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Tip: cfsavecontent and cfinclude within script based CFCs

6

Posted in ColdFusion | Posted on 12-22-2009 | 5,136 views

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
1case "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:

view plain print about
1case "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.

Comments

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Daniel Budde said on 12-23-2009 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.
Tony Nelson said on 12-23-2009 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.
Raymond Camden said on 12-23-2009 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.
Daniel Budde said on 12-23-2009 at 9:59 AM #
I do the same as well. All my variables used within the template are always located under (LOCAL.templateInfo).
Tony Nelson said on 12-23-2009 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.
Raymond Camden said on 12-23-2009 at 10:32 AM #
That's slick as crap. Thanks Tony.

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