Merge pull request #127 from ruby-no-kai/stop-enlarge-event-assets

PushEventAssetFileJob: avoid enlarging small images

Author: sorah

Dockerfile

@@ -74,7 +74,7 @@ RUN --mount=type=cache,target=/var/cache/apt,sharing=locked --mount=type=cache,t
  && rm -rf /var/lib/apt/lists/*
 
 COPY --from=vipsbuilder /opt/libvips /opt/libvips
-RUN ln -s /opt/libvips/bin/vipsthumbnail /usr/local/bin/vipsthumbnail \
+RUN for f in /opt/libvips/bin/vips*; do ln -s "$f" /usr/local/bin/; done \
  && echo /opt/libvips/lib > /etc/ld.so.conf.d/libvips.conf && ldconfig \
  && vipsthumbnail --vips-version
 

app/jobs/push_event_asset_file_job.rb

@@ -48,10 +48,12 @@ def convert_to_webp(asset_file)
       asset_file.get_object(response_target: f)
     end
 
+    thumbnail_size = thumbnail_size_for(input_path)
+
     _stdout, stderr, status = Open3.capture3(
       { 'VIPS_BLOCK_UNTRUSTED' => '1' },
       'vipsthumbnail', input_path.to_s,
-      '-s', '800',
+      '-s', thumbnail_size,
       '-o', output_path.to_s + '[Q=72,preset=drawing,smart_subsample=true,effort=6,strip=true]'
     )
     raise "vipsthumbnail failed (status=#{status.exitstatus}): #{stderr}" unless status.success?
@@ -61,6 +63,23 @@ def convert_to_webp(asset_file)
     content
   end
 
+  THUMBNAIL_MAX_SIZE = 800
+
+  # Avoid enlarging images smaller than THUMBNAIL_MAX_SIZE
+  def thumbnail_size_for(input_path)
+    stdout, _, status = Open3.capture3(
+      { 'VIPS_BLOCK_UNTRUSTED' => '1' },
+      'vipsheader', '-f', 'width', input_path.to_s
+    )
+    if status.success?
+      input_width = stdout.strip.to_i
+      if input_width > 0 && input_width < THUMBNAIL_MAX_SIZE
+        return input_width.to_s
+      end
+    end
+    THUMBNAIL_MAX_SIZE.to_s
+  end
+
   def push_to_github(gi, repo, asset_file, webp_content)
     octokit = gi.octokit
     images_path = @conference.github_repo_images_path.chomp('/')

spec/jobs/push_event_asset_file_job_spec.rb

@@ -118,6 +118,24 @@
       expect(Dir.exist?(tmpdir)).to be false
     end
 
+    it 'does not enlarge images smaller than 800px' do
+      allow(Open3).to receive(:capture3).and_call_original
+
+      vipsthumbnail_calls = []
+      allow(Open3).to receive(:capture3).and_wrap_original do |original, *args, **kwargs|
+        env, cmd, *rest = args
+        vipsthumbnail_calls << rest if cmd == 'vipsthumbnail'
+        original.call(*args, **kwargs)
+      end
+
+      described_class.perform_now(editing_history)
+
+      # test_image.png is 8x8 — size should be capped at input width
+      expect(vipsthumbnail_calls.length).to eq(1)
+      size_index = vipsthumbnail_calls.first.index('-s')
+      expect(vipsthumbnail_calls.first[size_index + 1]).to eq('8')
+    end
+
     it 'raises on vipsthumbnail failure' do
       allow(Open3).to receive(:capture3).and_return(['', 'error message', double(success?: false, exitstatus: 1)])
       expect { described_class.perform_now(editing_history) }.to raise_error(/vipsthumbnail failed/)