Rails - Aug 2006 - Understanding MVC - view customization after using scaffolds

All,

I have ordered AWDWR and am anxiously awaiting its arrival.  In the 
meantime I still am playing with ROR using radrails.  I have a few 
questions ...

I create a table named customers with the following details:

Field	Type	Null	Key	Default	Extra
id	int(11)	NO	PRI		auto_increment
customer_name	varchar(50)	NO
inbound_retention	int(11)	NO
outbound_retention	int(11)	NO
unix_admin_email	varchar(50)	NO
schedule_id	int(11)	NO
transfer_inbound_type	varchar(20)	NO
transfer_outbound_type	varchar(20)	NO
date_added	timestamp	YES		CURRENT_TIMESTAMP


I then run the scaffold generation:

ediweb> ruby script/generate scaffold customer Customerinfo
      exists  app/controllers/
      exists  app/helpers/
      exists  app/views/customerinfo
      exists  test/functional/
  dependency  model
      exists    app/models/
      exists    test/unit/
      exists    test/fixtures/
      create    app/models/customer.rb
      create    test/unit/customer_test.rb
      create    test/fixtures/customers.yml
   identical  app/views/customerinfo/_form.rhtml
      create  app/views/customerinfo/list.rhtml
      create  app/views/customerinfo/show.rhtml
      create  app/views/customerinfo/new.rhtml
      create  app/views/customerinfo/edit.rhtml
      create  app/controllers/customerinfo_controller.rb
      create  test/functional/customerinfo_controller_test.rb
      create  app/helpers/customerinfo_helper.rb
      create  app/views/layouts/customerinfo.rhtml
      create  public/stylesheets/scaffold.css

I understand this creates my model, controller, and view.  My question 
is if I want to only allow a user to see certain information in the list 
and only be able to add new information to certain fields where do I 
begin?  I look at my list.rhtml for customerinfo and see the following 
(after some other html):

  <% for column in Customer.content_columns %>
    <td><%=h customer.send(column.name) %></td>
  <% end %>

I realize this is what prints out each line, but how do I begin 
specifying only certain columns to be printed?  I guess I don''t 
understand the customer.send(column.name).  If someone has a good 
tutorial on customizing views when using scaffolds to build the initial 
files please link me.

Also, under new.rhtml I see:

<h1>New customer</h1>

<%= start_form_tag :action => ''create'' %>
  <%= render :partial => ''form'' %>
  <%= submit_tag "Create" %>
<%= end_form_tag %>

<%= link_to ''Back'', :action => ''list''
%>

What would I edit here to only allow certain fields in the table to be 
inserted?  Once again, a tutorial of ROR view customization would be 
greatly appreciated.  I''m very new to ROR and that book is going to
take
a few days to get here!

-James

-- 
Posted via http://www.ruby-forum.com/.

> 
>   <% for column in Customer.content_columns %>
>     <td><%=h customer.send(column.name) %></td>
>   <% end %>
> 
The above is just a looped method of showing all the content columns 
that exist in the Customer model. This code loops through the collection 
returned by the "content_columns" method and for each one it uses the 
"send" method to call the column method and return the attribute value
for that object.

Let''s assume Customer has these fields:

id   < won''t show anyway, not a "content" column
name
address
city
state
zip
credit_limit

The loop above will cycle through these fields, from "name" to 
"credit_limit" and for each one display the attribute value for the 
current object.

If you only want some user to be able to see name, city and state. You 
would just get rid of the loop, and make the scaffold code to look like:

  <td><%=h customer.name %></td>
  <td><%=h customer.city %></td>
  <td><%=h customer.state %></td>

c.
> 
> What would I edit here to only allow certain fields in the table to be 
> inserted?  Once again, a tutorial of ROR view customization would be 
> greatly appreciated.  I''m very new to ROR and that book is going
to take
> a few days to get here!
> 
The form itself is in the partial view, which is named "_form.rhtml". 
You would edit the form in that view to change what the user is allowed 
to edit on the form.

Answers to all your questions start here:
http://api.rubyonrails.org/

For instance, click on that link, scroll down in the bottom-left section 
and click on "render (ActionController::Base) and you will learn more 
than you want to know about rendering views.

Remember that the Ruby upon which Rails is based is pure 
object-oriented, so every time you see ".something", it''s a
method
that''s been defined to a class somewhere. For instance, scroll in that 
same section and click on "content_columns (ActiveRecord::Base)" to
find
out what that "Customer.content_columns" line is doing.

etc.

etc.

etc.

Good luck, be strong, hang with it. AWDWR will help immensely. As will 
Rails Recipes. Only, next time get the PDF version and you won''t have
to
wait. :)


-- 
Posted via http://www.ruby-forum.com/.

Incidentally, "send" is a method of Ruby''s base Object class.
It just
calls the method identified by the symbol in the argument. In the Rails 
case, it is calling the reader method for each attribute identified in 
the "Customer.content_columns" hash.

-- 
Posted via http://www.ruby-forum.com/.

Hi Cayce,

Cayce Balara wrote:
> 
> The above is just a looped method ...
> 
> Let''s assume Customer has these fields:
Nice post.

Best regards,
Bill