Node.js进行http/https请求和下载的实现实例

const http = require("http");   // 用于发起HTTP请求
const https = require("https"); // 用于发起HTTPS请求
const fs = require("fs");       // 用于文件操作（如保存图片）

const get_options = {
  hostname: "jsonplaceholder.typicode.com", // 目标服务器域名
  port: 443, // HTTPS 默认端口号为443  HTTP默认端口号为80
  path: "/posts/5", // 请求路径，获取 ID 为 5 的文章
  method: "GET", // 请求方法
};

//创建请求
const get_req = https.request(get_options, (res) => {
  let data = "";

  res.on("data", (chunk) => {
    data += chunk; // 将响应数据片段拼接到变量中
  });

  res.on("end", () => {
    const jsonData = JSON.parse(data); // 解析 JSON 数据
    console.log(jsonData); // 输出解析后的 JSON 对象
  });
});

get_req.on("error", (error) => {
  console.error(`Problem with request: ${error.message}`); // 处理请求错误
});

get_req.end(); // 发送请求

const post_options = {
  hostname: "jsonplaceholder.typicode.com",
  port: 443,
  path: "/posts",
  method: "POST",
  Headers: { // 设置请求头
    "Content-Type": "application/json", // 指定请求体类型为 JSON
    "Content-Length": Buffer.byteLength(
      JSON.stringify({
        userId: 1,
        title: "hello world",
        body: "你好",
      })
    ),
  },
};

const post_req = https.request(post_options, (res) => {
  let data = "";

  res.on("data", (chunk) => {
    data += chunk;
  });

  res.on("end", () => {
    const jsonData = JSON.parse(data);
    console.log(jsonData);
  });
});

post_req.on("error", (error) => {
  console.error(`Problem with request: ${error.message}`);
});

post_req.end();

const img_options = {
  hostname: "cdn2.thecatapi.com",
  port: 443,
  path: "/images/2OKotXbFe.jpg",
  method: "GET",
};

const img_req = https
  .request(img_options, (res) => {
    if (res.statusCode !== 200) {
      console.error(`Failed to fetch image, status code: ${res.statusCode}`);
      res.resume(); // 消耗响应数据以释放内存
      return;
    }

    const filePath = "./cat_image.jpg";
    const fileStream = fs.createWriteStream(filePath);

    res.pipe(fileStream);

    fileStream.on("finish", () => {
      fileStream.close(() => {
        console.log("Image saved successfully.");
      });
    });
  })
  .on("error", (err) => {
    console.error(`Error downloading image: ${err.message}`);
  });

img_req.end();