Execute code stored in database?

If its just a variable your inserting, you can simply do the following..

#Evaluate(QueryName.VariableToInput)#

If there is more then one variable on the template your best bet would be to write the template to the hard drive, include it, then delete it to clean up after yourself.  If you go this route it will help to have a 7200 RPM hard drive, if not a 10K or 15K SCSI drive.

<cfset UniqueFileName="#CreateUUID()#.cfm">
<cffile action="write" file="c:\#UniqueFileName#" output="#QueryName.TemplateToUse#">
<cfinclude template="#UniqueFileName#">
<cffile action="delete" file="c:\#UniqueFileName#">

Another idea is to use a RamDrive as the temporary storage means.  I prefer RamDiskNT and it essentially puts a portion of your memory into a virtual disk, thus giving you near immediate access to that information.

I had a similar problem where I had a piece of text that was stored in the DB, and in that piece of text users were allowed to put a symbol like so:

"Welcome #Name# to my website!"

And I would fill in the #Name# portion on the text dynamically later. But when I returned the string from the DB, it would have the variable #Name# in it, but Cold Fusion would simply ignore it of course as it would consider it a piece of text.

What I ended up doing was to simply replace all instance of "#Name#" with Evaluate("Name"). You could setup a Regular Expression to do this dynamically.

Now this worked for me because the code that was in the DB simply had some variables in it that needed to be processed. I don't think that there would be a way to process something like a CFLOOP within the code.

I don't think there is a viable solution to that. Creating and uniquely naming temporary files will work, but then what was the point of putting it in the DB anyhow since it's jsut going to get written to a file anyhow. You best bet might be instead to just create a bunch of files with some naminc convention, and store the location of these files in the DB rather than the actual code itself. Then when you do the CFINCLUDE, simly get the URL from the DB and CFINCLUDE the file.

TallerMike:

Yes, I have done that before too.  The only problem I saw with that was when I would be replacing multiple variables through a large template, it was not all that speedy.  (I was looping through something like 100 variables to replace)

One other thing to note is if you save files to the hard drive you will not want users (IE non-admin) writing the templates.  Otherwise they could put some very damaging code in there and comprimise your system.  If users are creating the templates you *must* go through the code to make sure they don't have access to most Cold Fusion functions.

rebies, this is true, it is a VERY slow process for either large templates or a large number of replaces. Especially if both cases. But it works if all you need to do is replace some variables like MailMerge (basically what I used it for).

yes a combination of "#" / "##" / Evaluate() / Evaluate(De())

shld see thigns for u !

the process depends on how u code it .... & what methodologies u follow !

K'Rgds
Anand

it is not clear what database return. whether it is return string of the template or template name. if it string the write one cfm file with this string. and use this file name in the cfinlude.

<cffile action="write" file="c:\<file_name>" output="#queryname.TemplateToUse#">
<cfinclude template="#file_name#">


if it is returning the template name

<cfset myTemplate = queryname.template_name>
<cfinclude template="#myTemplate#">

thanks everyone for your comments up until now I am getting the source for the DB and writing it to a file.I then Include that file, then delete it afterwards. The problem here is that the file you include hasa to be recompiled by ColdFusion on each page view and therefore resulting in slow page views.


Dash420,

I'm not sure what you are suggesting by your post can you please be more clear, thanks.

anandkp,

I am not sure what you are suggesting?

The source that I am drawing from the database is a complete cfml page with HTML and CFML code embeded in it.

show me the code that goes in teh DB & i'll explain it out !

give me a example with variables that have to be executed on the fly [in a loop] - thru includes etc ...

Time is taking in writing file. Every coldfusion file needs to complie when it is request.

dash420, Cold Fusion does cache the page in memory however, not the compiled version of it, just the CFML code so that it doesn't have to read the HD to get the CFML. If you had a large number of CFML files, lets say 50 Megs worth of them, and you had only set the file caching memory to 10 Megs, when it gets to the files that are NOT cached, the server will have to read from the HD to get the while, where as the cached files are already in memory. When you are creating temporary files to store the CFML that you pull from the DB, the server obviously will never cache these files as the file names will constantly change and the server will not be able to process them.

Even worse, the server may attempt to cache the file by putting it in memory when it reads the file. And in file caching, it's FIFO I would imagine, so if you did it enough, it would start to push your other files out of cache to make room for these temporary files that can never be read from cache again anyhow, thus making the other files on yoru system run slower because they may not be cached anymore.

TallerMike
if we cache the page. but contents of the page is not dynamic. then what will happen. my idea is cache the page where u know this static html. server no need to spend time in processing the page. but we can't take thsi risk where contents of the page is dynamic. Am i right?

regards,
Dash

You are all right in what you say. The route I chose was to only store the dynamic pages to  include files and the rest just do a straight dump to the page. It works, but like anticipated page loads on dynamic pages is very slow.

like i said, it all depends on ur requirements & how u code it .... & also what methodologies u follow !

:)

I know this doens't really apply to anything any more, but here is a cool little script I made that parses out any variables surrounded by # signs...

<CFSET mystring="Hello, ##fname##, Today is ##day##">

Original String: <CFOUTPUT>#mystring#</cfoutput><BR>

<!--- Replacement Variables --->
<CFSET Fname="Bob">
<CFSET Day="Tuesday">

<CFLOOP condition="#REFIND("##{1}[^(## )]+##{1}",mystring)# neq 0">
     <CFSET y=REFIND("##{1}[^(## )]+##{1}",mystring)+1>
     <CFSET c="#MID(mystring,y,REFIND("##",mystring,y)-y)#">
     <CFPARAM name="#c#" default="">
     <CFSET mystring=REPLACENOCASE(mystring,"###c###",evaluate(c),"ONE")>
</cfloop>

Final String: <CFOUTPUT>#mystring#</cfoutput>

Oh, and I forgot to mention one detail of step 3:

You'd also have to wrap the code in <cfsavecontent>, so that you could return the code as a String from the function in the Java object.

-M

What would be the advantage of doing that over simply writing the code to a file every time it's changed?

Well that is a matter if taste I guess. I personally prefer to have the logic that creates the cache files fired by the template doing the requests, rather than the template doing the updates.

The main reason is to allow you to treat the cache like it really IS a cache, i.e. its contents are temporary in nature and can be deleted at will with no side-effects.

If you only do the changes at update time, the disk based cache becomes "tied" to the state of the db. If for some reason cache files become deleted or something... The point is the requesting template needs to be capable of created the cache files _anyway_ in order to deal with problems like this, so you might as well have it do all the work.

You could of course do it both ways at once, I just dont like duplicating code like that.

Heath

Good call. I'll accept that.

I guess it depends on if these files are determined to be temporary or not.

Any of the the above solutions should work. One solution puts the processing time when the template is requested, and the other puts the time when the template is changed. The choice is yours.

One other point I should mention considering I came into this discussion kind of late. I personally agree with TallerMike's earlier assessment. This is NOT the best way to go about doing this. It would be much more effecient to just store the templates as files on disk and link them to the db using the filename.

My comment was made specifically to address the situation where this is for some reason not possible, and the templates MUST be stored in the database for some reason. If this is the case, I would be interested in hearing the reason.

If you have any choice in the matter I would recommend changing your approach, there is simply no upside to storing the templates in the db, _especially_ if you are going to cfinclude them, since that requires them to be disk based at some point anyway.

Heath