briany at qldlearning.com
Wed Jan 28 03:51:26 EST 2009
There may be a way to trick libURL into sending HEAD instead of GET,
but if you don't mind getting your hands dirty with sockets a bit, you
can do something like:
put "www.myserver.com:80" into tSocket
open socket tSocket
write "HEAD /path/to/file.html HTTP/1.0"&crlf&"Host: myserver.com" to
read form socket tSocket until empty
put it into tReply
close socket tSocket
Basically, you write a two line request to port 80 of the desired
server, then read back the reply. Line 1 of the reply will give you an
HTTP status code. The request just looks like:
LINE 1: HEAD /some/file/path HTTP/1.0
LINE 2: Host: www.someserver.com
Lines end with carriage return + linefeed.
Then the reply will give you something like "200 OK" in the first
line, or "404 NOT FOUND", etc.
Of course if you are checking for the existence of things, you will
have to handle failed connections. You could also use a shell() call
to something like curl, which has a flag to send HEAD requests.
> can anybody tell me how to retrieve only the header from a URL,
> using the HEAD method?
> "The HEAD method is identical to GET except that the server MUST NOT
> return a message-body in the response." (RFC 2616)
> This could be helpful to check the validity of URLs.
> Thomas Fischer
> Permosergasse 23a
> 5026 Salzburg
> Tel.: +43 662 621498
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