Initlializing blob data in the attach module

enbake_attach.gemspec

@@ -0,0 +1,18 @@
+Gem::Specification.new do |s|
+  s.name        = 'enbake_attach'
+  s.version     = '0.0.1'
+  s.date        = '2015-09-17'
+  s.summary     = "Enbake Attach"
+  s.description = "Enbake Attach is a Gem for handling attachments in Rails. Its a whoopie doo version of attachment_fu"
+  s.authors     = ["Ishwinder Singh"]
+  s.email       = 'singh.ishwinder@gmail.com'
+  s.files       = `git ls-files`.split($/)
+  s.require_paths = ["lib"]
+
+  s.add_dependency('exifr')
+  s.add_dependency('rmagick')
+
+  s.homepage    =
+    'http://github.com/ishwinder/enbake_attach'
+  s.license       = 'MIT'
+end

init.rb

@@ -1,9 +1,5 @@
 # Due to the sequence of dependency processing and plugin initialization, these statements cannot be used to auto-install
 # missing gems -they are here solely for documentation.
-config.gem 'exifr', :version => '>=1.0.3'
-config.gem 'rmagick', :version => '>=2.7.2', :lib => 'RMagick'
-config.gem 'aws-s3', :version => '>=0.6.2', :lib => 'aws/s3'
-
 require 'geometry'
 require 'hapgood/attach'
 

lib/enbake_attach.rb

@@ -0,0 +1,2 @@
+require 'geometry'
+require 'hapgood/attach'

lib/hapgood/attach.rb

@@ -1,4 +1,5 @@
 require 'hapgood/attach/sources'
+require 'base64'
 
 module Hapgood # :nodoc:
   module Attach # :nodoc:
@@ -35,7 +36,7 @@ def has_attachment(options = {})
         options[:store]            ||= Proc.new {|i, e| "file://localhost#{::File.join(RAILS_ROOT, 'public', 'attachments', [i,e].compact.join('.'))}"}
 
         # doing these shenanigans so that #attachment_options is available to processors and backends
-        class_inheritable_accessor :attachment_options
+        class_attribute :attachment_options
         self.attachment_options = options
 
         # only need to define these once on a class
@@ -113,7 +114,7 @@ def url
       # Setter for virtual url attribute used to reference external data sources.
       def url=(u)
         @url = u
-        return unless u
+        return unless u && !u.blank?
         destroy_source  # Discard any existing source
         begin
           self.source = Sources::Base.load(::URI.parse(u))
@@ -122,6 +123,16 @@ def url=(u)
         end
       end
 
+      def blob=(bl)
+        return unless bl
+        destroy_source  # Discard any existing source
+        begin
+          self.source = Sources::Base.load(Base64.decode64(bl[:data]), blob_metadata(bl))
+        rescue => e  # Can't do much here -we have to wait until the validation phase to resurrect/reconstitute errors
+          logger.error("Attach: *********ERROR: can't load blob data (#{e})")
+        end
+      end
+
       # Get the source.  Rescue exceptions and make them errors on the source virtual attribute.
       def source
         @source ||= uri && Sources::Base.reload(uri, stored_metadata)
@@ -232,6 +243,13 @@ def cgi_metadata(data)
         end
       end
 
+      def blob_metadata(b)
+        Hash.new.tap do |md|
+          md[:filename] = b[:filename]
+          md[:mime_type] = ::Mime::Type.lookup(b[:content_type])
+        end
+      end
+
       # Extract stored metadata from attributes to enrichen a purely binary source to the same level as a CGI-supplied source.
       def stored_metadata
         %w(filename mime_type).inject(Hash.new) {|hash, key| hash[key.to_sym] = self.send(key.to_sym);hash}

lib/hapgood/attach/sources/base.rb

@@ -14,8 +14,8 @@ module Sources
       #   data            : A blob (string) of the attachment's data
       #   tempfile        : A tempfile of the attachment
       class Base
-        class_inheritable_accessor :tempfile_path, :instance_writer => false
-        write_inheritable_attribute(:tempfile_path, File.join(RAILS_ROOT, 'tmp', 'attach'))
+        class_attribute :tempfile_path
+        self.tempfile_path = File.join(RAILS_ROOT, 'tmp', 'attach')
 
         attr_reader :error, :data
 
@@ -104,6 +104,17 @@ def change_image(&block)
           is.change_image(&block)
         end
 
+        def change_frame(i, &block)
+          is = self.is_a?(Sources::Rmagick) ? self : Sources::Rmagick.new(self)
+          is.change_frame(i, &block)
+        end
+
+        def frame_count
+          raise "Unable to process source" unless processable?
+          is = self.is_a?(Sources::Rmagick) ? self : Sources::Rmagick.new(self)
+          is.frame_count
+        end
+
         def valid?
           error.nil?
         end

lib/hapgood/attach/sources/blob.rb

@@ -5,6 +5,10 @@ module Attach # :nodoc:
     module Sources
       # Methods for blob sources
       class Blob < Hapgood::Attach::Sources::Base
+        def self.load(d, m={})
+          new(d, m)
+        end
+
         # Does this source persist at the URI independent of this application?
         def persistent?
           false

lib/hapgood/attach/sources/rmagick.rb

@@ -114,6 +114,32 @@ def change_image(&block)
           self
         end
 
+        # Method to get a particular frame.
+        def frame_image(fi)
+          @image ||= begin
+            format = self.class.format_for_mime_type(@source.mime_type)
+            read_spec = "#{@source.tempfile.path}[#{fi}]"
+            read_spec = "#{format}:" + read_spec if format
+            ::Magick::Image.read(read_spec).first
+          end
+        end
+
+        # Method to yield a particular frame.
+        # TODO: These methods should typically merge away with change_image methods above.
+        def change_frame(fi, &block)
+          yield frame_image(fi)
+          # TODO: Typical attach module dependencies. Always take care of these globals.
+          @tempfile = nil
+          @uri = nil # Once transformed, all external sources are invalid.
+          @blob = nil # Once transformed, we need to reset the data.  Now the getter can lazily load the blob.
+          @persistent = false
+          self
+        end
+
+        def frame_count
+          ::Magick::Image.read(@source.tempfile.path).length
+        end
+
         private
         # Extract useful information from (ExiF | IPTC) header, if possible.
         def exif_data