Hi, Weiguo...
> I am trying to get the last_modified_date for all the urls. But I found
> not every web server support this header information. Is there anyway that
> I can calculatet or get the modification date?
>
> I was using HTTP::Request.
Maybe this is not an answer what you want....,
Almost of all web servers which allows SSI do not reply content's last-modified
date.
So, if you want to get modified-date of contents on these web servers,
you must make effort to get information when the web-page modified.
I think, one way is to get content on interval and try to fetch when contents
modified.
Maybe you can make a script to get web-page with using LWP::UserAgent.
The another way is to request the cooperation of web-page's writer.
Because if the page can use SSI, the page can display its own modified time
by using <!--#flastmod file="diary.html"--> in its html file.
I know some agent programms which to display modified date&time like
"Asahina-Anthena"(http://masshy.fastwave.gr.jp/hina/release/)
or
"Natsu-mican"(http://amano.haun.org/natsumican.html)
uses conbinations of getting HTTP Header(last-modified),
getting modified message from SSI,
and from DI files.
There are some barriers to use these programms (because these software's
documentetions are written in Japanese only), but you can learn how they can do
get modified-date from reading these programms because they are written in our
common language, Perl.
Try.
S Komura
[EMAIL PROTECTED]
