IoT Platform:Connect a client to IoT Platform by using the SDK for Python 2.7

Development environment

In this example, Python 2.7 is used.

Download the SDK

We recommend that you use the Apache Qpid Proton 0.29.0 library. This library encapsulates the Python API. To download the library and view the instructions, visit Qpid Proton 0.29.0.

Install Qpid Proton. For more information, see Installing Qpid Proton.

After you install Qpid Proton, run the following Python command to check whether the SSL library is available:

import proton;print('%s' % 'SSL present' if proton.SSL.present() else 'SSL NOT AVAILABLE')

Sample code

# encoding=utf-8
import sys
import logging
import time
from proton.handlers import MessagingHandler
from proton.reactor import Container
import hashlib
import hmac
import base64
import os

reload(sys)
sys.setdefaultencoding('utf-8')
logging.basicConfig(level=logging.INFO, format='%(asctime)s - %(name)s - %(levelname)s - %(message)s')
logger = logging.getLogger(__name__)
console_handler = logging.StreamHandler(sys.stdout)


def current_time_millis():
    return str(int(round(time.time() * 1000)))


def do_sign(secret, sign_content):
    m = hmac.new(secret, sign_content, digestmod=hashlib.sha1)
    return base64.b64encode(m.digest())


class AmqpClient(MessagingHandler):
    def __init__(self):
        super(AmqpClient, self).__init__()

    def on_start(self, event):
        # The endpoint. For more information, see the "Connect an AMQP client to IoT Platform" topic. 
        url = "amqps://${YourHost}:5671"
        # If you hard-code the AccessKey pair in the project code, the AccessKey pair may be disclosed if the project code is leaked. In this case, the resources within your account become insecure. The following sample code provides an example on how to obtain the AccessKey pair from environment variables. This example is for reference only.
        accessKey = os.environ['ALIBABA_CLOUD_ACCESS_KEY_ID']
        accessSecret = os.environ['ALIBABA_CLOUD_ACCESS_KEY_SECRET']
        consumerGroupId = "${YourConsumerGroupId}"
        clientId = "${YourClientId}"
        # iotInstanceId: The ID of the IoT Platform instance. 
        iotInstanceId = "${YourIotInstanceId}"
        # The signature algorithm. Valid values: hmacmd5, hmacsha1, and hmacsha256. 
        signMethod = "hmacsha1"
        timestamp = current_time_millis()
        # The structure of the userName parameter. For more information, see the "Connect an AMQP client to IoT Platform" topic. 
        userName = clientId + "|authMode=aksign" + ",signMethod=" + signMethod \
                        + ",timestamp=" + timestamp + ",authId=" + accessKey \
                        + ",iotInstanceId=" + iotInstanceId + ",consumerGroupId=" + consumerGroupId + "|"
        signContent = "authId=" + accessKey + "&timestamp=" + timestamp
        # Calculate a signature. For more information about how to construct the password, see the "Connect an AMQP client to IoT Platform" topic. 
        passWord = do_sign(accessSecret.encode("utf-8"), signContent.encode("utf-8"))
        conn = event.container.connect(url, user=userName, password=passWord, heartbeat=60)
        self.receiver = event.container.create_receiver(conn)

    # If the connection is established, the following function is called: 
    def on_connection_opened(self, event):
        logger.info("Connection established, remoteUrl: %s", event.connection.hostname)

    # If the connection is closed, the following function is called: 
    def on_connection_closed(self, event):
        logger.info("Connection closed: %s", self)

    # If the remote server closes the connection due to an error, the following function is called: 
    def on_connection_error(self, event):
        logger.info("Connection error")

    # If an AMQP connection error occurs, such as an authentication error or a socket error, the following function is called: 
    def on_transport_error(self, event):
        if event.transport.condition:
            if event.transport.condition.info:
                logger.error("%s: %s: %s" % (
                    event.transport.condition.name, event.transport.condition.description,
                    event.transport.condition.info))
            else:
                logger.error("%s: %s" % (event.transport.condition.name, event.transport.condition.description))
        else:
            logging.error("Unspecified transport error")

    # If a message is received, the following function is called: 
    def on_message(self, event):
        message = event.message
        content = message.body.decode('utf-8')
        topic = message.properties.get("topic")
        message_id = message.properties.get("messageId")
        print("receive message: message_id=%s, topic=%s, content=%s" % (message_id, topic, content))
        event.receiver.flow(1)


Container(AmqpClient()).run()

You can configure the parameters in the preceding code based on the parameter description in the following table. For more information about other parameters, see Connect an AMQP client to IoT Platform.

Sample results

• If information similar to the following output is displayed, the AMQP client is connected to IoT Platform and can receive messages.

  Parameter	Example	Description
  message_id	2**************7	The ID of the message.
  topic	/***********/******/thing/event/property/post	The topic that is used to submit device properties.
  content	{"deviceType":"CustomCategory","iotId":"qPi***","requestId":"161***","checkFailedData":{},"productKey":"g4***","gmtCreate":1613635594038,"deviceName":"de***","items":{"Temperature":{"value":24,"time":1613635594036},"Humidity":{"value":26,"time":1613635594036}}}	The content of the message.

• If information similar to the following output is displayed, the AMQP client fails to connect to IoT Platform.

  You can check the code or network environment based on logs, resolve the issue, and then run the code again.

  

References

For more information about the error codes that are related to the server-side subscription feature, see the Error codes that are related to messages section of the "IoT Platform logs" topic.