golang Websocket Development Guide: Implementing real-time data visualization function

Golang Websocket is a powerful tool that enables real-time data visualization capabilities, allowing data to be transmitted in both directions between the server and the browser, thereby providing users with a rich interactive experience. In this article, we will explore how to develop real-time data visualization capabilities using Golang Websocket.

1. Determine the requirements

Before we start to use Golang Websocket to develop real-time data visualization functions, we need to determine the requirements. Common real-time data visualization functions include: interactive charts, real-time logs, real-time monitoring, etc. In this article, we will take real-time monitoring as an example to explain.

Our requirement is to obtain data from the server in real time and display it on the front-end page. Server data may be in various forms, for example, real-time data read from a database, or data obtained from other third-party data sources. For these different data forms, we need to adopt corresponding processing methods to convert them into a form that WebSocket can handle.

2. Create Golang Websocket server

First, we need to create a Golang Websocket server and implement data transmission. The following is a code example of a simple WebSocket server:

package main

import (
    "fmt"
    "log"
    "net/http"

    "github.com/gorilla/websocket"
)

var upgrader = websocket.Upgrader{
    ReadBufferSize: 1024,
    WriteBufferSize: 1024,
}

func wsHandler(w http.ResponseWriter, r *http.Request) {
    conn, err := upgrader.Upgrade(w, r, nil)
    if err != nil {
        log.Println(err)
        return
    }
    defer conn.Close()

    for {
        // 接收消息
        messageType, p, err := conn.ReadMessage()
        if err != nil {
            log.Println(err)
            return
        }
        // 处理消息
        err = conn.WriteMessage(messageType, p)
        if err != nil {
            log.Println(err)
            return
        }
    }
}

func main() {
    http.HandleFunc("/ws", wsHandler)
    if err := http.ListenAndServe(":8080", nil); err != nil {
        log.Fatal("ListenAndServe: ", err)
    }
}

This code is an implementation of a simple WebSocket server. Among them, we used the Gorilla WebSocket library as the WebSocket handler. Through this library, we can quickly establish a WebSocket connection for data transmission.

In the above code, we define an upgrader object, which specifies the read and write cache size of WebSocket. Then, we define a wsHandler function to receive and process WebSocket messages. In the main function, we register the websocket handler with the web server and specify the server port.

3. Interaction between client and server

Next, we need to implement the interaction between client and server. We can use JavaScript code in the browser to connect to the WebSocket server. After connecting to the server, we can use WebSocket's API to send and receive messages to the server.

The following is a simple JavaScript code example for connecting to a WebSocket server to send and receive data:

var ws = new WebSocket("ws://localhost:8080/ws");
ws.onopen = function(event) {
    console.log("WebSocket opened");
};
ws.onmessage = function(event) {
    console.log("WebSocket message received", event.data);
};
ws.onclose = function(event) {
    console.log("WebSocket closed");
};

// 发送消息到服务器
ws.send("Hello, WebSocket!");

In this example, we create a WebSocket object and specify The address of the WebSocket server. After the WebSocket is opened, we can use the onopen function handler to send a message to the server. When the server sends messages to the client, we can receive and process these messages through the onmessage function processor.

4. Use Golang Websocket to implement real-time monitoring

Finally, let’s take a look at how to use Golang Websocket to implement real-time monitoring. The real-time monitoring function usually requires displaying data in the form of charts on a Web page. We can use JavaScript libraries to draw these charts, for example, Chart.js or D3.js.

The following is a simple real-time monitoring example. We can use go language to get data from a certain data source. Once we have the data, we can stream it to a WebSocket client in real time and use JavaScript to update the chart in real time.

golang code example:

package main

import (
    "encoding/json"
    "log"
    "time"

    "github.com/gorilla/websocket"
)

var upgrader = websocket.Upgrader{
    ReadBufferSize: 1024,
    WriteBufferSize: 1024,
}

type message struct {
    Time   time.Time `json:"time"`
    Data   float64   `json:"data"`
}

func main() {
    http.HandleFunc("/ws", wsHandler)
    if err := http.ListenAndServe(":8080", nil); err != nil {
        log.Fatal("ListenAndServe: ", err)
    }
}

func wsHandler(w http.ResponseWriter, r *http.Request) {
    conn, err := upgrader.Upgrade(w, r, nil)
    if err != nil {
        log.Println(err)
        return
    }
    defer conn.Close()

    for {
        // 接收消息
        messageType, p, err := conn.ReadMessage()
        if err != nil {
            log.Println(err)
            return
        }
        // 处理消息
        err = conn.WriteMessage(messageType, p)
        if err != nil {
            log.Println(err)
            return
        }
    }
}

func sendData() {
    //模拟数据源
    var data float64 = 0

    //循环发送数据
    for {
        value := message{
            Time:   time.Now(),
            Data:   data,
        }

        //将数据转换为json
        valueEncoded, err := json.Marshal(value)
        if err != nil {
            log.Println(err)
            continue
        }

        //将数据发送给WebSocket客户端
        for _, conn := range conns {
            err := conn.WriteMessage(websocket.TextMessage, valueEncoded)
            if err != nil {
                log.Println(err)
                continue
            }
        }

        //等待1秒钟，模拟数据源实时推送
        time.Sleep(1 * time.Second)

        //模拟数据源增加
        data += 0.1
    }
}

In this example, we define a message structure and implement a sendData function. To simulate the data source, we use a loop that sends data cyclically. In each loop, we generate a message object and convert it to JSON format. Then, send the JSON formatted data to the WebSocket client.

JavaScript Example:

var ws = new WebSocket("ws://localhost:8080/ws");
ws.onopen = function(event) {
    console.log("WebSocket opened");
};
ws.onmessage = function(event) {
    var message = JSON.parse(event.data);
    console.log("WebSocket message received", message);
};
ws.onclose = function(event) {
    console.log("WebSocket closed");
};

//使用Chart.js绘制图表
var ctx = document.getElementById('myChart').getContext('2d');
var chart = new Chart(ctx, {
    type: 'line',
    data: {
        labels: [],
        datasets: [{
            label: "My Dataset",
            data: [],
            fill: false,
            borderColor: "#ff0000",
            borderWidth: 1
        }]
    },
    options: {
        scales: {
            xAxes: [{
                type: 'time',
                time: {
                    unit: 'second'
                }
            }]
        }
    }
});

//接收WebSocket数据，并在图表中实时更新
ws.onmessage = function(event) {
    var message = JSON.parse(event.data);
    chart.data.labels.push(message.time);
    chart.data.datasets[0].data.push(message.data);
    chart.update();
};

In this example, we first create a WebSocket object and initialize the form when it is opened. Once the data is received by the WebSocket client, we parse the data into JSON format and use Chart.js to update the data in real time in the chart.

This is just the basic implementation of the real-time data visualization function developed by Golang Websocket. Actual application scenarios will also involve multiple aspects such as data filtering, aggregation and visualization. But this article provides some basic templates and code to help you get started implementing these features.

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