Integration of Swoole and Redis: Quickly build a high-availability IM system

With the rise of mobile Internet, instant messaging (IM) systems have become an indispensable part of our daily lives. Therefore, developing a practical and high-performance IM system has become one of the goals pursued by many developers. In this process, Swoole and Redis are two commonly used performance tools that can help us quickly build a high-availability IM system.

This article will introduce the basic concepts and principles of Swoole and Redis, and give an IM system architecture case and implementation plan based on these two tools. I hope that through this article, readers can understand how to use these two tools to build a high-performance IM system.

1. Overview of Swoole and Redis

1.1 Swoole

Swoole is an advanced network framework based on PHP. It is a fully asynchronous, high-performance server-side engine that supports TCP, UDP, WebSocket and HTTP protocols. Swoole can greatly improve the performance and concurrency of PHP processes, mainly because of its reacto mechanism based on epoll or kqueue, which uses coroutine technology to implement non-blocking asynchronous programming.

1.2 Redis

Redis is an open source in-memory key-value database that supports a variety of data structures, including strings, hashes, lists, sets, and ordered sets. Redis has high performance and scalability and can handle millions of concurrent requests. Redis is mainly used in scenarios such as caching, message queues, and distributed locks.

2. Integration of Swoole and Redis

2.1 How Swoole works with Redis

There are usually two ways to use Redis in Swoole:

• Use Swoole Redis client
• Use Swoole Coroutine Redis client

Among them, Swoole Redis client is a traditional Redis client and needs to use a callback function to process the request response. ; The Coroutine Redis client handles requests and responses through coroutines, which is more convenient and efficient to use.

2.2 Architecture Description

In order to achieve real-time communication, IM systems usually use the WebSocket protocol to transmit messages. In this article, we will build a WebSocket server based on Swoole and Redis. The messages sent by the client will be saved in Redis and then pushed to other clients through the server.

• 1. The client sends the message to the WebSocket server
• 2. The WebSocket server saves the message to Redis
• 3. Redis pushes messages to the server
• 4. WebSocket server pushes messages to other clients

3. Implementation plan

Next, we will introduce the implementation plan in detail for each step.

3.1 Server code

(1) Start the WebSocket server

Use the WebSocket server API provided by Swoole to start the server, the code is as follows:

$server = new SwooleWebSocketServer("0.0.0.0", 9501);

$server->on('open', function (SwooleWebSocketServer $server, $frame) {
    echo "connection open
";
});

$server->on('message', function (SwooleWebSocketServer $server, $frame) {
    $redis = new SwooleCoroutineRedis();
    $redis->connect('127.0.0.1', 6379);
    $redis->lPush('messages', $frame->data);
});

$server->on('close', function (SwooleWebSocketServer $server, $fd) {
    echo "connection close
";
});

$server->start();

This In the code snippet, we use the $server->on() function to set the open, message and close event callback functions of WebSocket. When the client connects to the server, the code in the open function will be executed; when the client sends a message to the server, the code in the message function will be executed. In the message function, we create a Coroutine Redis client and cache the messages sent by the client into the Redis queue.

(2) Push messages to the client

Next, we need to implement the logic of the server pushing messages to the client. This can be achieved using the push() function provided by Swoole. The code is as follows:

// 推送消息给客户端
$server->tick(1000, function () use ($server) {
    $redis = new SwooleCoroutineRedis();
    $redis->connect('127.0.0.1', 6379);

    while ($message = $redis->rPop('messages')) {
        foreach ($server->connections as $fd) {
            $server->push($fd, $message);
        }
    }
});

In this code, we use the tick() function provided by Swoole to execute the code regularly, and use the Coroutine Redis client to execute the code from Redis Get the message and push the message to all clients.

3.2 Client code

The client code is relatively simple. We only need to use the WebSocket client to connect to the WebSocket server and send and receive data through JavaScript. The code is as follows:

<!DOCTYPE html>
<html>
<head>
    <meta charset="UTF-8">
    <title>IM System</title>
</head>
<body>
    <h1>IM System</h1>
    <form>
        <label for="name">Name:</label>
        <input type="text" id="name">
        <br><br>
        <label for="message">Message:</label>
        <input type="text" id="message">
        <br><br>
        <input type="submit" value="Send Message">
    </form>
    <br><br>
    <div id="message-list"></div>
    <script>
        var socket = new WebSocket('ws://localhost:9501');

        socket.onopen = function(event) {
            console.log('WebSocket connect succeed');
        };

        socket.onmessage = function(event) {
            var message = JSON.parse(event.data);

            var messageList = document.getElementById('message-list');
            var p = document.createElement('p');
            p.innerText = message.name + ": " + message.message;
            messageList.prepend(p);
        };

        document.querySelector('form').addEventListener('submit', function(event) {
            event.preventDefault();

            var name = document.getElementById('name').value;
            var message = document.getElementById('message').value;

            socket.send(JSON.stringify({
                name: name,
                message: message
            }));

            document.getElementById('message').value = "";
        });
    </script>
</body>
</html>

In this code, we first use the WebSocket client to connect to the WebSocket server. When the client connects successfully, we can send messages to the server through the send() method of the WebSocket object in JavaScript. We also need to set the onmessage callback function to receive messages pushed by the server.

4. Summary

In this article, we introduced the basic concepts and principles of Swoole and Redis, and shared a WebSocket server architecture case and implementation plan based on Swoole and Redis. Through this case, we can learn how Swoole and Redis work together to build a high-performance, high-availability IM system.

Of course, this is just a simple example. In practice, many aspects need to be considered, such as security, performance optimization, etc. I hope that readers can learn about the use of these two tools through this article. I also hope that readers can continue to study these two tools and other related technologies in depth and make more contributions to the development of high-performance applications.

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