Kong自定义Lua插件无法向Spring Boot REST API正常发送HTTP请求

我被这个问题困扰数周了。我为Kong编写了一个自定义Lua插件，用于将Kong接收到的请求转发至自定义认证服务，以下是Handler.lua代码：

-- Handler.lua

local http = require "resty.http"
local utils = require "kong.tools.utils"
local cjson = require("cjson")

local MessageForwarder = {
    VERSION = "1.0",
    PRIORITY = 1000,
}

local function forward_message(conf, request_method, request_path, request_headers, request_body)
  -- Make HTTP Request
  local httpc = http.new()
  local res, err = httpc:request_uri(conf.forward_host .. request_path, {
    method = request_method,
    headers = request_headers,
    body = request_body,
    ssl_verify = false
  })

  -- Checking response
  if not res then
    kong.log.err("Failed to forward request: ", err)
    return kong.response.exit(500)
  end

  if res.status ~= 200 then
    kong.log.err("Responded with status: ",res.status)
    return kong.response.exit(500)
  end

  return true -- all is well
end

local function forward_message_new(conf, request_method, request_path, request_headers, request_body)
  local server = assert(socket.bind("*", 0))
end

function MessageForwarder:access(conf)
  local request_path = kong.request.get_raw_path()
  local request_method = kong.request.get_method()
  local request_headers = kong.request.get_headers()

  local raw_request_body
  if raw_request_method ~= "GET" then
    raw_request_body = kong.request.get_raw_body()
  end

  local request_body = cjson.decode(raw_request_body)

  local auth_path = conf.auth_token_b2b_endpoint

  local bool = forward_message(conf, request_method, request_path, request_headers, request_body)

  return true
end


return MessageForwarder

接收该转发请求的Spring Boot REST API日志中返回如下错误：

WARN 20440 --- [nio-8010-exec-1] .w.s.m.s.DefaultHandlerExceptionResolver : Ignoring exception, response committed already: org.springframework.http.converter.HttpMessageNotReadableException: I/O error while reading input message
WARN 20440 --- [nio-8010-exec-1] .w.s.m.s.DefaultHandlerExceptionResolver : Resolved [org.springframework.http.converter.HttpMessageNotReadableException: I/O error while reading input message]

我已经通过Postman、Insomnia、其他Spring Boot应用及Ajax测试过这个Spring Boot API，均能正常工作，唯有该Kong自定义Lua插件调用出现问题。我怀疑自己在使用resty.http时未遵循某些规则，恳请各位提供解决方案。

补充：我参考了Kong博客的自定义认证与授权框架教程来适配需求。

内容的提问来源于stack exchange，提问作者Mehdi.