How to see http*.mp3 size before download ?

Can the size of any http be known before fetching it ?
Even if it has no descendant links ?

Surely the inability to decide whether to fetch or not, based
on the size of the servers 'offering' is a type of potential
mallicious attack from the server.

And related to this: what stops a client being indefinately
'held up' by a malicious server - like a D.O.S. attack ?

Thanks for any info.

== Chris Glur.

(E-Mail Removed) writes:

>Can the size of any http be known before fetching it ?
>Even if it has no descendant links ?

>Surely the inability to decide whether to fetch or not, based
>on the size of the servers 'offering' is a type of potential
>mallicious attack from the server.

As you download it will give you an estimate, usually.

And if it gets too big, cancel the download.


>And related to this: what stops a client being indefinately
>'held up' by a malicious server - like a D.O.S. attack ?

You. Just cancel the download.


>Thanks for any info.

>== Chris Glur.

(E-Mail Removed) écrivait news:Pv-
(E-Mail Removed):

> Can the size of any http be known before fetching it ?
> Even if it has no descendant links ?

The server response headers may send a "Content-Size:xxx" information to
the client. And so the client software may know the size of the data that
follow the headers.

But this is not always available. Most static file request (.html, .jpeg,
....) returns this information, but most script don't do it.

> And related to this: what stops a client being indefinately
> 'held up' by a malicious server - like a D.O.S. attack ?

Most cliet have a (large) timeout.


Regards