# Dynamic template system with RoR

**URL:** <https://www.ruby-forum.com/t/dynamic-template-system-with-ror/88551>\
**Category:** Rails\
**Created:** [March 12, 2007, 4:42pm UTC](https://www.ruby-forum.com/t/dynamic-template-system-with-ror/88551 "2007-03-12T16:42:26Z")\
**Posts on this page:** 7\
**Page:** 1

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**Author:** ![matthew](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/ed655f/32.png) [@matthew](https://www.ruby-forum.com/u/matthew)\
**Post date:** [March 12, 2007, 4:42pm UTC](https://www.ruby-forum.com/t/dynamic-template-system-with-ror/88551/1 "2007-03-12T16:42:26Z")

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I’m brand new to Ruby and Rails, but I’ve read a lot of the requisite  
tutorials and feel pretty comfortable with most of it. I’ve been  
developing sites in PHP for the better part of a decade, so please bear  
in mind that I’m still trying to break myself out of “thinking” in PHP.  
😉

The last remaining problem I can’t seem to find any answer to – maybe  
I’m just not searching correctly – is how to control the template  
system. Let me give you an example of what I want to do.

For this site, we will be accepting clients with their own domain name.  
All of these domain names will be pointed to the same directory on our  
server, where the client application lives. I need to be able to use all  
the same logic – the controllers, right? – but load a different  
template for each domain, so that each looks like its own site. I have  
already determined how to get the domain name being accessed, and can  
look up which theme the site is using in my database. My confusion comes  
in what to do next, and how to organize this.

In PHP, I would have a /themes/ directory with a bunch of different  
subdirectories, each containing a set of templates. When the client’s  
site first loads, I would do a query to find out which theme path they  
are supposed to be using. Let’s say it’s /themes/silver. I would set  
that as a session variable and use it whenever loading a template file.  
How should I approach this in RoR?

Thanks for your patience and help! Remember, I haven’t actually  
implemented anything in RoR yet, so speak slowly. 🙂

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**Author:** ![matthew](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/ed655f/32.png) [@matthew](https://www.ruby-forum.com/u/matthew)\
**Post date:** [March 12, 2007, 6:33pm UTC](https://www.ruby-forum.com/t/dynamic-template-system-with-ror/88551/2 "2007-03-12T18:33:14Z")

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On Mar 12, 2007, at 11:42 AM, Matthew wrote:

> template for each domain, so that each looks like its own site. I have  
> file.  
> How should I approach this in RoR?

There would be at least a couple of options, depending on how you  
want to implement the themes and how much they should differ from one  
another.

One would be to use the same views for the actions but have a  
different layout for each client. You could then use a method in your  
controller to select the appropriate layout:

class MyController \< ApplicationController  
layout :select\_layout

def my\_action  
# Perform action here  
end

private

# Say we have a field in our table defining the layout for the client

def select\_layout  
@client = Client.find() // whatever your query is  
layout = @client.layout  
end  
end

See the documentation for the layout method at:

[http://api.rubyonrails.org/classes/ActionController/Layout/](http://api.rubyonrails.org/classes/ActionController/Layout/)  
ClassMethods.html#M000129

Alternatively you could look at a theming engine like liquid: http://  
[home.leetsoft.com/liquid](http://home.leetsoft.com/liquid)

James.

–  
James S.

Work: [Processing Greenbelt 2009 – James Stewart](http://jystewart.net/process/)  
Play: [http://james.anthropiccollective.org](http://james.anthropiccollective.org)

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<div class="post-metadata">

**Author:** ![matthew](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/ed655f/32.png) [@matthew](https://www.ruby-forum.com/u/matthew)\
**Post date:** [March 12, 2007, 6:42pm UTC](https://www.ruby-forum.com/t/dynamic-template-system-with-ror/88551/3 "2007-03-12T18:42:17Z")

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> In PHP, I would have a /themes/ directory with a bunch of different  
> subdirectories, each containing a set of templates. When the client’s  
> site first loads, I would do a query to find out which theme path they  
> are supposed to be using. Let’s say it’s /themes/silver. I would set  
> that as a session variable and use it whenever loading a template file.  
> How should I approach this in RoR?

My initial thought is using layouts:

You can define the layout for a controller as a function, meaning you  
could  
do something like this

def MyController \< ApplicationController  
layout :themed\_layout

def themed\_layout  
session[:layout] ||= Layout.find\_by\_domain(`)
end
end`

What the above code does is call the themed\_layout function whenever  
someone  
accesses an action in MyController.  
The function will use some code to find out which layout should be used  
(Here, I’m doing it via a call to a lookup table in an imaginary DB),  
and  
cache that into the session[:layout] variable… meaning that the first  
time it is called, it pulls from the DB, and thereafter, it will simply  
use  
what’s stored in session[:layout]. If the session is somehow  
invalidated,  
it will re-make the DB call and restore it in the session.

Is this kind of what you’re looking for?

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<div class="post-metadata">

**Author:** ![matthew](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/ed655f/32.png) [@matthew](https://www.ruby-forum.com/u/matthew)\
**Post date:** [March 12, 2007, 7:19pm UTC](https://www.ruby-forum.com/t/dynamic-template-system-with-ror/88551/4 "2007-03-12T19:19:32Z")

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Thank you to both of you, I think that will get me somewhere. I think  
the rest of my task is to understand how RoR handles layouts. One  
additional piece of functionality I’d like is to be able to have one  
layout “fail back” to a default layout; that is, if the template file  
for the specified layout doesn’t exist, it will use a template file with  
that name in some default directory. That way, I can create themes that  
“inherit” from another theme, and only have the files that need to be  
changed in the new theme’s directory.

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<div class="post-metadata">

**Author:** ![matthew](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/ed655f/32.png) [@matthew](https://www.ruby-forum.com/u/matthew)\
**Post date:** [March 13, 2007, 8:41am UTC](https://www.ruby-forum.com/t/dynamic-template-system-with-ror/88551/5 "2007-03-13T08:41:24Z")

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Matt,  
I’m going to be trying to do exactly what you describe in your post.  
I’m going to try to build one domain CMS type website that handles  
many different domains and changes not only the data but also the HTML  
code on each site that comes from a database record.  
Would it be ok if I asked you a few questions along the way?  
David  
dak AT itracker DOT com

On Mar 12, 12:19 pm, Matthew R. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid)

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<div class="post-metadata">

**Author:** ![matthew](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/ed655f/32.png) [@matthew](https://www.ruby-forum.com/u/matthew)\
**Post date:** [March 13, 2007, 3:13pm UTC](https://www.ruby-forum.com/t/dynamic-template-system-with-ror/88551/6 "2007-03-13T15:13:09Z")

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BraveDave,

You’ll notice that I just posted this thread yesterday, and I’ve never  
written anything in Rails. I don’t think I’m the right person to ask!  
However, once I do figure it out, I’ll make sure I write up a guide and  
come back here and post it.

I’m still trying to figure out how to have the default fail-back method  
I talked about above.

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<div class="post-metadata">

**Author:** ![matthew](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/ed655f/32.png) [@matthew](https://www.ruby-forum.com/u/matthew)\
**Post date:** [March 13, 2007, 3:32pm UTC](https://www.ruby-forum.com/t/dynamic-template-system-with-ror/88551/7 "2007-03-13T15:32:28Z")

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You really need to read AWDWR (Agile Web D. With Rails… you  
can  
find it here: [http://www.pragmaticprogrammer.com/titles/rails](http://www.pragmaticprogrammer.com/titles/rails))… it’s  
great, it teaches you how to do most everything you want to do with  
Rails,  
and will give you a good framework to build on to find the things it  
doesn’t  
teach… basically, it seems like what you need is a mixture of layouts,  
partials, and the ability to use File.exist? wisely… I would  
_definitely_  
read that book, and quite probably also read Programming Ruby (  
[https://pragprog.com/titles/ruby/programming-ruby-2nd-edition/](http://pragmaticprogrammer.com/titles/ruby/index.html)) for a good intro  
to  
the language Rails was written with, and that you will be using to  
customize  
your Rails app to fit your needs.