MVC questions with rails

[Miquel_Cubel]

Hi,

    I have two doubts about the right way / place to write some

code.

    Question 1:
    I have a product and in the view I need to show a listbox with

all the categories of this product.
- Option1: in the controller make " @product_categories
= ProductCategori.all" and later in the view make " <%= f.collection_select(:product_category_id,
@product_categories, :id, :name) %>"
- Option2: in the view just write " <%=
f.collection_select(:product_category_id, ProductCategori.all,
:id, :name) %>"

    Question 2:   
    I need to list products with some complex logic
        - Option1: in the controller make "      @products

= Products.list(param1, param2)" and in the model "def self.list(param1, param2) " with all the
options joins, where, …
- Option2: Put all the logic in the controller and avoid
calling the model

    Greetings

[Colin_Law1 (Colin Law)]

Hi,

I have two doubts about the right way / place to write some code\.

Question 1:
I have a product and in the view I need to show a listbox with all the

categories of this product.
- Option1: in the controller make "@product_categories =
ProductCategori.all" and later in the view make "<%=
f.collection_select(:product_category_id, @product_categories, :id, :name)
%>"
- Option2: in the view just write "<%=
f.collection_select(:product_category_id, ProductCategori.all, :id, :name)
%>"

I would use option 1. The principle reason is that then if under some
circumstances you don't want to show them all then the logic can go in
the controller, leaving the view alone.

Question 2:
I need to list products with some complex logic
    \- Option1: in the controller make "@products = Products\.list\(param1,

param2)" and in the model "def self.list(param1, param2)" with all the
options joins, where, ...
- Option2: Put all the logic in the controller and avoid calling the
model

Never put logic in the controller if it can reasonably go in the
model. Then if the logic changes (maybe you change a detail of how
the data is stored in the database) this affects only the model and
not the controller also.
Rather than a simple method a scope may be more appropriate if the
purpose is to select a set of records from the db. That is what
scopes are for.

Colin

[Miquel_Cubel]

Thanks for the answer

El 02/02/2012 10:09, Colin Law escribi�:

Hi,

     I have two doubts about the right way / place to write some code.

     Question 1:
     I have a product and in the view I need to show a listbox with all the
categories of this product.
         - Option1: in the controller make "@product_categories =
ProductCategori.all" and later in the view make "<%=
f.collection_select(:product_category_id, @product_categories, :id, :name)
%>"
         - Option2: in the view just write "<%=
f.collection_select(:product_category_id, ProductCategori.all, :id, :name)
%>"

I would use option 1. The principle reason is that then if under some
circumstances you don't want to show them all then the logic can go in
the controller, leaving the view alone.

     I agree with this point of view, but in the other side, I find myself repeating "@product_categories = ProductCategori.all" in several controllers, like "new" and "edit", and later I found that with default scaffold, after submitting, if there is an error, this assignation doesn't work well, and I don't understand exactly why (in rails 3.1.3).

     Question 2:
     I need to list products with some complex logic
         - Option1: in the controller make "@products = Products.list(param1,
param2)" and in the model "def self.list(param1, param2)" with all the
options joins, where, ...
         - Option2: Put all the logic in the controller and avoid calling the
model

Never put logic in the controller if it can reasonably go in the
model. Then if the logic changes (maybe you change a detail of how
the data is stored in the database) this affects only the model and
not the controller also.
Rather than a simple method a scope may be more appropriate if the
purpose is to select a set of records from the db. That is what
scopes are for.

     Completely agree!

Colin

Thanks for clearing it up.

[Colin_Law1 (Colin Law)]

Thanks for the answer

Hi,

I have two doubts about the right way / place to write some code\.

Question 1:
I have a product and in the view I need to show a listbox with all

the
categories of this product.
- Option1: in the controller make "@product_categories =
ProductCategori.all" and later in the view make "<%=
f.collection_select(:product_category_id, @product_categories, :id,
:name)
%>"
- Option2: in the view just write "<%=
f.collection_select(:product_category_id, ProductCategori.all, :id,
:name)
%>"

I would use option 1. The principle reason is that then if under some
circumstances you don't want to show them all then the logic can go in
the controller, leaving the view alone.

I agree with this point of view, but in the other side, I find myself
repeating "@product_categories = ProductCategori.all" in several
controllers, like "new" and "edit",

Put it in a before_filter specifying the actions that need it.

and later I found that with default
scaffold, after submitting, if there is an error, this assignation doesn't
work well, and I don't understand exactly why (in rails 3.1.3).

I think you had better ask about that in a different thread if you
can't sort it out. Have you read the Rails Guide on Debugging which
shows techniques for debugging your code.

Colin