urllib2 不处理 http NO_CONTENT (204) 作为成功的 HTTPS 响应

Question

我在 digi Connectport X4 中使用嵌入式 python (2.4.3) 这是使用 HTTPS 发布到 Azure IoT 中心的代码：

import urllib, sys, datetime, time
import urllib2
iot_device_id = 'HTTP_Device'
iot_endpoint = 'https://winiothub.azure-devices.net/devices/' + iot_device_id + '/messages/events?api-version=2016-02-03'
sas_header = {'Authorization': 'SharedAccessSignature sr=winiothub.azure-devices.net%2Fdevices%2FHTTP_Device&sig=o7dndsA%2FJOnkzYRUhqAwMrQXVhOTpIJqJqILyGDdQAc%3D&se=1522414643'}
while True:
    #try:
        body_data = { 'gateway_serial': '123', 'readingvalue':'66.00', 'date': str(datetime.datetime.now())}
        iot_request = urllib2.Request(iot_endpoint, str(body_data), sas_header)
        resp = urllib2.urlopen(iot_request)
        contents = resp.read()
        resp.close()
        time.sleep(1)
    #except:
    #    print 'error'
    #    time.sleep(1)

代码实际上将消息发布到集线器，但抛出以下错误：

Traceback (most recent call last):
  File "C:\Users\JeffreyBiesecker\documents\visual studio 2017\Projects\NewGateAzure\NewGateAzure\NewGateAzure2.py", line 14, in ?
    urllib2.urlopen(iot_request)
  File "C:\Python24\lib\urllib2.py", line 130, in urlopen
    return _opener.open(url, data)
  File "C:\Python24\lib\urllib2.py", line 364, in open
    response = meth(req, response)
  File "C:\Python24\lib\urllib2.py", line 471, in http_response
    response = self.parent.error(
  File "C:\Python24\lib\urllib2.py", line 402, in error
    return self._call_chain(*args)
  File "C:\Python24\lib\urllib2.py", line 337, in _call_chain
    result = func(*args)
  File "C:\Python24\lib\urllib2.py", line 480, in http_error_default
    raise HTTPError(req.get_full_url(), code, msg, hdrs, fp)
urllib2.HTTPError: HTTP Error 204: No Content
Press any key to continue . . .

如果在嵌入式 Digi 网关中运行代码，或者如果我在 Visual Studio 中使用 2.4.3 版本的 Python 运行，我会收到错误。

Answer 1

urllib2.HttpError 包含收到的响应代码。因此，您可以捕获异常，测试 204，如果是这种情况，则可以安全地继续。否则，您可以处理（或重新抛出）异常。

try:
    resp = urllib2.urlopen(iot_request)
except urllib2.HTTPError as e:
    if e.code == 204: pass
    else: raise