使用node.js下载图像 [英] Downloading images with node.js

问题描述

我正在尝试使用node.js编写脚本下载图片。这是我到目前为止：

I'm trying to write a script to download images using node.js. This is what I have so far:

var maxLength = 10 // 10mb
var download = function(uri, callback) {
  http.request(uri)
    .on('response', function(res) {
      if (res.headers['content-length'] > maxLength*1024*1024) {
        callback(new Error('Image too large.'))
      } else if (!~[200, 304].indexOf(res.statusCode)) {
        callback(new Error('Received an invalid status code.'))
      } else if (!res.headers['content-type'].match(/image/)) {
        callback(new Error('Not an image.'))
      } else {
        var body = ''
        res.setEncoding('binary')
        res
          .on('error', function(err) {
            callback(err)
          })
          .on('data', function(chunk) {
            body += chunk
          })
          .on('end', function() {
            // What about Windows?!
            var path = '/tmp/' + Math.random().toString().split('.').pop()
            fs.writeFile(path, body, 'binary', function(err) {
              callback(err, path)
            })
          })
      }
    })
    .on('error', function(err) {
      callback(err)
    })
    .end();
}

然而，我想让这更加健壮：

I, however, want to make this more robust:

1. 有没有图书馆做这个，做得更好？


2. 是否有机会回应标题，关于内容类型）？


3. 是否有任何其他状态代码我应该关心？我应该打扰重定向吗？


4. 我想我读过某个地方， binary 编码将被弃用。那么我该怎么办？


5. 如何让这个工作在Windows上？


6. 其他任何方式可以使脚本更好？ li>
   

1. Are there libraries that do this and do this better?
2. Is there a chance that response headers lie (about length, about content type)?
3. Are there any other status codes I should care about? Should I bother with redirects?
4. I think I read somewhere that binary encoding is going to be deprecated. What do I do then?
5. How can I get this to work on windows?
6. Any other ways you can make this script better?

为什么：对于类似于imgur的功能，用户可以给我一个URL，我下载该图像，并重新映射多个大小的图像。

Why: for a feature similar to imgur where users can give me a URL, I download that image, and rehost the image in multiple sizes.

推荐答案

我建议使用请求模块。下载文件与以下代码一样简单：

I'd suggest using the request module. Downloading a file is as simple as the following code:

var fs = require('fs'),
    request = require('request');

var download = function(uri, filename, callback){
  request.head(uri, function(err, res, body){
    console.log('content-type:', res.headers['content-type']);
    console.log('content-length:', res.headers['content-length']);

    request(uri).pipe(fs.createWriteStream(filename)).on('close', callback);
  });
};

download('https://www.google.com/images/srpr/logo3w.png', 'google.png', function(){
  console.log('done');
});

这篇关于使用node.js下载图像的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！