feat: stream multipart file uploads to reduce memory usage

lib/httparty/request.rb

@@ -248,7 +248,14 @@ def setup_raw_request
         elsif options[:body].respond_to?(:to_hash) && !@raw_request['Content-Type']
           @raw_request['Content-Type'] = 'application/x-www-form-urlencoded'
         end
-        @raw_request.body = body.call
+
+        if body.streaming? && options[:stream_body] != false
+          stream = body.to_stream
+          @raw_request.body_stream = stream
+          @raw_request['Content-Length'] = stream.size.to_s
+        else
+          @raw_request.body = body.call
+        end
       end
 
       @raw_request.instance_variable_set(:@decode_content, decompress_content?)

lib/httparty/request/body.rb

@@ -1,6 +1,7 @@
 # frozen_string_literal: true
 
 require_relative 'multipart_boundary'
+require_relative 'streaming_multipart_body'
 
 module HTTParty
   class Request
@@ -30,6 +31,22 @@ def multipart?
         params.respond_to?(:to_hash) && (force_multipart || has_file?(params))
       end
 
+      def streaming?
+        multipart? && has_file?(params)
+      end
+
+      def to_stream
+        return nil unless streaming?
+        StreamingMultipartBody.new(prepared_parts, boundary)
+      end
+
+      def prepared_parts
+        normalized_params = params.flat_map { |key, value| HashConversions.normalize_keys(key, value) }
+        normalized_params.map do |key, value|
+          [key, value, file?(value)]
+        end
+      end
+
       private
 
       # https://html.spec.whatwg.org/#multipart-form-data

lib/httparty/request/streaming_multipart_body.rb

@@ -0,0 +1,188 @@
+# frozen_string_literal: true
+
+module HTTParty
+  class Request
+    class StreamingMultipartBody
+      NEWLINE = "\r\n"
+      CHUNK_SIZE = 64 * 1024 # 64 KB chunks
+
+      def initialize(parts, boundary)
+        @parts = parts
+        @boundary = boundary
+        @part_index = 0
+        @state = :header
+        @current_file = nil
+        @header_buffer = nil
+        @header_offset = 0
+        @footer_sent = false
+      end
+
+      def size
+        @size ||= calculate_size
+      end
+
+      def read(length = nil, outbuf = nil)
+        outbuf = outbuf ? outbuf.replace(''.b) : ''.b
+
+        return read_all(outbuf) if length.nil?
+
+        while outbuf.bytesize < length
+          chunk = read_chunk(length - outbuf.bytesize)
+          break if chunk.nil?
+          outbuf << chunk
+        end
+
+        outbuf.empty? ? nil : outbuf
+      end
+
+      def rewind
+        @part_index = 0
+        @state = :header
+        @current_file = nil
+        @header_buffer = nil
+        @header_offset = 0
+        @footer_sent = false
+        @parts.each do |_key, value, _is_file|
+          value.rewind if value.respond_to?(:rewind)
+        end
+      end
+
+      private
+
+      def read_all(outbuf)
+        while (chunk = read_chunk(CHUNK_SIZE))
+          outbuf << chunk
+        end
+        outbuf.empty? ? nil : outbuf
+      end
+
+      def read_chunk(max_length)
+        loop do
+          return nil if @part_index >= @parts.size && @footer_sent
+
+          if @part_index >= @parts.size
+            @footer_sent = true
+            return "--#{@boundary}--#{NEWLINE}".b
+          end
+
+          key, value, is_file = @parts[@part_index]
+
+          case @state
+          when :header
+            chunk = read_header_chunk(key, value, is_file, max_length)
+            return chunk if chunk
+
+          when :body
+            chunk = read_body_chunk(value, is_file, max_length)
+            return chunk if chunk
+
+          when :newline
+            @state = :header
+            @part_index += 1
+            return NEWLINE.b
+          end
+        end
+      end
+
+      def read_header_chunk(key, value, is_file, max_length)
+        if @header_buffer.nil?
+          @header_buffer = build_part_header(key, value, is_file)
+          @header_offset = 0
+        end
+
+        remaining = @header_buffer.bytesize - @header_offset
+        if remaining > 0
+          chunk_size = [remaining, max_length].min
+          chunk = @header_buffer.byteslice(@header_offset, chunk_size)
+          @header_offset += chunk_size
+          return chunk
+        end
+
+        @header_buffer = nil
+        @header_offset = 0
+        @state = :body
+        nil
+      end
+
+      def read_body_chunk(value, is_file, max_length)
+        if is_file
+          chunk = read_file_chunk(value, max_length)
+          if chunk
+            return chunk
+          else
+            @current_file = nil
+            @state = :newline
+            return nil
+          end
+        else
+          @state = :newline
+          return value.to_s.b
+        end
+      end
+
+      def read_file_chunk(file, max_length)
+        chunk_size = [max_length, CHUNK_SIZE].min
+        chunk = file.read(chunk_size)
+        return nil if chunk.nil?
+        chunk.force_encoding(Encoding::BINARY) if chunk.respond_to?(:force_encoding)
+        chunk
+      end
+
+      def build_part_header(key, value, is_file)
+        header = "--#{@boundary}#{NEWLINE}".b
+        header << %(Content-Disposition: form-data; name="#{key}").b
+        if is_file
+          header << %(; filename="#{file_name(value).gsub(/["\r\n]/, replacement_table)}").b
+          header << NEWLINE.b
+          header << "Content-Type: #{content_type(value)}#{NEWLINE}".b
+        end
+        header << NEWLINE.b
+        header
+      end
+
+      def calculate_size
+        total = 0
+        @parts.each do |key, value, is_file|
+          total += build_part_header(key, value, is_file).bytesize
+          total += content_size(value, is_file)
+          total += NEWLINE.bytesize
+        end
+        total += "--#{@boundary}--#{NEWLINE}".bytesize
+        total
+      end
+
+      def content_size(value, is_file)
+        if is_file
+          if value.respond_to?(:size)
+            value.size
+          elsif value.respond_to?(:stat)
+            value.stat.size
+          else
+            value.read.bytesize.tap { value.rewind }
+          end
+        else
+          value.to_s.b.bytesize
+        end
+      end
+
+      def content_type(object)
+        return object.content_type if object.respond_to?(:content_type)
+        require 'mini_mime'
+        mime = MiniMime.lookup_by_filename(object.path)
+        mime ? mime.content_type : 'application/octet-stream'
+      end
+
+      def file_name(object)
+        object.respond_to?(:original_filename) ? object.original_filename : File.basename(object.path)
+      end
+
+      def replacement_table
+        @replacement_table ||= {
+          '"'  => '%22',
+          "\r" => '%0D',
+          "\n" => '%0A'
+        }.freeze
+      end
+    end
+  end
+end

spec/httparty/request/body_spec.rb

@@ -226,4 +226,70 @@ def to_ary
       end
     end
   end
+
+  describe '#streaming?' do
+    let(:file) { File.open('spec/fixtures/tiny.gif') }
+
+    after { file.close }
+
+    context 'when params contains a file' do
+      let(:params) { { avatar: file } }
+      subject { described_class.new(params) }
+
+      it { expect(subject.streaming?).to be true }
+    end
+
+    context 'when force_multipart but no file' do
+      let(:params) { { name: 'John' } }
+      subject { described_class.new(params, force_multipart: true) }
+
+      it { expect(subject.streaming?).to be false }
+    end
+
+    context 'when params is a string' do
+      let(:params) { 'name=John' }
+      subject { described_class.new(params) }
+
+      it { expect(subject.streaming?).to be false }
+    end
+  end
+
+  describe '#to_stream' do
+    let(:file) { File.open('spec/fixtures/tiny.gif', 'rb') }
+
+    after { file.close }
+
+    context 'when streaming is possible' do
+      let(:params) { { avatar: file } }
+      subject { described_class.new(params) }
+
+      it 'returns a StreamingMultipartBody' do
+        expect(subject.to_stream).to be_a(HTTParty::Request::StreamingMultipartBody)
+      end
+
+      it 'produces equivalent content to call' do
+        allow(HTTParty::Request::MultipartBoundary).to receive(:generate).and_return('test-boundary')
+
+        stream = subject.to_stream
+        file.rewind
+        streamed_content = stream.read
+
+        file.rewind
+        body = described_class.new(params)
+        allow(HTTParty::Request::MultipartBoundary).to receive(:generate).and_return('test-boundary')
+        regular_content = body.call
+
+        expect(streamed_content).to eq(regular_content)
+      end
+    end
+
+    context 'when streaming is not possible' do
+      let(:params) { { name: 'John' } }
+      subject { described_class.new(params, force_multipart: true) }
+
+      it 'returns nil' do
+        expect(subject.to_stream).to be_nil
+      end
+    end
+  end
 end