Remove Ghostscript and PDF thumb generation.

.github/workflows/cucumber.yml

@@ -17,12 +17,10 @@ jobs:
       - name: Setup Redis
         uses: alphagov/govuk-infrastructure/.github/actions/setup-redis@main
 
-      - name: Install additional system dependencies
-        run: |
-          sudo apt-get update
-          sudo apt-get install -y --no-install-recommends ghostscript
       - name: Checkout repository
         uses: actions/checkout@v4
+        with:
+          show-progress: false
 
       - name: Setup Ruby
         uses: ruby/setup-ruby@v1

.github/workflows/minitest.yml

@@ -29,23 +29,20 @@ jobs:
       - name: Setup Redis
         uses: alphagov/govuk-infrastructure/.github/actions/setup-redis@main
 
-      - name: Install additional system dependencies
-        run: |
-          sudo apt-get update
-          sudo apt-get install -y --no-install-recommends ghostscript
-
       - name: Checkout repository
         uses: actions/checkout@v4
         with:
           repository: alphagov/whitehall
           ref: ${{ inputs.ref || github.ref }}
+          show-progress: false
 
       - name: Checkout Publishing API (for Content Schemas)
         uses: actions/checkout@v4
         with:
           repository: alphagov/publishing-api
           ref: ${{ inputs.publishingApiRef }}
           path: vendor/publishing-api
+          show-progress: false
 
       - name: Setup Ruby
         uses: ruby/setup-ruby@v1
@@ -80,4 +77,3 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - run: echo "All MiniTest tests have passed 🚀"
-

Dockerfile

@@ -18,7 +18,7 @@ RUN rails assets:precompile && rm -fr log
 
 
 FROM --platform=$TARGETPLATFORM $base_image
-RUN install_packages ghostscript imagemagick unzip zip
+RUN install_packages imagemagick unzip zip
 
 ENV GOVUK_APP_NAME=whitehall
 

app/helpers/attachments_helper.rb

@@ -42,7 +42,7 @@ def attachment_component_params(attachment, alternative_format_contact_email: ni
       params[:file_size] = attachment.file_size
     end
 
-    # PDF attachments get a thumbnail
+    # PDF attachments used to have a thumbnail, now just a generic icon.
     if attachment.pdf?
       params[:thumbnail_url] = attachment.file.thumbnail.url
       params[:number_of_pages] = attachment.number_of_pages

app/uploaders/attachment_uploader.rb

@@ -39,44 +39,13 @@ def set_correct_content_type(_ignore_argument)
   end
 
   def generate_thumbnail
-    get_first_page_as_png(105, 140)
+    FileUtils.cp(FALLBACK_PDF_THUMBNAIL, path)
   end
 
   def pdf?(file)
     file.content_type == PDF_CONTENT_TYPE
   end
 
-  def get_first_page_as_png(width, height)
-    output, exit_status = Timeout.timeout(THUMBNAIL_GENERATION_TIMEOUT) do
-      [
-        `#{pdf_thumbnail_command(width, height)}`,
-        $CHILD_STATUS.exitstatus,
-      ]
-    end
-
-    unless exit_status.zero?
-      Rails.logger.warn "Error thumbnailing PDF. Exit status: #{exit_status}; Output: #{output}"
-      use_fallback_pdf_thumbnail
-    end
-  rescue Timeout::Error => e
-    message = "PDF thumbnail generation took longer than #{THUMBNAIL_GENERATION_TIMEOUT} seconds. Using fallback pdf thumbnail: #{FALLBACK_PDF_THUMBNAIL}."
-    Rails.logger.warn message
-
-    GovukError.notify(
-      e,
-      extra: {
-        error_message: message,
-        path: relative_path,
-      },
-    )
-
-    use_fallback_pdf_thumbnail
-  end
-
-  def pdf_thumbnail_command(width, height)
-    %(gs -o #{path} -sDEVICE=pngalpha -dLastPage=1 -r72 -dDEVICEWIDTHPOINTS=#{width} -dDEVICEHEIGHTPOINTS=#{height} -dPDFFitPage -dUseCropBox #{path} 2>&1)
-  end
-
   def extension_allowlist
     EXTENSION_ALLOW_LIST
   end
@@ -240,10 +209,4 @@ def validate_zipfile_contents!(new_file)
     problem = examiners.detect { |examiner| !examiner.valid? }
     raise CarrierWave::IntegrityError, problem.failure_message if problem
   end
-
-private
-
-  def use_fallback_pdf_thumbnail
-    FileUtils.cp(FALLBACK_PDF_THUMBNAIL, path)
-  end
 end

config/brakeman.ignore

@@ -168,29 +168,6 @@
       ],
       "note": ""
     },
-    {
-      "warning_type": "Command Injection",
-      "warning_code": 14,
-      "fingerprint": "82dea23cb472eca9cd5c4217767e59cab37e956a57572095a7f225d47aff2db8",
-      "check_name": "Execute",
-      "message": "Possible command injection",
-      "file": "app/uploaders/attachment_uploader.rb",
-      "line": 54,
-      "link": "https://brakemanscanner.org/docs/warning_types/command_injection/",
-      "code": "`#{pdf_thumbnail_command(width, height)}`",
-      "render_path": null,
-      "location": {
-        "type": "method",
-        "class": "AttachmentUploader",
-        "method": "get_first_page_as_png"
-      },
-      "user_input": "pdf_thumbnail_command(width, height)",
-      "confidence": "Medium",
-      "cwe_id": [
-        77
-      ],
-      "note": ""
-    },
     {
       "warning_type": "Command Injection",
       "warning_code": 14,

docs/assets.md

@@ -134,11 +134,6 @@ that manage the successes and failures of the file uploads.
 > Whitehall creates up to 7 image sizes of each uploaded image. Urls to these images are published as part of the content
 > so that rendering applications can then show the best image size for the use case. 
 
-#### *Members of the public* want to see a thumbnail of pdfs where an embedded link to the pdf is provided
-
-> Whitehall generates thumbnails for pdf file attachments. Urls to both the pdf and its thumbnail are 
-> published as part of the content and then used by the rendering applications.
-
 #### *Members of the public* should see document content with working image and attachment urls
 
 > For *Editionable Content* types, such as **News Articles** or **Publication** - Publishing is prevented for documents

test/unit/app/uploaders/attachment_uploader_test.rb

@@ -227,25 +227,7 @@ class AttachmentUploaderPDFTest < ActiveSupport::TestCase
     AssetManagerCreateAssetWorker.drain
   end
 
-  test "should scale the thumbnail down proportionally to A4" do
-    AttachmentData.create!(file: file_fixture("two-pages-with-content.pdf"), attachable: @edition)
-
-    expect_thumbnail_sent_to_asset_manager_to_be_scaled_proportionally
-
-    AssetManagerCreateAssetWorker.drain
-  end
-
-  test "should use a generic thumbnail if conversion fails" do
-    AttachmentUploader.any_instance.stubs(:pdf_thumbnail_command).returns("false")
-    AttachmentData.create!(file: file_fixture("two-pages-with-content.pdf"), attachable: @edition)
-
-    expect_fallback_thumbnail_to_be_uploaded_to_asset_manager
-
-    AssetManagerCreateAssetWorker.drain
-  end
-
-  test "should use a generic thumbnail if conversion takes longer than 10 seconds to complete" do
-    AttachmentUploader.any_instance.stubs(:pdf_thumbnail_command).raises(Timeout::Error)
+  test "should always use the generic thumbnail for PDFs" do
     AttachmentData.create!(file: file_fixture("two-pages-with-content.pdf"), attachable: @edition)
 
     expect_fallback_thumbnail_to_be_uploaded_to_asset_manager
@@ -274,20 +256,6 @@ def expect_thumbnail_sent_to_asset_manager_to_be_an_actual_png
       end
     }.returns("id" => "http://asset-manager/assets/some-id", "name" => "pub-cover.png")
   end
-
-  def expect_thumbnail_sent_to_asset_manager_to_be_scaled_proportionally
-    Services.asset_manager.stubs(:create_asset).returns("id" => "http://asset-manager/assets/some-id", "name" => "pub-cover.png")
-    Services.asset_manager.expects(:create_asset).with { |value|
-      if value[:file].path.ends_with?(".png")
-        identify_details = `identify "#{Rails.root.join("public", value[:file].path)}"`
-
-        _path, _type, geometry, _rest = identify_details.split
-        width, height = geometry.split("x")
-
-        assert (width == "105" || height == "140"), "geometry should be proportional scaled, but was #{geometry}"
-      end
-    }.returns("id" => "http://asset-manager/assets/some-id", "name" => "pub-cover.png")
-  end
 end
 
 class AttachmentUploaderZipFileTest < ActiveSupport::TestCase