javascript - Node.js 使用请求模块从 url 下载图像给出 URI 错误

Question

我正在循环下载图像，当我将循环设置为for (var i = 0; i < 100; i++) {时我下载图像没有问题。但一旦我改变我的 i范围超过 99(包括 100)，所以类似:for (var i = 100; i < 200; i++) {或for (var i = 0; i < 200; i++) {我收到一个错误。这是我的代码:

var fs = require('fs');

var request = require('request');

var download = function(uri, filename, callback){
  request.head(uri, function(err, res, body){
    request(uri).pipe(fs.createWriteStream(filename)).on('close', callback);
  });
};

var arrLength = allProducts.length;

for (var i = 0; i < arrLength; i++) { 

    let imgName = allProducts[i].code;    
    let imgUrl = allProducts[i].nofrillsImgLink    

    download(`${imgUrl}`, `./allProductsImg/${imgName}.png`, function(){              
      });
};

这是我收到的错误:

events.js:287
      throw er; // Unhandled 'error' event
      ^

Error: Invalid URI "undefined"
    at Request.init (.../node_modules/request/request.js:273:31)
    at new Request (.../node_modules/request/request.js:127:8)
    at request (.../node_modules/request/index.js:53:10)
    at Request._callback (.../downloadImg.js:7:5)
    at self.callback (.../node_modules/request/request.js:185:22)
    at Request.emit (events.js:310:20)
    at Request.init (.../node_modules/request/request.js:273:17)
    at new Request (.../node_modules/request/request.js:127:8)
    at request (.../node_modules/request/index.js:53:10)
    at Function.head (.../node_modules/request/index.js:61:12)
Emitted 'error' event on Request instance at:
    at Request.init (.../node_modules/request/request.js:273:17)
    at new Request (.../node_modules/request/request.js:127:8)
    [... lines matching original stack trace ...]
    at Function.head (.../node_modules/request/index.js:61:12)

Answer 1

您可以更改此代码

var download = function(uri, filename, callback){
  request.head(uri, function(err, res, body){
    request(uri).pipe(fs.createWriteStream(filename)).on('close', callback);
  });
};

至

var download = function(uri, filename, callback){
  if(uri !== undefined){
    request.head(uri, function(err, res, body){
      request(uri).pipe(fs.createWriteStream(filename)).on('close', callback);
    });
  }
};