Class: EM::FastImage

Inherits:
Object
  • Object
show all
Includes:
Deferrable
Defined in:
lib/em-fastimage.rb

Defined Under Namespace

Modules: StreamUtil Classes: CannotParseImage, Exif, FastImageException, FiberStream, IOStream, ImageFetchFailure, MoreCharsNeeded, SizeNotFound, UnknownImageType

Constant Summary collapse

DefaultTimeout = 
2
LocalFileChunkSize = 
256

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(uri, options = {}) ⇒ FastImage

Returns a new instance of FastImage.



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# File 'lib/em-fastimage.rb', line 163

def initialize(uri, options={})
  @property = options[:type_only] ? :type : :size
  @timeout = options[:timeout] || DefaultTimeout
  @uri = uri

  if uri.respond_to?(:read)
    fetch_using_read(uri)
  else
    begin
      @parsed_uri = Addressable::URI.parse(uri)
    rescue Addressable::URI::InvalidURIError
      # fetch_using_open_uri
    else
      if @parsed_uri.scheme == "http" || @parsed_uri.scheme == "https"
        fetch_using_http
      else
        # fetch_using_open_uri
      end
    end
  end

  uri.rewind if uri.respond_to?(:rewind)

  raise SizeNotFound if options[:raise_on_failure] && @property == :size && !@size

rescue Timeout::Error, SocketError, Errno::ECONNREFUSED, Errno::EHOSTUNREACH, Errno::ECONNRESET,
  ImageFetchFailure, EOFError, Errno::ENOENT
  raise ImageFetchFailure if options[:raise_on_failure]
rescue NoMethodError  # 1.8.7p248 can raise this due to a net/http bug
  raise ImageFetchFailure if options[:raise_on_failure]
rescue UnknownImageType
  raise UnknownImageType if options[:raise_on_failure]
rescue CannotParseImage
  if options[:raise_on_failure]
    if @property == :size
      raise SizeNotFound
    else
      raise ImageFetchFailure
    end
  end

end

Instance Attribute Details

#bytes_read ⇒ Object (readonly)

Returns the value of attribute bytes_read.



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# File 'lib/em-fastimage.rb', line 55

def bytes_read
  @bytes_read
end

#size ⇒ Object (readonly)

Returns the value of attribute size.



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# File 'lib/em-fastimage.rb', line 53

def size
  @size
end

#type ⇒ Object (readonly)

Returns the value of attribute type.



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# File 'lib/em-fastimage.rb', line 53

def type
  @type
end

Class Method Details

.size(uri, options = {}) ⇒ Object

Returns an array containing the width and height of the image. It will return nil if the image could not be fetched, or if the image type was not recognised.

By default there is a timeout of 2 seconds for opening and reading from a remote server. This can be changed by passing a :timeout => number_of_seconds in the options.

If you wish FastImage to raise if it cannot size the image for any reason, then pass :raise_on_failure => true in the options.

FastImage knows about GIF, JPEG, BMP, TIFF, PNG and PSD files.

Example

require 'fastimage'

FastImage.size("http://stephensykes.com/images/ss.com_x.gif")
=> [266, 56]
FastImage.size("http://stephensykes.com/images/pngimage")
=> [16, 16]
FastImage.size("http://farm4.static.flickr.com/3023/3047236863_9dce98b836.jpg")
=> [500, 375]
FastImage.size("http://www-ece.rice.edu/~wakin/images/lena512.bmp")
=> [512, 512]
FastImage.size("test/fixtures/test.jpg")
=> [882, 470]
FastImage.size("http://pennysmalls.com/does_not_exist")
=> nil
FastImage.size("http://pennysmalls.com/does_not_exist", :raise_on_failure=>true)
=> raises FastImage::ImageFetchFailure
FastImage.size("http://stephensykes.com/favicon.ico", :raise_on_failure=>true)
=> raises FastImage::UnknownImageType
FastImage.size("http://stephensykes.com/favicon.ico", :raise_on_failure=>true, :timeout=>0.01)
=> raises FastImage::ImageFetchFailure
FastImage.size("http://stephensykes.com/images/faulty.jpg", :raise_on_failure=>true)
=> raises FastImage::SizeNotFound

Supported options

:timeout

Overrides the default timeout of 2 seconds. Applies both to reading from and opening the http connection.

:raise_on_failure

If set to true causes an exception to be raised if the image size cannot be found for any reason.



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# File 'lib/em-fastimage.rb', line 116

def self.size(uri, options={})
  (o = new(uri, options)).size
  o
end

.type(uri, options = {}) ⇒ Object

Returns an symbol indicating the image type fetched from a uri. It will return nil if the image could not be fetched, or if the image type was not recognised.

By default there is a timeout of 2 seconds for opening and reading from a remote server. This can be changed by passing a :timeout => number_of_seconds in the options.

If you wish FastImage to raise if it cannot find the type of the image for any reason, then pass :raise_on_failure => true in the options.

Example

require 'fastimage'

FastImage.type("http://stephensykes.com/images/ss.com_x.gif")
=> :gif
FastImage.type("http://stephensykes.com/images/pngimage")
=> :png
FastImage.type("http://farm4.static.flickr.com/3023/3047236863_9dce98b836.jpg")
=> :jpeg
FastImage.type("http://www-ece.rice.edu/~wakin/images/lena512.bmp")
=> :bmp
FastImage.type("test/fixtures/test.jpg")
=> :jpeg
FastImage.type("http://pennysmalls.com/does_not_exist")
=> nil
File.open("/some/local/file.gif", "r") {|io| FastImage.type(io)}
=> :gif
FastImage.type("test/fixtures/test.tiff")
=> :tiff
FastImage.type("test/fixtures/test.psd")
=> :psd

Supported options

:timeout

Overrides the default timeout of 2 seconds. Applies both to reading from and opening the http connection.

:raise_on_failure

If set to true causes an exception to be raised if the image type cannot be found for any reason.



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# File 'lib/em-fastimage.rb', line 159

def self.type(uri, options={})
  new(uri, options.merge(:type_only=>true)).type
end