Hi Jason,
I'll try to answer our questions.
Jason Southern wrote:
> It is my understanding that when ColdFusion receives a request for a
> template, it first attempts to locate an Application.cfm file by scanning
> the directory from the template's present location all the way to the
> document root. ColdFusion server reads and processes the first
> Application.cfm file it finds before processing the requested template.
>
> Is this understanding correct?
Yes, with one caveat. CF doesn't know where the document root might
be, so goes all the way up to the root ('/'). I don't like this,
it is expensive, but you can map directories that are not in your
webserver document tree via the CF administrator or even your web
server.
It is a good idea for performance and security to always have an
(empty except for a comment) Application.cfm at the top level of your
CFML doc tree.
> 1. Do variables scoped with the Application field type point to the same
> memory space for a given application as defined by <CFAPPLICATION> in
> Application.cfm? If not, how are variables scoped with the Application
> field type different from variables that exist in other field types such as
> CGI, Variables, Form, URL, etc.?
The Application scope is shared by all template which have the same
'Name' attribute for the CFAPPLICATION tag, yes.
> 2. Does ColdFusion execute variable assignment statements in
> Application.cfm on each request (e.g. <CFSET Application.var1 = "Test">)?
Yes, it does.
> 3. What does the IsDefined() function evaluate to determine if a variable
> has been defined? Does the following expression
> IsDefined("Application.var1") initiate a read on shared memory space? In
> other words, does a lock need to be placed around this expression as in the
> following example:
[example deleted]
Yes and yes.
IsDefined looks up the variable in the Symbol table for the scope.
It is reading shared memory and locks are required.
> 4. What is the difference between using Application.cfm to store
> application-level data and simply using <CFINCLUDE> to include another
> template that contains variable initialization statements like the
> statements below?
> <CSCRIPT>
> var1 = 12;
> var2 = 13;
> </CFSCRIPT>
Very little, other than their scope is shared and persistent,
so you can put things that are expensive (say a DB lookup of state
names)
but you want to have available across all pages in your application.
I hope this helps.
--
Tom Jordahl [EMAIL PROTECTED]
Allaire Development http://www.allaire.com
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