How does one use HTTP to check whether a URL actually is going to hit
something, or if it is instead going nowhere, without downloading the
whole result of the hit?

In article <1162554234.812496.15710@e3g2000cwe.googlegroups.c om>,
David at Alcatel <David.Hiskiyahu@alcatel.be> wrote:
>How does one use HTTP to check whether a URL actually is going to hit
>something, or if it is instead going nowhere, without downloading the
>whole result of the hit?

RFC 2616
The metainformation contained in the HTTP headers in response to a
HEAD request SHOULD be identical to the information sent in
response to a GET request. ...

Walter,

I guess that this means that there is no way to 'sniff' a URL without
biting it, right?

Walter Roberson wrote:
> RFC 2616
> The metainformation contained in the HTTP headers in response to a
> HEAD request SHOULD be identical to the information sent in
> response to a GET request. ...

In article <1162889201.480134.243710@f16g2000cwb.googlegroups .com>,
David at Alcatel <David.Hiskiyahu@alcatel.be> top-posted, now fixed:

>Walter,

Please do not top-post: it makes it difficult to develop a choerent
discussion.


>Walter Roberson wrote:
>> RFC 2616
>> The metainformation contained in the HTTP headers in response to a
>> HEAD request SHOULD be identical to the information sent in
>> response to a GET request. ...


>I guess that this means that there is no way to 'sniff' a URL without
>biting it, right?

Your original question was about finding out whether the query was
going to go anywhere, without having to download the whole thing. The
answer to that is that was that HEAD instead of GET should tell you that
unless they cheat on the protocol.

Now you appear to be asking whether there is a way to check the
validity of a URL without contacting the server. The answer to that is
NO. Even if the URL does not include a ? query (i.e., an obvious
dynamic component), the URL details might include portions which
were dynamically generated, either naturally (e.g., a date on dated
material that naturally expires such as CNN), or artificially for tracking
or advertising purposes.