implemented streaming parsing multipart/form-data as turbo takes 3x memory of uploading file(s) size during parsing multipart/form-data request

examples/multipart.lua

@@ -0,0 +1,49 @@
+--- Turbo.lua Multipart example
+--
+-- Copyright 2023 Gary Liu
+--
+-- Licensed under the Apache License, Version 2.0 (the "License");
+-- you may not use this file except in compliance with the License.
+-- You may obtain a copy of the License at
+--
+-- http://www.apache.org/licenses/LICENSE-2.0
+--
+-- Unless required by applicable law or agreed to in writing, software
+-- distributed under the License is distributed on an "AS IS" BASIS,
+-- WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+-- See the License for the specific language governing permissions and
+-- limitations under the License.
+
+local turbo = require "turbo"
+
+local UploadHandler = class("Upload", turbo.web.RequestHandler)
+
+function UploadHandler:post()
+    local response = {}
+    local form_args = self.request.connection.arguments
+    for name, arg_parts in pairs(form_args) do
+        for ind, arg in ipairs(arg_parts) do
+            local tab = response[name] or {}
+            if arg["content-type"] then
+                tab[ind] = {
+                    ["content-type"] = arg["content-type"],
+                    ["content-disposition"] = arg["content-disposition"],
+                    ["filepath"] = arg["filepath"],
+                    ["filelen"] = arg["filelen"] or #arg[1],
+                }
+            else
+                tab[ind] = arg[1]
+            end
+            response[name] = tab
+        end
+    end
+    self:write(response)
+end
+
+turbo.web.Application({
+    {"^/$", UploadHandler}
+}):listen(8888, nil, {
+streaming_multipart_bytes = 1*1024*1024,
+large_body_bytes = 1024,
+})
+turbo.ioloop.instance():start()

turbo/httpserver.lua

@@ -244,7 +244,19 @@ function httpserver.HTTPConnection:_on_headers(data)
             if headers:get("Expect") == "100-continue" then
                 self.stream:write("HTTP/1.1 100 (Continue)\r\n\r\n")
             end
-            self.stream:read_bytes(content_length, self._on_request_body, self)
+
+            local content_type = self._request.headers:get("Content-Type") or ""
+            if type(self.kwargs.streaming_multipart_bytes) == "number" and
+                content_length >= self.kwargs.streaming_multipart_bytes and
+                content_type:find("multipart/form-data", 1, true) then
+                local final_callback = function(self) self.request_callback(self._request) end
+                local stream_parse = httputil.StreamingParser:new(self)
+
+                self.stream:read_bytes_raw_buffer(content_length, final_callback, self,
+                    stream_parse.parse_large_multipart_body, stream_parse)
+            else
+                self.stream:read_bytes(content_length, self._on_request_body, self)
+            end
             return
         end
     end