From 1872c18e16842097e97a3c7f72f41664ae62e609 Mon Sep 17 00:00:00 2001
From: Sebastien Savater <savater.sebastien@gmail.com>
Date: Thu, 23 Apr 2020 10:21:03 +0200
Subject: [PATCH] Do not returns invalid content type on text files

---
 lib/carrierwave/sanitized_file.rb | 11 +++++++++--
 spec/fixtures/bork.ABCDE          |  0
 spec/sanitized_file_spec.rb       | 20 ++++++++++++++++++++
 3 files changed, 29 insertions(+), 2 deletions(-)
 create mode 100644 spec/fixtures/bork.ABCDE

diff --git a/lib/carrierwave/sanitized_file.rb b/lib/carrierwave/sanitized_file.rb
index fd5d3a378..734c00d54 100644
--- a/lib/carrierwave/sanitized_file.rb
+++ b/lib/carrierwave/sanitized_file.rb
@@ -330,9 +330,16 @@ def existing_content_type
 
     def mime_magic_content_type
       if path
-        File.open(path) do |file|
-          MimeMagic.by_magic(file).try(:type) || 'invalid/invalid'
+        type = File.open(path) do |file|
+          MimeMagic.by_magic(file).try(:type)
         end
+
+        if type.nil?
+          type = ::MiniMime.lookup_by_filename(path).try(:content_type)
+          type = 'invalid/invalid' unless type.nil? || type.start_with?('text/')
+        end
+
+        type
       end
     rescue Errno::ENOENT
       nil
diff --git a/spec/fixtures/bork.ABCDE b/spec/fixtures/bork.ABCDE
new file mode 100644
index 000000000..e69de29bb
diff --git a/spec/sanitized_file_spec.rb b/spec/sanitized_file_spec.rb
index 70298776d..306830c38 100644
--- a/spec/sanitized_file_spec.rb
+++ b/spec/sanitized_file_spec.rb
@@ -221,6 +221,26 @@
       expect(sanitized_file.content_type).to eq 'invalid/invalid'
     end
 
+    it "returns valid content type on text file" do
+      file = File.open(file_path('bork.txt'))
+
+      sanitized_file = CarrierWave::SanitizedFile.new(file)
+
+      expect { sanitized_file.content_type }.not_to raise_error
+
+      expect(sanitized_file.content_type).to eq 'text/plain'
+    end
+
+    it "returns missing content type with unknown extension" do
+      file = File.open(file_path('bork.ABCDE'))
+
+      sanitized_file = CarrierWave::SanitizedFile.new(file)
+
+      expect { sanitized_file.content_type }.not_to raise_error
+
+      expect(sanitized_file.content_type).to eq ""
+    end
+
     it "does not raise an error if the path is not present" do
       sanitized_file = CarrierWave::SanitizedFile.new(nil)