bot-telegram-nginx.lua

local function script_path() -- https://stackoverflow.com/a/39637679
	local str = debug.getinfo(2, 'S').source:sub(2)
	return str:match('(.*/)')
end

local function char_to_hex(str)
	return string.format("%%%02X", string.byte(str))
end
 
local function url_encode(str)
	local str = string.gsub(str, "\\", "\\")
	local str = string.gsub(str, "([^%w])", char_to_hex)
	return str
end
 
local function http_build_query(query)
	local buff=""
	for k, v in pairs(query) do
		buff = buff.. string.format("%s=%s&", k, url_encode(v))
	end
	local buff = string.reverse(string.gsub(string.reverse(buff), "&", "", 1))
	return buff
end

package.path = script_path() .. '?.lua;' .. package.path

local requests = require 'requests' -- https://luarocks.org/modules/jakeg/lua-requests
local json = require 'json' -- https://github.com/rxi/json.lua
local token = require 'token' -- ./token.lua

local function get_post_json()
	ngx.req.read_body()
	local args_str = ngx.var.request_body
	local ok, res = pcall(json.decode, args_str)
	if ok then return res end
end

local function send_text(id, text)
	local args = http_build_query{ chat_id = id, text = text }
	local response = requests.request('POST', 'https://api.telegram.org/bot' .. token .. '/sendMessage?' .. args)
end

local _POST = get_post_json()
if _POST and _POST.update_id then -- tg
	local msg = _POST.message.text
	if msg == 'ping' then
		send_text(_POST.message.chat.id, 'pong')
	end
end