python使用消息队列RabbitMq（进阶）

import pika
  
connection = pika.BlockingConnection(pika.ConnectionParameters(
               'localhost'))
channel = connection.channel()
  
#声明queue
channel.queue_declare(queue='hello')
  
# RabbitMQ a message can never be sent directly to the queue, it always needs to go through an exchange.
channel.basic_publish(exchange='',
                      routing_key='hello',
                      body='Hello World!')
print(" [x] Sent 'Hello World!'")
connection.close()

__author__ = 'hardy'
import pika
  
connection = pika.BlockingConnection(pika.ConnectionParameters(
               'localhost'))
channel = connection.channel()
  
  
#You may ask why we declare the queue again ‒ we have already declared it in our previous code.
# We could avoid that if we were sure that the queue already exists. For example if send.py program
#was run before. But we're not yet sure which program to run first. In such cases it's a good
# practice to repeat declaring the queue in both programs.
channel.queue_declare(queue='hello')
  
def callback(ch, method, properties, body):
    print(" [x] Received %r" % body)
  
channel.basic_consume(callback,
                      queue='hello',
                      no_ack=True)
  
print(' [*] Waiting for messages. To exit press CTRL+C')
channel.start_consuming()

消息队列的发送端流程

　　1、连接

connection = pika.BlockingConnection(pika.ConnectionParameters('localhost'))
channel = connection.channel()

　　2、声明queue

channel.queue_declare(queue='hello')

　　队列持久化

channel.queue_declare(queue='hello', durable=True)

　　

　　3、发送消息

channel.basic_publish(exchange='',
                      routing_key='hello',
                      body='Hello World!')

　　消息持久化（必须队列持久化）

channel.basic_publish(exchange='',
                      routing_key="hello",
                      body=message,
                      properties=pika.BasicProperties(
                         delivery_mode = 2, # make message persistent
                      ))

　　4、关闭

connection.close()

消息队列接收端流程

　　1、连接

connection = pika.BlockingConnection(pika.ConnectionParameters(
               'localhost'))
channel = connection.channel()

　　2、声明queue

channel.queue_declare(queue='hello')

　　3、创建回调函数（处理数据）

def callback(ch, method, properties, body):
    print(" [x] Received %r" % body)

　　4、设置

channel.basic_consume(callback,
                      queue='hello',
                      no_ack=True)

　　5、开始接收数据

channel.start_consuming()

　　6、确认消息被消费

def callback(ch, method, properties, body):
    print(" [x] Received %r" % body)
    time.sleep(body.count(b'.'))
    print(" [x] Done")
    ch.basic_ack(delivery_tag = method.delivery_tag)

　　

channel.basic_consume(callback,
                       queue='task_queue',
                       no_ack=True  #no_ack=True消息不需要确认，默认no_ack=false，消息需要确认
                       )