# -*- encoding: utf-8 -*-
"""
@Time    : 2021/6/12 23:43
@Author  : boli.hong
  RPC模式
"""
import pika
import sys

# 连接RabbitMQ服务器
connection = pika.BlockingConnection(pika.ConnectionParameters(host='localhost'))
channel = connection.channel()

# 创建队列
channel.queue_declare(queue='rpc_queue')


def fib(n):
    """
    斐波纳契数列
    注意：由于该方法是递归，这里是用来测试一些耗时任务
    """
    if n == 0:
        return 0
    elif n == 1:
        return 1
    else:
        return fib(n - 1) + fib(n - 2)


def on_request(ch, method, props, body):
    """
    回调方法，执行实际的操作并做出响应
    """
    n = int(body)

    print(" [.] fib(%s)" % (n,))
    response = fib(n)

    # 发送消息，交换器为默认交换器（空交换器）
    ch.basic_publish(exchange='',
                     routing_key=props.reply_to,
                     properties=pika.BasicProperties(correlation_id=props.correlation_id),
                     body=str(response))

    # 消息确认
    ch.basic_ack(delivery_tag=method.delivery_tag)


# 设置消费者允许的最大未确认消息数量为1
channel.basic_qos(prefetch_count=1)

# 定义队列的消费回调，将消息传递给回调函数同时关闭自动消息确认
channel.basic_consume(queue='rpc_queue', on_message_callback=on_request)

print(" [x] Awaiting RPC requests")

# 开始消费/接收消息，注意：这是一个死循环，相当于`while True`
channel.start_consuming()