python 请求/urllib3 连接池未捕获 HTTP 错误

Question

带有连接池的 python 请求 (urllib3) 没有捕获 http 错误。这是一个错误吗？还是我做错了什么？

#!/usr/bin/env python

import contextlib
import requests
import sys

connection_pool_size = 2
adapter = requests.adapters.HTTPAdapter(pool_connections=connection_pool_size,
                                        pool_maxsize=connection_pool_size)
r_session = requests.Session()
r_session.mount('http', adapter)

try:
    with contextlib.closing(r_session.get(sys.argv[1], timeout=30, allow_redirects=True)) as r:
        print 'success %r' % r
except requests.exceptions.HTTPError as e:
    print 'HTTPError %r' % e
except Exception as e:
    print 'Exception %r' % e

输出：

$ ./test.py https://github.com
success <Response [200]>
$ ./test.py https://github.com/sithlordyoyoma
success <Response [404]>

我期待 HTTPError 。我做错了吗？

我从这个线程 should I call close() after urllib.urlopen()? 得到的 contextlib 结束。正如 Alex Martelli 所建议的那样。

在没有连接的情况下实际运行的请求也显示此行为

#!/usr/bin/env python

import contextlib
import requests
import sys


try:
    with contextlib.closing(requests.get(sys.argv[1], timeout=30, allow_redirects=True)) as r:
        print 'success %r' % r
except requests.exceptions.HTTPError as e:
    print 'HTTPError %r' % e
except Exception as e:
    print 'Exception %r' % e

输出：

$ ./test.py https://github.com
success <Response [200]>
$ ./test.py https://github.com/sithlordyoyoma
success <Response [404]>

urllib2 正确地做到了这一点

#!/usr/bin/env python

import contextlib
import urllib2
import sys


try:
    with contextlib.closing(urllib2.urlopen(sys.argv[1], timeout=30)) as r:
        print 'success %r' % r
except urllib2.HTTPError as e:
    print 'HTTPError %r' % e
except Exception as e:
    print 'Exception %r' % e

输出：

$ ./test.py https://github.com
success <addinfourl at 4338734792 whose fp = <socket._fileobject object at 0x1025a5c50>>
$ ./test.py https://github.com/sithlordyoyoma
HTTPError HTTPError()

Answer 1

不管连接池如何，requests.post（和其他 HTTP 方法）都不会在 404 上引发 HTTPError。HTTPError 是通过调用 .raise_for_status() 引发的，如下例所示：

#!/usr/bin/env python

import requests

r = requests.post(
    'https://github.com/sithlordyoyoma',
    timeout=30,
    allow_redirects=True
)
print 'success %r' % r
r.raise_for_status()