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GlennNZ

2007-Nov-13 02:13 UTC

How to retrieve an object from form_remote_tag?

Hi everyone, my misadventures with rails continues...

If I have a cart object which contains CartItem objects and then use
partials to display them, how do I go about getting a copy of a
CartItem object to a controller method?

So if a partial displaying a CartItem had this code...

<% form_remote_tag :url => { :action => :delete_from_cart, :item =>
cart_item } do %>
  <%= submit_tag "Delete" %>
<% end %>

...then how do I access the CartItem object from the delete_from_cart
method.

At the moment I''m just trying to print out the name of the CartItem
using something like...

def delete_from_cart
  print params[:item].name
  #or maybe
  my_item = CartItem.new(params[:item])
  print my_item.name
end

...but neither work so obviously I''ve completely misinterpreted rails
again. I get an error like.

NoMethodError (undefined method `name'' for "#<CartItem:
0x47dd9f4>":String):[/quote]
Note that I can go <%= cart_item.name %> from the partial and it
prints to the browser fine, so there is a name method.

Any help will be great.

On a side note, where is the best place to go for Rails help? Is there
one particular forum that is more active than the others?
forums.devshed.com is pretty quite and railsforum seems quite young.


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William Pratt

2007-Nov-13 04:49 UTC

head link

Re: How to retrieve an object from form_remote_tag?

You are effectively passing the id (and you may need to use :item => 
cart_item.id unless you use :id like below) of the cart item in so you 
need to find it:
<% form_remote_tag :url => { :action => :delete_from_cart, :item => 
cart_item.id } do %>
    <%= submit_tag "Delete" %>
<% end %>
my_item = CartItem.find(params[:item])

btw, the idiomatic rails way is to pass it in as the id parameter like:

<% form_remote_tag :url => { :action => :delete_from_cart, :id => 
cart_item } do %>
    <%= submit_tag "Delete" %>
<% end %>

my_item = CartItem.find(params[:id])

-Bill

GlennNZ wrote:> Hi everyone, my misadventures with rails continues...
>
> If I have a cart object which contains CartItem objects and then use
> partials to display them, how do I go about getting a copy of a
> CartItem object to a controller method?
>
> So if a partial displaying a CartItem had this code...
>
> <% form_remote_tag :url => { :action => :delete_from_cart, :item
=>
> cart_item } do %>
>   <%= submit_tag "Delete" %>
> <% end %>
>
> ...then how do I access the CartItem object from the delete_from_cart
> method.
>
> At the moment I''m just trying to print out the name of the
CartItem
> using something like...
>
> def delete_from_cart
>   print params[:item].name
>   #or maybe
>   my_item = CartItem.new(params[:item])
>   print my_item.name
> end
>
> ...but neither work so obviously I''ve completely misinterpreted
rails
> again. I get an error like.
>
> NoMethodError (undefined method `name'' for "#<CartItem:
> 0x47dd9f4>":String):[/quote]
> Note that I can go <%= cart_item.name %> from the partial and it
> prints to the browser fine, so there is a name method.
>
> Any help will be great.
>
> On a side note, where is the best place to go for Rails help? Is there
> one particular forum that is more active than the others?
> forums.devshed.com is pretty quite and railsforum seems quite young.
>
>
> >
>   
-- 
Sincerely,

William Pratt


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GlennNZ

2007-Nov-13 06:45 UTC

head link

Re: How to retrieve an object from form_remote_tag?

Great, thanks for clearing that up. There is one thing though, my
understanding is that the find method is inherited from ActiveRecord
so that going

<% form_remote_tag :url => { :action => :delete_from_cart, :id =>
cart_item } do %>
    <%= submit_tag "Delete" %>
<%end%>

 is dependent on CartItem being an ActiveRecord object. As it turns
out, CartItem contains a Service object which inherits from
ActiveRecord so I''ve gone

... :id => cart_item.service.id ....
and
my_service = Service.find(params[:id])
accordingly.

My question is this. Is it possible to create my own find method for
the CartItem class so that it can look for an instance of CartItem?
For example, using
... :id => cart_item...
and then
print params[:id]
prints out something like #<CartItem:0x471a5a8>

so is it possible to create my own find method for CartItem using that
piece of information i.e.
def self.find(id)
  # something really clever
end

Cheers


On Nov 13, 5:49 pm, William Pratt
<bi...-YbheRAKfYF4eIZ0/mPfg9Q@public.gmane.org>
wrote:> You are effectively passing the id (and you may need to use :item =>
> cart_item.id unless you use :id like below) of the cart item in so you
> need to find it:
> <% form_remote_tag :url => { :action => :delete_from_cart, :item
=>
> cart_item.id } do %>
>     <%= submit_tag "Delete" %>
> <% end %>
> my_item = CartItem.find(params[:item])
>
> btw, the idiomatic rails way is to pass it in as the id parameter like:
>
> <% form_remote_tag :url => { :action => :delete_from_cart, :id
=>
> cart_item } do %>
>     <%= submit_tag "Delete" %>
> <% end %>
>
> my_item = CartItem.find(params[:id])
>
> -Bill
>
>
>
> GlennNZ wrote:
> > Hi everyone, my misadventures with rails continues...
>
> > If I have a cart object which contains CartItem objects and then use
> > partials to display them, how do I go about getting a copy of a
> > CartItem object to a controller method?
>
> > So if a partial displaying a CartItem had this code...
>
> > <% form_remote_tag :url => { :action => :delete_from_cart,
:item =>
> > cart_item } do %>
> >   <%= submit_tag "Delete" %>
> > <% end %>
>
> > ...then how do I access the CartItem object from the delete_from_cart
> > method.
>
> > At the moment I''m just trying to print out the name of the
CartItem
> > using something like...
>
> > def delete_from_cart
> >   print params[:item].name
> >   #or maybe
> >   my_item = CartItem.new(params[:item])
> >   print my_item.name
> > end
>
> > ...but neither work so obviously I''ve completely
misinterpreted rails
> > again. I get an error like.
>
> > NoMethodError (undefined method `name'' for
"#<CartItem:
> > 0x47dd9f4>":String):[/quote]
> > Note that I can go <%= cart_item.name %> from the partial and it
> > prints to the browser fine, so there is a name method.
>
> > Any help will be great.
>
> > On a side note, where is the best place to go for Rails help? Is there
> > one particular forum that is more active than the others?
> > forums.devshed.com is pretty quite and railsforum seems quite young.
>
> --
> Sincerely,
>
> William Pratt

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Frederick Cheung

2007-Nov-13 10:33 UTC

head link

Re: How to retrieve an object from form_remote_tag?

On 13 Nov 2007, at 06:45, GlennNZ wrote:
>
> My question is this. Is it possible to create my own find method for
> the CartItem class so that it can look for an instance of CartItem?
>
> For example, using
> ... :id => cart_item...
> and then
> print params[:id]
> prints out something like #<CartItem:0x471a5a8>
>
> so is it possible to create my own find method for CartItem using that
> piece of information i.e.
> def self.find(id)
>  # something really clever
> end
>
Well if you want instances of cart_item to persist across requests you  
will have to store them somewhere (database, session, memcache, flat  
file on your server etc etc...).
If you mean ''can i magically find an instance of cartitem that was  
created in  an earlier request and that I haven''t stored anywhere  
persistent'' then the answer is no (well you can limp along with class  
variables, but that doesn''t work in development mode or when you scale
past 1 mongrel).

Fre


> Cheers
>
>
> On Nov 13, 5:49 pm, William Pratt
<bi...-YbheRAKfYF4eIZ0/mPfg9Q@public.gmane.org> wrote:
>> You are effectively passing the id (and you may need to use :item =>
>> cart_item.id unless you use :id like below) of the cart item in so  
>> you
>> need to find it:
>> <% form_remote_tag :url => { :action => :delete_from_cart,
:item =>
>> cart_item.id } do %>
>>    <%= submit_tag "Delete" %>
>> <% end %>
>> my_item = CartItem.find(params[:item])
>>
>> btw, the idiomatic rails way is to pass it in as the id parameter  
>> like:
>>
>> <% form_remote_tag :url => { :action => :delete_from_cart, :id
=>
>> cart_item } do %>
>>    <%= submit_tag "Delete" %>
>> <% end %>
>>
>> my_item = CartItem.find(params[:id])
>>
>> -Bill
>>
>>
>>
>> GlennNZ wrote:
>>> Hi everyone, my misadventures with rails continues...
>>
>>> If I have a cart object which contains CartItem objects and then
use
>>> partials to display them, how do I go about getting a copy of a
>>> CartItem object to a controller method?
>>
>>> So if a partial displaying a CartItem had this code...
>>
>>> <% form_remote_tag :url => { :action => :delete_from_cart,
:item =>
>>> cart_item } do %>
>>>  <%= submit_tag "Delete" %>
>>> <% end %>
>>
>>> ...then how do I access the CartItem object from the  
>>> delete_from_cart
>>> method.
>>
>>> At the moment I''m just trying to print out the name of the
CartItem
>>> using something like...
>>
>>> def delete_from_cart
>>>  print params[:item].name
>>>  #or maybe
>>>  my_item = CartItem.new(params[:item])
>>>  print my_item.name
>>> end
>>
>>> ...but neither work so obviously I''ve completely
misinterpreted
>>> rails
>>> again. I get an error like.
>>
>>> NoMethodError (undefined method `name'' for
"#<CartItem:
>>> 0x47dd9f4>":String):[/quote]
>>> Note that I can go <%= cart_item.name %> from the partial and
it
>>> prints to the browser fine, so there is a name method.
>>
>>> Any help will be great.
>>
>>> On a side note, where is the best place to go for Rails help? Is  
>>> there
>>> one particular forum that is more active than the others?
>>> forums.devshed.com is pretty quite and railsforum seems quite
young.
>>
>> --
>> Sincerely,
>>
>> William Pratt
>
>
> >

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GlennNZ

2007-Nov-13 10:40 UTC

head link

Re: How to retrieve an object from form_remote_tag?

On Nov 13, 11:33 pm, Frederick Cheung
<frederick.che...-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
wrote:> On 13 Nov 2007, at 06:45, GlennNZ wrote:
>
>
>
>
>
> > My question is this. Is it possible to create my own find method for
> > the CartItem class so that it can look for an instance of CartItem?
>
> > For example, using
> > ... :id => cart_item...
> > and then
> > print params[:id]
> > prints out something like #<CartItem:0x471a5a8>
>
> > so is it possible to create my own find method for CartItem using that
> > piece of information i.e.
> > def self.find(id)
> >  # something really clever
> > end
>
> Well if you want instances of cart_item to persist across requests you
> will have to store them somewhere (database, session, memcache, flat
> file on your server etc etc...).
> If you mean ''can i magically find an instance of cartitem that was
> created in  an earlier request and that I haven''t stored anywhere
> persistent'' then the answer is no (well you can limp along with
class
> variables, but that doesn''t work in development mode or when you
scale
> past 1 mongrel).
>
> Fre
>
> > Cheers

I have a Cart object which has an Array of CartItems which in turn
holds a Service object which inherits from ActiveRecord. The Cart
object is stored in the session variable so yes, it is persistent and
therefore all the instances of CartItem should be persistent too.

>
> > On Nov 13, 5:49 pm, William Pratt
<bi...-YbheRAKfYF4eIZ0/mPfg9Q@public.gmane.org> wrote:
> >> You are effectively passing the id (and you may need to use :item
=>
> >> cart_item.id unless you use :id like below) of the cart item in so
> >> you
> >> need to find it:
> >> <% form_remote_tag :url => { :action =>
:delete_from_cart, :item =>
> >> cart_item.id } do %>
> >>    <%= submit_tag "Delete" %>
> >> <% end %>
> >> my_item = CartItem.find(params[:item])
>
> >> btw, the idiomatic rails way is to pass it in as the id parameter
> >> like:
>
> >> <% form_remote_tag :url => { :action =>
:delete_from_cart, :id =>
> >> cart_item } do %>
> >>    <%= submit_tag "Delete" %>
> >> <% end %>
>
> >> my_item = CartItem.find(params[:id])
>
> >> -Bill
>
> >> GlennNZ wrote:
> >>> Hi everyone, my misadventures with rails continues...
>
> >>> If I have a cart object which contains CartItem objects and
then use
> >>> partials to display them, how do I go about getting a copy of
a
> >>> CartItem object to a controller method?
>
> >>> So if a partial displaying a CartItem had this code...
>
> >>> <% form_remote_tag :url => { :action =>
:delete_from_cart, :item =>
> >>> cart_item } do %>
> >>>  <%= submit_tag "Delete" %>
> >>> <% end %>
>
> >>> ...then how do I access the CartItem object from the
> >>> delete_from_cart
> >>> method.
>
> >>> At the moment I''m just trying to print out the name
of the CartItem
> >>> using something like...
>
> >>> def delete_from_cart
> >>>  print params[:item].name
> >>>  #or maybe
> >>>  my_item = CartItem.new(params[:item])
> >>>  print my_item.name
> >>> end
>
> >>> ...but neither work so obviously I''ve completely
misinterpreted
> >>> rails
> >>> again. I get an error like.
>
> >>> NoMethodError (undefined method `name'' for
"#<CartItem:
> >>> 0x47dd9f4>":String):[/quote]
> >>> Note that I can go <%= cart_item.name %> from the
partial and it
> >>> prints to the browser fine, so there is a name method.
>
> >>> Any help will be great.
>
> >>> On a side note, where is the best place to go for Rails help?
Is
> >>> there
> >>> one particular forum that is more active than the others?
> >>> forums.devshed.com is pretty quite and railsforum seems quite
young.
>
> >> --
> >> Sincerely,
>
> >> William Pratt

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Thorsten Muller

2007-Nov-13 11:00 UTC

head link

Re: How to retrieve an object from form_remote_tag?

GlennNZ wrote:> On Nov 13, 11:33 pm, Frederick Cheung
<frederick.che...-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
> wrote:
>> > ... :id => cart_item...
>> Well if you want instances of cart_item to persist across requests you
>> > Cheers
> I have a Cart object which has an Array of CartItems which in turn
> holds a Service object which inherits from ActiveRecord. The Cart
> object is stored in the session variable so yes, it is persistent and
> therefore all the instances of CartItem should be persistent too.
so if i got that right you Cart defines (or should) an association like 
this:

class Cart < ActiveRecord::Base

has_many :services

...

then you could do something like

class Basket < ActiveRecord::Base

has_many :services do
  def my_finder
    # something real clever
  end
end

then you can access it eg.: @cart.services.my_finder

find details here: http://api.rubyonrails.org/
look for "Association extensions"
-- 
Posted via http://www.ruby-forum.com/.

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Frederick Cheung

2007-Nov-13 11:01 UTC

head link

Re: How to retrieve an object from form_remote_tag?

On 13 Nov 2007, at 10:40, GlennNZ wrote:>
> I have a Cart object which has an Array of CartItems which in turn
> holds a Service object which inherits from ActiveRecord. The Cart
> object is stored in the session variable so yes, it is persistent and
> therefore all the instances of CartItem should be persistent too.
If they''re stored in the session there''s no magic way for the
CartItem
class to find instances of itself, since models don''t have access to  
the session. presumably you could do something like  
session[:cart].find_cart_item(...)

Fred

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GlennNZ

2007-Nov-13 19:45 UTC

head link

Re: How to retrieve an object from form_remote_tag?

On Nov 14, 12:00 am, Thorsten Muller <rails-mailing-l...@andreas-
s.net> wrote:> GlennNZ wrote:
> > On Nov 13, 11:33 pm, Frederick Cheung
<frederick.che...-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
> > wrote:
> >> > ... :id => cart_item...
> >> Well if you want instances of cart_item to persist across requests
you
> >> > Cheers
> > I have a Cart object which has an Array of CartItems which in turn
> > holds a Service object which inherits from ActiveRecord. The Cart
> > object is stored in the session variable so yes, it is persistent and
> > therefore all the instances of CartItem should be persistent too.
>
> so if i got that right you Cart defines (or should) an association like
> this:
>
> class Cart < ActiveRecord::Base
>
> has_many :services
>
> ...
>
> then you could do something like
>
> class Basket < ActiveRecord::Base
>
> has_many :services do
>   def my_finder
>     # something real clever
>   end
> end
>
> then you can access it eg.: @cart.services.my_finder

Okay, it never occurred to me to use ActiveRecord on an object that
wasn''t actually a database table. Admittedly what I am playing around
with is derived from the shopping cart tutorial in the Agile Web
Development with Rails book. Currently my code works by doing the
following

#the partial
... :id => cart_item.service.id ....

#the controller
my_service = Service.find(params[:id])
session[:cart].remove_from_cart(my_service)

#Cart
def remove_from_cart(service)
  item = @items.find{ |item| item.service == service }
  @items.delete(item)
end


I should play around a bit more with active record. I''ve realised how
I''ve misinterpreted what the find method is doing and therefore why I
can''t use it for what I was trying to do originally.

Thanks for all the help, guys.

>
> find details here:http://api.rubyonrails.org/
> look for "Association extensions"
> --
> Posted viahttp://www.ruby-forum.com/.

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Rails - Nov 2007 - How to retrieve an object from form_remote_tag?

How to retrieve an object from form_remote_tag?

Re: How to retrieve an object from form_remote_tag?

Re: How to retrieve an object from form_remote_tag?

Re: How to retrieve an object from form_remote_tag?

Re: How to retrieve an object from form_remote_tag?

Re: How to retrieve an object from form_remote_tag?

Re: How to retrieve an object from form_remote_tag?

Re: How to retrieve an object from form_remote_tag?