(fā)一大，就會(huì)越過(guò)這個(gè)判斷條件出現(xiàn)會(huì)超發(fā)，redis的在這方面就體現(xiàn)優(yōu)勢(shì)了。
完整代碼github地址
更多關(guān)于PHP相關(guān)內(nèi)容感興趣的讀者可查看本站專題：《php+redis數(shù)據(jù)庫(kù)程序設(shè)計(jì)技巧總結(jié)》、《php面向?qū)ο蟪绦蛟O(shè)計(jì)入門教程》、《PHP基本語(yǔ)法入門教程》、《PHP數(shù)組(Array)操作技巧大全》、《php字符串(string)用法總結(jié)》、《php+mysql數(shù)據(jù)庫(kù)操作入門教程》及《php常見(jiàn)數(shù)據(jù)庫(kù)操作技巧匯總》
希望本文所述對(duì)大家PHP程序設(shè)計(jì)有所幫助。
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