执行终端命令并通过React+SSE接收实时输出-DEV365 开发者社区

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在这里，我将使用react + vite设置为UI，但是您可以使用所需的任何框架/库，因为这些基础知识将保持不变。

我假设您已经安装了nodejs并具有代码编辑器设置，并且您以前创建了在localhost:3000上运行的SSE服务器

mkdir ssedemoclient

yarn create vite

我还将安装尾风UI设置。查看tailwind official doc for setting up使用React+Vite。

将以下代码段添加到app.js。

import { useState } from "react";
import "./App.css";

let events = null;

function App() {
  const [commandOut, setCommandOut] = useState([]);
  const [isActive, setisActive] = useState(false);

  const sendCommand = (command) => {
    // close current event if user submit another command
    if (events) {
      console.log("close current event");
      setCommandOut([]);
      events.close();
    }

    if (!command) {
      console.log("Empty command");
      return;
    }

    // create event source
    events = new EventSource(`http://localhost:3000/run?command=${command}`);

    // add eventlistner for message output from command
    events.addEventListener(
      "stdout",
      function (e) {
        let parsedData = JSON.parse(e.data);
        console.log(parsedData);
        setCommandOut((pre) => [parsedData, ...pre]);
      },
      false
    );

    events.addEventListener(
      "stderr",
      function (e) {
        let parsedData = JSON.parse(e.data);
        console.log(parsedData);
        setCommandOut((pre) => [parsedData, ...pre]);
      },
      false
    );

    events.addEventListener(
      "err",
      function (e) {
        let parsedData = JSON.parse(e.data);
        console.log(parsedData);
        setCommandOut((pre) => [parsedData, ...pre]);
      },
      false
    );

    events.addEventListener(
      "open",
      function (e) {
        console.log("open");
        setisActive(true);
      },
      false
    );
    // event handler for command exit to stop retry
    events.addEventListener(
      "exit",
      function (e) {
        console.log("exited");
        events.close();
        setisActive(false);
      },
      false
    );

    events.addEventListener(
      "error",
      function (e) {
        if (e.readyState == EventSource.CLOSED) {
          // Connection was closed.
          setisActive(false);
        }
      },
      false
    );

    events.addEventListener("error", (e) => {
      console.log("An error occurred while attempting to connect.");
      setisActive(false);
      events.close();
    });
  };

  return (
    <div className="bg-slate-800 h-screen">
      <div className="container mx-auto ">
        <div className="h-[20vh]">
          <h1 className="text-3xl text-cyan-50 pt-10 font-bold text-center">
            Run command with SSE Demo
          </h1>
          <form
            onSubmit={(e) => {
              e.preventDefault();
              console.log(e.target[0].value);
              sendCommand(e.target[0].value);
            }}
          >
            <div className="flex flex-row justify-between align-middle self-center content-center pt-10 w-full">
              <input
                type="text"
                id="last_name"
                className="bg-gray-50 border border-gray-300 placeholder-gray-600 text-gray-900 text-sm rounded-lg focus:ring-blue-500 focus:border-blue-500 block w-[90%] p-2.5"
                placeholder="Enter command to run"
                required
              />
              {/* show only when listening to messeges */}
              <div
                className={`content-center flex flex-wrap ${
                  isActive ? "" : "hidden"
                }`}
              >
                {/* spinner animation on active conenction */}
                <svg
                  aria-hidden="true"
                  role="status"
                  className="inline w-6 h-6 mx-3 text-blue-600 animate-spin"
                  viewBox="0 0 100 101"
                  fill="none"
                  xmlns="http://www.w3.org/2000/svg"
                >
                  <path
                    d="M100 50.5908C100 78.2051 77.6142 100.591 50 100.591C22.3858 100.591 0 78.2051 0 50.5908C0 22.9766 22.3858 0.59082 50 0.59082C77.6142 0.59082 100 22.9766 100 50.5908ZM9.08144 50.5908C9.08144 73.1895 27.4013 91.5094 50 91.5094C72.5987 91.5094 90.9186 73.1895 90.9186 50.5908C90.9186 27.9921 72.5987 9.67226 50 9.67226C27.4013 9.67226 9.08144 27.9921 9.08144 50.5908Z"
                    fill="#a6c0d7"
                  />
                  <path
                    d="M93.9676 39.0409C96.393 38.4038 97.8624 35.9116 97.0079 33.5539C95.2932 28.8227 92.871 24.3692 89.8167 20.348C85.8452 15.1192 80.8826 10.7238 75.2124 7.41289C69.5422 4.10194 63.2754 1.94025 56.7698 1.05124C51.7666 0.367541 46.6976 0.446843 41.7345 1.27873C39.2613 1.69328 37.813 4.19778 38.4501 6.62326C39.0873 9.04874 41.5694 10.4717 44.0505 10.1071C47.8511 9.54855 51.7191 9.52689 55.5402 10.0491C60.8642 10.7766 65.9928 12.5457 70.6331 15.2552C75.2735 17.9648 79.3347 21.5619 82.5849 25.841C84.9175 28.9121 86.7997 32.2913 88.1811 35.8758C89.083 38.2158 91.5421 39.6781 93.9676 39.0409Z"
                    fill="currentColor"
                  />
                </svg>
              </div>
              {/* show connection close button */}
              {isActive && (
                <button
                  type="button"
                  className="text-white bg-slate-500 hover:bg-slate-600 p-2 font-medium rounded-lg text-sm px-5 mr-4"
                  onClick={() => {
                    console.log("event listen stopped");
                    events.close();
                    setisActive(false);
                  }}
                >
                  Stop
                </button>
              )}
              <button
                type="submit"
                className="text-white bg-blue-600 hover:bg-blue-800 p-2 font-medium rounded-lg text-sm px-5 "
              >
                Run
              </button>
            </div>
          </form>
        </div>
        {/* list down commands with timestamp */}
        <div className="text-white pt-10 whitespace-pre h-[80vh] overflow-y-auto">
          {commandOut.map((data, index) => (
            <div className="flex" key={index}>
              <div>
                <p className="mr-2 text-sky-400">{`${new Date()
                  .toLocaleString()
                  .replace("T", " ")} : `}</p>
                <p>{data.type}</p>
              </div>
              <p>{data.out}</p>
            </div>
          ))}
        </div>
      </div>
    </div>
  );
}

export default App;

EventSource是服务器SSE与客户端端集成的地方。

EventSource是一个JavaScript API，使客户端可以通过单个长期寿命的HTTP连接从服务器接收SSE。

然后，我们需要将事件listers添加到EventSource。在这里，我们需要收听我们从服务器端发送的事件，即stdout，stderr，err和exit Events。

我们维护一个用于管理命令输出的useState，一个用于保持命令执行状态的命令状态，因为我们可以执行诸如tail之类的命令以获取遵循文件更改实时更改的文件的实时更新。

exit eventlistener将关闭客户端端的连接，以免自动重试。

我们将状态更新为commandOut后，我们需要使用数组映射方法使用事件类型，时间和命令输出来渲染UI。

我添加了其他功能取消，我们可以关闭当前连接以停止收听事件。在这种情况下，客户端将关闭连接，并且在服务器上执行的命令也将被杀死。

如果一切顺利，您将在UI下方。