Class: FastImage

Inherits:
Object
  • Object
show all
Defined in:
lib/fastimage.rb

Defined Under Namespace

Modules: StreamUtil Classes: CannotParseImage, Exif, FastImageException, FiberStream, IOStream, ImageFetchFailure, 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/fastimage.rb', line 182

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 = self.class.parse_uri(uri)
    rescue 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, Net::HTTPBadResponse, 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/fastimage.rb', line 53

def bytes_read
  @bytes_read
end

#size ⇒ Object (readonly)

Returns the value of attribute size.



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# File 'lib/fastimage.rb', line 51

def size
  @size
end

#type ⇒ Object (readonly)

Returns the value of attribute type.



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# File 'lib/fastimage.rb', line 51

def type
  @type
end

Class Method Details

.parse_uri(location) ⇒ Object 



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# File 'lib/fastimage.rb', line 88

def self.parse_uri(location)
  (@uri_parser || URI).parse(location)
end

.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, ICO, CUR, PNG, PSD and WEBP 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)
=> [16, 16]
FastImage.size("http://stephensykes.com/images/squareBlue.icns", :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/fastimage.rb', line 136

def self.size(uri, options={})
  new(uri, options).size
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://stephensykes.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/fastimage.rb', line 178

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

.uri_parser=(parser) ⇒ Object

Parser object should respond to #parse and raise a URI::InvalidURIError if something goes wrong



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# File 'lib/fastimage.rb', line 72

def self.uri_parser=(parser)
  @uri_parser = parser
end

.use_addressable_uri_parser ⇒ Object

Helper that sets URI parsing to use the Addressable gem



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# File 'lib/fastimage.rb', line 77

def self.use_addressable_uri_parser
  require 'addressable/uri'
  self.uri_parser = Class.new do
    def self.parse(location)
      Addressable::URI.parse(location)
    rescue Addressable::URI::InvalidURIError
      raise URI::InvalidURIError
    end
  end
end