php socket如何实现长连接
<p><strong>长连接是什么？</strong></p><p> </p>
<p>朋友们应该都见过很多在线聊天工具和网页在线聊天的工具。学校内有一种熟悉的功能，如果有人回复你了，网站会马上出现提示，此时你并没有刷新页面；Gmail也有此功能，如果邮箱里收到了新的邮件，网站会马上提醒你，即使你的网页一直未刷新过。说到这里大家肯定不陌生，就是复用一个链接持续不断的进行数据交互。在现下很多互联网业务场景都需要长连接的支持，比如：游戏、聊天、信息推送等等等，这么多类似的功能都离不开长连接。前一章节介绍了php socket通信，本章来介绍一下php socket长连接。</p>
<p><strong>长连接和短链接</strong></p>
<p>短连接一般都是单项请求数据，服务器不能主动把数据“推”想客户端，但有了长连接就好多了，利用后端与前端的技术组合起来，可以实现服务器的“推送信息”功能，如果数据库里面有更新，后端程序可以立即把数据“推送出来”，而不要多次反复请求，多次建立连接，多次断开。</p>
<p>其大概有如下的几种解释：</p>
<ol class=" list-paddingleft-2">
<li>
<p>所谓长连接指建立SOCKET连接后不管是否使用都保持连接，但安全性较差；所谓短连接指建立SOCKET连接后发送后接收完数据后马上断开连接，一般银行都使用短连接</p>
</li>
<li>
<p>长连接就是指在基于tcp的通讯中，一直保持连接，不管当前是否发送或者接收数据。而短连接就是只有在有数据传输的时候才进行连接，客户－服务器通信/传输数据完毕就关闭连接。</p>
</li>
<li>
<p>通信方式 <br>各网元之间共有两种连接方式：长连接和短连接。所谓长连接，指在一个TCP连接上可以连续发送多个数据包，在TCP连接保持期间，如果没有数据包发送，需 要双方发检测包以维持此连接。短连接是指通信双方有数据交互时，就建立一个TCP连接，数据发送完成后，则断开此TCP连接，即每次TCP连接只完成一对 CMPP消息的发送。 <br>现阶段，要求ISMG之间必须采用长连接的通信方式，建议SP与ISMG之间采用长连接的通信方式。</p>
</li>
<li>
<p>短连接：比如http的，只是连接、请求、关闭，过程时间较短,服务器若是一段时间内没有收到请求即可关闭连接。长连接：有些服务需要长时间连接到服务器，比如CMPP，一般需要自己做在线维持。</p>
</li>
</ol>
<p><strong>实现socket长连接</strong></p>
<p>每次我们访问PHP脚本的时候，都是当所有的PHP脚本执行完成后，我们才得到返回结果。如果我们需要一个脚本持续的运行，那么我们就要通过php长连接的方式，来达到运行目的。</p>
<p>想要玩长连接就需要跟socket打交道，socket的封装自然是少不的了。下面就通过代码来进行socket长连接。</p>
<p><strong>其实例代码如下：</strong></p>
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<p class="line number1 index0 alt2">1</p>
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<p class="line number37 index36 alt2">37</p>
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</td>
<td class="code">
<div class="container">
<p class="line number1 index0 alt2"><code class="php plain"><?php</code></p>
<p class="line number2 index1 alt1"><code class="php variable">$sfd</code> <code class="php plain">= socket_create(AF_INET, SOCK_STREAM, 0); </code></p>
<p class="line number3 index2 alt2"><code class="php plain">socket_bind(</code><code class="php variable">$sfd</code><code class="php plain">, </code><code class="php string">"0.0.0.0"</code><code class="php plain">, 1234); </code></p>
<p class="line number4 index3 alt1"><code class="php plain">socket_listen(</code><code class="php variable">$sfd</code><code class="php plain">, 511); </code></p>
<p class="line number5 index4 alt2"><code class="php plain">socket_set_option(</code><code class="php variable">$sfd</code><code class="php plain">, SOL_SOCKET, SO_REUSEADDR, 1); </code></p>
<p class="line number6 index5 alt1"><code class="php plain">socket_set_nonblock(</code><code class="php variable">$sfd</code><code class="php plain">); </code></p>
<p class="line number7 index6 alt2"><code class="php variable">$rfds</code> <code class="php plain">= </code><code class="php keyword">array</code><code class="php plain">(</code><code class="php variable">$sfd</code><code class="php plain">); </code></p>
<p class="line number8 index7 alt1"><code class="php variable">$wfds</code> <code class="php plain">= </code><code class="php keyword">array</code><code class="php plain">(); </code></p>
<p class="line number9 index8 alt2"><code class="php spaces"> </code> </p>
<p class="line number10 index9 alt1"><code class="php keyword">do</code><code class="php plain">{ </code></p>
<p class="line number11 index10 alt2"><code class="php spaces"> </code><code class="php variable">$rs</code> <code class="php plain">= </code><code class="php variable">$rfds</code><code class="php plain">; </code></p>
<p class="line number12 index11 alt1"><code class="php spaces"> </code><code class="php variable">$ws</code> <code class="php plain">= </code><code class="php variable">$wfds</code><code class="php plain">; </code></p>
<p class="line number13 index12 alt2"><code class="php spaces"> </code><code class="php variable">$es</code> <code class="php plain">= </code><code class="php keyword">array</code><code class="php plain">(); </code></p>
<p class="line number14 index13 alt1"><code class="php spaces"> </code><code class="php variable">$ret</code> <code class="php plain">= socket_select(</code><code class="php variable">$rs</code><code class="php plain">, </code><code class="php variable">$ws</code><code class="php plain">, </code><code class="php variable">$es</code><code class="php plain">, 3); </code></p>
<p class="line number15 index14 alt2"><code class="php spaces"> </code><code class="php comments">//读取事件 </code></p>
<p class="line number16 index15 alt1"><code class="php spaces"> </code><code class="php keyword">foreach</code><code class="php plain">(</code><code class="php variable">$rs</code> <code class="php keyword">as</code> <code class="php variable">$fd</code><code class="php plain">){ </code></p>
<p class="line number17 index16 alt2"><code class="php spaces"> </code><code class="php keyword">if</code><code class="php plain">(</code><code class="php variable">$fd</code> <code class="php plain">== </code><code class="php variable">$sfd</code><code class="php plain">){ </code></p>
<p class="line number18 index17 alt1"><code class="php spaces"> </code><code class="php variable">$cfd</code> <code class="php plain">= socket_accept(</code><code class="php variable">$sfd</code><code class="php plain">); </code></p>
<p class="line number19 index18 alt2"><code class="php spaces"> </code><code class="php plain">socket_set_nonblock(</code><code class="php variable">$cfd</code><code class="php plain">); </code></p>
<p class="line number20 index19 alt1"><code class="php spaces"> </code><code class="php variable">$rfds</code><code class="php plain">[] = </code><code class="php variable">$cfd</code><code class="php plain">; </code></p>
<p class="line number21 index20 alt2"><code class="php spaces"> </code><code class="php functions">echo</code> <code class="php string">"new client coming, fd=$cfd\n"</code><code class="php plain">; </code></p>
<p class="line number22 index21 alt1"><code class="php spaces"> </code><code class="php plain">}</code><code class="php keyword">else</code><code class="php plain">{ </code></p>
<p class="line number23 index22 alt2"><code class="php spaces"> </code><code class="php variable">$msg</code> <code class="php plain">= socket_read(</code><code class="php variable">$fd</code><code class="php plain">, 1024); </code></p>
<p class="line number24 index23 alt1"><code class="php spaces"> </code> </p>
<p class="line number25 index24 alt2"><code class="php spaces"> </code><code class="php keyword">if</code><code class="php plain">(</code><code class="php variable">$msg</code> <code class="php plain"><= 0){ </code></p>
<p class="line number26 index25 alt1"><code class="php spaces"> </code><code class="php comments">//close </code></p>
<p class="line number27 index26 alt2"><code class="php spaces"> </code><code class="php plain">}</code><code class="php keyword">else</code><code class="php plain">{ </code></p>
<p class="line number28 index27 alt1"><code class="php spaces"> </code><code class="php functions">echo</code> <code class="php string">"on message, fd=$fd data=$msg\n"</code><code class="php plain">; </code></p>
<p class="line number29 index28 alt2"><code class="php spaces"> </code><code class="php plain">} </code></p>
<p class="line number30 index29 alt1"><code class="php spaces"> </code><code class="php plain">} </code></p>
<p class="line number31 index30 alt2"><code class="php spaces"> </code><code class="php plain">} </code></p>
<p class="line number32 index31 alt1"><code class="php spaces"> </code> </p>
<p class="line number33 index32 alt2"><code class="php spaces"> </code><code class="php comments">//写入事件 </code></p>
<p class="line number34 index33 alt1"><code class="php spaces"> </code><code class="php keyword">foreach</code><code class="php plain">(</code><code class="php variable">$ws</code> <code class="php keyword">as</code> <code class="php variable">$fd</code><code class="php plain">){ </code></p>
<p class="line number35 index34 alt2"><code class="php spaces"> </code><code class="php plain">socket_write(</code><code class="php variable">$fd</code><code class="php plain">, ........); </code></p>
<p class="line number36 index35 alt1"><code class="php spaces"> </code><code class="php plain">} </code></p>
<p class="line number37 index36 alt2"><code class="php plain">}</code><code class="php keyword">while</code><code class="php plain">(true);</code></p>
<p class="line number38 index37 alt1"><code class="php plain">?></code></p>
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</tbody>
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<p><strong>下面来提高下效率：</strong></p>
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<p class="line number34 index33 alt1">34</p>
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</td>
<td class="code">
<div class="container">
<p class="line number1 index0 alt2"><code class="php plain"><?php</code></p>
<p class="line number2 index1 alt1"><code class="php variable">$sfd</code> <code class="php plain">= stream_socket_server (</code><code class="php string">'tcp://0.0.0.0:1234'</code><code class="php plain">, </code><code class="php variable">$errno</code><code class="php plain">, </code><code class="php variable">$errstr</code><code class="php plain">); </code></p>
<p class="line number3 index2 alt2"><code class="php plain">stream_set_blocking(</code><code class="php variable">$sfd</code><code class="php plain">, 0); </code></p>
<p class="line number4 index3 alt1"><code class="php variable">$base</code> <code class="php plain">= event_base_new(); </code></p>
<p class="line number5 index4 alt2"><code class="php variable">$event</code> <code class="php plain">= event_new(); </code></p>
<p class="line number6 index5 alt1"><code class="php plain">event_set(</code><code class="php variable">$event</code><code class="php plain">, </code><code class="php variable">$sfd</code><code class="php plain">, EV_READ | EV_PERSIST, </code><code class="php string">'ev_accept'</code><code class="php plain">, </code><code class="php variable">$base</code><code class="php plain">); </code></p>
<p class="line number7 index6 alt2"><code class="php plain">event_base_set(</code><code class="php variable">$event</code><code class="php plain">, </code><code class="php variable">$base</code><code class="php plain">); </code></p>
<p class="line number8 index7 alt1"><code class="php plain">event_add(</code><code class="php variable">$event</code><code class="php plain">); </code></p>
<p class="line number9 index8 alt2"><code class="php plain">event_base_loop(</code><code class="php variable">$base</code><code class="php plain">); </code></p>
<p class="line number10 index9 alt1"><code class="php spaces"> </code> </p>
<p class="line number11 index10 alt2"><code class="php keyword">function</code> <code class="php plain">ev_accept(</code><code class="php variable">$socket</code><code class="php plain">, </code><code class="php variable">$flag</code><code class="php plain">, </code><code class="php variable">$base</code><code class="php plain">) </code></p>
<p class="line number12 index11 alt1"><code class="php plain">{ </code></p>
<p class="line number13 index12 alt2"><code class="php spaces"> </code><code class="php variable">$connection</code> <code class="php plain">= stream_socket_accept(</code><code class="php variable">$socket</code><code class="php plain">); </code></p>
<p class="line number14 index13 alt1"><code class="php spaces"> </code><code class="php plain">stream_set_blocking(</code><code class="php variable">$connection</code><code class="php plain">, 0); </code></p>
<p class="line number15 index14 alt2"><code class="php spaces"> </code><code class="php variable">$buffer</code> <code class="php plain">= event_buffer_new(</code><code class="php variable">$connection</code><code class="php plain">, </code><code class="php string">'ev_read'</code><code class="php plain">, NULL, </code><code class="php string">'ev_error'</code><code class="php plain">, </code><code class="php variable">$connection</code><code class="php plain">); </code></p>
<p class="line number16 index15 alt1"><code class="php spaces"> </code><code class="php plain">event_buffer_base_set(</code><code class="php variable">$buffer</code><code class="php plain">, </code><code class="php variable">$base</code><code class="php plain">); </code></p>
<p class="line number17 index16 alt2"><code class="php spaces"> </code><code class="php plain">event_buffer_timeout_set(</code><code class="php variable">$buffer</code><code class="php plain">, 30, 30); </code></p>
<p class="line number18 index17 alt1"><code class="php spaces"> </code><code class="php plain">event_buffer_watermark_set(</code><code class="php variable">$buffer</code><code class="php plain">, EV_READ, 0, 0xffffff); </code></p>
<p class="line number19 index18 alt2"><code class="php spaces"> </code><code class="php plain">event_buffer_priority_set(</code><code class="php variable">$buffer</code><code class="php plain">, 10); </code></p>
<p class="line number20 index19 alt1"><code class="php spaces"> </code><code class="php plain">event_buffer_enable(</code><code class="php variable">$buffer</code><code class="php plain">, EV_READ | EV_PERSIST); </code></p>
<p class="line number21 index20 alt2"><code class="php plain">} </code></p>
<p class="line number22 index21 alt1"><code class="php spaces"> </code> </p>
<p class="line number23 index22 alt2"><code class="php keyword">function</code> <code class="php plain">ev_error(</code><code class="php variable">$buffer</code><code class="php plain">, </code><code class="php variable">$error</code><code class="php plain">, </code><code class="php variable">$connection</code><code class="php plain">) </code></p>
<p class="line number24 index23 alt1"><code class="php plain">{ </code></p>
<p class="line number25 index24 alt2"><code class="php spaces"> </code><code class="php plain">event_buffer_disable(</code><code class="php variable">$buffer</code><code class="php plain">, EV_READ | EV_WRITE); </code></p>
<p class="line number26 index25 alt1"><code class="php spaces"> </code><code class="php plain">event_buffer_free(</code><code class="php variable">$buffer</code><code class="php plain">); </code></p>
<p class="line number27 index26 alt2"><code class="php spaces"> </code><code class="php plain">fclose(</code><code class="php variable">$connection</code><code class="php plain">); </code></p>
<p class="line number28 index27 alt1"><code class="php plain">} </code></p>
<p class="line number29 index28 alt2"><code class="php spaces"> </code> </p>
<p class="line number30 index29 alt1"><code class="php keyword">function</code> <code class="php plain">ev_read(</code><code class="php variable">$buffer</code><code class="php plain">, </code><code class="php variable">$connection</code><code class="php plain">) </code></p>
<p class="line number31 index30 alt2"><code class="php plain">{ </code></p>
<p class="line number32 index31 alt1"><code class="php spaces"> </code><code class="php variable">$read</code> <code class="php plain">= event_buffer_read(</code><code class="php variable">$buffer</code><code class="php plain">, 256); </code></p>
<p class="line number33 index32 alt2"><code class="php spaces"> </code><code class="php comments">//do something.... </code></p>
<p class="line number34 index33 alt1"><code class="php plain">}</code></p>
<p class="line number35 index34 alt2"><code class="php plain">?></code></p>
</div>
</td>
</tr>
</tbody>
</table>
<p>随着人数的增长，并发的提升，单个进程已经满足不了需求了，现成的就有扩展和库来解决这个事，比如：swoole,workerman等？但是，我们在使用php来开发web的时候，也没有使用webserver相关的库来做开发对不对？咱只是简单的echo而已。这些繁杂的事都交给了nginx或者是apache，是他们义无反顾的顶在前面，让我们可以专心写逻辑。写socket服务不比写web高级，都是打码，都是完成需求，通信那层都是固定的，只不过一个由nginx完成，另一个由自己完成。。可是现在不需要自己完成了，类似nginx+fpm的方案，fooking+fpm=php长连接，gateway用于承载连接，router用于转发消息。</p>
<p><strong>其代码如下所示：</strong></p>
<table class="syntaxhighlighterphp" border="0" cellspacing="0" cellpadding="0">
<tbody>
<tr>
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<p class="line number1 index0 alt2">1</p>
<p class="line number2 index1 alt1">2</p>
<p class="line number3 index2 alt2">3</p>
<p class="line number4 index3 alt1">4</p>
<p class="line number5 index4 alt2">5</p>
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</td>
<td class="code">
<div class="container">
<p class="line number1 index0 alt2"><code class="php plain"><?php</code></p>
<p class="line number2 index1 alt1"><code class="php variable">$sid</code> <code class="php plain">= </code><code class="php variable">$_SERVER</code><code class="php plain">[</code><code class="php string">'SESSIONID'</code><code class="php plain">];</code><code class="php comments">//这是sessionid </code></p>
<p class="line number3 index2 alt2"><code class="php variable">$data</code> <code class="php plain">= </code><code class="php functions">file_get_contents</code><code class="php plain">(</code><code class="php string">"php://input"</code><code class="php plain">);//这样就能拿到请求内容了 </code></p>
<p class="line number4 index3 alt1"><code class="php comments">//想要返回消息只需要两步 </code></p>
<p class="line number5 index4 alt2"><code class="php plain">header(</code><code class="php string">'Content-Length: 11'</code><code class="php plain">);</code><code class="php comments">//返回给客户端字节数 </code></p>
<p class="line number6 index5 alt1"><code class="php functions">echo</code> <code class="php string">"hello world"</code><code class="php plain">; </code></p>
<p class="line number7 index6 alt2"><code class="php comments">//想要给别的用户发消息 </code></p>
<p class="line number8 index7 alt1"><code class="php keyword">include</code> <code class="php string">'api.php'</code><code class="php plain">; </code></p>
<p class="line number9 index8 alt2"><code class="php variable">$router</code> <code class="php plain">= </code><code class="php keyword">new</code> <code class="php plain">RouterClient(</code><code class="php string">'router host'</code><code class="php plain">, </code><code class="php string">'router port'</code><code class="php plain">); </code></p>
<p class="line number10 index9 alt1"><code class="php variable">$router</code><code class="php plain">->sendMsg(用户sessionid, </code><code class="php string">"fuck you"</code><code class="php plain">); </code></p>
<p class="line number11 index10 alt2"><code class="php comments">//想要给所有人要消息 </code></p>
<p class="line number12 index11 alt1"><code class="php variable">$router</code><code class="php plain">->sendAllMsg(</code><code class="php string">"fuck all"</code><code class="php plain">); </code></p>
<p class="line number13 index12 alt2"><code class="php comments">//想给指定组发消息(类似redis的pub/sub) </code></p>
<p class="line number14 index13 alt1"><code class="php variable">$router</code><code class="php plain">->publish(</code><code class="php string">"channel name"</code><code class="php plain">, </code><code class="php string">"fuck all"</code><code class="php plain">);</code></p>
<p class="line number15 index14 alt2"><code class="php plain">?></code></p>
</div>
</td>
</tr>
</tbody>
</table><br><br>
来源：https://www.cnblogs.com/bluealine/p/11038782.html
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