路径:img 类型:JPG 随机函数

    function resim(url) {

    var http = require("http");
    var fs = require("fs");
    var sayi = Math.floor(Math.random()*10000000000);
    var uzanti = ".jpg";
    var file = fs.createWriteStream("img/"+sayi+uzanti);
    var request = http.get(url, function(response) {
  response.pipe(file);
});

        return sayi+uzanti;
}

也许node.js已经改变了，但似乎其他解决方案(使用node v8.1.2)有一些问题:

You don't need to call file.close() in the finish event. Per default the fs.createWriteStream is set to autoClose: https://nodejs.org/api/fs.html#fs_fs_createwritestream_path_options file.close() should be called on error. Maybe this is not needed when the file is deleted (unlink()), but normally it is: https://nodejs.org/api/stream.html#stream_readable_pipe_destination_options Temp file is not deleted on statusCode !== 200 fs.unlink() without a callback is deprecated (outputs warning) If dest file exists; it is overridden

下面是一个修改后的解决方案(使用ES6和promises)，它可以处理这些问题。

const http = require("http");
const fs = require("fs");

function download(url, dest) {
    return new Promise((resolve, reject) => {
        const file = fs.createWriteStream(dest, { flags: "wx" });

        const request = http.get(url, response => {
            if (response.statusCode === 200) {
                response.pipe(file);
            } else {
                file.close();
                fs.unlink(dest, () => {}); // Delete temp file
                reject(`Server responded with ${response.statusCode}: ${response.statusMessage}`);
            }
        });

        request.on("error", err => {
            file.close();
            fs.unlink(dest, () => {}); // Delete temp file
            reject(err.message);
        });

        file.on("finish", () => {
            resolve();
        });

        file.on("error", err => {
            file.close();

            if (err.code === "EEXIST") {
                reject("File already exists");
            } else {
                fs.unlink(dest, () => {}); // Delete temp file
                reject(err.message);
            }
        });
    });
}

现代版本(ES6, Promise, Node 12。X +)适用于https/http。它还支持重定向302和301。我决定不使用第三方库，因为它可以很容易地使用标准Node.js库。

// download.js
import fs from 'fs'
import https from 'https'
import http from 'http'
import { basename } from 'path'
import { URL } from 'url'

const TIMEOUT = 10000

function download (url, dest) {
  const uri = new URL(url)
  if (!dest) {
    dest = basename(uri.pathname)
  }
  const pkg = url.toLowerCase().startsWith('https:') ? https : http

  return new Promise((resolve, reject) => {
    const request = pkg.get(uri.href).on('response', (res) => {
      if (res.statusCode === 200) {
        const file = fs.createWriteStream(dest, { flags: 'wx' })
        res
          .on('end', () => {
            file.end()
            // console.log(`${uri.pathname} downloaded to: ${path}`)
            resolve()
          })
          .on('error', (err) => {
            file.destroy()
            fs.unlink(dest, () => reject(err))
          }).pipe(file)
      } else if (res.statusCode === 302 || res.statusCode === 301) {
        // Recursively follow redirects, only a 200 will resolve.
        download(res.headers.location, dest).then(() => resolve())
      } else {
        reject(new Error(`Download request failed, response status: ${res.statusCode} ${res.statusMessage}`))
      }
    })
    request.setTimeout(TIMEOUT, function () {
      request.abort()
      reject(new Error(`Request timeout after ${TIMEOUT / 1000.0}s`))
    })
  })
}

export default download

感谢安德烈·特卡琴科，我修改了他的要点

将其包含在另一个文件中并使用

const download = require('./download.js')
const url = 'https://raw.githubusercontent.com/replace-this-with-your-remote-file'
console.log('Downloading ' + url)

async function run() {
  console.log('Downloading file')
  try {
    await download(url, 'server')
    console.log('Download done')
  } catch (e) {
    console.log('Download failed')
    console.log(e.message)
  }
}

run()

编写自己的解决方案，因为现有的不符合我的要求。

包括:

HTTPS下载(http下载时切换包到http) 基于承诺的函数 处理转发路径(状态302) 浏览器头-需要在一些cdn 来自URL的文件名(以及硬编码) 错误处理

打印出来的，更安全。如果你使用的是纯JS(没有Flow，没有TS)，可以随意删除类型，或者转换为.d。ts文件

index.js

import httpsDownload from httpsDownload;
httpsDownload('https://example.com/file.zip', './');

httpsDownload.[js|ts]

import https from "https";
import fs from "fs";
import path from "path";

function download(
  url: string,
  folder?: string,
  filename?: string
): Promise<void> {
  return new Promise((resolve, reject) => {
    const req = https
      .request(url, { headers: { "User-Agent": "javascript" } }, (response) => {
        if (response.statusCode === 302 && response.headers.location != null) {
          download(
            buildNextUrl(url, response.headers.location),
            folder,
            filename
          )
            .then(resolve)
            .catch(reject);
          return;
        }

        const file = fs.createWriteStream(
          buildDestinationPath(url, folder, filename)
        );
        response.pipe(file);
        file.on("finish", () => {
          file.close();
          resolve();
        });
      })
      .on("error", reject);
    req.end();
  });
}

function buildNextUrl(current: string, next: string) {
  const isNextUrlAbsolute = RegExp("^(?:[a-z]+:)?//").test(next);
  if (isNextUrlAbsolute) {
    return next;
  } else {
    const currentURL = new URL(current);
    const fullHost = `${currentURL.protocol}//${currentURL.hostname}${
      currentURL.port ? ":" + currentURL.port : ""
    }`;
    return `${fullHost}${next}`;
  }
}

function buildDestinationPath(url: string, folder?: string, filename?: string) {
  return path.join(folder ?? "./", filename ?? generateFilenameFromPath(url));
}

function generateFilenameFromPath(url: string): string {
  const urlParts = url.split("/");
  return urlParts[urlParts.length - 1] ?? "";
}

export default download;

我建议你使用res.download，如下:

app.get('/download', function(req, res){
  const file = `${__dirname}/folder/abc.csv`;
  res.download(file); // Set disposition and send it.
});

我更喜欢request()，因为你可以同时使用http和https。

request('http://i3.ytimg.com/vi/J---aiyznGQ/mqdefault.jpg')
  .pipe(fs.createWriteStream('cat.jpg'))