Aws - AWS IoT Core Connection

2025-03-25

A client for connecting to AWS IoT Core, managing MQTT connections, and handling device shadows.

Constructor

Aws 

class Aws(client_id,server,port,keep_alive,ssl,ssl_params)

Parameters:

  • client_id (str) - The unique identifier for the IoT Thing.
  • server (str) - The AWS IoT Core endpoint.
  • port (int) - The MQTT port (default 8883 for TLS, 1883 for non-TLS).
  • keep_alive (int) - The keep-alive interval in seconds (default: 60).
  • ssl (bool) - Whether to use SSL/TLS (default: False. If True, encription is enabled, so we have to provide ssl_params).
  • ssl_params (dict) - SSL parameters for secure connection.

Example 

>>> # Create Aws object
>>> import aws
>>> aws = aws.Aws(client_id, server, port, keep_alive=60,ssl=True,ssl_params={"cert": 
certificate_content,"key": private_content})

MQTT Communication

Uses umqtt library methods to establish connection and communication with cloud.

aws.connect 

connect()

This method establishes a connection to AWS IoT Core.

Return Value:

None

aws.disconnect 

disconnect()

This method disconnects from AWS IoT Core.

Return Value:

None

aws.subscribe 

subscribe(topic)

Method for mqtt subscribing to a topic.

Parameters:

  • topic (str) - The MQTT topic to subscribe to.

Return Value:

None

aws.publish 

publish(topic, payload)

Method for mqtt publishing to a topic.

Parameters:

  • topic (str) - The MQTT topic to publish to.
  • payload (dict) - The message payload.

Return Value:

None

Shadow Device Management

aws.create_shadow 

create_shadow(shadow_name="", state="")

Parameters:

  • shadow_name (str) - The name of the shadow (optional).
  • state (dict) - The initial state of the shadow (optional).

Return Value:

None

aws.update_shadow 

update_shadow(shadow_name="", state="")

Parameters:

  • shadow_name (str) - The name of the shadow.
  • state (dict) - The new state of the shadow.

Return Value:

None

aws.get_shadow 

get_shadow(shadow_name="")

Parameters:

  • shadow_name (str) - The name of the shadow.

Return Value:

The current shadow state.

aws.delete_shadow 

delete_shadow(shadow_name="")

Parameters:

  • shadow_name (str) - The name of the shadow.

Return Value:

None

aws.connect_shadow 

connect_shadow(shadow_name="", topics=None)

Parameters:

  • shadow_name (str) - The name of the shadow (optional).
  • topics (list) - List of MQTT topics related to the shadow (optional).

Return Value:

None

aws.set_callback 

set_callback(topic_name, callback)

Parameters:

  • topic_name (str) - The MQTT topic for which the callback is set.

  • callback (function) - The function to be executed when a message is received. Prototype: 

      callback_function(msg)

    • Callback function parameter:

      • msg : dictionary type message. Already converted from JSON string to dictionary format.

Return Value:

None

Python Example 

import usr.aws as aws
import modem
import ujson
import sim  # Check if PIN verification is needed for your SIM card
import net

# AWS IoT credentials
certificate_content = """
-----BEGIN CERTIFICATE-----

-----END CERTIFICATE-----
"""

private_content = """
-----BEGIN RSA PRIVATE KEY-----

-----END RSA PRIVATE KEY-----
"""

client_id = 'qpthing'
server = 'abgka7vzgjoa0-ats.iot.eu-west-3.amazonaws.com'
port = 8883

def aws_callback(data):
    print("HELLO from 1234 topic callback")

def shadow_callback_get(data):
    print("HELLO from get accepted callback")

def shadow_callback_update(data):
    print("HELLO from update accepted callback")

def shadow_callback_delta(data):
    print("HELLO from update delta callback")

# Create AWS object
aws_obj = aws.Aws(client_id, server, port, keep_alive=60, ssl=True,
                  ssl_params={"cert": certificate_content, "key": private_content})
print("Created AWS object")

# Connect to AWS IoT
aws_obj.connect()
print("Connected to AWS IoT")

# Subscribe and publish
aws_obj.set_callback("1234", aws_callback)
aws_obj.subscribe("1234")
aws_obj.publish("7777", "Hello from QuecPython")
aws_obj.start()

# Shadow operations
aws_obj.create_shadow()
aws_obj.connect_shadow()
aws_obj.set_callback("$aws/things/qpthing/shadow/get/accepted", shadow_callback_get)
aws_obj.set_callback("$aws/things/qpthing/shadow/update/accepted", shadow_callback_update)
aws_obj.set_callback("$aws/things/qpthing/shadow/update/delta", shadow_callback_delta)
aws_obj.get_shadow()
aws_obj.update_shadow(state={"state": {"reported": {"welcome": "change reported"}}})