# Tutorial - Creating a Global REST Controller

**URL:** <https://www.ruby-forum.com/t/tutorial-creating-a-global-rest-controller/181840>\
**Category:** Rails\
**Created:** [January 19, 2010, 4:12am UTC](https://www.ruby-forum.com/t/tutorial-creating-a-global-rest-controller/181840 "2010-01-19T04:12:01Z")\
**Posts on this page:** 14\
**Page:** 1

<div class="post-metadata">

**Author:** ![elricstorm](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/e/da6949/32.png) [@elricstorm](https://www.ruby-forum.com/u/elricstorm)\
**Post date:** [January 19, 2010, 4:12am UTC](https://www.ruby-forum.com/t/tutorial-creating-a-global-rest-controller/181840/1 "2010-01-19T04:12:01Z")

</div>

# ========================================= Creating a Global REST Controller

Let’s imagine that you have an application that houses close to 400  
controllers. Each of these controllers accesses a specific model that  
contains normalized data. While there are a lot of tricks you can  
perform for normalization, let’s assume that after you further normalize  
and consolidate databases you still have 300 controllers left over.

Of these 300 controllers, half of them are composed of normal REST  
methods, and the other half are comprised of normal REST methods and  
special methods which perform specific actions.

This means that each of those controllers at a bare minimum could have  
close to 80 lines of code.

Everyone talks about thin controllers. I’m going to show you a way to  
create a Global REST controller that will make most if not all of your  
controllers very thin.

> <https://gist.github.com/280611>
>
> There are more than three files. show original

Take a look at the code above and look closely at the Global REST  
Controller.

Let’s pretend that you have a controller that manages pages, ie. a Pages  
Controller. It’s comprised of only index, new, edit, show, create,  
update, and destroy. No other actions.

By implementing a Global REST controller, you could place this in your  
pages controller:

class PagesController \< GlobalRestController  
end

… and that’s all you need (2 lines of code)

In your index.html.erb view you would replace one instance variable  
@pages with @objects and you are done.

Now then, going back to the old scenario I posted above, you could  
effectively take 150 controllers with say 78 lines of code and reduce  
11,700 lines of code down to … 300.

What could you do with your other 150 controllers?

class SomeOtherController \< GlobalRestController

def some\_custom\_action  
… etc.  
… etc.  
end

def some\_other\_custom\_action  
… etc.  
… etc.  
end

end

Your custom actions would be listed but you would automatically inherit  
the other 7 rest methods automatically. No extra code needed.

What if you want to overwrite one of the REST methods with a custom REST  
method of your own?

class SomeOtherController \< GlobalRestController

def index  
@pages = Page.find(:all, :conditions =\> ‘parent\_id IS NOT NULL’)

respond\_to do |format|  
format.html  
format.xml { render :xml =\> @pages }  
end  
end

end

You just simply place the REST method into your controller and it still  
picks up the other 6 REST methods. You then keep the index.html.erb  
page intact without @objects changes and you are done.

How well does this work?

I currently run a football statistics site that houses 75 controllers  
and (66 of them) are part of a Global REST Controller mechanism. I have  
had no issues whatsoever using it.

I hope this tutorial helps someone out. If you liked this tutorial, you  
can check out a very lengthy tutorial I wrote yesterday on mailers and  
observers here:

[http://www.ruby-forum.com/topic/202316](http://www.ruby-forum.com/topic/202316)

Take care.

---

<div class="post-metadata">

**Author:** ![elricstorm](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/e/da6949/32.png) [@elricstorm](https://www.ruby-forum.com/u/elricstorm)\
**Post date:** [January 19, 2010, 4:19am UTC](https://www.ruby-forum.com/t/tutorial-creating-a-global-rest-controller/181840/2 "2010-01-19T04:19:13Z")

</div>

In a follow-up on your edit.html.erb and new.html.erb you could use  
something similar:

Replace @page with @object. I’ve added a partial and a couple of  
example forms for these as well in the gist posted above.

---

<div class="post-metadata">

**Author:** ![elricstorm](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/e/da6949/32.png) [@elricstorm](https://www.ruby-forum.com/u/elricstorm)\
**Post date:** [January 19, 2010, 4:44am UTC](https://www.ruby-forum.com/t/tutorial-creating-a-global-rest-controller/181840/3 "2010-01-19T04:44:50Z")

</div>

Very cool. I’m glad to hear it is working out so well for you Alpha…

---

<div class="post-metadata">

**Author:** ![elricstorm](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/e/da6949/32.png) [@elricstorm](https://www.ruby-forum.com/u/elricstorm)\
**Post date:** [January 19, 2010, 6:45am UTC](https://www.ruby-forum.com/t/tutorial-creating-a-global-rest-controller/181840/4 "2010-01-19T06:45:38Z")

</div>

Interesting tutorial. Thanks.

I found there are a couple of little problems. First, your index view  
code has some extra closing round brackets, and then the destroy  
action redirects back to the deleted object. I took a little while to  
fork and update the controller code. Also made it a bit more DRY:

> <https://gist.github.com/alg/280670>

One question though, why wouldn’t you use, for example,  
inherited\_resources plugin for this purpose?

- Aleksey

---

<div class="post-metadata">

**Author:** ![elricstorm](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/e/da6949/32.png) [@elricstorm](https://www.ruby-forum.com/u/elricstorm)\
**Post date:** [January 19, 2010, 8:43am UTC](https://www.ruby-forum.com/t/tutorial-creating-a-global-rest-controller/181840/5 "2010-01-19T08:43:19Z")

</div>

On Jan 19, 12:43Â am, Aleksey G. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote:

> inherited\_resources plugin for this purpose?
> 
> - Aleksey

I don’t wanna speak for Alpha B., but straight plain inheritance is  
a simple answer to a common problem…

---

<div class="post-metadata">

**Author:** ![elricstorm](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/e/da6949/32.png) [@elricstorm](https://www.ruby-forum.com/u/elricstorm)\
**Post date:** [January 19, 2010, 9:00am UTC](https://www.ruby-forum.com/t/tutorial-creating-a-global-rest-controller/181840/6 "2010-01-19T09:00:40Z")

</div>

Alpha B. wrote:

> # ========================================= Creating a Global REST Controller
> 
> Let’s imagine that you have an application that houses close to 400  
> controllers. Each of these controllers accesses a specific model that  
> contains normalized data. While there are a lot of tricks you can  
> perform for normalization, let’s assume that after you further normalize  
> and consolidate databases you still have 300 controllers left over.

Why would you ever have that many controllers in the first place? That  
makes no sense.

> Of these 300 controllers, half of them are composed of normal REST  
> methods, and the other half are comprised of normal REST methods and  
> special methods which perform specific actions.
> 
> This means that each of those controllers at a bare minimum could have  
> close to 80 lines of code.

What? No. An 80-line controller means you have too much logic in the  
controller and not enough in the model.

> Everyone talks about thin controllers. I’m going to show you a way to  
> create a Global REST controller that will make most if not all of your  
> controllers very thin.

Why not just use make\_resourceful?

Best,  
–Â  
Marnen Laibow-Koser  
[http://www.marnen.org](http://www.marnen.org)  
removed\_email\_address@domain.invalid

---

<div class="post-metadata">

**Author:** ![elricstorm](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/e/da6949/32.png) [@elricstorm](https://www.ruby-forum.com/u/elricstorm)\
**Post date:** [January 19, 2010, 1:35pm UTC](https://www.ruby-forum.com/t/tutorial-creating-a-global-rest-controller/181840/7 "2010-01-19T13:35:24Z")

</div>

It seems like to create 300 ReST controllers via Rails Scaffolding or  
make\_resourceful, one would need to type all the specs for all the  
tables into the Rails Scaffolding generator. If I am reading  
correctly, one could use Global Rest Controllers on existing tables,  
and those controllers would read the tables structures for themselves.

I work a lot with legacy tables, so I would dislike typing the  
structure into the Rails Generator all the time. I don’t do that: I  
use home-brew Scaffolding Generators that read the table structure,  
like the old pre-Restful Rails scaffolding.

Anyway, could that be one difference?

Ron

---

<div class="post-metadata">

**Author:** ![elricstorm](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/e/da6949/32.png) [@elricstorm](https://www.ruby-forum.com/u/elricstorm)\
**Post date:** [January 19, 2010, 3:19pm UTC](https://www.ruby-forum.com/t/tutorial-creating-a-global-rest-controller/181840/8 "2010-01-19T15:19:59Z")

</div>

Aleksey G. wrote:

> Interesting tutorial. Thanks.
> 
> I found there are a couple of little problems. First, your index view  
> code has some extra closing round brackets, and then the destroy  
> action redirects back to the deleted object. I took a little while to  
> fork and update the controller code. Also made it a bit more DRY:
> 
> [global\_rest\_controller.rb · GitHub](http://gist.github.com/280670)
> 
> One question though, why wouldn’t you use, for example,  
> inherited\_resources plugin for this purpose?
> 
> - Aleksey

Thanks for that Aleksey, I had copied and pasted from an older  
controller that was using not so polished code.

I very rarely use plugins in my app. I don’t like to use code that I  
can’t control myself. I would rather find a plugin that is suitable,  
dive into the code, learn from it, and create my own modified plugins.

This is just a very simple tutorial outlining to some newer folk how  
they can create an inheritance template for their controllers.

I have my own private inheritance template for my models, which works  
equally well.

> Marnen Laibow-Koser  
> Why would you ever have that many controllers in the first place? That  
> makes no sense.

Your statement doesn’t make any sense. I’ll give you one answer before  
you throw out the assumptions once again mate. You really should stop  
doing that. My one application is comprised of:

4 separately run applications tied together on different servers.

---

<div class="post-metadata">

**Author:** ![elricstorm](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/e/da6949/32.png) [@elricstorm](https://www.ruby-forum.com/u/elricstorm)\
**Post date:** [January 19, 2010, 4:15pm UTC](https://www.ruby-forum.com/t/tutorial-creating-a-global-rest-controller/181840/9 "2010-01-19T16:15:13Z")

</div>

On Jan 19, 2:58Â pm, Marnen Laibow-Koser [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote:

> > I very rarely use plugins in my app. Â I don’t like to use code that I  
> > can’t control myself. Â I would rather find a plugin that is suitable,  
> > dive into the code, learn from it, and create my own modified plugins.
> 
> [http://c2.com/cgi/wiki?NotInventedHere](http://c2.com/cgi/wiki?NotInventedHere)
> 
> I have the opposite philosophy. Â If someone has already written  
> something suitable, I see little reason to duplicate their effort.  
> Extend it, sure. Â Write something that’s a better fit for me, sure.

I find it a difficult one to call - while the above is true it’s  
horrible find come rails upgrade time that the author has abandoned  
the project. Lots of rails plugins are small one man things - I would  
certainly hesitate to use a plugin unless either it has sufficient  
backing/momentum that I can trust it will stay around or I understand  
it enough that I could rewrite it if I had to.

> See, the number of controllers is a UI issue. Â No matter how many types  
> of object you’re dealing with under the hood, if the user has to  
> navigate among 300 controllers (which, after all, are generally the  
> user-facing part of the app), then in 99 cases out of 100, I’d say you  
> need to refactor the UI or split up the app.

That is assuming these are end user facing controllers (as opposed to  
ones for api clients). (and if the OP does indeed have 4 apps then  
they have already split up the app)

Fred

---

<div class="post-metadata">

**Author:** ![elricstorm](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/e/da6949/32.png) [@elricstorm](https://www.ruby-forum.com/u/elricstorm)\
**Post date:** [January 19, 2010, 3:58pm UTC](https://www.ruby-forum.com/t/tutorial-creating-a-global-rest-controller/181840/10 "2010-01-19T15:58:57Z")

</div>

Alpha B. wrote:

> Aleksey G. wrote:
> 
> > Interesting tutorial. Thanks.
> > 
> > I found there are a couple of little problems. First, your index view  
> > code has some extra closing round brackets, and then the destroy  
> > action redirects back to the deleted object. I took a little while to  
> > fork and update the controller code. Also made it a bit more DRY:
> > 
> > [global\_rest\_controller.rb · GitHub](http://gist.github.com/280670)
> > 
> > One question though, why wouldn’t you use, for example,  
> > inherited\_resources plugin for this purpose?
> > 
> > - Aleksey
> 
> Thanks for that Aleksey, I had copied and pasted from an older  
> controller that was using not so polished code.
> 
> I very rarely use plugins in my app. I don’t like to use code that I  
> can’t control myself. I would rather find a plugin that is suitable,  
> dive into the code, learn from it, and create my own modified plugins.

[http://c2.com/cgi/wiki?NotInventedHere](http://c2.com/cgi/wiki?NotInventedHere)

I have the opposite philosophy. If someone has already written  
something suitable, I see little reason to duplicate their effort.  
Extend it, sure. Write something that’s a better fit for me, sure.

But by just saying “I don’t like plugins”, you’re making yourself a lot  
of extra work for no good reason.

> This is just a very simple tutorial outlining to some newer folk how  
> they can create an inheritance template for their controllers.
> 
> I have my own private inheritance template for my models, which works  
> equally well.

Sure.

> > Marnen Laibow-Koser  
> > Why would you ever have that many controllers in the first place? That  
> > makes no sense.
> 
> Your statement doesn’t make any sense.

Of course it does. No matter how many models your app has, I can’t see  
why a well-designed app would ever need to expose 300 different types of  
resource – which is essentially what controllers are about.

> I’ll give you one answer before  
> you throw out the assumptions once again mate. You really should stop  
> doing that.

I’m not assuming anything in particular, so this is not relevant.

> My one application is comprised of:
> 
> 4 separately run applications tied together on different servers.

Then it isn’t one application. Or it’s one application run clustered.  
In neither case do I see this making the slightest difference to the  
number of controllers.

See, the number of controllers is a UI issue. No matter how many types  
of object you’re dealing with under the hood, if the user has to  
navigate among 300 controllers (which, after all, are generally the  
user-facing part of the app), then in 99 cases out of 100, I’d say you  
need to refactor the UI or split up the app.

Best,  
–Â  
Marnen Laibow-Koser  
[http://www.marnen.org](http://www.marnen.org)  
removed\_email\_address@domain.invalid

---

<div class="post-metadata">

**Author:** ![elricstorm](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/e/da6949/32.png) [@elricstorm](https://www.ruby-forum.com/u/elricstorm)\
**Post date:** [January 19, 2010, 4:40pm UTC](https://www.ruby-forum.com/t/tutorial-creating-a-global-rest-controller/181840/11 "2010-01-19T16:40:53Z")

</div>

Thanks again guys for your input. As a point of clarification…

My app(s) contain a combined 63 controllers across 4 applications, so if  
you wanted to divide that number by 4 you have less than 16 controllers.  
Many of these controllers are “not” client-facing controllers. I have  
really 6 client-facing controllers in my entire combined app cluster.

The point of this thread was how to reduce code duplication across  
multiple controllers. I threw out an absurd amount of controllers to  
make a point of reference.

As for the topic on plugins, I’m in agreement with Fred on this. I have  
experienced on quite a few occassions upgrading to a newer version of  
rails only to find out the author abandoned the project and I had to dig  
into the code and fix it all myself.

There are plugins that I do use that I do not create or modify myself  
that have substantial backing. RedCloth is an example of this.  
Restful\_Authentication is another.

---

<div class="post-metadata">

**Author:** ![elricstorm](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/e/da6949/32.png) [@elricstorm](https://www.ruby-forum.com/u/elricstorm)\
**Post date:** [January 19, 2010, 4:26pm UTC](https://www.ruby-forum.com/t/tutorial-creating-a-global-rest-controller/181840/12 "2010-01-19T16:26:33Z")

</div>

Frederick C. wrote:

> On Jan 19, 2:58Â pm, Marnen Laibow-Koser [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote:
> 
> > > I very rarely use plugins in my app. Â I don’t like to use code that I  
> > > can’t control myself. Â I would rather find a plugin that is suitable,  
> > > dive into the code, learn from it, and create my own modified plugins.
> > 
> > [http://c2.com/cgi/wiki?NotInventedHere](http://c2.com/cgi/wiki?NotInventedHere)
> > 
> > I have the opposite philosophy. Â If someone has already written  
> > something suitable, I see little reason to duplicate their effort.  
> > Extend it, sure. Â Write something that’s a better fit for me, sure.
> 
> I find it a difficult one to call - while the above is true it’s  
> horrible find come rails upgrade time that the author has abandoned  
> the project.

That’s certainly true.

> Lots of rails plugins are small one man things - I would  
> certainly hesitate to use a plugin unless either it has sufficient  
> backing/momentum that I can trust it will stay around or I understand  
> it enough that I could rewrite it if I had to.

Also a good point. I mention make\_resourceful because it doesn’t seem  
to be going away, and Hampton Catlin is certainly not going away (well,  
unless he pulls a \_why).

> > See, the number of controllers is a UI issue. Â No matter how many types  
> > of object you’re dealing with under the hood, if the user has to  
> > navigate among 300 controllers (which, after all, are generally the  
> > user-facing part of the app), then in 99 cases out of 100, I’d say you  
> > need to refactor the UI or split up the app.
> 
> That is assuming these are end user facing controllers (as opposed to  
> ones for api clients).

True, although what API you expose is sort of a UI issue. In any case,  
an API so bloated that it exposes 300 controllers is scary. 🙂

> (and if the OP does indeed have 4 apps then  
> they have already split up the app)

Right. In which case it’s not one app and, at least to me, it doesn’t  
mean much to count the total number of controllers across the 4 apps.

But on reflection, I see that the original point was code duplication,  
so from that point of view it _may_ make sense. Hmm.

> Fred

## Best,

Marnen Laibow-Koser  
[http://www.marnen.org](http://www.marnen.org)  
removed\_email\_address@domain.invalid

---

<div class="post-metadata">

**Author:** ![elricstorm](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/e/da6949/32.png) [@elricstorm](https://www.ruby-forum.com/u/elricstorm)\
**Post date:** [January 19, 2010, 8:49pm UTC](https://www.ruby-forum.com/t/tutorial-creating-a-global-rest-controller/181840/13 "2010-01-19T20:49:11Z")

</div>

> (Of course, those happen to be two of the most broken plugins in common  
> use…RedCloth, at least for a while, had sort of stagnated (is that  
> still so?), and restful\_authentication is based on generated crap code,  
> and should be abandoned completely in favor of Authlogic.)

RedCloth has gotten better and there are multiple versions of the gem  
with some being more updated than others. I try to find the people that  
use it the most and I use that gem or compile the binaries myself.

I liked restful authentication when I first tried it out but I have to  
agree with you that it’s missing a lot of features that I personally  
would like to have in an authentication system. I’ve had to tailor it  
to fit my needs. I’ll take a peek at Authlogic and see what it has to  
offer.

Not to get off topic, but what do you personally like about Authlogic,  
or some of the big features?

Thanks mate.

---

<div class="post-metadata">

**Author:** ![elricstorm](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/e/da6949/32.png) [@elricstorm](https://www.ruby-forum.com/u/elricstorm)\
**Post date:** [January 19, 2010, 6:49pm UTC](https://www.ruby-forum.com/t/tutorial-creating-a-global-rest-controller/181840/14 "2010-01-19T18:49:23Z")

</div>

Alpha B. wrote:

> Thanks again guys for your input. As a point of clarification…
> 
> My app(s) contain a combined 63 controllers across 4 applications, so if  
> you wanted to divide that number by 4 you have less than 16 controllers.  
> Many of these controllers are “not” client-facing controllers. I have  
> really 6 client-facing controllers in my entire combined app cluster.

Ah, that makes more sense. 🙂

> The point of this thread was how to reduce code duplication across  
> multiple controllers. I threw out an absurd amount of controllers to  
> make a point of reference.

OK. It seemed like you were talking about an actual case. Sorry for  
misunderstanding.

> As for the topic on plugins, I’m in agreement with Fred on this. I have  
> experienced on quite a few occassions upgrading to a newer version of  
> rails only to find out the author abandoned the project and I had to dig  
> into the code and fix it all myself.

I’ve only experienced that very rarely. Then again, I try not to choose  
plugins that look stagnant in the first place.

> There are plugins that I do use that I do not create or modify myself  
> that have substantial backing. RedCloth is an example of this.  
> Restful\_Authentication is another.

(Of course, those happen to be two of the most broken plugins in common  
use…RedCloth, at least for a while, had sort of stagnated (is that  
still so?), and restful\_authentication is based on generated crap code,  
and should be abandoned completely in favor of Authlogic.)

## Best,

Marnen Laibow-Koser  
[http://www.marnen.org](http://www.marnen.org)  
removed\_email\_address@domain.invalid