Files
Pico-2W-Computer-Power-Cont…/main.py

242 lines
6.6 KiB
Python

import os
import time
import network
import utime
import ubinascii
import uhashlib
import uasyncio as asyncio
from machine import Pin
from config import WIFI_SSID, WIFI_PASSWORD, PASSWORD
led = Pin("LED", Pin.OUT, value=0)
computer = Pin(2, Pin.OUT)
wlan = network.WLAN(network.STA_IF)
_nonce = ""
_nonce_ts = 0
NONCE_TTL_MS = 5 * 60 * 1000
HTML = """\
<!DOCTYPE html>
<html>
<head><title>Pico W</title></head>
<body>
<h1>Pico W - Computer Management</h1>
%s
<form id="form" method="POST" action="/computer">
<input type="hidden" id="nonce" name="nonce" value="%s">
<input type="hidden" id="hmac" name="hmac">
<input type="password" id="pwd" placeholder="Password" required>
<button type="submit">Turn On/Off</button>
</form>
<script src="/crypto-js.min.js"></script>
<script>
document.getElementById('form').addEventListener('submit', async function(event) {
event.preventDefault();
const pwd = document.getElementById('pwd').value;
const nonce = document.getElementById('nonce').value;
const hmac = CryptoJS.HmacSHA256(nonce, pwd).toString(CryptoJS.enc.Hex);
document.getElementById('hmac').value = hmac;
document.getElementById('pwd').value = '';
this.submit();
});
</script>
</body>
</html>
"""
MSG_WRONG = "<p><strong>Wrong password.</strong></p>"
MSG_OK = "<p>Signal sent to computer.</p>"
MSG_EXPIRED = "<p><strong>Session expired, please reload the page.</strong></p>"
def _new_nonce() -> str:
global _nonce, _nonce_ts
_nonce = ubinascii.hexlify(os.urandom(16)).decode()
_nonce_ts = utime.ticks_ms()
return _nonce
def _nonce_valid(received: str) -> bool:
expired = utime.ticks_diff(utime.ticks_ms(), _nonce_ts) > NONCE_TTL_MS
return (not expired) and (_nonce != "") and (received == _nonce)
def _invalidate_nonce():
global _nonce, _nonce_ts
_nonce = ""
_nonce_ts = 0
def hmac_sha256(key: str, message: str) -> str:
BLOCK = 64
k = key.encode() if isinstance(key, str) else key
m = message.encode() if isinstance(message, str) else message
if len(k) > BLOCK:
k = uhashlib.sha256(k).digest()
k = k + b'\x00' * (BLOCK - len(k))
ipad = bytes(b ^ 0x36 for b in k)
opad = bytes(b ^ 0x5c for b in k)
ih = uhashlib.sha256()
ih.update(ipad)
ih.update(m)
oh = uhashlib.sha256()
oh.update(opad)
oh.update(ih.digest())
return ubinascii.hexlify(oh.digest()).decode()
def ct_equal(a: str, b: str) -> bool:
if len(a) != len(b):
return False
result = 0
for x, y in zip(a.encode(), b.encode()):
result |= x ^ y
return result == 0
def url_decode(s):
s = s.replace("+", " ")
out = []
i = 0
while i < len(s):
if s[i] == "%" and i + 2 < len(s):
out.append(chr(int(s[i + 1:i + 3], 16)))
i += 3
else:
out.append(s[i])
i += 1
return "".join(out)
def parse_form(body):
params = {}
for pair in body.split("&"):
if "=" in pair:
k, v = pair.split("=", 1)
params[url_decode(k)] = url_decode(v)
return params
async def toggleComputer():
led.value(1)
computer.value(1)
await asyncio.sleep(0.5)
led.value(0)
computer.value(0)
def _do_connect():
wlan.active(True)
wlan.config(pm = 0xa11140) # disable power-save mode
wlan.connect(WIFI_SSID, WIFI_PASSWORD)
for _ in range(10):
status = wlan.status()
if status == network.STAT_GOT_IP:
print("Wi-Fi connected:", wlan.ifconfig()[0])
return True
if status < 0:
break
time.sleep(1)
print("Connection failed (status=%d)" % wlan.status())
return False
def connect_wifi():
while True:
print("Connecting to Wi-Fi…")
if _do_connect():
return
wlan.disconnect()
time.sleep(3)
async def wifi_watchdog():
while True:
await asyncio.sleep(5)
if wlan.status() != network.STAT_GOT_IP:
print("Wi-Fi lost - reconnecting…")
wlan.disconnect()
await asyncio.sleep(1)
while not _do_connect():
wlan.disconnect()
await asyncio.sleep(3)
print("Wi-Fi restored:", wlan.ifconfig()[0])
async def serve_client(reader, writer):
try:
request_line = await reader.readline()
if not request_line:
return
print("Request:", request_line.strip())
parts = request_line.decode().split()
method = parts[0] if parts else "GET"
path = parts[1] if len(parts) > 1 else "/"
content_length = 0
while True:
header = await reader.readline()
if header == b"\r\n":
break
if header.lower().startswith(b"content-length:"):
content_length = int(header.split(b":")[1].strip())
message = ""
if method == "GET" and path == "/crypto-js.min.js":
with open("crypto-js.min.js", "rb") as f:
js = f.read()
writer.write(
"HTTP/1.0 200 OK\r\n"
"Content-Type: application/javascript\r\n"
"Content-Length: %d\r\n\r\n" % len(js)
)
writer.write(js)
await writer.drain()
return
if method == "POST" and path == "/computer" and content_length > 0:
body = await reader.read(content_length)
params = parse_form(body.decode())
received_nonce = params.get("nonce", "")
received_hmac = params.get("hmac", "")
if not _nonce_valid(received_nonce):
message = MSG_EXPIRED
else:
expected = hmac_sha256(PASSWORD, received_nonce)
_invalidate_nonce()
if ct_equal(expected, received_hmac):
asyncio.create_task(toggleComputer())
message = MSG_OK
else:
message = MSG_WRONG
nonce = _new_nonce()
writer.write("HTTP/1.0 200 OK\r\nContent-type: text/html\r\n\r\n")
writer.write(HTML % (message, nonce))
await writer.drain()
except OSError as e:
print("Client disconnected unexpectedly:", e)
finally:
await writer.wait_closed()
async def main():
print("Connecting to network…")
connect_wifi()
print("Starting web server on port 80…")
asyncio.create_task(asyncio.start_server(serve_client, "0.0.0.0", 80))
asyncio.create_task(wifi_watchdog())
while True:
await asyncio.sleep(60)
try:
asyncio.run(main())
finally:
asyncio.new_event_loop()