Class: Thingfish::Processor::Image

Inherits:
Thingfish::Processor
  • Object
show all
Extended by:
Configurability, Loggability, Strelka::MethodUtilities
Defined in:
lib/thingfish/processor/image.rb

Overview

Image processor plugin for Thingfish

Defined Under Namespace

Classes: MagickOperations

Constant Summary collapse

VERSION =

Package version

'0.1.1'
REVISION =

Version control revision

%q$Revision: c3964930bd4f $
CONFIG_DEFAULTS =

The default dimensions of thumbnails

{
	thumbnail_dimensions: '100x100',
}
IGNORED_MIMETYPES =

An array of mediatypes to ignore, even though ImageMagick claims it groks them

%w[
	application/octet-stream
	text/html
	text/plain
	text/x-server-parsed-html
]

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize ⇒ Image

Set up a new Filter object



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# File 'lib/thingfish/processor/image.rb', line 69

def initialize( * ) # :notnew:
	super

	@supported_formats = find_supported_formats()
	@handled_types     = find_handled_types( @supported_formats )
	@generated_types   = find_generated_types( @supported_formats )
end

Instance Attribute Details

#generated_types ⇒ Object (readonly)

The mediatypes the plugin can generated in a response, as ThingFish::AcceptParam objects



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# File 'lib/thingfish/processor/image.rb', line 91

def generated_types
  @generated_types
end

#handled_types ⇒ Object (readonly)

The mediatypes the plugin accepts in a request, as ThingFish::AcceptParam objects



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# File 'lib/thingfish/processor/image.rb', line 87

def handled_types
  @handled_types
end

#supported_formats ⇒ Object (readonly)

The Hash of formats and the operations they support.



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# File 'lib/thingfish/processor/image.rb', line 83

def supported_formats
  @supported_formats
end

Class Method Details

.configure(config = nil) ⇒ Object

Configurability API – configure the processor with the :images section of the config.



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# File 'lib/thingfish/processor/image.rb', line 56

def self::configure( config=nil )
	config = self.defaults.merge( config || {} )

	self.thumbnail_dimensions = config[:thumbnail_dimensions].split('x', 2).map( &:to_i )
end

Instance Method Details

#handled_type?(type) ⇒ Boolean Also known as: is_handled_type?

Returns true if the given media type is one the processor handles. Overridden so the types can be used by the instance.

Returns:

  • (Boolean) 


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# File 'lib/thingfish/processor/image.rb', line 96

def handled_type?( type )
	self.log.debug "Looking for handled type for: %p" % [ type ]
	result = self.handled_types.find {|handled_type| type =~ handled_type }
	self.log.debug "  found: %p" % [ result ]
	return result
end

#inspect ⇒ Object

Return a human-readable representation of the receiving object suitable for debugging.



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# File 'lib/thingfish/processor/image.rb', line 145

def inspect
	return "#<%p:%#x %d supported image formats, %d readable, %d writable>" % [
		self.class,
		self.object_id * 2,
		self.supported_formats.size,
		self.handled_types.size,
		self.generated_types.size,
	]
end

#on_request(request) ⇒ Object

Synchronous processor API – extract metadata from uploaded images.



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# File 'lib/thingfish/processor/image.rb', line 106

def on_request( request )
	self.log.debug "Image-processing %p" % [ request ]
	image = case request.body
			when StringIO
				self.log.debug "  making a single image from a StringIO"
				Magick::Image.from_blob( request.body.read )
			else
				path = request.body.path
				self.log.debug "  making a flattened image out of %p" % [ path ]
				path = path.to_s + '[0]' # ImageMagick, read a single frame
				list = Magick::ImageList.new( path )
				list.flatten_images
			end

	image = image.first if image.respond_to?( :first )
	self.log.debug "  image is: %p" % [ image ]
	metadata = self.extract_image_metadata( image )
	self.log.debug "  extracted image metadata: %p" % [ metadata ]
	request.add_metadata( metadata )

	self.log.debug "  going to generate a thumbnail..."
	self.generate_thumbnail( image, metadata['title'] ) do |thumbio, thumb_metadata|
		self.log.debug "  generated: %p (%p)" % [ thumbio, thumb_metadata ]
		request.add_related_resource( thumbio, thumb_metadata )
	end

	self.log.debug "  destroying the image to free up memory"

rescue Magick::ImageMagickError => err
	self.log.error "Problem while processing file %p: %s" % [ err.class, err.message ]
	self.log.debug { err.backtrace.join( "\n  " ) }

ensure
	image.destroy! if image
end

#thumbnail_dimensions ⇒ Object

The (maximum) dimensions of generated thumbnails



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# File 'lib/thingfish/processor/image.rb', line 50

singleton_attr_accessor :thumbnail_dimensions