How can I make the images not cache on a htm file?

[Banditt]

I have a file:
(link removed by Banditt - no longer live)
that I link from RobinsjExcal skin. (right now I just relinked the Top250 link, but once I get this working I want to create a separate link).

The problem is, when the NMT loads the page, all of the HTML updates but the satellite image never does.
I have tried

• PHP header no cache elements
• META tags to no cache
  

Is there a way to make it so it always updates the images?

Thanks,
Brett

[excal]

Hmm...i'm not sure.

I can't promise it will..but i think you'd have a better chance of getting this answered in the user apps section...

Unless you have an objection, I'm gonna move it there.

[Banditt]

No problem - saw your post about moving the index thread herre, so I posted here

[excal]

Ya no problem... this just has more a technical aspect to it...so i think you'll be better served by some of the script experts in the user apps.

[lordy]

Have you tried putting a '?' at the end if the image name?

img src="blah.jpg?"

Might work? Might not!

[excal]

just outta curiosity...why would the ? work whats that doing in theory?

[lordy]

Some browsers see the ? on the url and suspect that because page contains a query string it is likely to change if the query string changes, so they dont cache it.

Just in case my effort was too simple to fool them - using a better dummy query *may* work... eg
img.jpg?a=1

[Banditt]

For each image, i could append a random number and hope that it doesn't duplicate:

Code:

image.jpg?rand=<?php echo rand(1, 1000000) ?>

but I wanted to see if there was a more global way to turn off caching for the whole page.

Brett

[ok]

(01-13-2009 06:00 PM)Banditt Wrote:  For each image, i could append a random number and hope that it doesn't duplicate:

Code:

image.jpg?rand=<?php echo rand(1, 1000000) ?>

but I wanted to see if there was a more global way to turn off caching for the whole page.

Brett

Also having a major problem with this. The PCH browser does not honour the usual http headers (i.e. Cache-control: and/or Expire: ). Which is a pain as it makes dynamic web content very hard to create from static html files. I have a gif on each movie page that shows whether I've seen the movie or not, and this information is dynamic. I can click on the gif (stored on a webserver as a script) and it will flip the state and in theory show me the altered state as a different gif. Problem is I don't see the new image before I've cleared the PCH browser cache from setup or powercycled the box. Works fine from my Firefox.

So, can Syabas please add some rudimentary cache control? Just a simple test for say "Cache-control: no-cache" to determine whether to write the reply to cache or not would do as a start.


And no, adding arguments to the url does not avoid the caching mechanism. Different arguments every time from a javascript will probably do it, but that's going to fill up the cache real quick.

OK

[excal]

filling up the cache shouldn't necissarily be a problem anymore...my understanding is that the new firmware made it so that when the cache gets full it deletes the oldest 2mb, and keeps going till its full...then deletes the oldest 2mb.

I may be off there, but i seem to recall reading thats what they did.

[AlexNC]

I would like to see a solution to this too. I made a htm file of my local weather stations forecast. Basically, I link it to their 5 day forcast jpg image, that they constantly update. My problem is that the PCH always shows an old cached image, rather than the current one.

[trunkmonkey]

(01-27-2009 11:36 PM)ok Wrote:  Also having a major problem with this. The PCH browser does not honour the usual http headers (i.e. Cache-control: and/or Expire: ). Which is a pain as it makes dynamic web content very hard to create from static html files. I have a gif on each movie page that shows whether I've seen the movie or not, and this information is dynamic. I can click on the gif (stored on a webserver as a script) and it will flip the state and in theory show me the altered state as a different gif. Problem is I don't see the new image before I've cleared the PCH browser cache from setup or powercycled the box. Works fine from my Firefox.

So, can Syabas please add some rudimentary cache control? Just a simple test for say "Cache-control: no-cache" to determine whether to write the reply to cache or not would do as a start.


And no, adding arguments to the url does not avoid the caching mechanism. Different arguments every time from a javascript will probably do it, but that's going to fill up the cache real quick.

OK

You are right that it would probably be trivial to look for "Cache-control: no-cache" meta tag, and that would probably be the simplest way that Syabas could support dynamic images.

I have typically worked around this by specifying dynamic facets of the image as part of the querystring... that is, a parameter for each property of an image that could change (e.g. size, highlight/focus state, etc).

Banditt Wrote:For each image, i could append a random number and hope that it doesn't duplicate:

Code:

image.jpg?rand=<?php echo rand(1, 1000000) ?>

but I wanted to see if there was a more global way to turn off caching for the whole page.

Brett

No need for using random numbers... just use the current date/time as ticks or whatever... seems natural for an image that changes based on time, yes?

I know its sucks a bit that it will slowly munch its way thru the cache space and evict other useful data, but as excal said, now that they have fixed the image caching bug, at least it doesn't bring down the box!

[Banditt]

The datetime stamp is a much better idea. I'll be switching all my stuff over to that