带有 Python 瓶颈的“HTTP 错误 400：错误请求”

Question

我有以下文件（associate.py）

import bottlenose
from bs4 import BeautifulSoup
from urllib2 import HTTPError

;; My real keys are here in reality, I just replaced them 
;; with the following because they are private.
credentials = {'access-key' : 'MY_ACCESS_KEY_GOES_HERE',
               'secret-key' : 'MY_SECRET_KEY_GOES_HERE',
               'associate-tag' : 'MY_ASSOCIATE_TAG'}

def error_handler(err):
  ex = err['exception']
  if isinstance(ex, HTTPError) and ex.code == 503:
    time.sleep(random.expovariate(0.1))
    return True

api = bottlenose.Amazon(credentials['access-key'],
                        credentials['secret-key'],
                        credentials['associate-tag'],
                        Parser=BeautifulSoup,
                        ErrorHandler=error_handler,
                        MaxQPS=0.9)

def get_item(asin):
  return api.ItemLookup(ItemId=asin,
                        ResponseGroup="Large,Images,ItemAttributes")

这是我使用上面的 Ipython 会话的结果：

In [1]: import associate

In [2]: associate.get_item("B003K1IJWC")
---------------------------------------------------------------------------
HTTPError                                 Traceback (most recent call last)
<ipython-input-2-31ffe6a959e1> in <module>()
----> 1 associate.get_item("B003K1IJWC")

/home/stephen/work/pantry/associate.pyc in get_item(asin)
     22 def get_item(asin):
     23   return api.ItemLookup(ItemId=asin,
---> 24                         ResponseGroup="Large,Images,ItemAttributes")

/home/stephen/work/pantry/bottlenose/api.pyc in __call__(self, **kwargs)
    240         # make the actual API call
    241         response = self._call_api(api_url,
--> 242                                   {'api_url': api_url, 'cache_url': cache_url})
    243 
    244         # decompress the response if need be

/home/stephen/work/pantry/bottlenose/api.pyc in _call_api(self, api_url, err_env)
    201                 else:
    202                     # the simple way
--> 203                     return urllib2.urlopen(api_request, timeout=self.Timeout)
    204             except:
    205                 if not self.ErrorHandler:

/usr/lib/python2.7/urllib2.pyc in urlopen(url, data, timeout)
    125     if _opener is None:
    126         _opener = build_opener()
--> 127     return _opener.open(url, data, timeout)
    128 
    129 def install_opener(opener):

/usr/lib/python2.7/urllib2.pyc in open(self, fullurl, data, timeout)
    408         for processor in self.process_response.get(protocol, []):
    409             meth = getattr(processor, meth_name)
--> 410             response = meth(req, response)
    411 
    412         return response

/usr/lib/python2.7/urllib2.pyc in http_response(self, request, response)
    521         if not (200 <= code < 300):
    522             response = self.parent.error(
--> 523                 'http', request, response, code, msg, hdrs)
    524 
    525         return response

/usr/lib/python2.7/urllib2.pyc in error(self, proto, *args)
    446         if http_err:
    447             args = (dict, 'default', 'http_error_default') + orig_args
--> 448             return self._call_chain(*args)
    449 
    450 # XXX probably also want an abstract factory that knows when it makes

/usr/lib/python2.7/urllib2.pyc in _call_chain(self, chain, kind, meth_name, *args)
    380             func = getattr(handler, meth_name)
    381 
--> 382             result = func(*args)
    383             if result is not None:
    384                 return result

/usr/lib/python2.7/urllib2.pyc in http_error_default(self, req, fp, code, msg, hdrs)
    529 class HTTPDefaultErrorHandler(BaseHandler):
    530     def http_error_default(self, req, fp, code, msg, hdrs):
--> 531         raise HTTPError(req.get_full_url(), code, msg, hdrs, fp)
    532 
    533 class HTTPRedirectHandler(BaseHandler):

HTTPError: HTTP Error 400: Bad Request

奇怪的是，上面的请求 associate.get_item("B003K1IJWC") 在我的笔记本电脑上工作得很好，但在我的桌面上却失败了。

我的笔记本电脑是带有 python 2.7.5 的 Crouton Ubuntu 12.04，我的桌面是带有 Python 2.7.6 的 Ubuntu 14.04。我很难解释为什么这适用于一个而不是另一个。如果您对前面的代码为什么不能在桌面上运行有任何猜测，我将不胜感激。签名请求是否存在加密问题？我只是被难住了，不知道如何进行。谢谢。

Answer 1

在启动 wireshark 并查看响应后，亚马逊礼貌地告诉我“时区已过期”。

好吧，这有点尴尬。看，我的桌面是双启动 Windows 8（用于游戏）和 Ubuntu。当我从一个操作系统启动到另一个操作系统时，我一直遇到很多时钟歪斜的问题。所以，天才，我决定将我的时区设置为冰岛雷克雅未克（UTC 偏移 +0），禁用互联网时间同步，并手动将我的时间设置为本地时间（在 Windows 和 ubuntu 上）。这解决了我的时间偏差问题。

亚马逊不喜欢这样。它说时间戳在我提出的请求中已过期。因此，我重新启用了互联网同步并将我的时区设置为美国洛杉矶。一切正常。