MD5 from HTTP without download?

[pseudorandom21]

Anyone know of a way to obtain an MD5 checksum of a file (through HTTP) before downloading it through HTTP?

[Narue]

That seems kind of silly to me. The point of a checksum is to verify the legitimacy of a file after downloading it. If you're getting the checksum before downloading the file it's no different from taking on faith that the file is legit in the first place.

[pseudorandom21]

That seems kind of silly to me. The point of a checksum is to verify the legitimacy of a file after downloading it. If you're getting the checksum before downloading the file it's no different from taking on faith that the file is legit in the first place.

Regardless I'm looking for a way to get the checksum without downloading the file.

[skatamatic]

That seems kind of silly to me. The point of a checksum is to verify the legitimacy of a file after downloading it. If you're getting the checksum before downloading the file it's no different from taking on faith that the file is legit in the first place.

Would make sense to get the checksum to compare it with a file on the local computer to determine if they are identical. (IE if I have an identical file, no point wasting the bandwidth downloading it).

[gusano79]

Anyone know of a way to obtain an MD5 checksum of a file (through HTTP) before downloading it through HTTP?

Only one way that I'm aware of: Request the file using a HEAD request instead of GET --the server should only return the HTTP headers for the file. One of the possible headers is Content-MD5 , which is a base64-encoded MD5 hash of the content. I say "possible" because it's entirely up to the server which headers it returns. If a server provides it, great; if not, you're out of luck.