Python中的多个意外POST请求

Question

我有这个程序使用请求库发送 GET 请求，然后将 POST 请求发送到另一台服务器。

import requests 

# inside the loop : 
headers = {'charset':'utf-8','Content-Type':'application/json'}
url = "http://someurl/_get_v2.php"
data = jenal

try :
    resp = requests.post(url,json=data,headers=headers, timeout=(connect_timeout,read_timeout))

    print "Post request sent" 
# If a connection error occurs, start from the beginning of the loop
except requests.exceptions.ConnectionError as e: 
    continue 
# If a read_timeout error occurs, start from the beginning of the loop
except requests.exceptions.ReadTimeout as e:  
    continue
time.sleep(10)

这是主循环的 POST 部分。我使用了 try ，除非程序遇到延迟，我不希望它因任何错误而停止，而是刷新并从循环的开头继续，以此类推。从逻辑上讲，程序应该没问题，但是当突然出现多个延迟时，程序会同时发送多个 POST 请求。

例如：日志应该是这样的： 10 发送。 20 发送。 30 发送。 已发送 45 个（延迟 5 秒）。 55已发送

但是发生的事情是这样的： 已发送 10 个 已发送 20 个 已发送 30 个 延迟..
45 已发送 45 已发送 已发送 45 个（同时发送了几份数据，这损坏了我的数据库） 55已发送

我应该如何防止多余的副本？

这是程序的第一部分。如果帖子部分有任何内容，这部分会重复，我每次都能看到打印：

connect_timeout = 3.05
read_timeout = 2

while True:
loop_time_start = time.time()
# GET

url_source = 'http://something/api_json.asp?cmd=list_metering&auth=YWRtaW46YWRtaW4='
try: 
    url = requests.get(url_source)
    print "GET request sent" 
except requests.exceptions.ConnectionError as e: continue

Answer 1

如果在代码中添加计时器会怎样。

import requests 
from datetime import datetime, time

posting = False

# inside the loop :

if not posting:
    posting = True

    headers = {'charset':'utf-8','Content-Type':'application/json'}
    url = "http://someurl/_get_v2.php"
    data = jenal

    start = datetime.now()
    try :
        resp = requests.post(url,json=data,headers=headers,timeout=(connect_timeout,read_timeout))

        print "Post request sent" 

        posting = False

    except requests.exceptions.ConnectionError as e:
        # If you continue here, then there will be no sleep.
        # If your POST fails straight away, it tries again straight away. 

        # You should print/log here so you know which exception is being caught.

        # Add Timer
        end = datetime.combine(start.date(), time(0))

        ShouldISleep(start, end)

        posting = False

        continue

    except requests.exceptions.ReadTimeout as e:
        # If you continue here, then there will be no sleep.
        # If your POST fails straight away, it tries again straight away.

        # You should print/log here so you know which exception is being caught.

        # Add Timer
        end = datetime.combine(start.date(), time(0))

        ShouldISleep(start, end)

        posting = False

        continue

    time.sleep(10)

创建一个函数

def ShouldISleep(t1, t2):
    passed = (t1 - t2).seconds
    if passed < 10:
        time.sleep(10 - passed)

Answer 2

I would recommend looking at the approved answer on this question.