# POST /photos
 # POST /photos.json
 def create

 @photo = Photo.new(params[:photo])
 @photo.lat = params["photo%5Blat%5D"].to_s
 @photo.lng = params["photo%5Blng%5D"].to_s
 @photo.description = params[:description]
 @photo.takenby = params[:takenby].to_s

 @photo.save

 puts "photos/create photos.inspect= #{@photo.inspect}"



 end

class Photo < ActiveRecord::Base


 attr_accessible :lat, :lng, :image
 vendor = params[:description]
 owner = params[:owner]
 Paperclip.interpolates :prefix  do |attachment, style|
 "#{owner}/#{Date.today.to_s }/#{vendor}"
 end


has_attached_file :image,
                :path => ":prefix/:basename.:extension",
                :styles => { :thumbnail => "57x57", :original => "100x100" },
                :storage => :s3,
                :s3_credentials => S3_CREDENTIALS

Started GET "/photos?lat=37.785834&lng=-122.406417" for 127.0.0.1 at 2012-09-26
  21:08:57 -0700
 21:08:57 web.1  | Processing by PhotosController#index as JSON
 21:08:57 web.1  |   Parameters: {"lat"=>"37.785834", "lng"=>"-122.406417"}
 21:08:57 web.1  | Completed 500 Internal Server Error in 4ms
 21:08:57 web.1  | NameError (undefined local variable or method `params' for #<Class:0x007fb7d4fa3320>):
 21:08:57 web.1  |   app/models/photo.rb:23:in `<class:Photo>'
 21:08:57 web.1  |   app/models/photo.rb:18:in `<top (required)>'
 21:08:57 web.1  |   app/controllers/photos_controller.rb:14:in `index'

photo.rb

 Paperclip.interpolates :prefix  do |attachment, style|
 "#{attachment.instance.takenby}/#{Date.today.to_s }/#{attachment.instance.description}"
 end

vendor = params[:description]
owner = params[:owner]

Paperclip.interpolates :description do |attachment, style|
  attachment.instance.description # or other attribute
end

has_attached_file :image,
                  :path => ":description/:basename.:extension",
                  :styles => { :thumbnail => "57x57", :original => "100x100" },
                  :storage => :s3,
                  :s3_credentials => S3_CREDENTIALS

obj.set_values(params)

def set_values(params)
  self.vendor = params[:description]
  self.owner = params[:owner]
end

<%= form_for (@post) do |f| %>

<%= form_for @post, :html => { :multipart => true } do |f| %>

<p>
<%= f.file_field :photo %>
  </p>