Kong Serverless Function

post-function.lua

local kong = kong
local re = ngx.re

local headers = kong.response.get_headers()
local content_type = headers["Content-Type"]
local supported_content_type = "(html|json|xml|plain|css)"

local function transform_body(body, old, new)
	return body:gsub(old, new)
end

if re.match(content_type, supported_content_type) then
	local body = kong.response.get_raw_body()
	if body then
		local old = "http://127.0.0.1/"
		local new = "http://localhost/"
		return kong.response.set_raw_body(transform_body(body, old, new))
	end
end