引发请求错误的最佳方法是什么？

Question

我正在阅读一些源代码，这些源代码会通过以下方式引发错误请求：

import requests

response = requests.get("www.google.com")   # This won't work because it's missing the http://
if response.ok is False or response.json()['status'] != 'success':
    raise Exception("API error: {}".format(response.json()['message']))

我在想最后两行可以替换为

response.raise_for_status()

我实际上没有看到返回的错误有任何区别。在这两种情况下都是

Traceback (most recent call last):
  File "/home/kurt/Documents/Scratch/requests_test.py", line 3, in <module>
    response = requests.get("www.google.com")   # This won't work because it's missing the http://
  File "/home/kurt/.local/lib/python2.7/site-packages/requests/api.py", line 69, in get
    return request('get', url, params=params, **kwargs)
  File "/home/kurt/.local/lib/python2.7/site-packages/requests/api.py", line 50, in request
    response = session.request(method=method, url=url, **kwargs)
  File "/home/kurt/.local/lib/python2.7/site-packages/requests/sessions.py", line 451, in request
    prep = self.prepare_request(req)
  File "/home/kurt/.local/lib/python2.7/site-packages/requests/sessions.py", line 382, in prepare_request
    hooks=merge_hooks(request.hooks, self.hooks),
  File "/home/kurt/.local/lib/python2.7/site-packages/requests/models.py", line 304, in prepare
    self.prepare_url(url, params)
  File "/home/kurt/.local/lib/python2.7/site-packages/requests/models.py", line 362, in prepare_url
    to_native_string(url, 'utf8')))
requests.exceptions.MissingSchema: Invalid URL 'www.google.com': No schema supplied. Perhaps you meant http://www.google.com?

在我看来raise_for_status() 更简洁，也许也不会丢失有关原始异常的信息（参见Use of "except Exception" vs. "except ... raise" in Python）。这确实是更好的方法吗？

Answer 1

response.raise_for_status() 仅在响应状态代码不是 200 响应时引发异常。第二种情况，response.json()['status'] != 'success' 为真，不覆盖。

但是，您有一个不同的错误。您永远无法进行if 测试，因为requests.get() 调用引发了异常。您未能传入架构（开头没有 http:// 或 https://）。因为在requests.get() 表达式中引发了异常，所以下一行根本不会执行。甚至没有发送请求，因此您也无法对响应做出任何断言。

测试有更多问题：

• requests.ok is False 不是惯用的 Python；你会改用not requests.ok
• 如果requests.ok is False 为真，那么requests.json() 调用很可能完全失败，因此使用response.json()['message']) 的下一行将产生不同的异常。