4 files changed, 27 insertions, 8 deletions
diff --git a/activestorage/lib/active_storage/service/s3_service.rb b/activestorage/lib/active_storage/service/s3_service.rb
index e4bd57048a..a73f6ab526 100644
--- a/activestorage/lib/active_storage/service/s3_service.rb
+++ b/activestorage/lib/active_storage/service/s3_service.rb
@@ -20,12 +20,14 @@ module ActiveStorage
       @upload_options = upload
     end
 
-    def upload(key, io, checksum: nil, content_type: nil, **)
+    def upload(key, io, checksum: nil, filename: nil, content_type: nil, disposition: nil, **)
       instrument :upload, key: key, checksum: checksum do
+        content_disposition = content_disposition_with(filename: filename, type: disposition) if disposition && filename
+
         if io.size < multipart_upload_threshold
-          upload_with_single_part key, io, checksum: checksum, content_type: content_type
+          upload_with_single_part key, io, checksum: checksum, content_type: content_type, content_disposition: content_disposition
         else
-          upload_with_multipart key, io, content_type: content_type
+          upload_with_multipart key, io, content_type: content_type, content_disposition: content_disposition
         end
       end
     end
@@ -103,16 +105,16 @@ module ActiveStorage
       MAXIMUM_UPLOAD_PARTS_COUNT = 10000
       MINIMUM_UPLOAD_PART_SIZE   = 5.megabytes
 
-      def upload_with_single_part(key, io, checksum: nil, content_type: nil)
-        object_for(key).put(body: io, content_md5: checksum, content_type: content_type, **upload_options)
+      def upload_with_single_part(key, io, checksum: nil, content_type: nil, content_disposition: nil)
+        object_for(key).put(body: io, content_md5: checksum, content_type: content_type, content_disposition: content_disposition, **upload_options)
       rescue Aws::S3::Errors::BadDigest
         raise ActiveStorage::IntegrityError
       end
 
-      def upload_with_multipart(key, io, content_type: nil)
+      def upload_with_multipart(key, io, content_type: nil, content_disposition: nil)
         part_size = [ io.size.fdiv(MAXIMUM_UPLOAD_PARTS_COUNT).ceil, MINIMUM_UPLOAD_PART_SIZE ].max
 
-        object_for(key).upload_stream(content_type: content_type, part_size: part_size, **upload_options) do |out|
+        object_for(key).upload_stream(content_type: content_type, content_disposition: content_disposition, part_size: part_size, **upload_options) do |out|
           IO.copy_stream(io, out)
         end
       end
diff --git a/activestorage/test/dummy/config/initializers/backtrace_silencers.rb b/activestorage/test/dummy/config/initializers/backtrace_silencers.rb
index d0f0d3b5df..8452ef9236 100644
--- a/activestorage/test/dummy/config/initializers/backtrace_silencers.rb
+++ b/activestorage/test/dummy/config/initializers/backtrace_silencers.rb
@@ -2,7 +2,7 @@
 # Be sure to restart your server when you modify this file.
 
 # You can add backtrace silencers for libraries that you're using but don't wish to see in your backtraces.
-# Rails.backtrace_cleaner.add_silencer { |line| line =~ /my_noisy_library/ }
+# Rails.backtrace_cleaner.add_silencer { |line| /my_noisy_library/.match?(line) }
 
 # You can also remove all the silencers if you're trying to debug a problem that might stem from framework code.
 # Rails.backtrace_cleaner.remove_silencers!
diff --git a/activestorage/test/fixtures/files/racecar.tif b/activestorage/test/fixtures/files/racecar.tif
index 0a11b22896..97430741e2 100644
--- a/activestorage/test/fixtures/files/racecar.tif
+++ b/activestorage/test/fixtures/files/racecar.tif
diff --git a/activestorage/test/service/s3_service_test.rb b/activestorage/test/service/s3_service_test.rb
index b9120770e6..3dd1b59681 100644
--- a/activestorage/test/service/s3_service_test.rb
+++ b/activestorage/test/service/s3_service_test.rb
@@ -77,6 +77,23 @@ if SERVICE_CONFIGURATIONS[:s3]
       @service.delete key
     end
 
+    test "upload with content disposition" do
+      key  = SecureRandom.base58(24)
+      data = "Something else entirely!"
+
+      @service.upload(
+        key,
+        StringIO.new(data),
+        checksum: Digest::MD5.base64digest(data),
+        filename: ActiveStorage::Filename.new("cool_data.txt"),
+        disposition: :attachment
+      )
+
+      assert_equal("attachment; filename=\"cool_data.txt\"; filename*=UTF-8''cool_data.txt", @service.bucket.object(key).content_disposition)
+    ensure
+      @service.delete key
+    end
+
     test "uploading a large object in multiple parts" do
       service = build_service(upload: { multipart_threshold: 5.megabytes })