第7章云平台

    以下是一个使用python和aws iot core的完整示例，演示如何将物联网设备连接到aws云平台，并利用aws lambda函数处理设备数据。

    首先，我们需要创建一个aws iot core东西，并注册一个设备。记下设备的证书信息，以便在后面的示例中使用。

    1 安装boto3和pyqt5库：

    ```bash

    pip install boto3

    pip install pyqt5

    ```

    2 创建一个aws lambda函数。在这个示例中，我们创建一个简单的lambda函数，它将接收来自设备的消息并将其打印到cloudwatch logs。

    ```python

    import json

    def lambda_handler(event, context):

    print(&34;received event: &34; + jsondumps(event, indent=2))

    ```

    3 编写连接到aws iot core的设备代码：

    ```python

    import sys

    import time

    import pyqt5qtcore

    from pyqt5qtcore import qthread, pyqtsignal, qt

    import boto3

    import hmac

    import hashlib

    import base64

    from cryptopublickey import rsa

    from cryptosignature import pkcs1_15

    配置aws iot

    endpoint = &34;your_aws_iot_endpoint&34;

    region_name = &34;your_aws_region&34;

    client_id = &34;your_client_id&34;

    thing_name = &34;your_thing_name&34;

    ca_file = &34;your_root_ca_filepem&34;

    cert_file = &34;your_certificate_filepemcrt&34;

    private_key_file = &34;your_private_key_filepem&34;

    mqtt设置

    mqtt_topic = &34;aws/things/{}/shadow/update/accepted&34;format(thing_name)

    mqtt_qos = 1

    lambda设置

    lambda_function_name = &34;your_lambda_function_name&34;

    初始化aws iot和lambda客户端

    iot = boto3client(&39;iot&39;, region_name=region_name, endpoint=endpoint)

    lambda_client = boto3client(&39;lambda&39;, region_name=region_name)

    设备客户端id

    client_id = &34;{}::{}&34;format(thing_name, client_id)

    生成mqtt客户端id

    client_id_mqtt = &34;{}::{}&34;format(thing_name, &39;mqtt&39;)

    生成mqtt用户名

    username_mqtt = &34;{}::{}&34;format(thing_name, &39;mqtt&39;)

    生成签名

    def calc_signature(key, data):

    signature = hmacnew(key, data, hashlibsha256)digest()

    signature = base64b64encode(signature)

    return signature

    连接aws iot

    def on_connected():

    print(&34;connected to aws iot&34;)

    iotpublish(

    topic=mqtt_topic,

    qos=mqtt_qos,

    payload=&34;{}&34;format(timetime())

    )

    订阅aws iot主题

    def on_subscribe():

    print(&34;subscribed to topic: {}&34;format(mqtt_topic))

    接收aws iot消息

    def on_message():

    print(&34;received message: {}&34;format(msgpayload))

    payload = jsonloads(msgpayload)

    print(&34;message data: {}&34;format(payload))

    调用lambda函数

    lambda_clientinvoke(

    functionname=lambda_function_name,

    invocationtype=&39;event&39;,

    payload=jsondumps(payload)

    )

    断开aws iot连接

    def on_disconnected():

    print(&34;disconnected from aws iot&34;)

    mqtt客户端

    def on_mqtt_message(client, userdata, msg):

    print(&34;received mqtt message: {}&34;format(msgpayload))

    mqtt连接丢失回调

    def on_mqtt_disconnect(client, userdata, rc):

    if rc != 0:

    print(&34;mqtt disconnected with result code {}&34;format(rc))

    else:

    print(&34;mqtt disconnected&34;)

    mqtt异常处理回调```

    这段代码中包含了连接到aws iot core设备、发布消息到aws iot主题、订阅主题、接收消息、调用lambda函数等功能。实际使用时，请根据您的设备和需求进行调整。