CORS issue on ESP32 with nodemcu lua - lua

Question

I want to create Esp32 based server and wanted to implement local REST api's so I took https://github.com/abobija/api32 help and written some api's everything working with chrome/postman but when tried to use with my mobile app not able to get the response but can able to post the data to esp32.
I'm getting this error
Access to XMLHttpRequest at 'http://192.168.0.10/' from origin 'http://localhost' has been blocked by CORS policy: No 'Access-Control-Allow-Origin' header is present on the requested resource.
my code is
Title : Library for easy way of creating HTTP JSON Api Service for ESP32
Author : Alija Bobija
Author-Website : https://abobija.com
GitHub Repo : https://github.com/abobija/api32
Dependencies:
- sjson
- encoder
]]
local Api32 = {}
local function str_starts_with(haystack, needle)
return haystack:sub(1, #needle) == needle
end
local function str_ends_with(str, ending)
return ending == "" or str:sub(-#ending) == ending
end
local function str_split(inputstr, sep)
if sep == nil then sep = "%s" end
local result = {}
for str in inputstr:gmatch("([^"..sep.."]+)") do table.insert(result, str) end
return result
end
local function json_parse(json_str)
local ok
local result
ok, result = pcall(sjson.decode, json_str)
if ok then return result end
return nil
end
local function json_stringify(table)
local ok
local json
ok, json = pcall(sjson.encode, table)
if ok then return json end
return nil
end
local function get_http_header_value(hname, hlines)
for _, hline in pairs(hlines) do
if str_starts_with(hline:lower(), hname:lower()) then
local colon_index = hline:find(':')
if colon_index ~= nil then
return hline:sub(colon_index + 2)
end
end
end
return nil
end
local function get_auth_from_http_header(hlines)
local auth_line = get_http_header_value('Authorization', hlines)
if auth_line == nil then return nil end
local parts = str_split(auth_line)
if #parts == 2 and parts[1]:lower() == 'basic' then
local key = parts[2]
parts = nil
local ok
local decoded_key
ok, decoded_key = pcall(encoder.fromBase64, key)
key = nil
if ok then
parts = str_split(decoded_key, ':')
decoded_key = nil
if #parts == 2 then
return {
user = parts[1],
pwd = parts[2]
}
end
end
end
return nil
end
local function parse_http_header(request, params)
local options = {
parse_auth = false
}
if params ~= nil then
if params.parse_auth ~= nil then options.parse_auth = params.parse_auth end
end
local hlines = str_split(request, "\r\n")
if #hlines > 0 then
local hline1_parts = str_split(hlines[1])
if #hline1_parts == 3 and hline1_parts[3] == 'HTTP/1.1' then
local result = {
method = hline1_parts[1],
path = hline1_parts[2],
std = hline1_parts[3]
}
hline1_parts = nil
result.content_length = get_http_header_value('Content-Length', hlines)
if options.parse_auth then
result.auth = get_auth_from_http_header(hlines)
end
hlines = nil
if result.content_length ~= nil then
result.content_length = tonumber(result.content_length)
end
return result
end
end
return nil
end
-- Extends one level only
local function extend(tbl, with)
if with ~= nil then
for k, v in pairs(with) do
if tbl[k] == nil then
tbl[k] = with[k]
end
end
end
return tbl
end
Api32.create = function(conf)
local self = extend({
http_body_min = 10,
http_body_max = 512,
port = 80,
auth = nil
}, conf)
local endpoints = {}
self.on = function(method, path, handler)
table.insert(endpoints, {
method = method,
path = path,
handler = handler
})
return self
end
self.on_get = function(path, handler)
return self.on('GET', path, handler)
end
self.on_post = function(path, handler)
return self.on('POST', path, handler)
end
local get_endpoint = function(method, path)
for _, ep in pairs(endpoints) do
if ep.method == method and ep.path == path then return ep end
end
return nil
end
local srv = net.createServer(net.TCP, 30)
local sending = false
local http_header = nil
local http_req_body_buffer = nil
local function stop_rec()
sending = false
http_header = nil
http_req_body_buffer = nil
end
local is_authorized = function()
return self.auth == nil or (
http_header ~= nil
and http_header.auth ~= nil
and self.auth.user == http_header.auth.user
and self.auth.pwd == http_header.auth.pwd
)
end
local function parse_http_request(sck)
local res = {}
local stream_file = nil
local send = function(_sck)
sending = true
local close_socket = false
if #res > 0 then
_sck:send(table.remove(res, 1))
elseif stream_file ~= nil then
local line = stream_file:readline()
if line ~= nil then
_sck:send(line)
else
stream_file:close()
stream_file = nil
close_socket = true
end
else
close_socket = true
end
if close_socket then
sending = false
_sck:close()
res = nil
end
end
sck:on('sent', send)
local response_status = '200 OK'
local content_type = 'application/json'
local response_body = nil
res[1] = 'HTTP/1.1 '
res[2] = 'Content-Type: CTYPE; charset=UTF-8\r\n'
if http_header == nil then
response_status = '400 Bad Request'
else
if not is_authorized() then
response_status = '401 Unauthorized'
res[#res + 1] = 'WWW-Authenticate: Basic realm="User Visible Realm", charset="UTF-8"\r\n'
else
local ep = get_endpoint(http_header.method, http_header.path)
if ep == nil then
response_status = '404 Not Found'
else
http_header = nil
if type(ep.handler) == 'function' then -- custom handler
local jreq = json_parse(http_req_body_buffer)
http_req_body_buffer = nil
local jres = ep.handler(jreq)
jreq = nil
response_body = json_stringify(jres)
jres = nil
elseif type(ep.handler) == 'string' then -- static file
-- ep.handler is filename in this case
http_req_body_buffer = nil
if not file.exists(ep.handler) then
response_status = '404 Not Found'
else
if str_ends_with(ep.handler, 'html') then
content_type = 'text/html'
end
stream_file = file.open(ep.handler)
end
end
end
end
end
res[1] = res[1] .. response_status .. "\r\n"
res[2] = res[2]:gsub('CTYPE', content_type)
res[#res + 1] = "\r\n"
if response_body ~= nil then
res[#res + 1] = response_body
response_body = nil
end
stop_rec()
send(sck)
end
local on_receive = function(sck, data)
if sending then return end
if http_header == nil then
local eof_head = data:find("\r\n\r\n")
local head_data = nil
if eof_head ~= nil then
head_data = data:sub(1, eof_head - 1)
http_req_body_buffer = data:sub(eof_head + 4)
end
data = nil
if head_data ~= nil then
http_header = parse_http_header(head_data, {
parse_auth = self.auth ~= nil
})
head_data = nil
end
if http_header ~= nil then
if http_header.content_length == nil
or http_header.content_length < self.http_body_min
or http_header.content_length > self.http_body_max then
-- It seems like request body is too short, too big or does not exist at all.
-- Parse request immediatelly
return parse_http_request(sck)
end
else
-- Received some data which does not represent the http header.
-- Let's parse it anyway because error 400 shoud be sent back to the client
return parse_http_request(sck)
end
end
if data ~= nil and http_header ~= nil then
-- Buffering request body
if http_req_body_buffer == nil then
http_req_body_buffer = data
else
http_req_body_buffer = http_req_body_buffer .. data
end
end
-- Check if body has received
if http_req_body_buffer ~= nil then
local http_body_len = http_req_body_buffer:len()
if (http_header.content_length ~= nil and http_body_len >= http_header.content_length)
or http_body_len >= self.http_body_max then
-- Received enough bytes of request body.
return parse_http_request(sck)
end
end
end
srv:listen(self.port, function(conn)
stop_rec()
conn:on('receive', on_receive)
conn:on('disconnection', stop_rec)
end)
return self
end
return Api32
and another module api32local
local M = {}
_G[moduleName] = M
if api == nil then
api = require('api32')
.create()
.on_get('/', function() return{message = 'Welcome to the API32!'} end)
.on_post("/house_lamp",function(jreq,raw_data)
if jreq==nil or raw_data==nil then return end
gpio.write(BLUE_LED, jreq.state)
print("led Post Command")
return{"lamp_status updated"}
end)
end
return M
for wifi
wifi.mode(wifi.SOFTAP)
cfg={}
cfg.ip='192.168.0.10'
cfg.netmask='255.255.255.0'
cfg.gateway='192.168.0.1'
cfg.dns='8.8.8.8'
wifi.ap.setip(cfg)
wifi.ap.config({
ssid = "****",
pwd = "*123456#",
auth=wifi.AUTH_OPEN,
auto = false
})
Myapi32_init=require'api32local'
wifi.ap.on("sta_connected", function(event, info) Myapi32_init.init_api32() print("MAC_id"..info.mac,"Name"..info.id) end)
wifi.start()
please help me debugging issue. Can't able to understand where to use cross origin headers and how, and about preflight concept which are importent for angular based android app to communicate locally(without internet) through http with ESP32