Add Thumbnail Module to handle Thumbnail Creation

lib/thumbnail/creation.rb

+module Thumbnail
+  module Creation
+
+    include Formats
+
+    def generate_thumbnail(input, filename, size)
+      unless accepted_formats.include? File.extname(filename)
+        return default_thumbnail
+      else
+        thumbnail = thumbnail_path(filename, size)
+        output = "#{root_dir}#{thumbnail}"
+        begin
+          if accepted_video_formats.include? File.extname(input)
+            generate_video_thumbnail(input, output, size)
+          else
+            generate_image_thumbnail(input, output, size)
+          end
+        rescue
+          return default_thumbnail
+        else
+          return thumbnail
+        end
+      end
+
+    end
+
+    private
+
+    def generate_video_thumbnail(input,output,size)
+      movie = FFMPEG::Movie.new(input)
+      frame = (movie.duration * 25/100).floor
+      movie.screenshot(output,
+                        { seek_time: frame, resolution: size },
+                        preserve_aspect_ratio: :width)
+    end
+
+    def generate_image_thumbnail(input,output,size)
+      # Read the image and resize it. The `change_geometry' method
+      # computes the new image geometry and yields to a block. The
+      # return value of the block is the return value of the method.
+      img = Magick::Image.read(input)[0]
+      img.change_geometry!(size) { |cols, rows| img.thumbnail! cols, rows }
+      img.write(output)
+    end
+
+    def encode_hash_from(object)
+      Digest::SHA1.hexdigest object
+    end
+
+    def thumbnail_path(filename, size)
+      thumbnail_name = encode_hash_from filename
+      thumbnail_path = "#{thumbnails_dir}/#{thumbnail_name}_#{size}.jpg"
+    end
+
+    def default_thumbnail
+      @default_thumbnail ||= "#{thumbnails_dir}/default_thumbnail.jpg"
+    end
+
+    def thumbnails_dir
+      @thumbnails_dir ||= "/thumbnails"
+    end
+
+    def root_dir
+      @root_dir ||= Rails.root.join('public')
+    end
+
+  end
+end

lib/thumbnail/formats.rb

+module Thumbnail
+  module Formats
+
+    def accepted_video_formats
+      lower = [".mp4", ".wmv", ".3gp", ".asf", ".avi", ".flv", ".mov", ".mpg", ".mpeg", ".rmvb", ".vob", ".webm"]
+      upper = [".MP4", ".WMV", ".3GP", ".ASF", ".AVI", ".FLV", ".MOV", ".MPG", ".MPEG", ".RMVB", ".VOB", ".WEBM"]
+      return lower + upper
+    end
+
+    def accepted_image_formats
+      lower = [".jpg", ".jpeg", ".gif", ".png", ".bmp", ".tif"]
+      upper = [".JPG", ".JPEG", ".GIF", ".PNG", ".BMP", ".TIF"]
+      return lower + upper
+    end
+
+    def accepted_other_formats
+      lower = [".pdf", ".pps"]
+      upper = [".PDF", ".PPS"]
+      return lower + upper
+    end
+
+    def accepted_formats
+      return accepted_video_formats + accepted_image_formats + accepted_other_formats
+    end
+
+  end
+end