Checks whether new file available

  • Thread starter Thread starter Abraham
  • Start date Start date
A

Abraham

Hello all.

I have a website that changes gif's when the user clicks things. I have
preloaded the gif's so that it is responsive. But over the last few days,
my ISP has been having trouble. Pings take half a second and are sometimes
lost entirely. I discovered that under bad circumstances, even though the
gif's have been preloaded, the site seems to hang. Turns out I can make it
responsive again by setting Internet Explorer not to check the cache.
Apparently, even asking the server "do you have a newer file?" slows it
down!

Out there across this beautiful world, someone else may have an ISP with
problems, so I would like to arrange things so it'll work even in these
circumstances. That seems to mean, persuade Internet Explorer not to check
for newer files.

I can't tell my users to change their settings. They are financial people,
not computer scientists, and they would geek if I asked them to navigate
through the menus. I thought about giving all my image files a date in
2007, in hopes that Internet Explorer contains code like:

if (date_of_file_on_disk > todays_date)
dont_ask_server_about_a_newer_file;

Has someone else dealt with this, and knows a trick to persuade Internet
Explorer to accept the files it has?


Regards,

Abraham
 
....
Has someone else dealt with this, and knows a trick to persuade Internet
Explorer to accept the files it has?
Click to expand...



If you are sure that all your users are using IE5 or greater there's this
(from a previous post):

<excerpt>
(Just my interpretation of what I was reading.)

---
http://msdn.microsoft.com/workshop/author/perf/perftips.asp?frame=true#Use_Cache-Control_Extensions
Click to expand...

The only "No-check" in that article looks to me like an abstraction
to label the Green line in the diagram. I would say that

Post-check=mm
defines the end of the "No-check" interval
(green line in the diagram)
and the beginning of the "Pre-check" interval
(yellow line in the diagram).

Pre-check=nn
defines the end of the "Post-check" interval
(yellow line in the diagram)
and the beginning of the (indefinite) Pre-check interval
(red line in the diagram)

I wish that the article made clearer if HTTP/1.1 is a requirement
for this feature. There is a loose implication that it is.
For example here is an extract from the RFC referenced:
http://www.cis.ohio-state.edu/cgi-bin/rfc/rfc2068.html#sec-14.9
<extract>
Note that HTTP/1.0 caches may not implement Cache-Control
and may only implement Pragma: no-cache (see section 14.32).
</extract>


HTH

Robert Aldwinckle
 
Hello Robert.

Well, it has taken a while, but this problem is solved. My internet
host (myhosting.com -- I recommend them) changed a setting on a
directory I created called expires_22_september_2006. I think they're
using Microsoft's Internet Information Services.

Once the setting is changed, the files that are downloaded are marked
to expire next year. You can see this if you go to your \Documents and
Settings\<yourname>\Local Settings\Temporary Internet Files folder.
Look at the column headed Expires.

Apparently, this is how Google avoids serving its logo over and over.
It's set to expire in 2038.

Thanks for putting me on the right track, Robert.


Regards,

Abraham
 
Back
Top