Rails - how to create file (XML) and save it into Amazon S3 bucket?

Question

I need to generate all my products from database table into the XML file. Because my app run on Heroku, I need to use Amazon S3 as the storage.

Here's an example of on how to save an image:

has_attached_file :photo,
       :styles => {
       :thumb=> "100x100#",
       :small  => "400x400>" },
     :storage => :s3,
     :s3_credentials => "#{RAILS_ROOT}/config/s3.yml",
     :path => "/:style/:id/:filename"

Which makes me a bit confused... because I am not sure about the logic of this task. My idea is to run an action (say create_xml_feed ) in the Products controller

 xml = Builder::XmlMarkup.new( :indent => 2 )
 xml.instruct! :xml, :encoding => "ASCII"
 xml.product do |p|
   p.name "Test"
 end

But here comes the problem - I don't know, how to save the newly created file into Amazon S3 Bucket.

I'd be grateful for each advance, thank you

Answer 1

First, create an active record class to hold your uploaded XML file. After this you can write the logic to create your xml string, create a new file by first creating a new instance of the XmlUploader class, then create the xml string you want, save it in a file and then assign this file as the attachment file. Once you save your xml file will be uploaded to s3.

class XmlUploader < ActiveRecord::Base
  has_attached_file :uploaded_file, :storage => :s3,
  :s3_credentials => "#{RAILS_ROOT}/config/s3.yml",
  :path => "/:id/:filename"

  def create_uploaded_file
    xml = ::Builder::XmlMarkup.new( :indent => 2 )
    xml.instruct! :xml, :encoding => "ASCII"
    xml.product do |p|
      p.name "Test"
    end
    file_to_upload = File.open("some-file-name", "w")     
    file_to_upload.write(xml)
    file_to_upload.close()
    self.uploaded_file = File.open("some-file-name")
    self.save!
  end
end

class CreateXmlUploaders < ActiveRecord::Migration
  def change
    create_table :xml_uploaders do |t|
      t.attachment :uploaded_file
      t.timestamps
    end
  end
end

xml_file = XmlUploader.new
xml_file.create_uploaded_file