I have a link to two files, they may be the same file but they may not be the same URL. I want to figure out if they are the same by checking the content-length before doing a full download. Whats the best way to do this? Currently i am using webbrowser control to load the page and extract data then using WebClient.Download to get the file. If there a way i can use WebClient to check the filesize before DLing the entire file?
+3
A:
Equality of lengths does not mean that files are identical. However, if you're sure that this is enough to assert equality, you can issue a HttpWebRequest with Method set to HEAD: this will only download file headers, including content-length.
Anton Gogolev
2009-07-24 10:55:26
assuming that the content-length header gets set which may vary depending on the web server and whether any server side code is involved in the downloading
RobV
2009-07-24 10:56:51
HEAD requests are SUPPOSED to be processed the same as normal, then have the body discarded... But you're right, some systems are probably lazy.
Matthew Scharley
2009-07-24 11:54:39