Play with lua coroutines. Make async http function synchronous

coroutinize.lua

-- idea source: https://luyuhuang.tech/2020/09/13/callback-to-coroutine.html

-- Async request demo
--[[ http.Fetch("https://httpbin.org/get?a=b&c=d", function(code, content)
	print("code, content", code, content)
end, function(err)
	print("Error", err)
end, {
	header_asd = "qwe"
})
]]

local function coroutinize(f, ...)
	local co = coroutine.create(f)
	local function exec(...)
		local ok, data = coroutine.resume(co, ...)
		if not ok then
			error(debug.traceback(co, data))
		end
		if coroutine.status(co) ~= "dead" then
			data(exec)
		end
	end
	exec(...)
end

local function http_fetch_sync(url, headers)
	return coroutine.yield(function(cb)
		http.Fetch(url, function(...)
			cb({resolve = {...}})
		end, function(...)
			cb({reject = {...}})
		end, headers)
	end)
end

coroutinize(function()
	local res = http_fetch_sync("https://poll.gmod.app/asd?sleep=3")
	PRINT("data received 1:", util.JSONToTable(res.resolve[1]))

	local res = http_fetch_sync("https://httpbin.org/get?a=b&c=d")
	PRINT("data received 2:", util.JSONToTable(res.resolve[1]))

	local res = http_fetch_sync("https://poll.gmod.app/asd?sleep=3")
	PRINT("data received 3:", util.JSONToTable(res.resolve[1]))
end)

local http_get = require("http_async").get -- http.Fetch

local function fetch(url)
	local th = coroutine.running()
	
	http_get(url, function(a, b, c, d)
		coroutine.resume(th, {a = a, b = b, c = c, d = d})
	end, function(err)
		coroutine.resume(th, {err = err})
	end)

	return coroutine.yield()
end

local function fetch_all_urls(cb)
	coroutine.wrap(function()
		local res1 = fetch("https://httpbin.org/get")
		local res2 = fetch("https://httpbin.org/get")
		local res3 = fetch("https://httpbin.org/get")
		cb({res1, res2, res3})
	end)()
end

fetch_all_urls(fp{PRINT, "hello"})