Python，UTF-8 URI解码

Question

Python新手（ofcourse）在解码URI编码的字符串时遇到了一些问题。

我的代码：

#/usr/bin/env python 
# -*- coding: utf-8 -*- 
# Encoding: UTF-8 
... 
import urllib 
... 
secondTag = urllib.unquote(secondTag).decode('utf8') 
... 

当

secondTag = "flashvars=%7B%22video%22%3A%7B%22videoReferences%22%3A%5B%7B%22url%22%3A%22http%3A%2F%2Fsvtplay6a-f.akamaihd.net%2Fz%2Fse%2Fopen%2F20160405%2F1114066-002A%2FPG-1114066-002A-AFFARENRAMEL-01_%2C988%2C240%2C348%2C456%2C636%2C1680%2C2796%2C.mp4.csmil%2Fmanifest.f4m%22%2C%22playerType%22%3A%22flash%22%7D%5D%2C%22subtitleReferences%22%3A%5B%7B%22url%22%3A%22http%3A%2F%2Fmedia.svt.se%2Fdownload%2Fmcc%2Ftest%2Fcore-prd%2FSUB-1114066-002A-AFFARENRAMEL%2FSUB-1114066-002A-AFFARENRAMEL.wsrt%22%7D%5D%2C%22position%22%3A0%7D%2C%22statistics%22%3A%7B%22client%22%3A%22nojs%22%2C%22mmsClientNr%22%3A%221001001%22%2C%22programId%22%3A%221114066-002A%22%2C%22statisticsUrl%22%3A%22%2F%2Fld.svt.se%2Fsvt%2Fsvt%2Fs%3Fnojs.Aff%C3%A4ren%20Ramel.Avsnitt%202%22%2C%22title%22%3A%22Avsnitt%202%22%2C%22folderStructure%22%3A%22Aff%C3%A4ren%20Ramel%22%7D%2C%22context%22%3A%7B%7D%7D" 

结果是：

File "/home/mythtv/bin/pyPirateDownloader/svtPlay.py", line 70, in checkSecondSvtPage 
secondTag = urllib.unquote(secondTag).decode('utf8') 
File "/usr/lib64/python2.7/encodings/utf_8.py", line 16, in decode 
return codecs.utf_8_decode(input, errors, True) 
UnicodeEncodeError: 'ascii' codec can't encode characters in position 509-510: ordinal not in range(128) 

然而，当我在Python控制台运行相同的我得到预期的结果：

>>> import urllib 
>>> secondTag = "flashvars=%7B%22video%22%3A%7B%22videoReferences%22%3A%5B%7B%22url%22%3A%22http%3A%2F%2Fsvtplay6a-f.akamaihd.net%2Fz%2Fse%2Fopen%2F20160405%2F1114066-002A%2FPG-1114066-002A-AFFARENRAMEL-01_%2C988%2C240%2C348%2C456%2C636%2C1680%2C2796%2C.mp4.csmil%2Fmanifest.f4m%22%2C%22playerType%22%3A%22flash%22%7D%5D%2C%22subtitleReferences%22%3A%5B%7B%22url%22%3A%22http%3A%2F%2Fmedia.svt.se%2Fdownload%2Fmcc%2Ftest%2Fcore-prd%2FSUB-1114066-002A-AFFARENRAMEL%2FSUB-1114066-002A-AFFARENRAMEL.wsrt%22%7D%5D%2C%22position%22%3A0%7D%2C%22statistics%22%3A%7B%22client%22%3A%22nojs%22%2C%22mmsClientNr%22%3A%221001001%22%2C%22programId%22%3A%221114066-002A%22%2C%22statisticsUrl%22%3A%22%2F%2Fld.svt.se%2Fsvt%2Fsvt%2Fs%3Fnojs.Aff%C3%A4ren%20Ramel.Avsnitt%202%22%2C%22title%22%3A%22Avsnitt%202%22%2C%22folderStructure%22%3A%22Aff%C3%A4ren%20Ramel%22%7D%2C%22context%22%3A%7B%7D%7D" 
>>> secondTag = urllib.unquote(secondTag).decode('utf8') 
>>> print secondTag 
flashvars={"video":{"videoReferences":[{"url":"http://svtplay6a-f.akamaihd.net/z/se/open/20160405/1114066-002A/PG-1114066-002A-AFFARENRAMEL-01_,988,240,348,456,636,1680,2796,.mp4.csmil/manifest.f4m","playerType":"flash"}],"subtitleReferences":[{"url":"http://media.svt.se/download/mcc/test/core-prd/SUB-1114066-002A-AFFARENRAMEL/SUB-1114066-002A-AFFARENRAMEL.wsrt"}],"position":0},"statistics":{"client":"nojs","mmsClientNr":"1001001","programId":"1114066-002A","statisticsUrl":"//ld.svt.se/svt/svt/s?nojs.Affären Ramel.Avsnitt 2","title":"Avsnitt 2","folderStructure":"Affären Ramel"},"context":{}} 

Ofcourse这是一些编码问题，我想这与'ä'字符有关，因为当不存在瑞典字符时不会出现这个问题，但我只是不知道为什么以及如何修理它。

有人能够解释，也许有帮助吗？

感谢 /乔恩

Answer 1

请注意，这是一个Unicode编码错误：这是不是没有对其进行解码，这是它未能对其进行编码！

因为Python 2自动在str和unicode之间转换，所以如果尝试解码unicode字符串，则可能会出现编码错误。

这可能是正在发生的事情在这里：我在文件中设定，secondTag是unicode对象：然后urllib.unquote会返回一个unicode对象，所以当你试图将其解码它首先尝试将其编码为str对象，它可以使用默认的ascii编码对其进行解码，该编码失败。

有没有特别优雅的方式来处理这个问题。可能最优雅的方式是urllib.unquote(secondTag.encode('utf8')).decode('utf8')。如果你想处理已经是str的情况，你可以很容易地添加if isinstance(secondTag, unicode) else secondTag。