Fix multiple image edit uploads

lib/openai/resources/images.rb

@@ -87,6 +87,7 @@ def create_variation(params)
       # @see OpenAI::Models::ImageEditParams
       def edit(params)
         parsed, options = OpenAI::ImageEditParams.dump_request(params)
+        parsed = prepare_edit_body(parsed)
         if parsed[:stream]
           message = "Please use `#edit_stream_raw` for the streaming use case."
           raise ArgumentError.new(message)
@@ -148,6 +149,7 @@ def edit(params)
       # @see OpenAI::Models::ImageEditParams
       def edit_stream_raw(params)
         parsed, options = OpenAI::ImageEditParams.dump_request(params)
+        parsed = prepare_edit_body(parsed)
         unless parsed.fetch(:stream, true)
           message = "Please use `#edit` for the non-streaming use case."
           raise ArgumentError.new(message)
@@ -286,6 +288,18 @@ def generate_stream_raw(params)
         )
       end
 
+      # @api private
+      #
+      # @param parsed [Hash{Symbol=>Object}]
+      #
+      # @return [Hash{Symbol=>Object}]
+      private def prepare_edit_body(parsed)
+        # The Images API uses a bracketed multipart field name for multiple image uploads.
+        return parsed unless parsed[:image].is_a?(Array)
+
+        parsed.transform_keys { _1 == :image ? :"image[]" : _1 }
+      end
+
       # @api private
       #
       # @param client [OpenAI::Client]

test/openai/resources/images_test.rb

@@ -47,6 +47,41 @@ def test_edit_required_params
     end
   end
 
+  def test_edit_encodes_multiple_images_as_an_array_multipart_field
+    requests = []
+    client = Object.new
+    client.define_singleton_method(:request) do |**request|
+      requests << request
+      request
+    end
+    images = OpenAI::Resources::Images.new(client: client)
+    files = [
+      OpenAI::FilePart.new("first", filename: "first.png"),
+      OpenAI::FilePart.new("second", filename: "second.png")
+    ]
+
+    images.edit(image: files, prompt: "Combine them")
+    images.edit_stream_raw(image: files, prompt: "Combine them")
+
+    requests.each do |request|
+      names = multipart_field_names(request)
+      assert_equal(2, names.count("image[]"))
+      refute_includes(names, "image")
+    end
+  end
+
+  def test_edit_preserves_the_scalar_image_multipart_field
+    client = Object.new
+    client.define_singleton_method(:request) { |**request| request }
+    images = OpenAI::Resources::Images.new(client: client)
+
+    request = images.edit(image: OpenAI::FilePart.new("first", filename: "first.png"), prompt: "Edit it")
+
+    names = multipart_field_names(request)
+    assert_equal(1, names.count("image"))
+    refute_includes(names, "image[]")
+  end
+
   def test_generate_required_params
     response = @openai.images.generate(prompt: "A cute baby sea otter")
 
@@ -66,4 +101,10 @@ def test_generate_required_params
       }
     end
   end
+
+  private def multipart_field_names(request)
+    _headers, stream = OpenAI::Internal::Util.encode_content(request.fetch(:headers), request.fetch(:body))
+    body = stream.respond_to?(:read) ? stream.read : stream.to_a.join
+    body.scan(/Content-Disposition: form-data; name="([^"]+)"/).flatten
+  end
 end