Rails - Oct 2005 - What is the "right" way to program this?

Hi everybody,

These are my first steps using RoR. I''m trying to modify the code 
created by scaffold. So the methods new and create in the controller 
look like this:

   def new
     @myfile = Myfile.new
     id = @params[:id]
     if id == nil
     	id = 0
     end
     @myfile.folder_id = id #save the new file in the correct spot
   end

   def create
     @myfile = Myfile.new(params[:myfile])
     if @myfile.save
       flash[''notice''] = ''Myfile was successfully
created.''
       redirect_to :controller => ''folder'', :action =>
''list''
     else
       render_action ''new''
     end
   end

In the "new" view I''m storing the folder_id in a hidden form
field like
this:

   <%= hidden_field ''folder'', ''folder_id''
%>

- Is this the right way or can/should this be solved without using the 
hidden form feild??

- Also, after saving how can I redirect to the id in the hidden form field?

- Last question: I''m using folder_id (this is the name of the field in 
the database and it works fine), but @myfile.folder is actually 
referencing the folder object. However when I try to store a folder with 
Myfile like this: @myfile.folder = @params[:folder] I get an error 
message. Is using folder_id a good idea??

Thanks!

Grt,
Mischa.

Mischa Berger wrote:
> - Is this the right way or can/should this be solved without using the
> hidden form feild??
You could just pass it in the parameters to your action when you start
your form tag (via form helper).
> - Also, after saving how can I redirect to the id in the hidden form field?
Just use redirect_to, with parameters (action, id, etc.) to get it where
you want.
> - Last question: I''m using folder_id (this is the name of the
field in
> the database and it works fine), but @myfile.folder is actually
> referencing the folder object. However when I try to store a folder with
> Myfile like this: @myfile.folder = @params[:folder] I get an error
> message. Is using folder_id a good idea??
I''m confused on this one..  The Rails idiom is to have "id"
as a primary
key, and something "folder_id" for references into a table named
"folders".

--Steve

Thanks, for your help.
>>- Last question: I''m using folder_id (this is the name of the
field in
>>the database and it works fine), but @myfile.folder is actually
>>referencing the folder object. However when I try to store a folder with
>>Myfile like this: @myfile.folder = @params[:folder] I get an error
>>message. Is using folder_id a good idea??
> 
> 
> I''m confused on this one..  The Rails idiom is to have
"id" as a primary
> key, and something "folder_id" for references into a table named
"folders".
Yes I''m using folder_id to reference a table named folders, but it
seems
using both @myfile.folder_id = 1 and myfile.folder = Folder.find(1) work 
fine. I guess the second way of storing a myfile in a folder is the 
preferred way?

Grt,
Mischa.

> Yes I''m using folder_id to reference a table named folders, but it
> seems using both @myfile.folder_id = 1 and myfile.folder =  
> Folder.find(1) work fine. I guess the second way of storing a  
> myfile in a folder is the preferred way?
1) @myfile.folder_id = 1
2) @myfile.folder = Folder.find(1)

Yeah, go with the second one. It''s more stylish :) And yeah, I guess  
it''s the preferred way

Are you trying to upload a file?

Oh, and a small tip. You can rewrite this:

     if id == nil
         id = 0
     end

into this

     id = 0 if id == nil

That''s an "if modifier" in Ruby




cheers, rob

The first saves you a query though :-)

Jaap

On 10/22/05, Mischa Berger
<spmm_pls-/E1597aS9LQAvxtiuMwx3w@public.gmane.org>
wrote:
> Thanks, for your help.
>
> >>- Last question: I''m using folder_id (this is the name of
the field in
> >>the database and it works fine), but @myfile.folder is actually
> >>referencing the folder object. However when I try to store a folder
with
> >>Myfile like this: @myfile.folder = @params[:folder] I get an error
> >>message. Is using folder_id a good idea??
> >
> >
> > I''m confused on this one..  The Rails idiom is to have
"id" as a primary
> > key, and something "folder_id" for references into a table
named "folders".
> Yes I''m using folder_id to reference a table named folders, but it
seems
> using both @myfile.folder_id = 1 and myfile.folder = Folder.find(1) work
> fine. I guess the second way of storing a myfile in a folder is the
> preferred way?
>
> Grt,
> Mischa.
>
> _______________________________________________
> Rails mailing list
> Rails-1W37MKcQCpIf0INCOvqR/iCwEArCW2h5@public.gmane.org
> http://lists.rubyonrails.org/mailman/listinfo/rails
>

> Are you trying to upload a file?
Yes, to the database.
> Oh, and a small tip. You can rewrite this:
> 
>     if id == nil
>         id = 0
>     end
> 
> into this
> 
>     id = 0 if id == nil
> 
> That''s an "if modifier" in Ruby
Thanks for the tip!

Grt,
Mischa.

On Oct 22, 2005, at 3:07 PM, Mischa Berger wrote:
>> Are you trying to upload a file?
>>
> Yes, to the database.
>
>
>> Oh, and a small tip. You can rewrite this:
>>     if id == nil
>>         id = 0
>>     end
>> into this
>>     id = 0 if id == nil
>> That''s an "if modifier" in Ruby
>>
> Thanks for the tip!
>
> Grt,
> Mischa.
>
You can also write this as:

id.nil? || 0

And then if id is nil it will be set to 0 if it is not nil it will be  
left alone.

Cheers-

-Ezra Zygmuntowicz
WebMaster
Yakima Herald-Republic Newspaper
ezra-gdxLOakOTQ9oetBuM9ipNAC/G2K4zDHf@public.gmane.org
509-577-7732



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> You can also write this as:
>
> id.nil? || 0
>
> And then if id is nil it will be set to 0 if it is not nil it will be
> left alone.
>
That doesn''t work for me:

irb(main):002:0> id = nil
=> nil
irb(main):003:0> id.nil?
=> true
irb(main):004:0> id.nil? || 0
=> true
irb(main):005:0> id
=> nil


this alternative does work:

irb(main):008:0> id.nil? && id=0
=> 0
irb(main):009:0> id
=> 0
irb(main):010:0> id = 4
=> 4
irb(main):011:0> id.nil? && id=0
=> false
irb(main):012:0> id
=> 4

and this:

irb(main):014:0> id = nil
=> nil
irb(main):015:0> !id.nil? || id = 0
=> 0
irb(main):016:0> id
=> 0
irb(main):017:0> id = 4
=> 4
irb(main):018:0> !id.nil? || id = 0
=> true
irb(main):019:0> id
=> 4

tho i''m not sure whether these are as clear as the original suggestion
of
id = 0 if id == nil


Greg

>     id = 0 if id == nil
Some other alternatives:

id = 0 if id.nil?

Or

id = 0 unless id 

Or 

id ||= 0

-----Original Message-----
From: rails-bounces-1W37MKcQCpIf0INCOvqR/iCwEArCW2h5@public.gmane.org
[mailto:rails-bounces-1W37MKcQCpIf0INCOvqR/iCwEArCW2h5@public.gmane.org] On
Behalf Of Mischa Berger
Sent: Sunday, 23 October 2005 8:07 AM
To: rails-1W37MKcQCpIf0INCOvqR/iCwEArCW2h5@public.gmane.org
Subject: [Rails] Re: What is the "right" way to program this?
> Are you trying to upload a file?
Yes, to the database.
> Oh, and a small tip. You can rewrite this:
> 
>     if id == nil
>         id = 0
>     end
> 
> into this
> 
>     id = 0 if id == nil
> 
> That''s an "if modifier" in Ruby
Thanks for the tip!

Grt,
Mischa.

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Perhaps this is what you mean:  id ||= 0
>
> You can also write this as:
>
> id.nil? || 0
>
> And then if id is nil it will be set to 0 if it is not nil it will be
> left alone.
>

irb(main):020:0> id=nil
=> nil
irb(main):021:0> id ||= 0
=> 0
irb(main):022:0> id
=> 0