Add support for Data Uri Scheme

lib/fastimage.rb

@@ -28,7 +28,7 @@
 # or referrer which some servers require. Pass an :http_header argument to specify headers,
 # e.g., :http_header => {'User-Agent' => 'Fake Browser'}.
 #
-# FastImage can give you information about the parsed display orientation of an image with Exif 
+# FastImage can give you information about the parsed display orientation of an image with Exif
 # data (jpeg or tiff).
 #
 # === Examples
@@ -59,6 +59,8 @@ require 'addressable/uri'
 require 'delegate'
 require 'pathname'
 require 'zlib'
+require 'base64'
+
 
 class FastImage
   attr_reader :size, :type, :content_length, :orientation
@@ -184,6 +186,8 @@ class FastImage
 
     if uri.respond_to?(:read)
       fetch_using_read(uri)
+    elsif uri.start_with?('data:')
+      fetch_using_base64(uri)
     else
       begin
         @parsed_uri = Addressable::URI.parse(uri)
@@ -351,7 +355,7 @@ class FastImage
         else
           @orientation = 1
         end
-        
+
         instance_variable_set("@#{@property}", result)
       else
         raise CannotParseImage
@@ -366,6 +370,11 @@ class FastImage
     send("parse_size_for_#{@type}")
   end
 
+  def fetch_using_base64(uri)
+    data = uri.split(',')[1]
+    fetch_using_read StringIO.new(Base64.decode64(data))
+  end
+
   module StreamUtil # :nodoc:
     def read_byte
       read(1)[0].ord
@@ -468,7 +477,7 @@ class FastImage
     when "<?"
       :svg if @stream.peek(100).include?("<svg")
     end
-    
+
     parsed_type or raise UnknownImageType
   end
 
@@ -644,7 +653,7 @@ class FastImage
       end
 
       parse_exif_ifd
-      
+
       @orientation ||= 1
     end
 

test/test.rb

@@ -56,6 +56,9 @@ LargeImageFetchLimit = 2  # seconds
 HTTPSImage = "https://upload.wikimedia.org/wikipedia/commons/b/b4/Mardin_1350660_1350692_33_images.jpg"
 HTTPSImageInfo = [:jpeg, [9545, 6623]]
 
+DataUriImage = "data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAIAAAABCAYAAAD0In+KAAAAD0lEQVR42mNk+M9QzwAEAAmGAYCF+yOnAAAAAElFTkSuQmCC"
+DataUriImageInfo = [:png, [2, 1]]
+
 GoodFixtures.each do |fn, info|
   FakeWeb.register_uri(:get, "#{TestUrl}#{fn}", :body => File.join(FixturePath, fn))
 end
@@ -358,11 +361,19 @@ class FastImageTest < Test::Unit::TestCase
     url = "#{TestUrl}test.gif"
     assert_equal 1, FastImage.new(url).orientation
   end
-  
+
   def test_should_raise_when_handling_invalid_ico_files
     stringio = StringIO.new("\x00\x00003")
     assert_raises(FastImage::UnknownImageType) do
       FastImage.type(stringio, :raise_on_failure => true)
     end
   end
+
+  def test_should_support_data_uri_scheme_images
+    assert_equal DataUriImageInfo[0], FastImage.type(DataUriImage)
+    assert_equal DataUriImageInfo[1], FastImage.size(DataUriImage)
+    assert_raises(FastImage::ImageFetchFailure) do
+      FastImage.type("data:", :raise_on_failure => true)
+    end
+  end
 end