纯PHP实现定时器任务（Timer），php实现定时器timer-php手册-php.cn

纯PHP实现定时器任务（Timer），php实现定时器timer

　　定时器任务，在WEB应用比较常见，如何使用PHP实现定时器任务，大致有两种方案：1）使用Crontab命令，写一个shell脚本，在脚本中调用PHP文件,然后定期执行该脚本；2）配合使用ignore_user_abort()和set_time_limit()，使脚本脱离浏览器运行。前者是利用Linux的特性，和PHP本身没有多大关系，后者使用场景有限，且只能由一次HTTP请求触发该脚本，执行完后退出。那么我们如何使用纯PHP实现纯粹的定时器任务，且能适应认识任务业务需求？

基础知识

　　此程序在Linux下开发，以cli模式运行，一下是基本知识的简要介绍。

CLI：PHP的命令行模式，常见的WEB应用使用的是fpm；
进程：进程是程序运行的基本单元，进程之间是独立运行且互不干扰的，有独立的运行空间，每个进程都有一个进程控制块；
进程间通信：既然进程是独立运行，我们需要一种机制保证不同进程信息的交换，进程间通信主要包括：管道，IPC（共享内存，信号，消息队列），套接字；
PCNTL扩展：PHP的一个进程扩展，主要用到pcntl_alarm()函数，详细介绍请查阅官网.

实现原理　　　　

　　用一个三维数组保存所有需要执行的任务，一级索引为时间戳,值为执行任务的方法、回调参数等,具体数组形式如下:

<span>array</span><span>(
        </span>'1438156396' => <span>array</span><span>(
                </span><span>array</span>(1,<span>array</span>('Class','Func'), <span>array</span>(), <span>true</span>),<span>  
        )
)
说明</span>:
1438156396<span> 时间戳
</span><span>array</span>(1,<span>array</span>('Class','Func'), <span>array</span>(), <span>true</span><span>) 
参数依次表示</span>: 执行时间间隔,回调函数,传递给回调函数的参数,是否持久化(ture则一直保存在数据中,否则执行一次后删除)

Salin selepas log masuk

　　这些任务可以是任意类的方法。既然是定时任务，我们需要一个类似计时的东东，此方案采用信号量去做，每一秒向当前进程发送SIGALRM信号，并捕获该信号，触发信号处理函数，循环遍历数据，判断是否有当前时间需要执行的任务。如果有则采用回调方式触发，并把参数传递给该方法。

<span>  1</span> <?<span>php
</span><span>  2</span> <span>/*</span><span>*
</span><span>  3</span> <span>*定时器
</span><span>  4</span> <span>*/</span>
<span>  5</span> <span>class</span><span> Timer
</span><span>  6</span> <span>{
</span><span>  7</span>     <span>//</span><span>保存所有定时任务</span>
<span>  8</span>     <span>public</span> <span>static</span> <span>$task</span> = <span>array</span><span>();
</span><span>  9</span> 
<span> 10</span>         <span>//</span><span>定时间隔</span>
<span> 11</span>         <span>public</span> <span>static</span> <span>$time</span> = 1<span>;
</span><span> 12</span> 
<span> 13</span>         <span>/*</span><span>*
</span><span> 14</span> <span>    *开启服务
</span><span> 15</span> <span>        *@param $time int
</span><span> 16</span>        <span>*/</span>
<span> 17</span>     <span>public</span> <span>static</span> <span>function</span> run(<span>$time</span> = <span>null</span><span>)
</span><span> 18</span> <span>        {
</span><span> 19</span>         <span>if</span>(<span>$time</span><span>)
</span><span> 20</span> <span>            {
</span><span> 21</span>                     self::<span>$time</span> = <span>$time</span><span>;
</span><span> 22</span> <span>            }
</span><span> 23</span>             self::<span>installHandler();
</span><span> 24</span>             pcntl_alarm(1<span>);
</span><span> 25</span> <span>         }
</span><span> 26</span>         <span>/*</span><span>*
</span><span> 27</span> <span>        *注册信号处理函数
</span><span> 28</span>         <span>*/</span>
<span> 29</span>         <span>public</span> <span>static</span> <span>function</span><span> installHandler()
</span><span> 30</span> <span>        {
</span><span> 31</span>             pcntl_signal(SIGALRM, <span>array</span>('Timer','signalHandler'<span>));
</span><span> 32</span> <span>        }
</span><span> 33</span> 
<span> 34</span>         <span>/*</span><span>*
</span><span> 35</span> <span>        *信号处理函数
</span><span> 36</span>         <span>*/</span>
<span> 37</span>         <span>public</span> <span>static</span> <span>function</span><span> signalHandler()
</span><span> 38</span> <span>        {
</span><span> 39</span>             self::<span>task();
</span><span> 40</span>         <span>//</span><span>一次信号事件执行完成后,再触发下一次</span>
<span> 41</span>         pcntl_alarm(self::<span>$time</span><span>);
</span><span> 42</span> <span>        }
</span><span> 43</span> 
<span> 44</span>         <span>/*</span><span>*
</span><span> 45</span> <span>        *执行回调
</span><span> 46</span>         <span>*/</span>
<span> 47</span>         <span>public</span> <span>static</span> <span>function</span><span> task()
</span><span> 48</span> <span>        {
</span><span> 49</span>             <span>if</span>(<span>empty</span>(self::<span>$task</span><span>))
</span><span> 50</span>             {<span>//</span><span>没有任务,返回</span>
<span> 51</span>                     <span>return</span><span> ;
</span><span> 52</span> <span>            }
</span><span> 53</span>             <span>foreach</span>(self::<span>$task</span> <span>as</span> <span>$time</span> => <span>$arr</span><span>)
</span><span> 54</span> <span>        {
</span><span> 55</span>                     <span>$current</span> = <span>time</span><span>();
</span><span> 56</span>         
<span> 57</span>                 <span>foreach</span>(<span>$arr</span> <span>as</span> <span>$k</span> => <span>$job</span><span>)
</span><span> 58</span>             {<span>//</span><span>遍历每一个任务</span>
<span> 59</span>                         <span>$func</span> = <span>$job</span>['func'];    <span>/*</span><span>回调函数</span><span>*/</span>
<span> 60</span>                         <span>$argv</span> = <span>$job</span>['argv'];    <span>/*</span><span>回调函数参数</span><span>*/</span>
<span> 61</span>                 <span>$interval</span> = <span>$job</span>['interval'];    <span>/*</span><span>时间间隔</span><span>*/</span>
<span> 62</span>                         <span>$persist</span> = <span>$job</span>['persist'];    <span>/*</span><span>持久化</span><span>*/</span>
<span> 63</span> 
<span> 64</span>                         <span>if</span>(<span>$current</span> == <span>$time</span><span>)
</span><span> 65</span>                         {<span>//</span><span>当前时间有执行任务
</span><span> 66</span> 
<span> 67</span> <span>                    //调用回调函数,并传递参数</span>
<span> 68</span>                                <span>call_user_func_array</span>(<span>$func</span>, <span>$argv</span><span>);
</span><span> 69</span>                     
<span> 70</span>                     <span>//</span><span>删除该任务</span>
<span> 71</span>                             <span>unset</span>(self::<span>$task</span>[<span>$time</span>][<span>$k</span><span>]);
</span><span> 72</span> <span>                        }
</span><span> 73</span>                         <span>if</span>(<span>$persist</span><span>)
</span><span> 74</span>                         {<span>//</span><span>如果做持久化,则写入数组,等待下次唤醒</span>
<span> 75</span>                                self::<span>$task</span>[<span>$current</span>+<span>$interval</span>][] = <span>$job</span><span>;
</span><span> 76</span> <span>                        }
</span><span> 77</span> <span>            }
</span><span> 78</span>             <span>if</span>(<span>empty</span>(self::<span>$task</span>[<span>$time</span><span>]))
</span><span> 79</span> <span>            {
</span><span> 80</span>                 <span>unset</span>(self::<span>$task</span>[<span>$time</span><span>]);
</span><span> 81</span> <span>            }
</span><span> 82</span> <span>            }
</span><span> 83</span> <span>        }
</span><span> 84</span> 
<span> 85</span>         <span>/*</span><span>*
</span><span> 86</span> <span>        *添加任务
</span><span> 87</span>         <span>*/</span>
<span> 88</span>         <span>public</span> <span>static</span> <span>function</span> add(<span>$interval</span>, <span>$func</span>, <span>$argv</span> = <span>array</span>(), <span>$persist</span> = <span>false</span><span>)
</span><span> 89</span> <span>        {
</span><span> 90</span>             <span>if</span>(<span>is_null</span>(<span>$interval</span><span>))
</span><span> 91</span> <span>            {
</span><span> 92</span>                 <span>return</span><span>;
</span><span> 93</span> <span>            }
</span><span> 94</span>             <span>$time</span> = <span>time</span>()+<span>$interval</span><span>;
</span><span> 95</span>         <span>//</span><span>写入定时任务</span>
<span> 96</span>         self::<span>$task</span>[<span>$time</span>][] = <span>array</span>('func'=><span>$func</span>, 'argv'=><span>$argv</span>, 'interval'=><span>$interval</span>, 'persist'=><span>$persist</span><span>);
</span><span> 97</span> <span>        }
</span><span> 98</span> 
<span> 99</span>         <span>/*</span><span>*
</span><span>100</span> <span>        *删除所有定时器任务
</span><span>101</span>         <span>*/</span>
<span>102</span>         <span>public</span> <span>function</span><span> dellAll()
</span><span>103</span> <span>        {
</span><span>104</span>             self::<span>$task</span> = <span>array</span><span>();
</span><span>105</span> <span>        }
</span><span>106</span> }

Salin selepas log masuk

　　这是定时器类核心部分,有一个静态变量保存有所有需要执行的任务,这里为什么是静态的呢?大家自行思考.当进程接受到 SIGALRM 信号后,触发 signalHandler 函数,随后循序遍历数组查看是否有当前时间需要执行的任务,有则回调,并传递参数,删除当前job,随后检查是否要做持久化任务,是则继续将当前job写入事件数组等待下次触发,最后再为当前进程设置一个闹钟信号.可以看出这个定时器,只要触发一次就会从内部再次触发,得到自循环目的.

<span> 1</span> <?<span>php
</span><span> 2</span> 
<span> 3</span> <span>class</span><span> DoJob
</span><span> 4</span> <span>{
</span><span> 5</span>     <span>public</span> <span>function</span> job( <span>$param</span> = <span>array</span><span>() )
</span><span> 6</span> <span>    {
</span><span> 7</span>         <span>$time</span> = <span>time</span><span>();
</span><span> 8</span>         <span>echo</span> "Time: {<span>$time</span>}, Func: ".<span>get_class</span>()."::".<span>__FUNCTION__</span>."(".json_encode(<span>$param</span>).")\n"<span>;
</span><span> 9</span> <span>    }
</span><span>10</span> }

Salin selepas log masuk

　　这是回调类及函数,为方便说明,加入不少调试信息.Timer类及回调都有了,我们看看使用场景是怎么样的.

<span> 1</span> <?<span>php
</span><span> 2</span> 
<span> 3</span> <span>require_once</span>(__DIR__."/Timer.php"<span>);
</span><span> 4</span> <span>require_once</span>(__DIR__."/DoJob.php"<span>);
</span><span> 5</span> 
<span> 6</span> 
<span> 7</span> Timer::<span>dellAll();
</span><span> 8</span> 
<span> 9</span> Timer::add( 1, <span>array</span>('DoJob','job'), <span>array</span>(),<span>true</span><span>);
</span><span>10</span> 
<span>11</span> Timer::add( 3, <span>array</span>('DoJob','job'),<span>array</span>('a'=>1), <span>false</span><span>);
</span><span>12</span> 
<span>13</span> <span>echo</span> "Time start: ".<span>time</span>()."\n"<span>;
</span><span>14</span> Timer::<span>run();
</span><span>15</span> 
<span>16</span> <span>while</span>(1<span>)
</span><span>17</span> <span>{
</span><span>18</span>     <span>sleep</span>(1<span>);
</span><span>19</span> <span>    pcntl_signal_dispatch();
</span><span>20</span> }

Salin selepas log masuk

　　代码非常短,这里注册了两个job,随后运行定时器,在一个无限循环里捕捉信号触发动作,如果不捕获将无法触发事先注册的处理函数.这样一个自循环的定时器开发完成.运行结果如下:

　　如我们场景类添加的任务一样,在90的时候执行了两个任务,一个为持久化的不带参数的job,一个为非持久化带参数的job,随后非持久化job不再执行.

总结

在收到信号前,当前进程不能退出.这里我使用了条件永远为真的循环.在我们实际生产环境中,需要创造这么一个先决条件,比如说,我们有一组服务,这些服务都是一直运行的,不管是IO访问,等待socket链接等等,当前服务都不会终止,即使进程阻塞也不会有问题,这种场景,也就是有一个一直运行的服务中使用.
目前PHP只支持以秒为单位的触发,不支持更小时间单位,对位定时任务而言基本足够