Merge pull request #159 from delphaber/fix-html-with-inline-svg-detection

sdsykes · web-flow · commit 6b0c533e218a · 2026-03-07T14:06:33.000+02:00
Fix HTML with inline SVG being incorrectly detected as SVG
diff --git a/lib/fastimage/fastimage_parsing/type_parser.rb b/lib/fastimage/fastimage_parsing/type_parser.rb
@@ -57,7 +57,12 @@ def type
         # unknown. We assume the <svg tag cannot be within 10 chars of the end of
         # the file, and is within the first 1000 chars.
         begin
-          :svg if (1..100).detect {|n| @stream.peek(10 * n).include?("<svg")}
+          :svg if (1..100).any? { |n|
+            peeked = @stream.peek(10 * n)
+            svg_index = peeked.index("<svg")
+            html_index = peeked.index(/<html/i)
+            svg_index && (!html_index || svg_index < html_index)
+          }
         rescue FiberError, FastImage::CannotParseImage
           nil
         end
diff --git a/test/fixtures/test8.html b/test/fixtures/test8.html
@@ -0,0 +1,7 @@
+<!DOCTYPE html>
+<html lang="en">
+<head><title>Test</title></head>
+<body>
+  <svg viewBox="0 0 100 100"><rect width="50" height="50"/></svg>
+</body>
+</html>
diff --git a/test/test.rb b/test/test.rb
@@ -189,6 +189,12 @@ def test_should_raise_image_fetch_failure_error_if_net_unreach_exception_happens
     end
   end
 
+  def test_should_raise_unknown_image_type_when_file_is_html_with_inline_svg
+    assert_raises(FastImage::UnknownImageType) do
+      FastImage.size(File.join(FixturePath, "test8.html"), :raise_on_failure=>true)
+    end
+  end
+
   def test_should_raise_unknown_image_type_when_file_is_non_svg_xml
     ["test.xml", "test2.xml"].each do |fn|
       assert_raises(FastImage::UnknownImageType) do
