class LetterBox:
def __init__(self,
display_obj,
notifier_obj,
lid_sensor_obj,
font_obj,
nvs_namespace='LBOX_CFG'):
self.__namespace = NVS(nvs_namespace) # non-volatile storage
self.__display = display_obj
self.__render_font = font_obj
self.__notifier = notifier_obj
self.__lid_sensor = lid_sensor_obj
self.__wifi_manager = __LetterBoxWiFiManager(
display_obj=self.__display,
font_obj=self.__render_font,
ap_ssid="LetterBox",
ap_password='******')
self.__requester = ConnectedRequester(self.__wifi_manager)
self.serial_number = None
self.private_key = None
def initialize(self):
initial_config_done = None
try:
self.__store_keys() # write any new keys if given
initial_config_done = self.__namespace.get_i32(
"config_done") # check if this var exists in NVS
except OSError: #means config hasn't been done
print("Initializing device...")
self.__onboard_device(
) # onboard the device (register the public key)
self.__display_no_letter_text(
) # tell user to go register on front-end
self.__namespace.set_i32("config_done",
1) # don't come back here again
self.__namespace.commit()
print("Device initialized.")
finally:
initial_config_done = self.__namespace.get_i32(
"config_done") #should be done now
if initial_config_done == 1:
self.serial_number = bytearray(
12) # store the serial number for easy access
self.__namespace.get_blob("serial_number", self.serial_number)
self.serial_number = self.serial_number.decode('utf-8')
print("Serial number is {0}.".format(self.serial_number))
self.private_key = bytearray(
self.__namespace.get_i32(
"pri_key_len")) # and store the private key
self.__namespace.get_blob("pri_key", self.private_key)
self.private_key = self.private_key.decode('utf-8')
print('Private key loaded.')
return True
return False # shouldn't happen
def __onboard_device(self):
print("Onboarding device...")
# Onboarding consists of registering your serial number and public key with the server
status_code = 0
attempt_serial = unique_id() # first serial to try is the MAC address
pub_key = bytearray(self.__namespace.get_i32("pub_key_len"))
self.__namespace.get_blob("pub_key", pub_key)
pub_key_b64 = b2a_base64(pub_key).strip().decode('utf-8')
while status_code != 200: # will keep generating new serials until one works
self.serial_number = hexlify(attempt_serial).strip().decode(
'utf-8').upper()
r = self.__requester.request(
'POST',
'https://letterbox.mayursaxena.com/.netlify/functions/onboard',
json={
'id': self.serial_number,
'pk': pub_key_b64
})
status_code = r.status_code
print('{0}: {1}'.format(r.status_code, r.reason))
attempt_serial = urandom(6)
r.close()
self.__namespace.set_blob(
'serial_number',
self.serial_number) # store the serial that worked in NVS
self.__namespace.commit()
print("Device onboarded with serial {0}.".format(self.serial_number))
async def poll_async(self):
while True:
try:
gc.collect() # something about memory
gc.threshold(gc.mem_free() // 4 + gc.mem_alloc())
print("Polling for new image...")
url = "https://letterbox.mayursaxena.com/.netlify/functions/waiting"
r = self.__requester.request('POST',
url,
json={
"id": self.serial_number,
"content": 1
})
if r.status_code != 200:
print('{0} {1}: {2}'.format(r.status_code, r.reason,
r.text))
else:
json_resp = r.json()
if 'content' in json_resp:
img_bytes = self.__decrypt_img(
loads(
a2b_base64(
json_resp["content"]).strip().decode(
'utf-8')))
notify_task = uasyncio.create_task(
self.__start_notifier()) # start spinning!
print('Waiting for lid to open...')
await self.__wait_for_lid('open'
) # "blocks" until lid opens
notify_task.cancel() # stop spinning
self.__display_image(
img_bytes) # put the image on the screen
print('Waiting for lid to close...')
await self.__wait_for_lid(
'close') # "blocks" until lid closes
self.__acknowledge_image(
json_resp["sha"]) # delete image off the server
self.__display.clear(
) # clear the display to avoid burn-in (necessary?)
r.close()
await uasyncio.sleep(30) # wait 30 seconds between each poll
except Exception as e:
print("Encountered error in poll: {0}".format(e))
async def __wait_for_lid(self, state):
state = state.lower()
if state not in ('open', 'close'):
return False
p_last = 0 # need to have two consecutive readings in order to trigger
LOWER_BOUND = 500 # any reading above this on the photoresistor we're assuming means the lid is off
while True:
p_now = self.__lid_sensor.read()
if LOWER_BOUND <= p_last and LOWER_BOUND <= p_now and state == 'open':
return True
elif p_last < LOWER_BOUND and p_now < LOWER_BOUND and state == 'close':
return True
p_last = p_now
await uasyncio.sleep(1) # wait one second between each reading
async def __start_notifier(self):
# Servo motors have frequencies of 50Hz, meaning they update every 20ms
# Duty ranges from 20 - 120 ==> 0 deg to 180 deg
self.__notifier.duty(70)
try:
curr_duty = self.__notifier.duty()
# make an array from 70...20...120...70
duties = [i for i in range(curr_duty, 20, -1)] + [
i for i in range(20, 120)
] + [i for i in range(120, curr_duty, -1)]
while True:
for i in duties:
self.__notifier.duty(i)
await uasyncio.sleep(0.005) # sleep for 5ms
await uasyncio.sleep(3) # 3 seconds between each sweep
except uasyncio.CancelledError:
print('Cancelling notifier...')
raise
finally:
self.__notifier.duty(70) # reset the position to 90 degrees
print('Notifier cancelled.')
def __display_image(self, img_bytes):
self.__display.clear() # clear the image and put out a new image
self.__display.draw_image(bytes=img_bytes)
def __acknowledge_image(self, file_hash):
print('Acknowledging image...')
#send a message of form hash;timestamp (probably doesn't need to be b64)
to_send = {
'id':
self.serial_number,
'message':
b2a_base64('{0};{1}'.format(file_hash,
timestamp())).strip().decode('utf-8')
}
signature = generate_rsa_signature(to_send['message'],
self.private_key)
to_send['signature'] = b2a_base64(signature).strip().decode('utf-8')
# sign a message saying we've seen the image
r = self.__requester.request(
'POST',
'https://letterbox.mayursaxena.com/.netlify/functions/received',
json=to_send)
print('{0} {1}: {2}'.format(r.status_code, r.reason, r.text))
r.close()
def __decrypt_img(self, json_payload):
# decrypt key and IV using our RSA private key, then decrypt the image using AES
dec_key = a2b_base64(
rsa_decrypt(a2b_base64(json_payload['k']), self.private_key))
dec_iv = a2b_base64(
rsa_decrypt(a2b_base64(json_payload['i']), self.private_key))
decryptor = aes(dec_key, 2, dec_iv)
dec = decryptor.decrypt(a2b_base64(json_payload['d']))
# server uses DEFLATE to keep sizes down
return inflate(dec)
def bootup(self):
print('Device has been initialized... Beginning normal bootup.')
# ensure LetterBox has WiFi, then set the time via NTP
self.__wifi_manager.ensure_connection()
for attempt in range(1, 4):
try:
settime()
print('Time set.')
break
except:
print('Error setting time (attempt #{0}).'.format(attempt))
def __display_no_letter_text(self):
# Prompt the user to go register.
self.__display.clear()
self.__display.draw_text(0, 0, 'No letters yet!', self.__render_font,
65535)
self.__display.draw_text(0, 36, 'Register this device to be',
self.__render_font, 65535)
self.__display.draw_text(0, 72, 'able to send letters.',
self.__render_font, 65535)
self.__display.draw_text(0, 108, 'Head on over to:',
self.__render_font, 65535)
self.__display.draw_text(0, 144, 'letterbox.mayursaxena.com',
self.__render_font, 65535)
self.__display.draw_text(0, 180, 'and register this serial #:',
self.__render_font, 65535)
self.__display.draw_text(0, 216, self.serial_number,
self.__render_font, 65535)
def __store_keys(self):
try:
with open('private.key', 'r') as f:
print("Storing private key...")
pri = f.read()
self.__namespace.set_blob('pri_key', pri)
self.__namespace.set_i32('pri_key_len', len(pri))
self.__namespace.commit()
remove_file('private.key')
print('Key stored.')
except OSError:
pass
try:
with open('public.crt', 'r') as f:
print("Storing public key...")
pub = f.read()
self.__namespace.set_blob('pub_key', pub)
self.__namespace.set_i32('pub_key_len', len(pub))
self.__namespace.commit()
remove_file('public.crt')
print('Key stored.')
except OSError:
pass
print(e)
try:
nvs.get_i32("key1") # not found
except OSError as e:
print(e)
try:
nvs.get_i32("blob1") # not found (blob1 exists but diff type)
except OSError as e:
print(e)
try:
buf3 = bytearray(10)
nvs.get_blob("blob1", buf3) # invalid length (too short)
except OSError as e:
print(e)
nvs.commit() # we're not verifying that this does anything, just doesn't error
# test using a second namespace and that it doesn't interfere with first
nvs2 = NVS("mp-test2")
try:
print(nvs2.get_i32("key2"))
except OSError as e:
print(e)
nvs2.set_i32("key2", 7654)
print(nvs.get_i32("key2"))
print(nvs2.get_i32("key2"))
# clean-up (the namespaces will remain)
nvs.erase_key("key2")
nvs.erase_key("blob1")
nvs.erase_key("blob2")
nvs = NVS("uinstaller")
nvs_launcher = NVS("launcher")
def install(app_name):
nvs.set_blob('to_install', app_name)
nvs.commit()
system.start('uinstaller')
if system.__current_app__ == 'uinstaller':
appname = bytearray(40)
nvs.get_blob("to_install", appname)
to_install = appname.decode("utf-8").rstrip('\x00')
nvs.set_blob('to_install', "")
nvs.commit()
print('Installing %s' % to_install)
if not to_install:
system.reboot()
### For some reason normal uinterface.connect_wifi() doesn't
### work from dashboard.terminal.installer, so we have to do this
### odd workaround of connecting twice.
uinterface.connect_wifi()
uinterface.loading_text('Installing %s' % to_install)
gc.collect()
if woezel.install(to_install):
# Reset launcher's selected index to newly installed app
nvs_launcher.set_i32('index', 0)
app_file_bytes = bytearray(50)
nvs.get_blob("uninstall_name", app_bytes)
nvs.get_blob("uninstall_file", app_file_bytes)
app = app_bytes.decode("utf-8").rstrip('\x00')
app_file = app_file_bytes.decode("utf-8").rstrip('\x00')
if (not app) or not (app_file):
system.home()
agreed = interface.confirmation_dialog('Uninstall \'%s\'?' % app)
if not agreed:
system.home()
interface.loading_text("Removing " + app + "...")
install_path = woezel.get_install_path()
print(app)
print(app_file)
print(install_path)
for rm_file in os.listdir("%s/%s" % (install_path, app_file)):
os.remove("%s/%s/%s" % (install_path, app_file, rm_file))
os.rmdir("%s/%s" % (install_path, app_file))
nvs.set_blob('uninstall_name', '')
nvs.set_blob('uninstall_file', '')
nvs.commit()
interface.skippabletext("Uninstall completed!")
system.home()