Raymond Camden's ColdFusion Blog: Tip: cfsavecontent and cfinclude within script based CFCs

Tip: cfsavecontent and cfinclude within script based CFCs

Ok, so I know that I've said (many times) that including layout in a CFC is generally a bad idea. I still think it is. But like most rules there are always exceptions. Normally this wouldn't be a big deal, but HTML and JavaScript within a script based component is - well - it's ugly. Here is an example:

view plain print about

case "textbox": {
	return s & '<input type="text" name="#arguments.name#" value="#currentValue#">';
}

1  case "textbox": {
2      return s & '<input type="text" name="#arguments.name#" value="#currentValue#">';
3  }

This simple example works, but more complex HTML gets messier. I could have switched the component over to tags. It's not like that would be the end of the world! But then I remember - you can use savecontent within script based cfcs. So instead of the inline HTML you see above, I now use:

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case "event date": {
	savecontent variable="s" {
		include "render/eventdate.cfm";
	}
	return s;
}

1  case "event date": {
2      savecontent variable="s" {
3          include "render/eventdate.cfm";
4      }
5      return s;
6  }

Woot. I wish I had remembered this when I began the project, but I'm guessing I'll be getting used to ColdFusion 9 syntax until right around the release of ColdFusion 10.

This entry was posted on Tuesday, December 22, 2009 at 9:29 PM. It was filed in the following categories: ColdFusion. It has been viewed 3,751 times and has 6 comments.

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Comment 1 written by Daniel Budde on 23 December 2009, at 8:09 AM

Although, I am not on CF9 yet, I have ran into this in the past when I wanted to e-mail template based reports from within my CFC. The reports already existed as HTML templates within the application, so the easy fix was to use <cfsavecontent> with a <cfinclude>.

It always makes me feel a little bad to have to break encapsulation, but as you say, there are those exceptions to the rule. I always just comment them well and since they are few and far between, they have just never caused any trouble.
Comment 2 written by Tony Nelson on 23 December 2009, at 9:34 AM

You'll want to be careful when using .cfm mixins inside singleton components to make sure any variables declared within the mixin are thread-safe.
Comment 3 written by Raymond Camden on 23 December 2009, at 9:54 AM

Agreed. I'm forcing myself to use local.x for all variables. I normally do NOT like local.foo, I just var scope, but for this component I'm using it as a way to ensure I'm always local.
Comment 4 written by Daniel Budde on 23 December 2009, at 9:59 AM

I do the same as well. All my variables used within the template are always located under (LOCAL.templateInfo).
Comment 5 written by Tony Nelson on 23 December 2009, at 10:31 AM

If you don't want to have to use local.x everywhere, you could create a small Include.cfc proxy for including templates.

case "event date": {
         return new Include("render/eventdate.cfm",arguments);
}

Include.cfc:
component {
   public string function init(template, params) {
      structDelete(variables, "init");
      structDelete(variables, "this");
      structAppend(variables, arguments.params);
      savecontent variable="local.html" {
         include arguments.template;
      }
      return local.html;
   }
}

Now any variables declared inside render/eventdate.cfm won't bleed into your component.
Comment 6 written by Raymond Camden on 23 December 2009, at 10:32 AM

That's slick as crap. Thanks Tony.