即使出现错误仍继续执行python脚本

Question

我有一个记录房间温度的Python脚本，并使用请求库发送数据。有时我失去了wifi信号，脚本在请求出错后完全停止。

import sys
import time
import Adafruit_DHT
import requests

raspid = 1
sensor = 11
pin = 25

while True:   
    humidity, temperature = Adafruit_DHT.read_retry(sensor, pin)
    if humidity is not None and temperature is not None:
        datos = {'temperatura': 'temperature', 'humedad': 'humidity', 'raspid': 'raspid'}
        r = requests.post("http://httpbin.org/post", data=datos)
        print(r.text)
    else:
        print ('Error de lectura!')
        time.sleep(15)

从wifi断开时出错

Traceback (most recent call last):
  File "/home/pi/Desktop/dht11 request post.py", line 19, in <module>
    r = requests.post("http://mehr.cl/link.php", data=datos)
  File "/usr/lib/python2.7/dist-packages/requests/api.py", line 94, in post
    return request('post', url, data=data, json=json, **kwargs)
  File "/usr/lib/python2.7/dist-packages/requests/api.py", line 49, in request
    return session.request(method=method, url=url, **kwargs)
  File "/usr/lib/python2.7/dist-packages/requests/sessions.py", line 457, in request
    resp = self.send(prep, **send_kwargs)
  File "/usr/lib/python2.7/dist-packages/requests/sessions.py", line 569, in send
    r = adapter.send(request, **kwargs)
  File "/usr/lib/python2.7/dist-packages/requests/adapters.py", line 407, in send
    raise ConnectionError(err, request=request)
ConnectionError: ('Connection aborted.', error(101, 'Network is unreachable'))
>>> 

有没有一种方法可以忽略错误并重试？

Answer 1

是的，有。它确实在尝试，并捕获任何引发的错误。

下面是它的基本工作原理：

try:
    # Some action that could raise an error

except:
    # What to do when an error occurs

有关更深入的解释，请查看文档：Errors and Exceptions。

有几个内置的例外，ConnectionError就是其中之一。如果您知道所期望的确切异常，则必须将其添加到except子句中：

try:
    # Actions that might raise a ConnectionError

except ConnectionError:
    # Process the error, for instance, try again

Answer 2

您可能希望使用try-except语句。如下所示

while True:
    try:
        #action which may create an error
    except Exception as exc:
        print('[!!!] {err}'.format(err=exc))
        #action to perform: Nothing in your case

请注意，一个好的实践是一个错误的should never pass silently。

​

在注释中的讨论之后，还要注意，如果您使用Exception处理错误，您仍然可以手动停止while-loop，因为您使用的是python27。

​

Answer 3

您可以将循环包装在try语句中。

while True:  
    try: 
        humidity, temperature = Adafruit_DHT.read_retry(sensor, pin)
        if humidity is not None and temperature is not None:
            datos = {'temperatura': 'temperature', 'humedad': 'humidity', 'raspid': 'raspid'}
            r = requests.post("http://httpbin.org/post", data=datos)
            print(r.text)
        else:
            print ('Error de lectura!')
            time.sleep(15)
            sys.exit(1)
    except ConnectionError:
      continue

这样，当您断开连接时，您的代码将避开错误，从而防止它停止。