writing proper “HEAD” and “GET” request in winsock c++

问题

Actually I was coding for downloading the files in HTTP using winsock c++ and to get the details I fired "HEAD" header..

(this is what actually I did)

HEAD /files/ODBC%20Programming%20in%20C%2B%2B.pdf HTTP/1.0
Host: devmentor-unittest.googlecode.com

Response was:

HTTP/1.0 404 Not Found
Content-Type: text/html; charset=UTF-8
Set-Cookie: PREF=ID=feeed8106df5e5f1:TM=1370157208:LM=1370157208:S=10bN4nrXqkcCDN5n; expires=Tue, 02-Jun-2015 07:13:28 GMT; path=/; domain=devmentor-unittest.googlecode.com
X-Content-Type-Options: nosniff
Date: Sun, 02 Jun 2013 07:13:28 GMT
Server: codesite_downloads
Content-Length: 974
X-XSS-Protection: 1; mode=block
X-Frame-Options: SAMEORIGIN

But if I do:

GET /files/ODBC%20Programming%20in%20C%2B%2B.pdf HTTP/1.0
Host: devmentor-unittest.googlecode.com

The file sucessfully gets downloaded....

After then after I download, again if I fire the HEAD request... it also brings up the following

HTTP/1.0 200 OK
Content-Length: 320381
Content-Type: application/pdf
Content-Disposition: attachment; filename="ODBC Programming in C++.pdf"
Accept-Ranges: bytes
Date: Sun, 02 Jun 2013 05:47:11 GMT
Last-Modified: Sun, 11 Nov 2007 03:17:59 GMT
Expires: Sun, 09 Jun 2013 05:47:11 GMT
Cache-Control: public, max-age=604800
Server: DFE/largefile
//something like this.....

Question: why "HEAD" is returning the false "error not found" at first but the file gets downloaded in using "GET" and after downloading "HEAD" also returns goodies i need...where have i mistaken..

The file I am trying to download here is "http://devmentor-unittest.googlecode.com/files/ODBC%20Programming%20in%20C%2B%2B.pdf" (just for example)

回答1:

The problem is not on your end. Google Code simply does not implement HEAD correctly. This was reported 5 years ago and is still an open issue:

Issue 660: support HTTP HEAD method for file download urls

来源：https://stackoverflow.com/questions/16881613/writing-proper-head-and-get-request-in-winsock-c