Python demo

The demo is as follows:

#!/usr/bin/env python
# coding=utf8

import os
import time
from aliyunsdkcore.acs_exception.exceptions import ServerException
from aliyunsdkcore.client import AcsClient
from aliyunsdkdybaseapi.request.v20170525.QueryTokenForMnsQueueRequest import QueryTokenForMnsQueueRequest
from aliyunsdkcore.profile import region_provider
from datetime import datetime
from aliyunsdkdybaseapi.mns.account import Account
from aliyunsdkdybaseapi.mns.queue import *
from aliyunsdkdybaseapi.mns.mns_exception import *

try:
    import json
except ImportError:
    import simplejson as json


# TODO: Replace this with the message type you want to receive.
message_type = "<MessageType>"
# TODO: Replace this with your queue name. After you enable the message service in the Alibaba Cloud Communication console, you can find the queue name on the page.
queue_name = "<QueueName>"

# The fixed endpoint of Alibaba Cloud Communication.
endpoint = "https://1943695596114318.mns.cn-hangzhou.aliyuncs.com/"
# An Alibaba Cloud account AccessKey has full access to all APIs. Use a Resource Access Management (RAM) user for API calls and routine O&M.
# Do not save your AccessKey ID and AccessKey secret in your project code. Leaking your AccessKey threatens the security of all resources in your account.
# This example uses environment variables to store the AccessKey ID and AccessKey secret for API authentication.
acs_client = AcsClient(os.getenv("SECRET_AK_ENV"), os.getenv("SECRET_SK_ENV"), "cn-hangzhou")
region_provider.add_endpoint("Dybaseapi", "dybaseapi.aliyuncs.com", "cn-hangzhou")


# The Alibaba Cloud Communication service token expires and must be dynamically updated.
class Token():
    def __init__(self):
        self.token = None
        self.tmp_access_id = None
        self.tmp_access_key = None
        self.expire_time = None

    def is_refresh(self):
        if self.expire_time is None:
            return 1
        # Compare the expiration time with the current system time. Refresh the token 2 minutes in advance.
        now = datetime.now()
        expire = datetime.strptime(self.expire_time, "%Y-%m-%d %H:%M:%S")
        if expire <= now or (expire - now).seconds < 120:
            return 1
        return 0

    def refresh(self):
        print("start refresh token...")
        request = QueryTokenForMnsQueueRequest()
        request.set_MessageType(message_type)
        request.set_QueueName(queue_name)
        response = acs_client.do_action_with_exception(request)
        # print response
        if response is None:
            raise ServerException("GET_TOKEN_FAIL", "No response when getting the token")

        response_body = json.loads(response)

        if response_body.get("Code") != "OK":
            raise ServerException("GET_TOKEN_FAIL", "Failed to get the token")

        sts_token = response_body.get("MessageTokenDTO")
        self.tmp_access_key = sts_token.get("AccessKeySecret")
        self.tmp_access_id = sts_token.get("AccessKeyId")
        self.expire_time = sts_token.get("ExpireTime")
        self.token = sts_token.get("SecurityToken")

        print("finish refresh token...")


# Initialize token, my_account, and my_queue
token, my_account, my_queue = Token(), None, None

# Read and delete messages in a loop until the queue is empty.
# The receive message request uses long polling. The wait_seconds parameter specifies a long polling period of 3 seconds.

## Long polling explained:
### If the queue contains messages, the request returns immediately.
### If the queue is empty, the request waits on the MNS server for 3 seconds. If a message is written to the queue during this time, the request immediately returns the message. After 3 seconds, the request returns a "queue is empty" response.

wait_seconds = 3
print("%sReceive And Delete Message From Queue%s\nQueueName:%s\nWaitSeconds:%s\n" % (
    10 * "=", 10 * "=", queue_name, wait_seconds))

while True:
    receipt_handles = []
    # Read messages
    try:
        # Check if the token has expired and needs to be refreshed.
        if token.is_refresh() == 1:
            # Refresh the token.
            token.refresh()
            if my_account:
                my_account.mns_client.close_connection()
                my_account = None

        if not my_account:
            my_account = Account(endpoint, token.tmp_access_id, token.tmp_access_key, token.token)
            my_queue = my_account.get_queue(queue_name)

        # Receive messages.
        recv_msgs = my_queue.batch_receive_message(10, wait_seconds)

        for recv_msg in recv_msgs:
            # TODO: Add your business logic here.

            # receipt_handles.append(recv_msg.receipt_handle)
            print("Receive Message Succeed! ReceiptHandle:%s MessageBody:%s MessageID:%s" % (
                recv_msg.receipt_handle, recv_msg.message_body, recv_msg.message_id))

    except MNSExceptionBase as e:
        if e.type == "QueueNotExist":
            print("Queue not exist, please create queue before receive message.")
            break
        elif e.type == "MessageNotExist":
            print("Queue is empty! sleep 10s")
            time.sleep(10)
            continue
        print("Receive Message Fail! Exception:%s\n" % e)
        break

    # Delete messages.
    try:
        if len(receipt_handles) > 0:
            # my_queue.batch_delete_message(receipt_handles)
            print("Delete Message Succeed!  ReceiptHandles:%s" % receipt_handles)
    except MNSExceptionBase as e:
        print("Delete Message Fail! Exception:%s\n" % e)