fix thumbnail generation

app/workers/thumbnail_generate_worker.rb

@@ -4,15 +4,20 @@ require 'screencap'
 class ThumbnailGenerateWorker
   include Sidekiq::Worker
 
-  def perform(attachment_id, media_path = nil)
+  def perform(attachment_id, media_path = nil, force = false)
     attachment = ::LearningObject::Attachment.find(attachment_id)
-    return false if attachment.nil?
-
-    media = media_path.nil? ? bitstream_download(attachment.id_dspace) : create_media(media_path)
-
-    thumbnail = thumbnail_service.create_thumbnail(media) unless media.blank?
-
-    attachment.update(thumbnail: thumbnail) unless thumbnail.blank?
+    return false if attachment.nil? || (!attachment.thumbnail.blank? && !force)
+
+    # object from dspace
+    if media_path.nil?
+      media = bitstream_download(attachment.id_dspace)
+      create_thumbnail(media, attachment)
+      File.unlink(media) if File.exist?(media.path)
+    # new object
+    else
+      create_media(media_path, attachment)
+      create_thumbnail(media)
+    end
   end
 
   private
@@ -22,6 +27,14 @@ class ThumbnailGenerateWorker
     File.open path
   end
 
+  def create_thumbnail(media, attachment)
+    thumbnail = thumbnail_service.create_thumbnail(media)
+    return false if thumbnail.blank?
+
+    attachment.update(thumbnail: thumbnail)
+    File.unlink(thumbnail) if File.exist?(thumbnail.path)
+  end
+
   def bitstream_download(id)
     client = DspaceService.create_client
     client.bitstreams.retrieve(id: id).open

lib/tasks/thumbnail.rake

 require 'rainbow'
 
 namespace :thumbnail do
-  desc "Portal MEC thumnail task"
-
+  desc 'Create thumbnail to every learning object without one'
   task :create_missing, [:log] => [:environment] do |t, args|
-    desc "Create thumbnail to all learning objects"
     include Log::Logging
 
     args.with_defaults(:log => STDOUT)
@@ -12,10 +10,10 @@ namespace :thumbnail do
     Log::Logging.logger = Log::DatabaseLogger.new(args.log)
     logger.level = Log::DatabaseLogger::CREATE
 
-    logger.info " --> Creating thumbnails"
+    logger.info ' --> Creating thumbnails'
 
     LearningObject.missing_thumbnail.find_each do |object|
-      ThumbnailGenerateWorker.perform_async(object.attachments.first.id) unless object.attachments.blank?
+      object.attachments.where(bundle_name: 'ORIGINAL').find_each { |a| ThumbnailGenerateWorker.perform_async(a.id) } unless object.attachments.blank?
     end
 
     logger.close

lib/thumbnail/generatable_strategy.rb

@@ -15,7 +15,11 @@ module Thumbnail
     ##
     # Checks if the strategy can generate a thumbnail of that +media+
     def can_generate?(media)
-      raise NotImplementedError
+      if File == media.class
+        mime = MimeMagic.by_magic(media)
+        return mime.type.include? yield unless mime.blank?
+      end
+      false
     end
 
   end

lib/thumbnail/strategies/image_thumbnail_generator.rb

@@ -7,10 +7,9 @@ module Thumbnail
       end
 
       def can_generate?(media)
-        return MimeMagic.by_magic(media).type.include? "image"  if File == media.class
-        false
+        super { 'image' }
       end
 
     end
   end
-end
\ No newline at end of file
+end

lib/thumbnail/strategies/pdf_thumbnail_generator.rb

@@ -11,8 +11,7 @@ module Thumbnail
       end
 
       def can_generate?(media)
-        return MimeMagic.by_magic(media).type.include? "pdf" if File == media.class
-        false
+        super { 'pdf' }
       end
 
       private
@@ -24,4 +23,4 @@ module Thumbnail
 
     end
   end
-end
\ No newline at end of file
+end

lib/thumbnail/strategies/url_thumbnail_generator.rb

@@ -17,4 +17,4 @@ module Thumbnail
 
     end
   end
-end
\ No newline at end of file
+end

lib/thumbnail/strategies/video_thumbnail_generator.rb

@@ -21,8 +21,7 @@ module Thumbnail
       end
 
       def can_generate?(media)
-        return MimeMagic.by_magic(media).type.include? "video"  if File == media.class
-        false
+        super { 'video' }
       end
       private