PHP 微信小程序 WebSocket MySQL Redis实现聊天功能

1.Mysql 实现离线消息池。如果一个用户不在线，则其他用户发送给他的消息暂时存储在mysql。待该用户上线时，再从离线消息池取出发送。

2.Redis 实现每个连接websocket的服务都唯一绑定一个用户。通过用户账号 = fd 存到redis中。

微信小程序：

websocket.php代码：

<?php
//创建WebSocket Server对象，监听0.0.0.0:9501端口
$ws = new Swoole\WebSocket\Server('0.0.0.0', 9501);//连接Redis
$redis=new Redis();
$redis->connect('服务器地址',6379);//连接MySQL
$con=mysqli_connect("服务器地址","数据库名称","数据库密码","数据表名称"); //监听WebSocket连接打开事件
$ws->on('Open', function ($ws, $request) {});//监听WebSocket消息事件
$ws->on('Message', function ($ws, $frame) use($redis) {$data=json_decode($frame->data,true);echo "{$frame->data}\n";print_r($data['me']);echo "\n";switch($data['type']){case 'open':echo "我：".$data['me'];echo "\n";//将登录者“我”的fd存入至Redis$redis->set($data['me'],$frame->fd);$me=$redis->get($data['me']);echo $me;echo "\n";//在数据库查询我离线时，别人给我发的消息$sql = "SELECT `me`,`content` from chats where `to` = '{$data['me']}' order by `add_time` asc";$result = mysqli_query($con,$sql);//如果有，展示出来，即把消息推给客户端，即推送给“我”if ($result) {$re = [];while($row = mysqli_fetch_assoc($result)) {array_push($re, $row);}mysqli_free_result($result);foreach ($re as $v) {$msg = ['msg' => $v['content']];$ws->push($frame->fd,json_encode($msg,true));}//推送给“我”之后，便将该消息删除处理$sql = "DELETE FROM chats where `to` = '{$data['me']}'";mysqli_query($con,$sql);}break;case 'chat':echo "给：".$data['to'];echo "\n";//从Redis中取出“当前好友”的fd$to=$redis->get($data['to']);echo "给的fd：".$to;echo "\n";            //所有在线的用户$fds = []; foreach($ws->connections as $fd){array_push($fds, $fd);}//判断“我”的“当前好友”是否在线if (in_array($to,$fds)) {$msg = ['msg' => $data['msg'],];//如果在线，直接推送要发送的消息$ws->push($to,json_encode($msg,256));} else {//如果不在线，将要发送的消息存入至数据表$add_time = date('Y-m-d H:i:s');$sql = "INSERT INTO chats(`to`,`me`,`content`,`add_time`) values ('{$data['to']}','{$data['me']}','{$data['msg']}','{$add_time}')";mysqli_query($con,$sql);}break;}
});//监听WebSocket连接关闭事件
$ws->on('Close', function ($ws, $fd) {echo "client-{$fd} is closed\n";
});$ws->start();

MySQL表字段：