# AJAX Controller/View Methods/Helpers in Extension/Tag Block

**URL:** <https://www.ruby-forum.com/t/ajax-controller-view-methods-helpers-in-extension-tag-block/106895>\
**Category:** Radiant CMS\
**Created:** [June 15, 2007, 4:42am UTC](https://www.ruby-forum.com/t/ajax-controller-view-methods-helpers-in-extension-tag-block/106895 "2007-06-15T04:42:43Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![emice](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/e/67e7ee/32.png) [@emice](https://www.ruby-forum.com/u/emice)\
**Post date:** [June 15, 2007, 4:42am UTC](https://www.ruby-forum.com/t/ajax-controller-view-methods-helpers-in-extension-tag-block/106895/1 "2007-06-15T04:42:43Z")

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So I’ve got this project where I would like Radiant to render the  
initial page, but do subsequent updates to various divs via AJAX. I  
decided this because I don’t want a separate but identical layout files  
within Radiant and the app/views/layout of my extension. I won’t be the  
one to use this CMS once it is installed and if the user has to come  
back to me for minor layout changes once things are in place, that won’t  
be nice.

I created an extension with the idea that I would create a tag for each  
div and define them to render the same partials that my the AJAX calls  
return, just with some default parameters. I imagined I would use  
render\_component or maybe render\_partial but quickly found there is no  
controller to make these accessible from the tag definition context.  
Without partials and without helpers like form\_remote\_tag and  
link\_to\_remote, I found myself putting lots of raw html and javascript  
(Prototype Ajax.request methods) in each tag block. Pretty nasty, so I  
scrapped that.

Another solution would be the ability to render snippets from my  
controller instead of the usual views. I’ve looked at Radiant on Rails  
but support for processing Radiant tags while doing such output is still  
a work in progress. Even if tag processing is finished soon, there is  
still the issue of getting to Prototype/AJAX helper methods into those  
snippets. I really like the idea of using snippets via my controller  
though, if it were combined with an extension that exposes rails  
Form/Prototype/Javascript helpers via Radiant Tags, that could maybe  
work, without introducing that complexity into the core Radiant code.

For example, instead of my controller/view outputting an entire AJAX  
sortable table, if I could define it as a snippet w/ the appropriate  
AJAX helpers in place as Radiant tags, the end user could then tweak  
considerably more, adding/dropping columns or changing class/id/css  
information. I’ve already created radiant tags to access and iterate  
over rows in my model so I think this would be a nice fit.

Which brings me back to my original approach, accessing rails  
view/controller helpers from an extension tag block. I’ve read a few  
posts where people were trying to do this, but they all have their  
problems. Below are my experiences with various ways I’ve tried to get  
around this.

* * *

Mental Tags - FormTagHelper?  
[http://www.ruby-forum.com/topic/104454#232664](http://www.ruby-forum.com/topic/104454#232664)

This could allow tags to use rails helpers, thought it may be buggy. But  
without the ability to render snippets from my controller, it is only a  
half solution as my the AJAX responses from my controller will need to  
output snippets, which RadiantOnRails does, but without processing  
Radiant tags, so it would only work for the initial request served up by  
Radiant. I could use a separate partial for the AJAX responses but I  
don’t want my user making changes in the CMS and finding the AJAX  
responses look different.

* * *

ActionView helpers in a behavior - I think I got it!  
[http://www.ruby-forum.com/topic/73437](http://www.ruby-forum.com/topic/73437)

Same issues as above, possible bugs, no controller access to output  
snippets after tag expansion.

* * *

RJS/Tracking Controller through Radiant Extension?  
[http://www.ruby-forum.com/topic/107811#244757](http://www.ruby-forum.com/topic/107811#244757)

Requires modifying a page’s process method to look for AJAX requests,  
but I thought my extension’s controller can already receive requests  
directed to it, so I don’t see the point.

* * *

[Radiant] Can you use controllers/views within a tag  
[http://lists.radiantcms.org/pipermail/radiant/2007-February/003407.html](http://lists.radiantcms.org/pipermail/radiant/2007-February/003407.html)

Ahh, bring a controller instance into my Tag module/mixin. This may be  
my best solution at this point. This would allow me to render entire  
divs using single tags that output partials using my controller - the  
same partials that my AJAX responses will continue to return. No need to  
import rails view helpers into my tag module, and no need to render  
snippets from the controller with tag processing. Not as as flexible as  
I would like, but this approach doesn’t require me to duplicate the site  
layout in app/views/layouts. The sample code in the above post doesn’t  
work as is, it needed a few changes, which the the guys in #ruby-lang  
help me come up with. Posted below, with asterisks by the added/changed  
lines -

def activate

- require ‘application’

- SiteController.class\_eval do  
def show\_uncached\_page(url)  
puts ‘!!!in show\_uncached\_page’  
@page = find\_page(url)

unless @page.nil?  
@page.process\_controller(self)  
@cache.cache\_response(url, response) if live? and @page.cache?  
@performed\_render = true  
else  
render :template =\> ‘site/not\_found’, :status =\> 404  
end

```
  rescue Page::MissingRootPageError

```

redirect\_to welcome\_url  
end  
end

- Page.class\_eval do  
attr\_accessor :controller

```
Page.send :include, MemberDirectoryTags

```

end

So after that, from your tag definition, you just call -

tag.globals.page.controller.render\_component\_as\_string :controller =\>  
“member\_directory”, :action =\> “sortable\_table”

Right? Nope. render\_component\_as\_string is protected.

* * *

So I tried something different -

From my controller (MemberDirectoryController) -  
def sortable\_table\_as\_string  
render\_component\_as\_string :controller =\> “member\_directory”,  
:action =\> “sortable\_table”, :params =\> { :person =\> “david” }  
end

From my tag definition -  
tag ‘member\_test\_tag’ do |tag|  
@controller = MemberDirectoryController.new  
puts @controller  
@controller.sortable\_table\_as\_string  
end

well when I use \<r:member\_test\_tag /\> this displays in my browser -  
can’t dup NilClass

Through using some output statements I found this happens during  
render\_component\_as\_string in my controller. I’m guessing the controller  
needs more initialization than just calling new on it.

* * *

And finally I tried…  
(asterisks on lines added over prior example)

def activate

```
require 'application'

SiteController.class_eval do

  def show_uncached_page(url)

```

puts ‘!!!in show\_uncached\_page’  
@page = find\_page(url)

unless @page.nil?  
@page.process\_controller(self)  
@cache.cache\_response(url, response) if live? and @page.cache?  
@performed\_render = true  
else  
render :template =\> ‘site/not\_found’, :status =\> 404  
end

```
  rescue Page::MissingRootPageError

```

redirect\_to welcome\_url  
end

- 

```
def unprotected_render_component_as_string(options)

```

- 

```
render_component_as_string options

```

- 

```
end

```

end

Page.class\_eval do  
attr\_accessor :controller

```
def process_controller(controller)

```

puts ‘!!!in process\_controller’  
@controller = controller  
process(controller.request, controller.response)  
end  
end

Page.send :include, MemberDirectoryTags

end

Like my past attempts but I attempted to get around the protected  
render\_component\_as\_string and half-initialized controller by adding a  
public instance method to SiteController called  
unprotected\_render\_component\_as\_string(options) to expose the protected  
method.

And in my tag definition file I put:  
tag.globals.page.controller.unprotected\_render\_component\_as\_string  
:controller =\> “member\_directory”, :action =\> “sortable\_table”

The \<r:member\_test\_tag /\> produced the error “interning empty string”

Below is the framework trace -  
/usr/lib/ruby/gems/1.8/gems/radiant-0.6.1/lib/login\_system.rb:16:in  
`intern' /usr/lib/ruby/gems/1.8/gems/radiant-0.6.1/lib/login_system.rb:16:in `authenticate’

## Looks like an authentication issue? I don’t really know.

Well, that is it. I’ve outlined this quest to get things working with  
AJAX so it will be available as a use case, and maybe help the devs  
decide how to go forward with official changes to accommodate such apps.  
I very much like Radiant for non-ajax use, I’ll be keeping an eye on it  
for future projects as well.

If someone could point out how to access render\_component\_as\_string from  
my tag definition I’d be grateful. I’ve got to move on with this project  
so I will be doubling up on my layouts for now, but if there is a way,  
I’d like to know.

---

<div class="post-metadata">

**Author:** ![emice](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/e/67e7ee/32.png) [@emice](https://www.ruby-forum.com/u/emice)\
**Post date:** [June 15, 2007, 5:39am UTC](https://www.ruby-forum.com/t/ajax-controller-view-methods-helpers-in-extension-tag-block/106895/2 "2007-06-15T05:39:26Z")

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On Jun 14, 2007, at 10:42 PM, Lindsay Pallickal wrote:

> So I’ve got this project where I would like Radiant to render the  
> initial page, but do subsequent updates to various divs via AJAX.

Wow. That’s a long post, and I confess that I cannot read it fully at  
the moment.

I would point you to the work I was doing during RailsConf: http://  
[dev.radiantcms.org/svn/radiant/trunk/extensions/forms](http://dev.radiantcms.org/svn/radiant/trunk/extensions/forms). There is a  
file in there, lib/forms/tags.rb, which shows how one can do anything  
with Rails view helpers in Radiant tags. Be sure to also look at the  
files lib/ext/page.rb and lib/ext/site\_controller.rb, as some  
modifications to Radiant were necessary, which I expect to push back  
into core.

Fun stuff.

aiwilliams

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**Author:** ![emice](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/e/67e7ee/32.png) [@emice](https://www.ruby-forum.com/u/emice)\
**Post date:** [June 16, 2007, 12:24am UTC](https://www.ruby-forum.com/t/ajax-controller-view-methods-helpers-in-extension-tag-block/106895/3 "2007-06-16T00:24:33Z")

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Adam W. wrote:

> I would point you to the work I was doing during RailsConf: http://  
> [dev.radiantcms.org/svn/radiant/trunk/extensions/forms](http://dev.radiantcms.org/svn/radiant/trunk/extensions/forms). There is a  
> file in there, lib/forms/tags.rb, which shows how one can do anything  
> with Rails view helpers in Radiant tags. Be sure to also look at the  
> files lib/ext/page.rb and lib/ext/site\_controller.rb, as some  
> modifications to Radiant were necessary, which I expect to push back  
> into core.

Very nice, this is a big step in the right direction. To make things  
truly DRY for an AJAX application though, this should be combined with  
the ability to render snippets from an extension controller. I mentioned  
this in my post above, and Radiant on Rails allows this, but without tag  
processing/expansion. AJAX responses are dynamic content, so without the  
ability to use tags, controllers will still have to rely on regular  
app/view partials for responses, instead of snippets that can be  
customized by the CMS user.

For now I guess I’ll use these helpers in a tag to generate some  
javascript that will load the dynamic content from my controller/view  
with the page load. I suppose I could have done that without these  
helpers, but they should make it cleaner and easier. This solution will  
have to load some kind of default view if the user doesn’t have  
javascript though, so it still won’t be totally DRY as non-javascript  
users will have their content generated through tags and not the  
controller/view.

But I won’t need two sets of layouts now, just the ones entered into  
Radiant, so it it will be safe for the CMS user to tweak that without  
controller/view portions of the site going out of sync.

Helpful, thanks.

-Lindsay

---

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**Author:** ![emice](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/e/67e7ee/32.png) [@emice](https://www.ruby-forum.com/u/emice)\
**Post date:** [July 27, 2010, 11:11pm UTC](https://www.ruby-forum.com/t/ajax-controller-view-methods-helpers-in-extension-tag-block/106895/4 "2010-07-27T23:11:06Z")

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Adam W. wrote:

> On Jun 14, 2007, at 10:42 PM, Lindsay Pallickal wrote:
> 
> > So I’ve got this project where I would like Radiant to render the  
> > initial page, but do subsequent updates to various divs via AJAX.
> 
> Wow. That’s a long post, and I confess that I cannot read it fully at  
> the moment.
> 
> I would point you to the work I was doing during RailsConf: http://  
> [dev.radiantcms.org/svn/radiant/trunk/extensions/forms](http://dev.radiantcms.org/svn/radiant/trunk/extensions/forms). There is a  
> file in there, lib/forms/tags.rb, which shows how one can do anything  
> with Rails view helpers in Radiant tags. Be sure to also look at the  
> files lib/ext/page.rb and lib/ext/site\_controller.rb, as some  
> modifications to Radiant were necessary, which I expect to push back  
> into core.
> 
> Fun stuff.
> 
> aiwilliams

I know this is a fairly old post, but this is exactly what I have been  
looking for. Can someone point me to the examples? Or is there perhaps a  
better way the solve this problem nowadays?