CFCACHE and the Fall of Rome

This post is more than 2 years old.

I'm not a huge fan of the CFCACHE tag. It's a blunt instrument and I wish CF would natively roll in a nicer caching system (like, oh say, ScopeCache, not that I'm biased or anything). A user wrote in with a question about CFCACHE. Turns out that when you use cfcache, it outputs a HTML comment before the text which can totally break some browsers.

Luckily - this was actually one of the things fixed in 8.0.1.

Unluckily for the user - he was still on ColdFusion 7.

I thought I'd try to get fancy and use onRequest - another feature I'm not a big fan of - but this seemed like a perfect use for it. I tried something like so:

<cffunction name="onRequest" returnType="void"> <cfargument name="thePage" type="string" required="true"> <cfset var content = ""> <cfsavecontent variable="content"><cfinclude template="#arguments.thePage#"></cfsavecontent> <!--- look for comment at beginning ---> <cfset content = rereplace(content, ""^<!--.*?-->$"", "")> <cfoutput>#content#</cfoutput> </cffunction>

At first - this did nothing. Then I remember that the default behavior of cfcache is to cache both on the client and the server. I switched my cfcache tag to use action=servercache, but unfortunately, you can't use cfcache inside custom tags, and that includes tags like cfsavecontent.

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Archived Comments

Comment 1 by Bryan Rapp posted on 4/18/2008 at 12:25 AM

It not only breaks some browser rendering, it breaks most XML parsing as I learned while trying to implement some basic RSS/Atom feed caching. I was disappointed to see the problem was still in CF8, but very glad to learn it was fixed in 8.0.1. I ended up just using cfschedule to cache higher traffic feeds. It works fine for a few things, but could be tough to manage with a large number of pages.

Comment 2 by Steve Bryant posted on 4/18/2008 at 1:00 AM

Would something taking advantage of getPageContext() work? I have had to do content replacement with that before.

<cfset content = getPageContext().getOut().getString()>
<cfset content = rereplace(content, "^<!--.*?-->$", "")>
<cfcontent reset="Yes">

Untested - I am just spit-balling.

Comment 3 by Raymond Camden posted on 4/18/2008 at 1:03 AM

Wow, that's a no - cuz even without the cfsavecontent it fails. It must be that it's being used inside a CFC method.

Comment 4 by David posted on 4/22/2008 at 12:44 PM

You could use the content filter function of FusionReactor?

Comment 5 by Kevin Penny posted on 9/18/2008 at 7:47 PM

Even though it states in the release notes that the cfcache 'heading' comment has been fixed for xhtml compliance in 8.01 release - and states in the release notes that it has been fixed - "70372 The cfcache tag inserted a comment that invalidated XHTML and XML
Tags - cfcache"

it's still appearing in our headers on an 8.01 upgraded server (we're not the only ones http://software.groupbrowse...

Any one still seeing this after an upgrade?

Comment 6 by Joel posted on 10/14/2008 at 11:45 PM

I posted the message you linked to. :) Unfortunately I'm back here because I'm still searching for an answer. It's perplexing, given that Adobe says they've fixed this bug.

Comment 7 by Matt posted on 3/11/2009 at 8:12 PM

Ditto on this, just tried cfcache on my server and still have this comment tag appearing breaking xhtml compliance.

how annoying!