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Jul 16, 2003, 12:36pm

I would like some more detailed info on how exactly the browser
determines if content is stale for a given object path.

The docs imply that the browser 'checks the date', but the only
way to do so is by looking at the HTTP headers, and there are
a lot of different kinds of HTTP headers that control content caching.

I am noticing that any content created via 'create picture' commands
is downloaded completely anew every session even though there
is no 'update=' attached to it, and the server is reporting the content
as fully cacheable.

I have a museum with about 60 nice hi-res monet images that are
completely static, but every time someone comes into the world
they have to fully download about 4 megabytes of images because
they are all implemented via a 'create picture'.

I know I can workaround this using create texture instead of create
picture (assuming I construct a picture object that is to my liking and
does not use any textures for any other parts of itself), but it would
be nice if 'create picture' just honored the servers caching policies
and simply checked to see if the file has actually changed first.

Jul 16, 2003, 12:45pm

create texture uses mipmapping, create picture does not

[View Quote]

Jul 16, 2003, 2:07pm

Whether the browser is using mipmapping or not has nothing to
do with my question. Mipmapping is something the browser may
or may not do to my content once it has downloaded it, but it
certainly has no effect on whether the content has actually
changed, or on whether the content should be downloaded
again if it has not changed.

And there is no reason that the mipmaps should change if
the content has not. If I give you an image today, the mipmaps
you generate from it are going to be the same as what you
generate tomorrow if I give you the same image.

If you connect to your ISP through a caching proxy server
like most large ISP's *they* will honor the caching headers
I am putting on my content, and all the AW browser is doing
is downloading the content from your ISP's hard drive. They
aren't getting it again from me.... so mipmaps or not.. the
browser is wasting bandwidth needlessly.

I can prevent this from wasting my servers bandwidth to some
extent, but I would like to also prevent the users from having
to download content when they don't need to. If I want the
users to update the images used with create picture, I will put
an explicit update command on only those items.

What I would like is some official guidance from AW about
how to work with their browser to conserve bandwidth and
ensure a better user experience.

Maybe (in the spirit of hacks) they could allow update=-1
which would mean 'never'.

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Jul 16, 2003, 2:37pm

Well..it doesn't happen in my world. So it must be a world setting or a setting on the
server where the pics are stored.

[View Quote]

Jul 16, 2003, 3:22pm

That's great news. So all that is needed is for someone to provide
the detailed information I asked for in my original post, and everything
will be just peachy.

To recap:

"What is the specific method the browser uses to determine if
content is out of date and needs to be downloaded afresh?"

I already know it "checks the date". Which date does it check? Does it
check the "Last Modified" date, the "Expires" date or does it look
for an ETag? does it use the Cache-Control header max-age value at
all? Does it honor any of the other Cache-control headers?

Knowing that your world works doesn't answer my question any
more than knowing that pictures don't use mipmaps.

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