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PHP Websocket development tutorial, building real-time questionnaire function

WBOYOriginal: 2023-12-17 14:46:171022browse

PHP Websocket开发教程，构建实时问卷调查功能

PHP Websocket development tutorial, building a real-time questionnaire function, requiring specific code examples

Websocket technology is an emerging network protocol that can be built in web applications Real-time communication capabilities. Unlike the traditional HTTP protocol, the Websocket protocol can achieve two-way communication and can send and receive data uninterrupted. In this article, we will introduce how to build a real-time survey function using PHP and Websocket technology, and provide specific code examples.

Installing Ratchet on the server

Ratchet is a PHP library for developing Websocket applications. Before you begin, you need to install Ratchet on your server. Use the following command:

composer require cboden/ratchet

Write the Websocket server code

First, we need to create a Ratchet WebSocket server. In this example, we will put all the code in a PHP file. In this file, we will create a class that will extend the RatchetWebSocketWsServer class. In the constructor we will initialize an instance variable $clients which will store the connected clients.

The following is the server code:

<?php

require __DIR__ . '/vendor/autoload.php'; // 引入 ratchet

use RatchetMessageComponentInterface;
use RatchetConnectionInterface;
use RatchetWebSocketWsServer;

class PollServer implements MessageComponentInterface {
    protected $clients;

    public function __construct() {
        $this->clients = new SplObjectStorage;
    }

    public function onOpen(ConnectionInterface $conn) {
        $this->clients->attach($conn);
        echo 'Client ' . $conn->resourceId . ' connected
';
    }

    public function onClose(ConnectionInterface $conn) {
        $this->clients->detach($conn);
        echo 'Client ' . $conn->resourceId . ' disconnected
';
    }

    public function onMessage(ConnectionInterface $from, $msg) {
        echo 'Received message ' . $msg . ' from client ' . $from->resourceId . "
";
        // 在这里处理逻辑...
    }

    public function onError(ConnectionInterface $conn, Exception $e) {
        echo "An error has occurred: {$e->getMessage()}
";
        $conn->close();
    }
}

$server = new RatchetApp('localhost', 8080); // 创建一个新的 WebSocket 服务器
$server->route('/poll', new WsServer(new PollServer())); // 定义路由
$server->run(); // 启动服务器

The above code defines a class named PollServer, which implements the RatchetMessageComponentInterface interface. MessageComponentInterface The interface is very simple. It has only four methods, namely onOpen, onClose, onMessage and onError . These methods are called when the client connects to the server, when it disconnects from the server, when a new message is received, and when an error is encountered. In the above code, we simply output some logs, but you can change it as needed when dealing with the actual logic.

Next, we need to pass the PollServer class to the constructor of the RatchetWebSocketWsServer class. This will create a new WebSocket server that will communicate with the client using the WebSocket protocol.

Finally, we need to define a route so that clients can connect to the server. In the code above, we define a route named /poll. In a production environment, you should use the real domain name and port for the WebSocket server.

Writing client-side code

In this example, we will use JavaScript to write client-side code. First, add the following code in the HTML file to create a WebSocket connection:

<!DOCTYPE html>
<html>
<head>
    <title>Real-time Poll</title>
</head>
<body>
    <h1>Real-time Poll</h1>
    <script>
        const connection = new WebSocket('ws://localhost:8080/poll'); // 替换为真实的域名和端口

        connection.addEventListener('open', () => {
            console.log('Connected');
        });

        connection.addEventListener('message', event => {
            const message = JSON.parse(event.data);
            console.log('Received', message);
        });

        connection.addEventListener('close', () => {
            console.log('Disconnected');
        });

        connection.addEventListener('error', error => {
            console.error(error);
        });
    </script>
</body>
</html>

The above code creates a new WebSocket object named connection and uses ws:/ /localhost:8080/poll as the server URL. In a production environment, you should replace this URL with the real server domain name and port.

Next, we added several event listeners to handle connection establishment, message reception, connection disconnection and error events. When a message is received, we use JSON.parse to parse the message into a JavaScript object and log it on the console.

Implementing the real-time questionnaire function

Now that we have created the WebSocket server and client, we need to implement the real-time questionnaire function. Consider the following code example:

public function onMessage(ConnectionInterface $from, $msg) {
    echo 'Received message ' . $msg . ' from client ' . $from->resourceId . "
";
    $data = json_decode($msg, true);
    switch ($data['action']) {
        case 'vote':
            $vote = $data['vote'];
            $this->broadcast([
                'action' => 'update',
                'votes' => [
                    'yes' => $this->getVoteCount('yes'),
                    'no' => $this->getVoteCount('no')
                ]
            ]);
            break;
    }
}

private function broadcast($message) {
    foreach ($this->clients as $client) {
        $client->send(json_encode($message));
    }
}

private function getVoteCount($option) {
    // 在这里查询投票选项的数量...
}

In the above code, we handle the message sent by the client in the onMessage method. This method decodes the message and checks the action field using the switch statement. If action equals vote, then we update the vote count and send the update to all clients using the broadcast method.

In the broadcast method, we use a loop to loop through all clients and send the message to each client. This method sends a JSON-encoded message to the client, which will be used with the event handler registered in connection.addEventListener('message', ...) event handler.

Full Code Examples

The following are complete versions of all code examples in this article:

server.php:

<?php

require __DIR__ . '/vendor/autoload.php';

use RatchetMessageComponentInterface;
use RatchetConnectionInterface;
use RatchetWebSocketWsServer;

class PollServer implements MessageComponentInterface {
    protected $clients;

    public function __construct() {
        $this->clients = new SplObjectStorage;
    }

    public function onOpen(ConnectionInterface $conn) {
        $this->clients->attach($conn);
        echo 'Client ' . $conn->resourceId . ' connected
';
    }

    public function onClose(ConnectionInterface $conn) {
        $this->clients->detach($conn);
        echo 'Client ' . $conn->resourceId . ' disconnected
';
    }

    public function onMessage(ConnectionInterface $from, $msg) {
        echo 'Received message ' . $msg . ' from client ' . $from->resourceId . "
";
        $data = json_decode($msg, true);
        switch ($data['action']) {
            case 'vote':
                $vote = $data['vote'];
                $this->broadcast([
                    'action' => 'update',
                    'votes' => [
                        'yes' => $this->getVoteCount('yes'),
                        'no' => $this->getVoteCount('no')
                    ]
                ]);
                break;
        }
    }

    public function onError(ConnectionInterface $conn, Exception $e) {
        echo "An error has occurred: {$e->getMessage()}
";
        $conn->close();
    }

    private function broadcast($message) {
        foreach ($this->clients as $client) {
            $client->send(json_encode($message));
        }
    }

    private function getVoteCount($option) {
        // 在这里查询投票选项的数量...
    }
}

$server = new RatchetApp('localhost', 8080);
$server->route('/poll', new WsServer(new PollServer()));
$server->run();

index .html:

<!DOCTYPE html>
<html>
<head>
    <title>Real-time Poll</title>
</head>
<body>
    <h1>Real-time Poll</h1>
    <form>
        <label><input type="radio" name="vote" value="yes"> Yes</label>
        <label><input type="radio" name="vote" value="no"> No</label>
        <button type="submit">Vote</button>
    </form>
    <ul>
        <li>Yes: <span id="yes-votes">0</span></li>
        <li>No: <span id="no-votes">0</span></li>
    </ul>
    <script>
        const connection = new WebSocket('ws://localhost:8080/poll');

        connection.addEventListener('open', () => {
            console.log('Connected');
        });

        connection.addEventListener('message', event => {
            const message = JSON.parse(event.data);
            if (message.action === 'update') {
                document.getElementById('yes-votes').textContent = message.votes.yes;
                document.getElementById('no-votes').textContent = message.votes.no;
            }
        });

        connection.addEventListener('close', () => {
            console.log('Disconnected');
        });

        connection.addEventListener('error', error => {
            console.error(error);
        });

        document.querySelector('form').addEventListener('submit', event => {
            event.preventDefault();
            const vote = document.querySelector('input[name="vote"]:checked').value;
            connection.send(JSON.stringify({
                action: 'vote',
                vote: vote
            }));
        });
    </script>
</body>
</html>

In the above code example, we provide a simple HTML form for sending voting results to the server. When the user submits the form, we send the voting results as a JSON object to a WebSocket connection on the server.

When the client receives the update message, we update the voting results in the HTML.

Summary

In this article, we introduced how to build a real-time survey function using PHP and Websocket technology, and provided specific code examples. Websocket technology can be used to implement various real-time communication functions, such as chat rooms, games, real-time updates, etc. If you want to learn more about Websocket technology, we recommend checking out Ratchet's documentation, which provides many detailed guides and examples on Websocket development.

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