From 5b951f012e04e6ef97e4ef645d53bdf433a9eb7f Mon Sep 17 00:00:00 2001
From: erdgeist <erdgeist@erdgeist.org>
Date: Tue, 21 Jul 2026 21:02:16 +0200
Subject: Implement model side of PDF raster preview generation

---
 app/models/concerns/file_attachment.rb     | 24 ++++++++++++++++++------
 lib/tasks/assets.rake                      |  6 ++++--
 test/controllers/assets_controller_test.rb | 16 ++++++----------
 3 files changed, 28 insertions(+), 18 deletions(-)

diff --git a/app/models/concerns/file_attachment.rb b/app/models/concerns/file_attachment.rb
index 548531f..6221312 100644
--- a/app/models/concerns/file_attachment.rb
+++ b/app/models/concerns/file_attachment.rb
@@ -31,6 +31,7 @@ module FileAttachment
 
   IMAGE_CONTENT_TYPES    = %w[image/jpeg image/gif image/png image/webp].freeze
   VECTOR_CONTENT_TYPES   = %w[image/svg+xml].freeze
+  RASTERIZED_CONTENT_TYPES = %w[application/pdf].freeze
   DISPLAYABLE_AS_IMAGE   = IMAGE_CONTENT_TYPES + VECTOR_CONTENT_TYPES
 
   included do
@@ -60,6 +61,11 @@ module FileAttachment
     has_variant?(:medium)
   end
 
+  def variant_filename(style)
+    return upload_file_name if style == :original || !RASTERIZED_CONTENT_TYPES.include?(upload_content_type)
+    File.basename(upload_file_name, ".*") + ".png"
+  end
+
   private
 
   def build_upload_proxy
@@ -89,11 +95,7 @@ module FileAttachment
     FileUtils.mkdir_p(File.dirname(original_path))
     FileUtils.cp(uploaded_file.tempfile.path, original_path)
 
-    if IMAGE_CONTENT_TYPES.include?(upload_content_type)
-      generate_variants(original_path)
-    elsif VECTOR_CONTENT_TYPES.include?(upload_content_type)
-      generate_svg_variants(original_path)
-    end
+    generate_all_variants(original_path)
   end
 
   def generate_variants(original_path)
@@ -112,6 +114,16 @@ module FileAttachment
     end
   end
 
+  def generate_all_variants(original_path)
+    if IMAGE_CONTENT_TYPES.include?(upload_content_type)
+      generate_variants(original_path)
+    elsif VECTOR_CONTENT_TYPES.include?(upload_content_type)
+      generate_svg_variants(original_path)
+    elsif RASTERIZED_CONTENT_TYPES.include?(upload_content_type)
+      generate_variants("#{original_path}[0]")
+    end
+  end
+
   def delete_upload_files
     dir = upload_root.join(id.to_s)
     FileUtils.rm_rf(dir) if Dir.exist?(dir)
@@ -135,7 +147,7 @@ module FileAttachment
 
     def url(style = :original)
       return "" if @record.upload_file_name.blank?
-      "/system/uploads/#{@record.id}/#{style}/#{@record.upload_file_name}"
+      "/system/uploads/#{@record.id}/#{style}/#{@record.variant_filename(style)}"
     end
 
     def content_type
diff --git a/lib/tasks/assets.rake b/lib/tasks/assets.rake
index 9d4b048..e778021 100644
--- a/lib/tasks/assets.rake
+++ b/lib/tasks/assets.rake
@@ -1,7 +1,9 @@
 namespace :assets do
   desc "Regenerate ImageMagick variants for every image asset from its stored original -- rerun whenever a new style is added to FileAttachment::STYLES after assets already exist. Scope to one asset first with ASSET_ID=123."
   task :regenerate_variants => :environment do
-    scope = Asset.images
+    scope = Asset.where(upload_content_type: FileAttachment::IMAGE_CONTENT_TYPES +
+                                              FileAttachment::VECTOR_CONTENT_TYPES +
+                                              FileAttachment::RASTERIZED_CONTENT_TYPES)
     scope = scope.where(id: ENV["ASSET_ID"]) if ENV["ASSET_ID"].present?
 
     scope.find_each do |asset|
@@ -12,7 +14,7 @@ namespace :assets do
         next
       end
 
-      asset.send(:generate_variants, original_path)
+      asset.send(:generate_all_variants, original_path)
       puts "Regenerated variants for Asset##{asset.id} (#{asset.name})"
     end
   end
diff --git a/test/controllers/assets_controller_test.rb b/test/controllers/assets_controller_test.rb
index 59ebab5..f834541 100644
--- a/test/controllers/assets_controller_test.rb
+++ b/test/controllers/assets_controller_test.rb
@@ -70,7 +70,7 @@ class AssetsControllerTest < ActionController::TestCase
 
   # --- create with PDF ---
 
-  test "create asset with PDF upload generates only original" do
+  test "create asset with PDF upload generates rasterized variants" do
     uploaded = Rack::Test::UploadedFile.new(
       Rails.root.join('test', 'fixtures', 'files', 'test_document.pdf'),
       'application/pdf'
@@ -81,18 +81,14 @@ class AssetsControllerTest < ActionController::TestCase
     assert_response :redirect
 
     asset = Asset.last
-    assert_equal 'test_document.pdf', asset.upload_file_name
-    assert_equal 'application/pdf',   asset.upload_content_type
-
-    # only original should exist, no image variants
-    original_path = Rails.root.join('public', 'system', 'uploads',
-                                    asset.id.to_s, 'original', 'test_document.pdf')
+    original_path = asset.send(:file_path, :original)
     assert File.exist?(original_path), "Expected original at #{original_path}"
+    assert_equal 'test_document.pdf', File.basename(original_path)
 
     %w[medium thumb headline large].each do |style|
-      path = Rails.root.join('public', 'system', 'uploads',
-                             asset.id.to_s, style, 'test_document.pdf')
-      assert !File.exist?(path), "Expected no #{style} variant for PDF"
+      path = asset.send(:file_path, style)
+      assert File.exist?(path), "Expected a #{style} variant at #{path}"
+      assert_equal '.png', File.extname(path), "Expected #{style} variant to be a PNG, not a PDF"
     end
   end
 
-- 
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