Need to clear cache to see dynamic changes?

Question

I have a Flash site/movie that loads several JPG's via
button.
I'm using loadMovie.
Client is saying that he has to clear his cache to see
chaqnges when replacing or updating these images.
Same is happening on some dynamivc text files.
I should know this by now but....
Why and can I avoid this?
Thanks in adavance. Client is asking.

Answer 1

Leo,
> I have a Flash site/movie that loads several JPG's
> via button.
>
> Client is saying that he has to clear his cache to see
> chaqnges when replacing or updating these images.
Yup, this happens. :-/
> I should know this by now but....
>
> Why and can I avoid this?
The theory behind cacheing is actually a good thing. After
all, why
waste network traffic if the user already has the file,
right? The trouble
is, browsers don't always seem able to know when a file is
new. It may be
due to the slight differences in your clock and your client's
clock,
especially if you're uploading and checking these in a very
quick
turnaround.
The solution is to "trick" your browser into thinking it's
requesting a
new file. One way to do this is to append a query string to
the end of your
requests for external files.
In the loadMovie() parameter that specifies the URL, do
something like
this ...
"blah/blah/sample.jpg?ver=001"
... which essentially appends a fake variable, ver (for
version), to your
request. When you make a change, update that 001 to a 002,
and so on.
Pretty slick. I would also do this in the HTML that actually
embeds the
SWF.
"blah/blah/sample.swf?ver=001"
... in both the object and embed tags.
If you really want to get fancy, use the Math.random()
method to
generate a new number every time. In your ActionScript ...
"blah/blah/sample.jpg?ver=" + Math.random()
... but remember, that means your client will re-download
this file *every
time*. That may be what you want during testing, but it's
almost certainly
not what you want when the project is complete -- so don't
forget to remove
this trick later.
David
stiller (at) quip (dot) net
Dev essays:
http://www.quip.net/blog/
"Luck is the residue of good design."