has_finder and Geokit

rubyonrails-talk
1

I have recently discovered the brilliant has_finder. It allows you to name your ActiveRecord searches, and stack them together. It fulfills a similar need to scope_out.

One of my searches is location based, using the excellent plugin Geokit. http://geokit.rubyforge.org/. Normally I can do a spatial search like so:

MyModel.find(:all, :origin => [lat, lng], :within => miles_in_int)

When I try to do this within a has_finder finder (see below), it complains :origin and :within can not be find. It must be accessing the finder methods directly without going through Geokit.

has_finder :proximity, lambda {|lat, lon| { :origin => [lat, lon], :within => 100 } }

normal has_finder has_finder :of_type, lambda {|type_id| { :conditions => {:feature_type_id => type_id} } }

I am not sure how it all works under the hood. Can anyone advice on getting this to work? Any pointers would really help.

I'll take a look at the source code in the mean time.

Thanks, Xin

2

It would be nice if this would work. I'm using GeoKit with named_scope in Rails 2.1.

3

Mark Jameson wrote:

It would be nice if this would work. I'm using GeoKit with named_scope in Rails 2.1.

I got this working and it was really easy.

Models with "acts_as_mappable" have a method for distance_sql(origin, units=default_units, formula=default_formula). I used this to create my condition.

I am using anonymous scopes in a Search model which provides search for an Organization model, but a similar technique should work with named_scope. See this Railscast on creating a search with anonymous scopes: #112 Anonymous Scopes - RailsCasts

I have "acts_as_mappable" on both my Search model and on my Organization model. This allows me to build a scope condition like this:

scope = scope.conditions "#{Organization.distance_sql(self)} < #{self.distance}"

Note that "self" is the search in this case.

I hope this helps.

BB