【轻松掌握】Swoole简单入门教程，让你成为PHP高手！

Swoole简单入门示例

Swoole可以让PHP 开发人员可以编写高性能的异步并发 TCP、UDP、Unix Socket、HTTP，WebSocket 服务。Swoole 可以广泛应用于互联网、移动通信、企业软件、云计算、网络游戏、物联网(IOT)、车联网、智能家居等领域。

前提

使用Composer构建项目，构建好项目。

或者利用搜索引擎。

本篇介绍以下几个示例：

一、使用Swoole发送邮件

二、使用Swoole实现在线聊天

三、使用Systemctl管理Swoole服务

四、使用Swoole实现毫秒级定时任务

五、使用Websocket上传文件

使用composer安装邮件发送组件：phpmailer

composer require phpmailer/phpmailer

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主程序

在目录：src/app/下建立Mail.php，用作Swoole服务端主程序。


namespace Shanhubei\Swoole;use swoole_server;
use Redis;
use PHPMailer\PHPMailer\PHPMailer;
use PHPMailer\PHPMailer\Exception;class Mail
{protected $serv;protected $host = '127.0.0.1';protected $port = 9502;// 进程名称protected $taskName = 'swooleMailer';// PID路径protected $pidPath = '/run/swooleMail.pid';// 设置运行时参数protected $options = ['worker_num' => 4, //worker进程数,一般设置为CPU数的1-4倍  'daemonize' => true, //启用守护进程'log_file' => '/data/logs/swoole.log', //指定swoole错误日志文件'log_level' => 0, //日志级别 范围是0-5，0-DEBUG，1-TRACE，2-INFO，3-NOTICE，4-WARNING，5-ERROR'dispatch_mode' => 1, //数据包分发策略,1-轮询模式'task_worker_num' => 4, //task进程的数量'task_ipc_mode' => 3, //使用消息队列通信，并设置为争抢模式//'heartbeat_idle_time' => 600, //一个连接如果600秒内未向服务器发送任何数据，此连接将被强制关闭//'heartbeat_check_interval' => 60, //启用心跳检测，每隔60s轮循一次];// 邮件服务器配置protected $mailConfig = ['smtp_server' => 'smtp.163.com','username' => 'username@163.com','password' => '密码/口令',// SMTP 密码/口令'secure' => 'ssl', //Enable TLS encryption, `ssl` also accepted'port' => 465, // tcp邮件服务器端口];// 安全密钥protected $safeKey = 'MDDGnQE33ytd2jDFADS39DSEWsdD24sK';public function __construct($mailConfig, $options = []){// 构建Server对象，监听端口$this->serv = new swoole_server($this->host, $this->port);if (!empty($options)) {$this->options = array_merge($this->options, $options);}$this->serv->set($this->options);$this->mailConfig = $mailConfig;// 注册事件$this->serv->on('Start', [$this, 'onStart']);$this->serv->on('Connect', [$this, 'onConnect']);$this->serv->on('Receive', [$this, 'onReceive']);$this->serv->on('Task', [$this, 'onTask']);  $this->serv->on('Finish', [$this, 'onFinish']);$this->serv->on('Close', [$this, 'onClose']);// 启动服务//$this->serv->start();}protected function init(){//}public function start(){// Run worker$this->serv->start();}public function onStart($serv){// 设置进程名cli_set_process_title($this->taskName);//记录进程id,脚本实现自动重启$pid = "{$serv->master_pid}\n{$serv->manager_pid}";file_put_contents($this->pidPath, $pid);}//监听连接进入事件public function onConnect($serv, $fd, $from_id){$serv->send($fd, "Hello {$fd}!" );}// 监听数据接收事件public function onReceive(swoole_server $serv, $fd, $from_id, $data){$res['result'] = 'failed';$key = $this->safeKey;$req = json_decode($data, true);$action = $req['action'];$token = $req['token'];$timestamp = $req['timestamp'];if (time() - $timestamp > 180) {$res['code'] = '已超时';$serv->send($fd, json_encode($res));exit;}$token_get = md5($action.$timestamp.$key);if ($token != $token_get) {$res['msg'] = '非法提交';$serv->send($fd, json_encode($res));exit;}$res['result'] = 'success';$serv->send($fd, json_encode($res)); // 同步返回消息给客户端$serv->task($data);  // 执行异步任务}/*** @param $serv swoole_server swoole_server对象* @param $task_id int 任务id* @param $from_id int 投递任务的worker_id* @param $data string 投递的数据*/public function onTask(swoole_server $serv, $task_id, $from_id, $data){$res['result'] = 'failed';$req = json_decode($data, true);$action = $req['action'];echo date('Y-m-d H:i:s')." onTask: [".$action."].\n";switch ($action) {case 'sendMail': //发送单个邮件$mailData = ['emailAddress' => '2823175272@qq.com','subject' => 'swoole demo','body' => '测试This is the HTML message body <b>in bold!</b>,<br/>欢迎访问<a href="http://www.shanhubei.com/">www.shanhubei.com</a>'];$this->sendMail($mailData);break;case 'sendMailQueue': // 批量队列发送邮件$this->sendMailQueue();break;default:break;}}/*** @param $serv swoole_server swoole_server对象* @param $task_id int 任务id* @param $data string 任务返回的数据*/public function onFinish(swoole_server $serv, $task_id, $data){//}// 监听连接关闭事件public function onClose($serv, $fd, $from_id) {echo "Client {$fd} close connection\n";}public function stop(){$this->serv->stop();}private function sendMail($mail_data = []){$mail = new PHPMailer(true);try {$mailConfig = $this->mailConfig;//$mail->SMTPDebug = 2;        // 启用Debug$mail->isSMTP();   // Set mailer to use SMTP$mail->Host = $mailConfig['smtp_server'];  // SMTP服务$mail->SMTPAuth = true;                  // Enable SMTP authentication$mail->Username = $mailConfig['username'];    // SMTP 用户名$mail->Password = $mailConfig['password'];     // SMTP 密码/口令$mail->SMTPSecure = $mailConfig['secure'];     // Enable TLS encryption, `ssl` also accepted$mail->Port = $mailConfig['port'];    // TCP 端口$mail->CharSet  = "UTF-8"; //字符集$mail->Encoding = "base64"; //编码方式//Recipients$mail->setFrom($mailConfig['username'], 'Shanhubei'); //发件人地址，名称$mail->addAddress($mail_data['emailAddress'], '亲');     // 收件人地址和名称//$mail->addCC('hellowebanet@163.com'); // 抄送//Attachmentsif (isset($mail_data['attach'])) {$mail->addAttachment($mail_data['attach']);         // 添加附件}//$mail->addAttachment('/tmp/image.jpg', 'new.jpg');    // Optional name//Content$mail->isHTML(true);                                  // Set email format to HTML$mail->Subject = $mail_data['subject'];$mail->Body    = $mail_data['body'];//$mail->AltBody = '这是在不支持HTML邮件客户端的纯文本格式';$mail->send();return true;} catch (\Exception $e) {echo 'Message could not be sent. Mailer Error: '. $mail->ErrorInfo;return false;}}// 邮件发送队列private function sendMailQueue(){$redis = new Redis();$redis->connect('127.0.0.1', 6379);//$password = '123';//$redis->auth($password);swoole_timer_tick(1000, function($timer) use ($redis) { // 启用定时器，每1秒执行一次$value = $redis->lpop('mailerlist');if($value){//echo '获取redis数据:' . $value;$json = json_decode($value, true);$start = microtime(true);$rs = $this->sendMail($json);$end = microtime(true);if ($rs) {echo '发送成功！'.$value.', 耗时:'. round($end - $start, 3).'秒'.PHP_EOL;} else { // 把发送失败的加入到失败队列中，人工处理$redis->rpush("mailerlist_err", $value);}}else{swoole_timer_clear($timer); // 停止定时器echo "Emaillist出队完成";}});}}

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运行服务端

在public/目录下建立mailServer.php，代码如下：


require dirname(__DIR__) . '/vendor/autoload.php';use Shanhubei\Swoole\Mail;$config = ['smtp_server' => 'smtp.163.com','username' => 'xxxxx@163.com','password' => 'xxxx',// SMTP 密码/口令'secure' => 'ssl', //Enable TLS encryption, `ssl` also accepted'port' => 465, // tcp邮件服务器端口
];
$server = new Mail($config);
$server->start();

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你可以注册一个163邮箱，然后开通smtp功能。我DEMO中使用的是163邮箱发邮件发多了被封号了，所以在线演示demo没上传了。配置好邮件服务器参数后，运行：

php mailServer.php

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此时再使用命令netstat -lntp查看进程。

运行客户端

在public/目录下新建mailClient.php，代码如下：

class Client
{private $client;public function __construct() {$this->client = new swoole_client(SWOOLE_SOCK_TCP);}public function connect($type) {if( !$this->client->connect("127.0.0.1", 9502 , 1) ) {echo "Error: {$this->client->errMsg}[{$this->client->errCode}]\n";}// fwrite(STDOUT, "请输入消息 Please input msg：");// $msg = trim(fgets(STDIN));$action = 'sendMail';if($type == 'q'){$action = 'sendMailQueue';}$time = time();$key = 'MDDGnQE33ytd2jDFADS39DSEWsdD24sK';$token = md5($action.$time.$key);$data = ['action' => $action,'token' => $token,'timestamp' => $time];$msg = json_encode($data);$this->client->send( $msg );$message = $this->client->recv();echo "Get Message From Server:{$message}\n";}
}$type = 'q';  //区分批量和单个发送标志if($type == 'q'){$redis = new \Redis();$redis->connect('127.0.0.1', 6379);//$password = '123456x';///$redis->auth($password);$arr = [];$arr[0] = ['subject' => '注册cloudfog-HA','emailAddress' => '2823175272@qq.com','body' => '您好，您的CloudFog使用的用户名是：123, 密码是：123。<br/>请不要将此邮件泄漏给他人，并尽快登录CloudFog更换新密码。如有疑问请联系管理员。'];$arr[1] = ['subject' => '注册cloudfog2','emailAddress' => '2823175272@qq.com','body' => '<a href="https://www.shanhubei.com" target="_blank">网易邮箱</a>'];foreach ($arr as $k=>$v) {$redis->rpush("mailerlist", json_encode($v, JSON_UNESCAPED_UNICODE));}   
}$client = new Client();
$client->connect($type);

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运行命令启动客户端：

php mailClient.php

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此时在命令行窗口会返回如下信息：

[root@localhost public]# php mailClient.php 
Get Message From Server:{"result":"success"}

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这样就已经执行邮件发送任务了，如果出现故障，可以查看日志文件/data/logs/swoole.log。

然后你可以去查看对方邮箱是否收到相关邮件。

本文中使用了redis作为简单队列，你也可以使用复杂点的队列rabbitmq。你也可以使用Crontab来做定时任务，不过它最小粒度是分钟级别的。当然对于批量发送邮件，如果你不用php的话，可以用Python或者Java，它们都有相当成熟的解决方案。

二、使用Swoole实现在线聊天

建立服务端主程序

准备工作就绪后，我们开始来撸代码。

首先在项目目录：src/app/ 下建立Chat.php，用作Swoole服务端主程序。

Chat.php文件的主体结构是这样的：


namespace Shanhubei\Swoole;
use swoole_websocket_server;
class Chat
{protected $ws;protected $host = '0.0.0.0';protected $port = 9504;// 进程名称protected $taskName = 'swooleChat';// PID路径protected $pidFile = '/run/swooleChat.pid';// 设置运行时参数protected $options = ['worker_num' => 4, //worker进程数,一般设置为CPU数的1-4倍  'daemonize' => true, //启用守护进程'log_file' => '/data/logs/chatswoole.log', //指定swoole错误日志文件'log_level' => 3, //日志级别 范围是0-5，0-DEBUG，1-TRACE，2-INFO，3-NOTICE，4-WARNING，5-ERROR'dispatch_mode' => 1, //数据包分发策略,1-轮询模式];public function __construct($options = []){$this->ws = new swoole_websocket_server($this->host, $this->port);if (!empty($options)) {$this->options = array_merge($this->options, $options);}$this->ws->set($this->options);$this->ws->on("open", [$this, 'onOpen']);$this->ws->on("message", [$this, 'onMessage']);$this->ws->on("close", [$this, 'onClose']);}public function start(){// Run worker$this->ws->start();}public function onOpen(swoole_websocket_server $ws, $request){// 设置进程名cli_set_process_title($this->taskName);//记录进程id,脚本实现自动重启$pid = "{$ws->master_pid}\n{$ws->manager_pid}";file_put_contents($this->pidFile, $pid);echo "server: handshake success with fd{$request->fd}\n";}public function onMessage(swoole_websocket_server $ws, $frame){//$ws->push($frame->fd, "server-push:".date("Y-m-d H:i:s"));$connets = $ws->connections;echo count($connets)."\n";echo $frame->data. "\n";if ($frame->data == '美女') {$mmpic = ['http://pic15.photophoto.cn/20100402/0036036889148227_b.jpg','http://pic23.nipic.com/20120814/5914324_155903179106_2.jpg','http://pic40.nipic.com/20140403/8614226_162017444195_2.jpg'];$picKey = array_rand($mmpic);$ws->push($frame->fd, file_get_contents($mmpic[$picKey]), WEBSOCKET_OPCODE_BINARY);} else {$ws->push($frame->fd, $this->reply($frame->data));}}public function onClose($ws, $fid){echo "client {$fid} closed\n";foreach ($ws->connections as $fd) {$ws->push($fd, $fid. '已离开！');}}private function reply($str) {$str = mb_strtolower($str);switch ($str) {case 'hello':$res = 'Hello, Friend.';break;case 'fuck':$res = 'Fuck bitch.';break;case 'ping':$res = 'PONG.';break;case 'time':$res = date('H:i:s');break;default:$res = $str;break;}return $res;}
}

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我们需要往onMessage()方法里填代码。在这里，服务端接收客户端消息，并作出相应动作。Websocket可以向客户端发送字符串、二进制等形式消息。

public function onMessage(swoole_websocket_server $ws, $frame){//$ws->push($frame->fd, "server-push:".date("Y-m-d H:i:s"));if ($frame->data == '美女') {$mmpic = ['http://pic15.photophoto.cn/20100402/0036036889148227_b.jpg','http://pic23.nipic.com/20120814/5914324_155903179106_2.jpg','http://pic40.nipic.com/20140403/8614226_162017444195_2.jpg'];$picKey = array_rand($mmpic); //随机返回一张图片$ws->push($frame->fd, file_get_contents($mmpic[$picKey]), WEBSOCKET_OPCODE_BINARY);} else {$ws->push($frame->fd, $this->reply($frame->data));}}private function reply($str) {$str = mb_strtolower($str);switch ($str) {case 'hello':$res = 'Hello, Friend.';break;case 'fuck':$res = 'Fuck bitch.';break;case 'ping':$res = 'PONG.';break;case 'time':$res = date('H:i:s');break;default:$res = $str;break;}return $res;}

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将上面代码加入到Chat.php中，用来处理接收消息并响应回复。响应回复的内容可以根据实际情况修改，本代码只是用来演示。

启动服务端

在public/目录下建立chatServer.php，代码如下：

require dirname(__DIR__) . '/vendor/autoload.php';use Shanhubei\Swoole\Chat;$opt = ['daemonize' => true
];
$ws = new Chat($opt);
$ws->start();

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然后运行以下代码启动服务端：php chatServer.php 如果一切正常，你可以netstat -lntp看一下，系统会监听进程名为swooleChat，端口为9504的服务。

启动客户端

我们使用HTML5的websocket客户端来连接服务端，本地建立wsClient.html

<!DOCTYPE html>
<html>
<head><meta charset="utf-8"><meta http-equiv="X-UA-Compatible" content="IE=edge"><meta name=viewport content="width=device-width,initial-scale=1,maximum-scale=1,user-scalable=no"><title>Client</title><link rel="stylesheet" href="https://cdn.bootcss.com/bootstrap/3.3.5/css/bootstrap.min.css"><link rel="stylesheet" href="css/chat.css">
</head>
<body><div id="chat-wrap"><div id="result"></div><ul class="chat-thread"><li class="you"><img class="head" src="images/head1.jpg" alt=""><p>Are we meeting today?</p></li><li class="you"><img class="head" src="images/head1.jpg" alt=""><p>yes</p></li><li class="me"><img class="head" src="images/head1.jpg" alt=""><p>一部分保持在行尾，另一部分换到下一行。</p></li><li class="you"><img class="head" src="images/head1.jpg" alt=""><p>yes</p></li><li class="you"><img class="head" src="images/head1.jpg" alt=""><p>yes</p></li></ul></div><div class="send"><form action=""><input type="text" class="form-control" id="m" autocomplete="off" placeholder="请输入内容"><button type="submit" class="btn btn-info">发送</button></form></div>
<!-- <div><div id="result"></div><form class="form-inline" action=""><div class="form-group"><input type="text" class="form-control" id="m" autocomplete="off" placeholder="请输入内容"></div><button type="submit" class="btn btn-info">发送</button></form>
</div> -->
<script src="https://cdn.bootcss.com/jquery/2.2.4/jquery.min.js"></script>
<script>
if ("WebSocket" in window) {var ws = new WebSocket("ws://192.168.3.105:9504");var result = document.querySelector('#result');var chatthread = document.querySelector('.chat-thread');chatthread.scrollTop = chatthread.scrollHeight;ws.onopen = function() {result.innerHTML = '已连接上！';$('#result').show().html('已连接上！').fadeOut(1500);console.log('已连接上！');}document.querySelector('form').onsubmit = function(e) {var msg = document.querySelector('#m').value;ws.send(msg);$('.chat-thread').append('<li class="me"><img class="head" src="images/head1.jpg" alt=""><p>'+msg+'</p></li>');chatthread.scrollTop = chatthread.scrollHeight;document.querySelector('#m').value = '';return false;}ws.onmessage = function(e) {if(e.data instanceof Blob) {// var img = document.createElement("img");// img.src = window.URL.createObjectURL(e.data);// result.appendChild(img);// var d = window.URL.createObjectURL(e.data);// console.log(d);var img = '<img src="'+window.URL.createObjectURL(e.data)+'" width="180"/>';$('.chat-thread').append('<li class="you"><img class="head" src="images/head1.jpg" alt=""><p>'+img+'</p></li>');}else {// var p = document.createElement("p");// p.innerHTML = e.data;// result.appendChild(p);$('.chat-thread').append('<li class="you"><img class="head" src="images/head1.jpg" alt=""><p>'+e.data+'</p></li>');}chatthread.scrollTop = chatthread.scrollHeight;}ws.onclose = function() {console.log('连接已关闭！');}
} else {alert('您的浏览器不支持 WebSocket！');
}
</script>
</body>
</html>

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然后用浏览器打开wsClient.html，你可以看到一个聊天窗口，一开始会提示连接成功，然后你可以在输入框中输入你想说的话，如“美女”等等。

三、使用Systemctl管理Swoole服务

配置Swoole服务

有了Systemctl，我们可以轻松配置我们的Swoole服务，下面以Swoole聊天服务为例：

首先在/usr/lib/systemd/system/目录下，新建文件swoolechat.service，并加入以下代码：

[Unit]
Description=Swoole Chat Server
After=network.target syslog.target[Service]
Type=forking
LimitNOFILE=65535
ExecStart=/usr/local/php/bin/php /home/web/swoole/public/chatServer.php
ExecReload=/bin/kill -USR1 $MAINPID
Restart=always[Install]
WantedBy=multi-user.target graphical.target

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然后保存好文件，并使用如下命令重新载入所有的[Unit]文件，确保我们添加进去的service能被系统加载并生效。

systemctl  daemon-reload

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验证

现在我们来验证服务，首先启动swoole服务：

systemctl start swoolechat.service

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然后使用以下命令查看swoole服务是否正常:

systemctl status swoolechat.service

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四、使用Swoole实现毫秒级定时任务

接着服务端代码 public\taskServer.php ：


require dirname(__DIR__) . '/vendor/autoload.php';use Shanhubei\Swoole\Task;$opt = ['daemonize' => false
];
$ser = new Task($opt);
$ser->start();

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客户端代码 public\taskClient.php :

class Client
{private $client;public function __construct() {$this->client = new swoole_client(SWOOLE_SOCK_TCP);}public function connect() {if( !$this->client->connect("127.0.0.1", 9506 , 1) ) {echo "Error: {$this->client->errMsg}[{$this->client->errCode}]\n";}fwrite(STDOUT, "请输入消息 Please input msg：");$msg = trim(fgets(STDIN));$this->client->send( $msg );$message = $this->client->recv();echo "Get Message From Server:{$message}\n";}
}$client = new Client();
$client->connect();

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验证效果

1.启动服务端：

php taskServer.php

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2.客户端输入：

另开命令行窗口，执行

[root@localhost public]# php taskClient.php 
请输入消息 Please input msg：hello
Get Message From Server:{"result":"success"}

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五、使用Websocket上传文件

服务端

我们继续使用Swoole实验室：1-使用Composer构建项目构建好的项目，新建文件\src\app\Uploader.php：

namespace Shanhubei\Swoole;
use swoole_websocket_server;class Uploader
{protected $ws;protected $host = '0.0.0.0';protected $port = 9505;// 进程名称protected $taskName = 'swooleUploader';// PID路径protected $pidFile = '/run/swooleUploader.pid';// 设置运行时参数protected $options = ['worker_num' => 4, //worker进程数,一般设置为CPU数的1-4倍  'daemonize' => true, //启用守护进程'log_file' => '/data/logs/uploadswoole.log', //指定swoole错误日志文件'log_level' => 3, //日志级别 范围是0-5，0-DEBUG，1-TRACE，2-INFO，3-NOTICE，4-WARNING，5-ERROR'dispatch_mode' => 1, //数据包分发策略,1-轮询模式];public function __construct($options = []){$this->ws = new swoole_websocket_server($this->host, $this->port);if (!empty($options)) {$this->options = array_merge($this->options, $options);}$this->ws->set($this->options);$this->ws->on("open", [$this, 'onOpen']);$this->ws->on("message", [$this, 'onMessage']);$this->ws->on("close", [$this, 'onClose']);}public function start(){// Run worker$this->ws->start();}public function onOpen(swoole_websocket_server $ws, $request){// 设置进程名cli_set_process_title($this->taskName);//记录进程id,脚本实现自动重启$pid = "{$ws->master_pid}\n{$ws->manager_pid}";file_put_contents($this->pidFile, $pid);echo "server: handshake success with fd{$request->fd}\n";$msg = '{"msg": "connect ok"}';$ws->push($request->fd, $msg);}public function onMessage(swoole_websocket_server $ws, $frame){$opcode = $frame->opcode;if ($opcode == 0x08) {echo "Close frame received: Code {$frame->code} Reason {$frame->reason}\n";} else if ($opcode == 0x1) {echo "Text string\n";} else if ($opcode == 0x2) {echo "Binary data\n"; //} else {echo "Message received: {$frame->data}\n";}$filename = './files/aaa.jpg';file_put_contents($filename, $frame->data);echo "file path : {$filename}\n";$ws->push($frame->fd, 'upload success');}public function onClose($ws, $fid){echo "client {$fid} closed\n";foreach ($ws->connections as $fd) {$ws->push($fd, $fid. '已断开！');}}
}

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$frame->opcode，WebSocket的OpCode类型，可以通过它来判断传输的数据是文本内容还是二进制数据。

新建public/uploadServer.php，用于启动服务端脚本：


require dirname(__DIR__) . '/vendor/autoload.php';use Shanhubei\Swoole\Uploader;$opt = ['daemonize' => false
];
$ws = new Uploader($opt);
$ws->start();

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客户端

在本地站点建立客户端文件upload.html。只需在页面中放置一个文件选择控件和一个用于输出上传信息的div#log。

<input type="file" id="myFile">
<div id="log"></div>

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当选择好本地文件后，触发onchange事件，这个时候客户端尝试与服务端建立websocket连接，然后开始读取本地文件，读取完成后将数据发送给服务端。

$('#myFile').on('change', function(event) {var ws = new WebSocket("ws://192.168.3.106:9505");ws.onopen = function() {log('已连接上！');}ws.onmessage = function(e) {log("收到服务器消息:" + e.data + "'\n");if (e.data == 'connect ok') {log('开始上传文件');} if (e.data == 'upload success') {log('上传完成');ws.close();} else {var file = document.getElementById("myFile").files[0];var reader = new FileReader();reader.readAsArrayBuffer(file);reader.onload = function(e) {ws.send(e.target.result);log('正在上传数据...');}}}ws.onclose = function() {console.log('连接已关闭！');log('连接已关闭！');}
});
//在消息框中打印内容
function log(text) {$("#log").append(text+"<br/>");
}

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这里讲一下HTML5的FileReader 对象，FileReader允许Web应用程序异步读取存储在用户计算机上的文件(或原始数据缓冲区)的内容，使用 File 或 Blob 对象指定要读取的文件或数据。FileReader提供了几种读取文件的方法：

reader.readAsArrayBuffer(file|blob)：用于启动读取指定的 Blob 或 File 内容。读取文件后，会在内存中创建一个ArrayBuffer对象(二进制缓冲区)，将二进制数据存放在其中。当读取操作完成时，readyState 变成 DONE(已完成)，并触发 loadend 事件，同时 result 属性中将包含一个 ArrayBuffer 对象以表示所读取文件的数据。通过此方式，可以直接在网络中传输二进制内容。此外对于大文件我们可以分段读取二进制内容上传。
reader.readAsDataURL(file|blob)：该方法会读取指定的 Blob 或 File 对象。读取操作完成的时候，readyState 会变成已完成(DONE)，并触发 loadend 事件，同时 result 属性将包含一个data:URL格式的字符串(base64编码)以表示所读取文件的内容。
FileReader.readAsText(file|blob)：可以将 Blob 或者 File 对象转根据特殊的编码格式转化为内容(字符串形式)。当转化完成后， readyState 这个参数就会转换为 done 即完成态， event(“loadend”) 挂载的事件会被触发，并可以通过事件返回的形参得到中的 FileReader.result 属性得到转化后的结果。
FileReader.readAsBinaryString()：读取文件内容为二进制字符串，已废除，不要用了。

运行服务端