使用 node.js 下载图像 [英] Downloading images with node.js
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问题描述
我正在尝试编写一个脚本来使用 node.js 下载图像.这是我目前所拥有的:
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,我想让它更健壮:
I, however, want to make this more robust:
- 是否有图书馆可以做到这一点并且做得更好?
- 响应标头是否有可能撒谎(关于长度、关于内容类型)?
- 还有其他我应该关心的状态代码吗?我应该为重定向而烦恼吗?
- 我想我在某处读到
binary
编码将被弃用.那我该怎么办? - 我怎样才能让它在 Windows 上工作?
- 还有什么其他方法可以让这个脚本变得更好?
- Are there libraries that do this and do this better?
- Is there a chance that response headers lie (about length, about content type)?
- Are there any other status codes I should care about? Should I bother with redirects?
- I think I read somewhere that
binary
encoding is going to be deprecated. What do I do then? - How can I get this to work on windows?
- Any other ways you can make this script better?
原因:对于类似于 imgur 的功能,用户可以给我一个 URL,我下载该图像,并以多种尺寸重新托管该图像.
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 请求模块一>.下载文件就像下面的代码一样简单:
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');
});
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