From 1dfd53164e66f9c4de427c821c27c953b65bec80 Mon Sep 17 00:00:00 2001
From: MAEDA Go <maeda@farend.jp>
Date: Sun, 30 Aug 2026 14:45:10 +0900
Subject: [PATCH 1/2] Preview Adobe Illustrator files saved in the PDF
 compatible format

---
 app/controllers/attachments_controller.rb     |  6 +++-
 app/models/attachment.rb                      | 13 +++++++
 .../functional/attachments_controller_test.rb | 35 +++++++++++++++++++
 test/unit/attachment_test.rb                  | 18 ++++++++++
 4 files changed, 71 insertions(+), 1 deletion(-)

diff --git a/app/controllers/attachments_controller.rb b/app/controllers/attachments_controller.rb
index 283803d7b..92cf7b760 100644
--- a/app/controllers/attachments_controller.rb
+++ b/app/controllers/attachments_controller.rb
@@ -58,7 +58,7 @@ class AttachmentsController < ApplicationController
           render :action => 'diff'
         elsif @attachment.is_image?
           render :action => 'image'
-        elsif @attachment.is_pdf?
+        elsif @attachment.pdf_previewable?
           render :action => 'pdf'
         elsif @attachment.is_text? && @attachment.filesize <= Setting.file_max_size_displayed.to_i.kilobyte
           @content = File.read(@attachment.diskfile, :mode => "rb")
@@ -299,6 +299,10 @@ class AttachmentsController < ApplicationController
       content_type =
         Redmine::MimeType.of(attachment.filename).presence ||
         "application/octet-stream"
+    elsif Marcel::Magic.child?(content_type, "application/pdf")
+      # Send PDF compatible files, such as Illustrator files, as PDF so that
+      # browsers display them inline
+      content_type = "application/pdf"
     end

     if is_thumb && !content_type.start_with?("image/")
diff --git a/app/models/attachment.rb b/app/models/attachment.rb
index 6ac97daf3..2d349f0e9 100644
--- a/app/models/attachment.rb
+++ b/app/models/attachment.rb
@@ -326,6 +326,19 @@ class Attachment < ApplicationRecord
     Redmine::MimeType.of(filename) == "application/pdf"
   end

+  # Returns true for attachments that can be previewed as PDF files,
+  # including PDF compatible files such as Adobe Illustrator
+  # (application/illustrator)
+  def pdf_previewable?
+    if content_type.blank? || content_type == 'application/octet-stream'
+      # The type of attachments created before Redmine started detecting the
+      # content type from the file contents can only be guessed from the name
+      is_pdf?
+    else
+      !!Marcel::Magic.child?(content_type, 'application/pdf')
+    end
+  end
+
   def is_video?
     Redmine::MimeType.is_type?('video', filename)
   end
diff --git a/test/functional/attachments_controller_test.rb b/test/functional/attachments_controller_test.rb
index f2eefcb4a..4050dcaa9 100644
--- a/test/functional/attachments_controller_test.rb
+++ b/test/functional/attachments_controller_test.rb
@@ -406,6 +406,41 @@ class AttachmentsControllerTest < Redmine::ControllerTest
     assert_match %r{\Aattachment}, @response.headers['Content-Disposition']
   end

+  def test_show_pdf_compatible_illustrator_file_should_be_previewed
+    set_tmp_attachments_directory
+    attachment = Attachment.create!(
+      :file => mock_file_with_options(
+        :original_filename => 'logo.ai',
+        :content => File.binread("#{Rails.root}/test/fixtures/files/hello.pdf")
+      ),
+      :author_id => 2,
+      :container => Issue.find(1)
+    )
+    assert_equal 'application/illustrator', attachment.content_type
+
+    get(:show, :params => {:id => attachment.id})
+    assert_response :success
+    assert_select 'div.filecontent.pdf object[type=?]', 'application/pdf'
+  end
+
+  def test_download_pdf_compatible_illustrator_file_should_be_sent_inline_as_pdf
+    set_tmp_attachments_directory
+    attachment = Attachment.create!(
+      :file => mock_file_with_options(
+        :original_filename => 'logo.ai',
+        :content => File.binread("#{Rails.root}/test/fixtures/files/hello.pdf")
+      ),
+      :author_id => 2,
+      :container => Issue.find(1)
+    )
+
+    get(:download, :params => {:id => attachment.id})
+    assert_response :success
+    # Sent as PDF so that browsers display it inline
+    assert_equal 'application/pdf', @response.media_type
+    assert_match %r{\Ainline}, @response.headers['Content-Disposition']
+  end
+
   def test_download_version_file_with_issue_tracking_disabled
     Project.find(1).disable_module! :issue_tracking
     get(:download, :params => {:id => 9})
diff --git a/test/unit/attachment_test.rb b/test/unit/attachment_test.rb
index 820feafde..9b6301c09 100644
--- a/test/unit/attachment_test.rb
+++ b/test/unit/attachment_test.rb
@@ -838,4 +838,22 @@ class AttachmentTest < ActiveSupport::TestCase
       assert_equal expected, Attachment.new(:filename => filename).is_pdf?, filename
     end
   end
+
+  def test_pdf_previewable
+    to_test = {
+      ['application/pdf', 'report.pdf'] => true,
+      # PDF compatible Illustrator files are detected as application/illustrator
+      ['application/illustrator', 'logo.ai'] => true,
+      # Illustrator files saved in the PostScript format are not PDF files
+      ['application/postscript', 'logo.ai'] => false,
+      # The type of attachments created before Redmine started detecting the
+      # content type from the file contents can only be guessed from the name
+      ['application/octet-stream', 'report.pdf'] => true,
+      ['application/octet-stream', 'logo.ai'] => false,
+    }
+    to_test.each do |(content_type, filename), expected|
+      attachment = Attachment.new(:content_type => content_type, :filename => filename)
+      assert_equal expected, attachment.pdf_previewable?, "#{content_type} (#{filename})"
+    end
+  end
 end
--
2.55.0