Hi to all,
I''m needing some help here ... I want to do an extension on a
has_and_belongs_to_many to build a custom add method to the
association.
i have a table locations that has a many-to-many association with a
tags tabel using a locations_tags table.
i want to add a method to the Location has_and_belongs_to_many
association so that i can do something like this on the location
model:
myLocation.tags.add_by_names ''tag1 tag2 tag3''
On the extension i want to do something like this:
class Location < ActiveRecord::Base
has_and_belongs_to_many :tags do
def add_by_names tag_names
tag_names.split(" ").each do |tag_name|
tag = Tag.find_by_name(tag_name) || Tag.create(:name => tag_name)
tags << tag unless tags.find(tag.id)
end
end
end
The problem is, that i cant feager out how to have access to location
tags collection inside my custom create method.
Is there a way to do this?
any help or point to some examples welcome.
thanks.
Pedro.
Hi Pedro,
I''ve been playing around with association extensions lately, and you
should know they aren''t 100% stable yet. But they do work pretty well
for most stuff.
Something that isn''t obvious is that the context for code in the
extension is the association itself. That means that a message on self
will be sent to the association object, in your example,
myLocation.tags.
Here''s how I would write what you''re attempting:
class Location < ActiveRecord::Base
has_and_belongs_to_many :tags do
def add_by_names(tag_names)
tag_names.split(" ").each { |name| find_or_create_by_name(name)
}
end
end
That''s untested but I think it should work ok. Note that I used the
dynamic finder find_or_create_by_name, which is pretty handy for just
what you''re doing.
--josh
Pedro Costa wrote:> Hi to all,
>
> I''m needing some help here ... I want to do an extension on a
> has_and_belongs_to_many to build a custom add method to the
> association.
>
> i have a table locations that has a many-to-many association with a
> tags tabel using a locations_tags table.
>
> i want to add a method to the Location has_and_belongs_to_many
> association so that i can do something like this on the location
> model:
>
> myLocation.tags.add_by_names ''tag1 tag2 tag3''
>
> On the extension i want to do something like this:
>
> class Location < ActiveRecord::Base
> has_and_belongs_to_many :tags do
> def add_by_names tag_names
> tag_names.split(" ").each do |tag_name|
> tag = Tag.find_by_name(tag_name) || Tag.create(:name =>
> tag_name)
> tags << tag unless tags.find(tag.id)
> end
> end
> end
>
> The problem is, that i cant feager out how to have access to location
> tags collection inside my custom create method.
>
> Is there a way to do this?
>
> any help or point to some examples welcome.
>
> thanks.
> Pedro.
--
Posted via http://www.ruby-forum.com/.
Hi Josh, I tried the code you sent, but its only saving the tag records and not the association itself (the locations_tags record)... The myLocations.tags does not contain the new tags after calling: myLocation.tags.add_by_names Any sugestions? thanks. Pedro. On 2/26/06, Josh Susser <josh@hasmanythrough.com> wrote:> Hi Pedro, > > I''ve been playing around with association extensions lately, and you > should know they aren''t 100% stable yet. But they do work pretty well > for most stuff. > > Something that isn''t obvious is that the context for code in the > extension is the association itself. That means that a message on self > will be sent to the association object, in your example, > myLocation.tags. > > Here''s how I would write what you''re attempting: > > class Location < ActiveRecord::Base > has_and_belongs_to_many :tags do > def add_by_names(tag_names) > tag_names.split(" ").each { |name| find_or_create_by_name(name) } > end > end > > That''s untested but I think it should work ok. Note that I used the > dynamic finder find_or_create_by_name, which is pretty handy for just > what you''re doing. > > --josh > > > Pedro Costa wrote: > > Hi to all, > > > > I''m needing some help here ... I want to do an extension on a > > has_and_belongs_to_many to build a custom add method to the > > association. > > > > i have a table locations that has a many-to-many association with a > > tags tabel using a locations_tags table. > > > > i want to add a method to the Location has_and_belongs_to_many > > association so that i can do something like this on the location > > model: > > > > myLocation.tags.add_by_names ''tag1 tag2 tag3'' > > > > On the extension i want to do something like this: > > > > class Location < ActiveRecord::Base > > has_and_belongs_to_many :tags do > > def add_by_names tag_names > > tag_names.split(" ").each do |tag_name| > > tag = Tag.find_by_name(tag_name) || Tag.create(:name => > > tag_name) > > tags << tag unless tags.find(tag.id) > > end > > end > > end > > > > The problem is, that i cant feager out how to have access to location > > tags collection inside my custom create method. > > > > Is there a way to do this? > > > > any help or point to some examples welcome. > > > > thanks. > > Pedro. > > > -- > Posted via http://www.ruby-forum.com/. > _______________________________________________ > Rails mailing list > Rails@lists.rubyonrails.org > http://lists.rubyonrails.org/mailman/listinfo/rails >
Hi,
Got it to work. Just a litle more magic required :) (added self << find
... )
class Location < ActiveRecord::Base
has_and_belongs_to_many :tags do
def add_by_names(tag_names)
self << tag_names.split(" ").each { |name|
find_or_create_by_name(name) }
end
end
thanks a lot for you help.
Pedro.
On 2/26/06, Pedro Costa <pedrof.costa@gmail.com>
wrote:> Hi Josh,
>
> I tried the code you sent, but its only saving the tag records and not
> the association itself (the locations_tags record)...
>
> The myLocations.tags does not contain the new tags after calling:
>
> myLocation.tags.add_by_names
>
> Any sugestions?
>
> thanks.
> Pedro.
>
> On 2/26/06, Josh Susser <josh@hasmanythrough.com> wrote:
> > Hi Pedro,
> >
> > I''ve been playing around with association extensions lately,
and you
> > should know they aren''t 100% stable yet. But they do work
pretty well
> > for most stuff.
> >
> > Something that isn''t obvious is that the context for code in
the
> > extension is the association itself. That means that a message on self
> > will be sent to the association object, in your example,
> > myLocation.tags.
> >
> > Here''s how I would write what you''re attempting:
> >
> > class Location < ActiveRecord::Base
> > has_and_belongs_to_many :tags do
> > def add_by_names(tag_names)
> > tag_names.split(" ").each { |name|
find_or_create_by_name(name) }
> > end
> > end
> >
> > That''s untested but I think it should work ok. Note that I
used the
> > dynamic finder find_or_create_by_name, which is pretty handy for just
> > what you''re doing.
> >
> > --josh
> >
> >
> > Pedro Costa wrote:
> > > Hi to all,
> > >
> > > I''m needing some help here ... I want to do an extension
on a
> > > has_and_belongs_to_many to build a custom add method to the
> > > association.
> > >
> > > i have a table locations that has a many-to-many association with
a
> > > tags tabel using a locations_tags table.
> > >
> > > i want to add a method to the Location has_and_belongs_to_many
> > > association so that i can do something like this on the location
> > > model:
> > >
> > > myLocation.tags.add_by_names ''tag1 tag2 tag3''
> > >
> > > On the extension i want to do something like this:
> > >
> > > class Location < ActiveRecord::Base
> > > has_and_belongs_to_many :tags do
> > > def add_by_names tag_names
> > > tag_names.split(" ").each do |tag_name|
> > > tag = Tag.find_by_name(tag_name) || Tag.create(:name
=>
> > > tag_name)
> > > tags << tag unless tags.find(tag.id)
> > > end
> > > end
> > > end
> > >
> > > The problem is, that i cant feager out how to have access to
location
> > > tags collection inside my custom create method.
> > >
> > > Is there a way to do this?
> > >
> > > any help or point to some examples welcome.
> > >
> > > thanks.
> > > Pedro.
> >
> >
> > --
> > Posted via http://www.ruby-forum.com/.
> > _______________________________________________
> > Rails mailing list
> > Rails@lists.rubyonrails.org
> > http://lists.rubyonrails.org/mailman/listinfo/rails
> >
>
Oh cool, nice work. I didn''t know that part of the incantation. That looks so pretty. I''m really starting to like association extensions a lot. --josh Pedro Costa wrote:> Got it to work. Just a litle more magic required :) (added self << find > ... ) > > class Location < ActiveRecord::Base > has_and_belongs_to_many :tags do > def add_by_names(tag_names) > self << tag_names.split(" ").each { |name| find_or_create_by_name(name) } > end > end-- Posted via http://www.ruby-forum.com/.
couldn''t agree more. really beautiful stuff ... On 2/27/06, Josh Susser <josh@hasmanythrough.com> wrote:> Oh cool, nice work. I didn''t know that part of the incantation. That > looks so pretty. I''m really starting to like association extensions a > lot. > > --josh > > Pedro Costa wrote: > > Got it to work. Just a litle more magic required :) (added self << find > > ... ) > > > > class Location < ActiveRecord::Base > > has_and_belongs_to_many :tags do > > def add_by_names(tag_names) > > self << tag_names.split(" ").each { |name| find_or_create_by_name(name) } > > end > > end > > -- > Posted via http://www.ruby-forum.com/. > _______________________________________________ > Rails mailing list > Rails@lists.rubyonrails.org > http://lists.rubyonrails.org/mailman/listinfo/rails >