# Application structure tutorials?

**URL:** <https://www.ruby-forum.com/t/application-structure-tutorials/72802>\
**Category:** Rails\
**Created:** [October 19, 2006, 1:15am UTC](https://www.ruby-forum.com/t/application-structure-tutorials/72802 "2006-10-19T01:15:51Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![unknown](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/u/4bbf92/32.png) [@unknown](https://www.ruby-forum.com/u/unknown)\
**Post date:** [October 19, 2006, 1:15am UTC](https://www.ruby-forum.com/t/application-structure-tutorials/72802/1 "2006-10-19T01:15:51Z")

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Hi,

now that I’ve done a few Rails tutorials and understand the basics of  
AR,  
migrations, templates and such, I would like to embark on my first own  
project. It’s a rewrite, so most of the functionality has been done  
already  
(by me). But there is something that I missed in all the tutorials I’ve  
read: structure design.

Assume you have a web app that has users who can sign up, login and  
logout,  
and users can seach for, and CRUD, some sort of items which get saved in  
your database. Plus you have a WelcomeController that does the main  
page,  
the “about us” links, partner sites and so on.

The question is: how do I integrate all this? For example, I need some  
actions that are available globally. For every page request I need to  
find  
out whether the user is logged in and display his account info in the  
sidebar. I guess I need a :before\_filter to do this, but how does this  
work  
exactly?  
I would also like to offer a search form on the main page without having  
to  
resort to linking to “Search:” first.

I have a class “User” and a user\_controller. Does logging in and out  
belong  
into this controller or does it make sense to create another  
model/controller (Login) for this?

The user has\_many addresses and has\_many cars (for example). What’s the  
best  
way of presenting this info to the user in a way that he can most easily  
edit all his info? Are there usability studies somewhere that weigh  
different presentation structures?

For what should I create partials, which page elements should commonly  
be  
cached, should I use link\_to for all (even static) links? How do I  
include completely static data (does Rails realize whether a static file  
with the given path exists? Does that maybe depend on the webserver  
used,  
and the .htaccess files?)

I have a feeling I’m missing the “big picture” here … I think I got a  
rough idea how parts of Rails work but I don’t know how to make them  
work  
together to fit my project.

Any pointers to documentation would be great.

Thanks!

Jens

---

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**Author:** ![unknown](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/u/4bbf92/32.png) [@unknown](https://www.ruby-forum.com/u/unknown)\
**Post date:** [October 19, 2006, 1:35am UTC](https://www.ruby-forum.com/t/application-structure-tutorials/72802/2 "2006-10-19T01:35:53Z")

</div>

> The question is: how do I integrate all this? For example, I need some  
> actions that are available globally. For every page request I need to find  
> out whether the user is logged in and display his account info in the  
> sidebar. I guess I need a :before\_filter to do this, but how does this work  
> exactly?

In your app/controllers/application.rb, create a :before\_filter that  
does  
whatever checking you need it to do, then set say ‘@user’ to the  
logged in user, otherwise set it to nil. Now you have ‘@user’  
available in all of your controllers and views. Personally I don’t like  
@user since you might have an admin that manages a @user and then you’ve  
got conflicts. Maybe @the\_end\_user or @the\_logged\_in\_user or even just  
@the\_user.

> I would also like to offer a search form on the main page without having to  
> resort to linking to “Search:” first.

Create app/views/shared/\_search.rhtml with the search form “bucket” html  
content. Then on whatever page (or in your layout) you want that on do:

\<%= render :partial =\> ‘shared/search’ %\>

> I have a class “User” and a user\_controller. Does logging in and out belong  
> into this controller or does it make sense to create another  
> model/controller (Login) for this?

I’d leave it in the user controller.

[http://host/user/login](http://host/user/login)  
[http://host/user/logout](http://host/user/logout)  
[http://host/user/settings](http://host/user/settings)  
etc…

> The user has\_many addresses and has\_many cars (for example). What’s the best  
> way of presenting this info to the user in a way that he can most easily  
> edit all his info? Are there usability studies somewhere that weigh  
> different presentation structures?

I dunno, but I imagine there’s lots of info on how to do this…

> For what should I create partials,

Whatever you might think you need to share b/n views. Or if you know  
you  
might be updating a part of your site with ajax, make that into a  
partial  
so it’s easy to do…

> which page elements should commonly be cached,

Impossible to say without knowing your usage patterns. If nothing  
changes, cache it. If it’s highly dynamic, don’t.

> should I use link\_to for all (even static) links?

Sure.

> How do I include completely static data (does Rails realize whether a  
> static file with the given path exists? Does that maybe depend on the  
> webserver used, and the .htaccess files?)

What type of static data? Images, Javascript, Stylesheets all have  
their  
own helper methods. Use those. Otherwise for PDF/downloads just use  
link\_to. For flash and embedded things, just wrap it up in the right  
tags  
yourself (or see if there’s a helper which there probably is)

> Any pointers to documentation would be great.

good luck!

---

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**Author:** ![unknown](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/u/4bbf92/32.png) [@unknown](https://www.ruby-forum.com/u/unknown)\
**Post date:** [October 20, 2006, 12:51am UTC](https://www.ruby-forum.com/t/application-structure-tutorials/72802/3 "2006-10-20T00:51:58Z")

</div>

Philip H. wrote:

> In your app/controllers/application.rb, create a :before\_filter that does  
> whatever checking you need it to do, then set say ‘@user’ to the  
> logged in user, otherwise set it to nil. Now you have ‘@user’  
> available in all of your controllers and views. Personally I don’t like  
> @user since you might have an admin that manages a @user and then you’ve  
> got conflicts. Maybe @the\_end\_user or @the\_logged\_in\_user or even just  
> @the\_user.

Hello Philip,

thanks for your reply! I’m guessing that using your suggested method, I  
can  
define exceptions here, right? I.e. I don’t need to check for a user if  
the  
user calls User#login (because only anonymous users can do that) or  
Welcome#about\_us (because there, I don’t care whether he’s logged in).

How would I define exceptions? Can I say

```
    :before_filter check_user, :except => User#login, 

```

Welcome#about\_us

? AFAIUnderstand the docs, I can only specify exceptions within the same  
controller.

> > I would also like to offer a search form on the main page without having  
> > to resort to linking to “Search:” first.
> 
> Create app/views/shared/\_search.rhtml with the search form “bucket” html  
> content. Then on whatever page (or in your layout) you want that on do:
> 
> \<%= render :partial =\> ‘shared/search’ %\>

OK, that looks simple. Thanks 🙂

> > I have a class “User” and a user\_controller. Does logging in and out  
> > belong into this controller or does it make sense to create another  
> > model/controller (Login) for this?
> 
> I’d leave it in the user controller.
> 
> [http://host/user/login](http://host/user/login)  
> [http://host/user/logout](http://host/user/logout)  
> [http://host/user/settings](http://host/user/settings)  
> etc…

Makes sense. How about an admin user? I’m planning to also do

```
    :before_filter :check_admin, only => :list, :edit, ...

```

where

```
    def check_admin
            @user.is_admin
    end

```

Does creating a seperate “admin” controller make sense? I think not,  
since  
the admin is just a special form of “user” (right)?

> > The user has\_many addresses and has\_many cars (for example). What’s the  
> > best way of presenting this info to the user in a way that he can most  
> > easily edit all his info? Are there usability studies somewhere that  
> > weigh different presentation structures?
> 
> I dunno, but I imagine there’s lots of info on how to do this…

I imagine too, but most of the people who have it charge for it 🙂  
I guess you need a certain expertise to make the site “feel” good.

> > For what should I create partials,  
> > Whatever you might think you need to share b/n views. Or if you know you  
> > might be updating a part of your site with ajax, make that into a partial  
> > so it’s easy to do…

Ah. Good thinking. Yes, I’m planning to add a lot of AJAX later on.

> > which page elements should commonly be cached,
> 
> Impossible to say without knowing your usage patterns. If nothing  
> changes, cache it. If it’s highly dynamic, don’t.

Rails includes a profiler, right? So I can see how long stuff takes.

In my old PHP app, populating a select list out of the DB, which was  
displayed on the main page, took nearly 80% of the total rendering time.  
It  
was still about 0.5s, on average, but the server load went down an order  
of  
magnitude after I started caching that HTML snippet.

> > should I use link\_to for all (even static) links?
> 
> Sure.

Devil’s advocate … isn’t that unnecessarily slower than using direct  
links? 😉

Well, I guess I’ll have to profile it …

> > How do I include completely static data (does Rails realize whether a  
> > static file with the given path exists? Does that maybe depend on the  
> > webserver used, and the .htaccess files?)
> 
> What type of static data? Images, Javascript, Stylesheets all have their  
> own helper methods. Use those. Otherwise for PDF/downloads just use  
> link\_to. For flash and embedded things, just wrap it up in the right tags  
> yourself (or see if there’s a helper which there probably is)

“static data” as in “About us” and “Contact us” pages, terms of service  
and  
whatever else.

> > Any pointers to documentation would be great.
> 
> good luck!

Thanks! 🙂

Jens

---

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**Author:** ![unknown](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/u/4bbf92/32.png) [@unknown](https://www.ruby-forum.com/u/unknown)\
**Post date:** [October 20, 2006, 1:38am UTC](https://www.ruby-forum.com/t/application-structure-tutorials/72802/4 "2006-10-20T01:38:08Z")

</div>

> > 
> 
> thanks for your reply! I’m guessing that using your suggested method, I can  
> define exceptions here, right? I.e. I don’t need to check for a user if the  
> user calls User#login (because only anonymous users can do that) or  
> Welcome#about\_us (because there, I don’t care whether he’s logged in).
> 
> How would I define exceptions? Can I say
> 
> ```
> :before_filter check_user, :except => User#login, Welcome#about_us
> 
> ```
> 
> ? AFAIUnderstand the docs, I can only specify exceptions within the same  
> controller.

Sure. But take a look at application.rb. It’s a ApplicationController  
class. And if you look at your other xxxx\_controller.rb files you’ll  
see  
that those classes inherit from ApplicationController. So by putting it  
in  
application.rb you’re putting it in all your models.

You’re right though. If you had User#login and Foo#login and had your  
before filter look like this:

:before\_filter check\_user, :except =\> [:login, :about\_us]

I don’t know how it would know which is which. But I haven’t checked  
the  
source to see if there’s a way to specify specific controllers…

> Does creating a seperate “admin” controller make sense? I think not, since  
> the admin is just a special form of “user” (right)?

Depends on how you have things setup. If an admin is just a user with  
an  
is\_admin boolean field, then probably not. But I don’t know your app 🙂

> > Impossible to say without knowing your usage patterns. If nothing  
> > changes, cache it. If it’s highly dynamic, don’t.
> 
> Rails includes a profiler, right? So I can see how long stuff takes.
> 
> In my old PHP app, populating a select list out of the DB, which was  
> displayed on the main page, took nearly 80% of the total rendering time. It  
> was still about 0.5s, on average, but the server load went down an order of  
> magnitude after I started caching that HTML snippet.

Yes. You can benchmark as well as just watch the output of your  
development.log and it will tell you how long it took doing each step.

> > > should I use link\_to for all (even static) links?
> > 
> > Sure.
> 
> Devil’s advocate … isn’t that unnecessarily slower than using direct  
> links? 😉

Probably. But it’s easier. And if you cache it doesn’t matter. And as  
a  
bonus in 6 months when your site is massively popular and you realize  
you  
need to put all your images/stylsheets/javascript on another server to  
spread the load if you’ve used the tags you can set a config option to  
have it prepend the server name to all those links automatically.

> > > How do I include completely static data (does Rails realize whether a  
> > > static file with the given path exists? Does that maybe depend on the  
> > > webserver used, and the .htaccess files?)
> > 
> > What type of static data? Images, Javascript, Stylesheets all have  
> > their
> 
> > own helper methods. Use those. Otherwise for PDF/downloads just use  
> > link\_to. For flash and embedded things, just wrap it up in the right tags  
> > yourself (or see if there’s a helper which there probably is)
> 
> “static data” as in “About us” and “Contact us” pages, terms of service and  
> whatever else.

If it were me, I’d just put it in the appropriate view files and cache  
it.

-philip