Add inline_svg_data_url helper to return SVG as base64 data URL

lib/inline_svg/action_view/helpers.rb

@@ -22,6 +22,15 @@ def inline_svg(filename, transform_params = {})
         render_inline_svg(filename, transform_params)
       end
 
+      def inline_svg_data_url(filename, transform_params = {})
+        svg = render_inline_svg(filename, transform_params)
+        svg = svg.sub(/<\?xml.*?\?>/, "").strip
+        svg = svg.gsub(/<!--.*?-->/m, "")
+        svg = svg.gsub(/\s+/, " ")
+        base64 = [svg].pack("m0")
+        "data:image/svg+xml;base64,#{base64}"
+      end
+
       private
 
       def render_inline_svg(filename, transform_params = {})

spec/helpers/inline_svg_spec.rb

@@ -263,4 +263,76 @@ def transform(doc)
   describe '#inline_svg_tag' do
     it_behaves_like "inline_svg helper", helper_method: :inline_svg_pack_tag
   end
+
+  describe '#inline_svg_data_url' do
+    let(:helper) { (Class.new { include InlineSvg::ActionView::Helpers }).new }
+
+    it 'returns a base64 data URL for a simple SVG' do
+      input_svg = '<svg xmlns="http://www.w3.org/2000/svg"></svg>'
+      allow(InlineSvg::AssetFile).to receive(:named).with('simple.svg').and_return(input_svg)
+      data_url = helper.inline_svg_data_url('simple.svg')
+      expect(data_url).to start_with('data:image/svg+xml;base64,')
+      decoded = data_url.sub('data:image/svg+xml;base64,', '').unpack1('m0')
+      expect(decoded).to include('<svg')
+      expect(decoded).to include('</svg>')
+    end
+
+    it 'removes XML declaration and minifies whitespace' do
+      input_svg = "<?xml version=\"1.0\"?><svg>   <rect/>  </svg>"
+      allow(InlineSvg::AssetFile).to receive(:named).with('xml.svg').and_return(input_svg)
+      data_url = helper.inline_svg_data_url('xml.svg')
+      decoded = data_url.sub('data:image/svg+xml;base64,', '').unpack1('m0')
+      expect(decoded).not_to include('<?xml')
+      expect(decoded).to eq('<svg> <rect></rect> </svg>')
+    end
+
+    it 'applies transformations' do
+      input_svg = '<svg></svg>'
+      allow(InlineSvg::AssetFile).to receive(:named).with('title.svg').and_return(input_svg)
+      data_url = helper.inline_svg_data_url('title.svg', title: 'Test Title')
+      decoded = data_url.sub('data:image/svg+xml;base64,', '').unpack1('m0')
+      expect(decoded).to include('<title>Test Title</title>')
+    end
+  end
+
+  it 'normalizes all whitespace (tabs, newlines, multiple spaces) to a single space' do
+    input_svg = "<svg>\n\t   <rect/>\n\t</svg>"
+    allow(InlineSvg::AssetFile).to receive(:named).with('whitespace.svg').and_return(input_svg)
+    data_url = helper.inline_svg_data_url('whitespace.svg')
+    decoded = data_url.sub('data:image/svg+xml;base64,', '').unpack1('m0')
+    expect(decoded).to eq('<svg> <rect></rect> </svg>')
+  end
+
+  it 'removes comments from SVG content' do
+    input_svg = '<svg><!-- comment --><rect/></svg>'
+    allow(InlineSvg::AssetFile).to receive(:named).with('comment.svg').and_return(input_svg)
+    data_url = helper.inline_svg_data_url('comment.svg')
+    decoded = data_url.sub('data:image/svg+xml;base64,', '').unpack1('m0')
+    expect(decoded).to include('<svg><rect></rect></svg>')
+    expect(decoded).not_to include('<!--')
+  end
+
+  it 'returns a base64 data URL for fallback SVG if original is missing' do
+    allow(InlineSvg::AssetFile).to receive(:named).with('missing.svg').and_raise(InlineSvg::AssetFile::FileNotFound.new)
+    fallback_svg = '<svg><rect/></svg>'
+    allow(InlineSvg::AssetFile).to receive(:named).with('fallback.svg').and_return(fallback_svg)
+    data_url = helper.inline_svg_data_url('missing.svg', fallback: 'fallback.svg')
+    decoded = data_url.sub('data:image/svg+xml;base64,', '').unpack1('m0')
+    expect(decoded).to include('<svg><rect></rect></svg>')
+  end
+
+  it 'returns a placeholder SVG as base64 data URL if file is missing and no fallback' do
+    allow(InlineSvg::AssetFile).to receive(:named).with('missing.svg').and_raise(InlineSvg::AssetFile::FileNotFound.new)
+    data_url = helper.inline_svg_data_url('missing.svg')
+    decoded = data_url.sub('data:image/svg+xml;base64,', '').unpack1('m0')
+    expect(decoded).to include('<svg></svg>')
+  end
+
+  it 'escapes malicious input in placeholder SVG as base64 data URL' do
+    malicious = "--></svg><script>alert(1)</script><svg>.svg"
+    allow(InlineSvg::AssetFile).to receive(:named).with(malicious).and_raise(InlineSvg::AssetFile::FileNotFound.new)
+    data_url = helper.inline_svg_data_url(malicious)
+    decoded = data_url.sub('data:image/svg+xml;base64,', '').unpack1('m0')
+    expect(decoded).to include('<svg></svg>')
+  end
 end