问题:

I need to get the Content-Length and Content-Type headers of large files with Node.

Unfortunately, the server I'm dealing with doesn't allow HEAD requests, and the files are too large to make an entire GET request.

I'm looking for something like this python code:

import requests

r = requests.get(url, stream=True)
content_length = r.headers['Content-Length']
content_type = r.headers['Content-Type']

The stream=True parameter means that the file won't be fully downloaded.

回答1:

If you're using the request package, you could do something like this:

const request = require('request');
const r = request(url);
r.on('response', response => {
    const contentLength = response.headers['content-length'];
    const contentType = response.headers['content-type'];
    // ...
    r.abort();
});

回答2:

The http library of nodejs by default it will not fetch everything but give the callback will contain the IncomingMessage object, to construct the full response you would have to listen to .on('data').

Take a look at:

https://nodejs.org/api/http.html#http_http_get_options_callback

If you then want to "ignore" the incoming data, you can just call res.abort(). Calling this will cause remaining data in the response to be dropped and the socket to be destroyed.