Caching images & ASP pages

[CJM]

I've had some periodic problems on certain (intranet)servers where IIS seems
to be caching thing in an unexpected way, or is server cached pages where
new content is expected.

The first situation is where we have a standard Top + Left + Content
framset; the left frame contains a menu which shows standard options - when
the user logs in, extra menu options are available to them, depending on
their priveleges. The menu is generated from a DB in ASP, and when the user
logs in, Javascript is used to reload the page in the left frame - eg.
re-generate menu based on logged-in user.

This used to work on all servers, but at some point in time I found that
people were logging in but were stuck with the standard menu. If we
right-clicked in the menu and chose refresh, often the correct (eg expanded)
menu would be shown.

I'm not sure where the problem is IIS or could be controlled in ASP...

The second problem is on my development machine; when I browse to my
development copy of the intranet, I dont get the icons for each menu item.
However, when I browse to the live Intranet system, the correct graphics are
shown.

Screenshots:
My machine - http://www.brightnorth.com/news/menu1.gif
Normal site - http://www.brightnorth.com/news/menu2.gif

I'm assuming that this one is purely an IIS problem. Any thoughts?

 

[Aaron [SQL Server MVP]]

Some info here:
http://www.aspfaq.com/2022

 

[CJM]

Aaron/Stephen,

Thanks. I'd actually already discovered this info while waiting (on Aaron's
site of course!)

Clearly this stops the ASP menu caching problem but not the menu icons....
Any ideas about these?

Chris

 

[Aaron [SQL Server MVP]]

Clearly this stops the ASP menu caching problem but not the menu icons....

Any ideas about these?

How often are you changing the menu icons, really? If you change the
graphics, change the name too. Then the browser won't look at the old
images still in the cache.

A

 

[CJM]

How often are you changing the menu icons, really? If you change the
graphics, change the name too. Then the browser won't look at the old
images still in the cache.

The images never change. Well, they havent so far...

It's not like it's picking up old graphics... it's presumably picking up the
right graphics but not showing them... that is, the images appear to take up
space, but just arent visible...!

The images are each surrounded by an anchor, since they are also used within
the javascript menu top expand each menu group - this functionality still
works...

it's puzzling!

Chris

 

[Aaron [SQL Server MVP]]

The images never change. Well, they havent so far...

It's not like it's picking up old graphics... it's presumably picking up the
right graphics but not showing them... that is, the images appear to take up
space, but just arent visible...!

? So why do you think this is a caching issue?

A

 

[[MSFT]]

Hi Chris,

If you choose to view the source code of page in IE, did you see the code
the those images?

Luke

 

[CJM]

Luke,

Yes the images are present in the HTML.

I did wonder if the CSS was hiding the images but the same CSS is used on
the development site as is on the live site.

cheers

Chris

 

[[MSFT]]

If right click the place, the select "Show Picture", will the image occur?
Are these images files in same folder with your web pages?

Luke

 

[CJM]

The image files are in a different folder...

My original problem was that the sub-item images didnt appear, but the main
item images did. In this case, by using show picture the images *would*
appear.

Now both images dont appear, and show picture doesnt seem to work. I'm not
aware of any change in circumstance, but clearly there must be some.

Chris

 

[[MSFT]]

Hi Chris,

In IE, delete all the Internet temporary files. Will this help? And, is the
treeview a server side control? a thrid party component?

Luke

 

[CJM]

Luke,

The problem is the same for all users who access the site not just mine.
Besides, this problem has been going on for months, during which time I've
deleted the temporary files plenty of times. However, I thought I'd better
try especially for you(!), but I'm afraid this time was no different
either...

The treeview is handcoded using ASP/JScript - well, I use a ProjectSeven
(PVII) menu script as the basis.

Cheers

Chris

 

[CJM]

Got the problem sorted now. I re-checked the logs and the two images
concerned were coming up as 404's - there was a small typo in the code! I
didnt notice before because the images are part of a large group that all
were coming up as 200 - didnt notice the 2 x 404 in the middle.

Apologies and thanks for your help.