rake task to generate objc models from rails ones

objective_resource_skeleton.rake

desc "Generate iPhone Models"
task :objective_resource_skeleton => :environment do
  output_path = "#{Rails.root}/doc/iphone_models"
  #get all our models
  model_files = Dir.glob("#{Rails.root}/app/models/*.rb").each { |file| require file }
  models = Object.subclasses_of(ActiveRecord::Base).select { |model| 
    File.exist?("#{Rails.root}/app/models/#{model.name.underscore}.rb")
  }
  #make sure our output path exists
  FileUtils.mkdir_p(output_path)
  models.each do |model|
    model_downcase_name = "#{model.name[0,1].downcase}#{model.name[1..-1]}"
    fields = []
    properties = []
    column_names = []
    object_column_names = []
    model.columns.each do |c|
      field_type = "NSString*"
      case c.type
      when :integer
        field_type = "NSInteger"
      when :decimal
        field_type = "CGFloat"
      when :boolean
        field_type = "BOOL"
      when :date, :datetime
        field_type = "NSDate*"
      end
      object_type = field_type.include?("*")
      #set the field properties depending on if its an object or not
      field_properties = object_type ? "nonatomic, retain, readwrite" : "nonatomic, assign, readwrite"
      #use a special classNameId format for ids, otherwise ue regular camelcase with the first char being lower
      column_downcase_name = (c.name == 'id' ? "#{model_downcase_name}Id" : "#{c.name[0,1].downcase}#{c.name.camelcase[1..-1]}")
      column_names << column_downcase_name
      object_column_names << column_downcase_name if object_type
      fields << "#{field_type} #{column_downcase_name};"
      properties << "@property (#{field_properties}) #{field_type} #{column_downcase_name};"        
    end
    #write the files
    File.open("#{output_path}/#{model.name}.h","w") do |f| 
      f.puts(H_CODE_TEMPLATE % [model.name, fields.join("\n  "), properties.join("\n")])
    end
    File.open("#{output_path}/#{model.name}.m","w") do |f| 
      f.puts(M_CODE_TEMPLATE % [model.name, model.name, column_names.join(", "), object_column_names.map{|c| "[#{c} release];"}.join("\n  ")])
    end
  end
  #create an archive of the models
  `cd #{output_path} && tar -zcf iphone_models.tgz *.m *.h`
end
#add in your own headers and comments
H_CODE_TEMPLATE = <<-CODE
#import "ObjectiveResource.h"
@interface %s : NSObject
{
  %s
}
%s
@end
CODE

M_CODE_TEMPLATE = <<-CODE
#import "%s.h"
@implementation %s
@synthesize %s;

-(void) dealloc
{
  //release the object columns
  %s
  [super dealloc];
}
@end
CODE