Load and stacks...

[Dave Cragg]

On 21 Jan 2007, at 19:16, David Bovill wrote:

> I have not used "load" much... just starting some experiments. Am I  
> right
> that you can "load" stacks and then go to the url and it will fetch  
> the
> stack from the cache?

That's right. But don't be misled by thinking this is a special  
feature of stacks that are downloaded by "load url". You can "go" to  
any stack whose file data is held in any kind of "data container"  
such as a variable, custom property or url. The following will work too:

on mouseUp
   answer file ""
   if it is not empty then
     put url ("binfile:" & it) into tStackData
     go tStackData
   end if
end mouseUp

As any data retrieved by "load url" is held in a cache, and as  
subsequent calls using "get url" will retrieve the data from the  
cache, using "go url "http://whatever/whatever.rev" is just taking  
advantage of the above feature. (What I'm trying to say is that "load/ 
get url" wasn't designed with the idea of opening stacks in mind. The  
ability to do that is just a consequence of an already existing  
feature.)

>
> The other thing I cannot figure out is how to find out the name of  
> the file
> in the cache

Do you mean the name of the file, or the name of the stack? The  
cachedUrls() function will return of the currently cached URLs. I  
don't know of a straightforward way to get the name of a stack in the  
url cache. Possible ways are to "toplevel" the url and then  
immediately get the name of the topStack, or write the url to a local  
file and get the stack name from the file.

> (and where the cache is).

It's just a local script variable in the libUrl script.

>  It would be
> nice to store the cache somewhere permanent and take advantage of  
> the asynch
> load.

You could use libUrlDownloadToFile to do an asynchronous load  
directly to a file instead of the cache. Or in the callback message  
for load, save the url to a local file. For example:

load url myUrl with message "loaded"

on loaded pUrl, pStatus
   if pStatus = "cached" then
     put url pUrl into url ("binfile:" & pathToLocalFile)
   end if
   unload url pUrl
end loaded

Cheers
Dave