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Fix MicroPython 1.23 compatibility issues #3

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Fix MicroPython 1.23 compatibility issues #3

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1043bdf
Fix MicroPython 1.23+ compatability issue due to breaking change in t…
Jul 28, 2024
97daf53
allow example code to work on older micropython versions
Jul 28, 2024
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56 changes: 45 additions & 11 deletions main.py
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Original file line number Diff line number Diff line change
@@ -1,8 +1,10 @@
import os
import sys
import time
import ujson
import machine
import network
import ssl
from umqtt.simple import MQTTClient

#Enter your wifi SSID and password below.
Expand All @@ -15,22 +17,21 @@
aws_endpoint = b'AWS_ENDPOINT.amazonaws.com'

#If you followed the blog, these names are already set.
# To validate the IoT endpoint, the Amazon Root CA cert is needed.
# You can get this from https://www.amazontrust.com/repository/AmazonRootCA1.pem
# This can also be downloaded when creating the certs for your device in the IoT Console
# For more details:
# https://docs.aws.amazon.com/iot/latest/developerguide/server-authentication.html#server-authentication-certs
thing_name = "BlogThing"
client_id = "BlogClient"
private_key = "private.pem.key"
private_cert = "cert.pem.crt"

#Read the files used to authenticate to AWS IoT Core
with open(private_key, 'r') as f:
key = f.read()
with open(private_cert, 'r') as f:
cert = f.read()
ca_cert = "AmazonRootCA1.pem"

#These are the topics we will subscribe to. We will publish updates to /update.
#We will subscribe to the /update/delta topic to look for changes in the device shadow.
topic_pub = "$aws/things/" + thing_name + "/shadow/update"
topic_sub = "$aws/things/" + thing_name + "/shadow/update/delta"
ssl_params = {"key":key, "cert":cert, "server_side":False}

#Define pins for LED and light sensor. In this example we are using a FeatherS2.
#The sensor and LED are built into the board, and no external connections are required.
Expand All @@ -51,12 +52,37 @@
print('Connection successful')
print('Network config:', wlan.ifconfig())

def mqtt_connect(client=client_id, endpoint=aws_endpoint, sslp=ssl_params):
mqtt = MQTTClient(client_id=client, server=endpoint, port=8883, keepalive=1200, ssl=True, ssl_params=sslp)
def connect_to_iot(mqtt_client):
print("Connecting to AWS IoT...")
mqtt.connect()
mqtt_client.connect()
print("Done")
return mqtt
return mqtt_client

# used for micropython 1.23 and above
def mqtt_connect_new(client=client_id, endpoint=aws_endpoint, key=private_key, cert=private_cert, ca=ca_cert):
ctx = ssl.SSLContext(ssl.PROTOCOL_TLS_CLIENT)

# cert and key must be strings if using a file path.
# If these are bytes (b""), then they are interpreted as the cert data
ctx.load_cert_chain(cert, key)

# to verify the IoT Endpoint's certificate is valid
ctx.load_verify_locations(cafile=ca)
ctx.verify_mode = ssl.CERT_REQUIRED

mqtt = MQTTClient(client_id=client, server=endpoint, port=8883, keepalive=1200, ssl=ctx)
return connect_to_iot(mqtt)

# used for micropython 1.22 and below
def mqtt_connect(client=client_id, endpoint=aws_endpoint):
with open(private_key, 'r') as f:
key = f.read()
with open(private_cert, 'r') as f:
cert = f.read()

sslp = {"key": key, "cert": cert, "server_side": False}
mqtt = MQTTClient(client_id=client, server=endpoint, port=8883, keepalive=1200, ssl=True, ssl_params=sslp)
return connect_to_iot(mqtt)

def mqtt_publish(client, topic=topic_pub, message=''):
print("Publishing message...")
Expand All @@ -74,6 +100,14 @@ def mqtt_subscribe(topic, msg):
def led_state(message):
led.value(message['state']['led']['onboard'])

# determine micropython version
# change the connection implementation if 1.23+ due to a breaking change with ssl
# see: https://github.com/micropython/micropython-lib/pull/793
if sys.implementation.version[1] >= 23:
mqtt_connect = mqtt_connect_new
else:
mqtt_connect = mqtt_connect

#We use our helper function to connect to AWS IoT Core.
#The callback function mqtt_subscribe is what will be called if we
#get a new message on topic_sub.
Expand Down