Paperclip processors allow you to modify attached files when they are attached in any way you are able. Paperclip itself uses command-line programs for its included Thumbnail processor, but custom processors are not required to follow suit.
Processors are required to be defined inside the Paperclip module and are also required to be a subclass of Paperclip::Processor. There is only one method you must implement to properly be a subclass: make, but initialize may also be of use. Both methods accept 3 arguments: the file that will be operated on (which is an instance of File), a hash of options that were defined in has_attached_file’s style hash, and the Paperclip::Attachment itself.
All make needs to return is an instance of File (Tempfile is acceptable) which contains the results of the processing.
See Paperclip.run for more information about using command-line utilities from within Processors.
# File lib/paperclip/processor.rb, line 32 def self.make file, options = {}, attachment = nil new(file, options, attachment).make end
# File lib/paperclip/processor.rb, line 23 def initialize file, options = {}, attachment = nil @file = file @options = options @attachment = attachment end
The convert method runs the convert binary with the provided arguments. See Paperclip.run for the available options.
# File lib/paperclip/processor.rb, line 38 def convert(arguments = "", local_options = {}) Paperclip.run('convert', arguments, local_options) end
The identify method runs the identify binary with the provided arguments. See Paperclip.run for the available options.
# File lib/paperclip/processor.rb, line 44 def identify(arguments = "", local_options = {}) Paperclip.run('identify', arguments, local_options) end
# File lib/paperclip/processor.rb, line 29 def make end