WebSocketd使用介绍

柔情只为你懂 2021-05-12 11:49 527阅读 0赞

WebSocketd是WebSocket的守护进程（命令行工具），负责处理WebSocket连接，并启动服务器应用程序来处理WebSockets，在应用程序和Web浏览器之间传递消息，无需任意依赖包且进程独立。WebSocketd是一款非常特别的WebSocket服务器，它的最大特点是后台脚本不限语言，其标准输入stdin就是WebSocket的输入，标准输出stdout就是WebSocket的输出。

WebSocketd本质上是命令行的WebSocket代理，只要在命令行可以执行的程序，都可以通过它与浏览器进行WebSocket通信。

官网：

*  [http://websocketd.com/][http_websocketd.com]
 *  [https://github.com/joewalnes/websocketd/][https_github.com_joewalnes_websocketd]

**安装：**

下载：
    wget https://github.com/joewalnes/websocketd/releases/download/v0.3.1/websocketd-0.3.1-linux_amd64.zip
    unzip websocketd-0.3.1-linux_amd64.zip
    
    环境变量：
    解压后是一个二进制文件，将websocketd二进制复制到/usr/bin目录下即可。

**简单示例：**

1）shell脚本

#!/bin/bash
    for ((COUNT = 1; COUNT <= 10; COUNT++)); do
      echo $COUNT
      sleep 1
    done

2）启动websocketd：

chmod 777 count.sh
    nohup websocketd --port=63800 ./count.sh >/dev/null 2>&1 &

3）浏览器测试：

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2xpdXhpYW83MjM4NDY_size_16_color_FFFFFF_t_70][]

4）html文件：

<!doctype html>
    <html lang="">
    <head>
        <meta charset="utf-8">
        <meta name="description" content="">
        <meta name="viewport" content="width=device-width, initial-scale=1">
        <meta http-equiv="x-ua-compatible" content="ie=edge">
        <title>websocketd</title>
    </head>
    <body>
    <h2>websocketd 客户端的简单测试</h2>
    <pre id="log"></pre>
    <script>
        // helper function: log message to screen
        function log(msg) {
            document.getElementById('log').textContent += msg + '\n';
        }
    
        // setup websocket with callbacks
        var ws = new WebSocket('ws://192.168.18.12:8080/');
        ws.onopen = function() {
            console.log('CONNECT');
        };
        ws.onclose = function() {
            console.log('DISCONNECT');
            ws.close();
        };
        ws.onmessage = function(event) {
            console.log('MESSAGE: ' + event.data);
        };
    </script>
    </body>
    </html>

客户端js可能会出现超时链接的，可以使用这个库ReconnectingWebSocket：[https://github.com/joewalnes/reconnecting-websocket][https_github.com_joewalnes_reconnecting-websocket]

**分析**：websocketd启动后会监听对应的websocket端口，当有客户端再次连接上时，websocketd会执行对应的shell脚本，并将每一步的标准输出作为消息发送到websocket通道。执行完shell脚本后，websocketd会断开本次连接，再次处于监听状态，当有请求到来会再次执行脚本...

**说明**：支持多client连接，每个client连接后，都将看到count.sh从头开始运行的过程数据(应该是独立的，每来一个请求，被包装的脚本从头运行)

**注意**：这里使用了一个shell脚本作为例子，其实我们可以将任何语言的程序（python、java...）输入给websocketd。详情见：[https://github.com/joewalnes/websocketd/tree/master/examples][https_github.com_joewalnes_websocketd_tree_master_examples]

**websocketd参数：**

1）--staticdir：

staticdir表示允许WebSocketd作为静态文件提供，也就是说在当前项目指定通知执行的语言脚本同名的Web页面作为静态文件。

$ websocketd --staticdir=. --port=9501 ./test.sh

2）--devconsole：

devconsole标志会使内置的控制台WebSocketd与WebSocket端点进行手工交互。改参数主要是用来调试，调试带有交互功能的程序，手写js比较不方便，官方也给出了调试模式：[https://github.com/joewalnes/websocketd/wiki/Developer-console][https_github.com_joewalnes_websocketd_wiki_Developer-console]

注：devconsole与staticdir不能不同使用，内置开发控制台旨在提供临时用户界面，用于构建真实的用户界面。

3）为websocketd配置nginx代理：

$ vim test.conf
    server {
        listen 443 ssl http2;
        server_name www.test.com;
     
        ssl_certificate /etc/test/full_chain.pem;
        ssl_certificate_key /etc/test/private.key;
     
        location /wssd
        {
            proxy_pass http://lnmp-php:8888;
            proxy_http_version 1.1;
            proxy_set_header Upgrade $http_upgrade;
            proxy_set_header Connection "Upgrade";
            proxy_set_header X-Real-IP $remote_addr;
            proxy_read_timeout 600;
    
        }
    }

上面的例子是单向数据（服务端——>客户端），接下来看一个交互性更强的例子(greeter.py)

脚本

from sys import stdin, stdout
    
    # For each line FOO received on STDIN, respond with "Hello FOO!".
    while True:
      line = stdin.readline().strip()
      print('Hello %s!' % line)
      stdout.flush() # Remember to flush

启动websocketd：

chmod +x count.py
    websocketd --port=8080 ./greeter.py

前端html：

<!DOCTYPE html>
    <head>
    <title>websocketd test</title>
    </head>
    <body>
    <pre id="log"></pre>
    <script>
      // helper function: log message to screen
      function log(msg) {
            document.getElementById('log').textContent += msg + '\n';
      }
      // setup websocket with callbacks
      var ws = new WebSocket('ws://localhost:8080/');
      ws.onopen = function() {
              log('CONNECT');
              // input
              ws.send("wwj");
      };
      ws.onclose = function() {
            log('DISCONNECT');
            ws.close();
      };
      ws.onmessage = function(event) {
            log('MESSAGE: ' + event.data);
      };
    </script>
    </body>

![2020010811321492.png][]

参考：

[https://www.jianshu.com/p/385d2ecf718f][https_www.jianshu.com_p_385d2ecf718f]

[https://www.cnblogs.com/tinywan/p/6826125.html][https_www.cnblogs.com_tinywan_p_6826125.html]

[https://blog.just4fun.site/post/%E5%B7%A5%E5%85%B7/websocketd/\#%E4%B8%80%E4%B8%AA%E5%8F%AF%E4%BA%A4%E4%BA%92%E7%9A%84%E4%BE%8B%E5%AD%90][https_blog.just4fun.site_post_E5_B7_A5_E5_85_B7_websocketd_E4_B8_80_E4_B8_AA_E5_8F_AF_E4_BA_A4_E4_BA_92_E7_9A_84_E4_BE_8B_E5_AD_90]

[https://www.ruanyifeng.com/blog/2017/05/websocket.html][https_www.ruanyifeng.com_blog_2017_05_websocket.html]

[http_websocketd.com]: https://links.jianshu.com/go?to=http%3A%2F%2Fwebsocketd.com%2F
[https_github.com_joewalnes_websocketd]: https://links.jianshu.com/go?to=https%3A%2F%2Fgithub.com%2Fjoewalnes%2Fwebsocketd%2F
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2xpdXhpYW83MjM4NDY_size_16_color_FFFFFF_t_70]: /images/20210511/d5a1f8c9034f49569aecdd9e8d768a8b.png
[https_github.com_joewalnes_reconnecting-websocket]: https://github.com/joewalnes/reconnecting-websocket
[https_github.com_joewalnes_websocketd_tree_master_examples]: https://github.com/joewalnes/websocketd/tree/master/examples
[https_github.com_joewalnes_websocketd_wiki_Developer-console]: https://github.com/joewalnes/websocketd/wiki/Developer-console
[2020010811321492.png]: /images/20210511/ecaf5b67d74343359f1cfa78ccb2d246.png
[https_www.jianshu.com_p_385d2ecf718f]: https://www.jianshu.com/p/385d2ecf718f
[https_www.cnblogs.com_tinywan_p_6826125.html]: https://www.cnblogs.com/tinywan/p/6826125.html
[https_blog.just4fun.site_post_E5_B7_A5_E5_85_B7_websocketd_E4_B8_80_E4_B8_AA_E5_8F_AF_E4_BA_A4_E4_BA_92_E7_9A_84_E4_BE_8B_E5_AD_90]: https://blog.just4fun.site/post/%E5%B7%A5%E5%85%B7/websocketd/#%E4%B8%80%E4%B8%AA%E5%8F%AF%E4%BA%A4%E4%BA%92%E7%9A%84%E4%BE%8B%E5%AD%90
[https_www.ruanyifeng.com_blog_2017_05_websocket.html]: https://www.ruanyifeng.com/blog/2017/05/websocket.html