【Python开发】Url中文字符时记得转码edcode("utf-8")

在url中使用中文其实是一个坏习惯，会带来一系列的转码问题，我更喜欢英文译名或者id来标识某个uri。但是现实往往是残酷的，特别是在我们调用别人服务时候，有时候被逼无奈使用中文URL。

Python中unicode转码一向是让人头疼的问题。数次碰壁之后，我也摸出了一些门道，研读完Python字符串的encode与decode 之后，就自认为找到了万金油，谁知道这次又碰上这个老冤家。

`01`	`Traceback (most recent call last):`

`02`	`File` `"<stdin>", line` `1,` `in` `<module>`

`03`	`File` `"/usr/lib/python2.6/urllib2.py", line` `126,` `in` `urlopen`

`04`	`return` `_opener.open(url, data, timeout)`

`05`	`File` `"/usr/lib/python2.6/urllib2.py", line` `391,` `in` `open`

`06`	`response` `=` `self._open(req, data)`

`07`	`File` `"/usr/lib/python2.6/urllib2.py", line` `409,` `in` `_open`

`08`	`'_open', req)`

`09`	`File` `"/usr/lib/python2.6/urllib2.py", line` `369,` `in` `_call_chain`

`10`	`result` `=` `func(*args)`

`11`	`File` `"/usr/lib/python2.6/urllib2.py", line` `1170,` `in` `http_open`

`12`	`return` `self.do_open(httplib.HTTPConnection, req)`

`13`	`File` `"/usr/lib/python2.6/urllib2.py", line` `1142,` `in` `do_open`

`14`	`h.request(req.get_method(), req.get_selector(), req.data, headers)`

`15`	`File` `"/usr/lib/python2.6/httplib.py", line` `914,` `in` `request`

`16`	`self._send_request(method, url, body, headers)`

`17`	`File` `"/usr/lib/python2.6/httplib.py", line` `951,` `in` `_send_request`

`18`	`self.endheaders()`

`19`	`File` `"/usr/lib/python2.6/httplib.py", line` `908,` `in` `endheaders`

`20`	`self._send_output()`

`21`	`File` `"/usr/lib/python2.6/httplib.py", line` `780,` `in` `_send_output`

`22`	`self.send(msg)`

`23`	`File` `"/usr/lib/python2.6/httplib.py", line` `759,` `in` `send`

`24`	`self.sock.sendall(str)`

`25`	`File` `"<string>", line` `1,` `in` `sendall`

`26`	`UnicodeEncodeError:` `'ascii'` `codec can't encode characters` `in` `position` `7-8: ordinal` `not` `in` `range(128)`

这次错误引发是在 urlopen() 引起的，很有特色，开始使用 url.encode('utf-8') 就可以解决了。今天我做了一些测试。

1. ascii + unicode 测试

`01`	`>>>` `'a'` `+` `u'b'`

`02`	`>>>` `'你'` `+` `u'好'`

`03`	`Traceback (most recent call last):`

`04`	`File` `"<stdin>", line` `1,` `in` `<module>`

`05`	`UnicodeDecodeError:` `'ascii'` `codec can't decode byte` `0xe4` `in` `position` `0: ordinal` `not` `in` `range(128)`

`06`	`>>> u'你'` `+` `u'好'`

`07`	`u'u4f60u597d'`

`08`	`>>> u'a'` `+` `'你'` `+` `u'好'`

`09`	`Traceback (most recent call last):`

`10`	`File` `"<stdin>", line` `1,` `in` `<module>`

`11`	`UnicodeDecodeError:` `'ascii'` `codec can't decode byte` `0xe4` `in` `position` `0: ordinal` `not` `in` `range(128)`

上面的测试说明ascii码和unicode码相连操作，结论是有中文记得带上u，就不会有问题。 Python默认解码器是ascii，无法解码unicode中的中文。

2. urllib2的测试

`01`	`>>>` `import` `urllib2`

`02`	`>>> h1` `=` `'http://baidu.com'`

`03`	`>>> urllib2.urlopen(h1)`

`04`	`<addinfourl at` `153439532` `whose fp` `=` `<socket._fileobject` `object` `at` `0xb74e51ac>>`

`05`	`>>> h2` `=` `u'http://baidu.com'`

`06`	`>>> urllib2.urlopen(h2)`

`07`	`<addinfourl at` `153440236` `whose fp` `=` `<socket._fileobject` `object` `at` `0x925912c>>`

`08`	`>>> h3` `=` `'http://baidu.com?w=测试'`

`09`	`>>> urllib2.urlopen(h3)`

`10`	`<addinfourl at` `153482348` `whose fp` `=` `<socket._fileobject` `object` `at` `0x92593ac>>`

`11`	`>>> h4` `=` `u'http://baidu.com?w=测试'`

`12`	`>>> urllib2.urlopen(h4)`

`13`	`Traceback (most recent call last):`

`14`	`File` `"<stdin>", line` `1,` `in` `<module>`

`15`	`File` `"/usr/lib/python2.6/urllib2.py", line` `126,` `in` `urlopen`

`16`	`return` `_opener.open(url, data, timeout)`

`17`	`File` `"/usr/lib/python2.6/urllib2.py", line` `391,` `in` `open`

`18`	`response` `=` `self._open(req, data)`

`19`	`File` `"/usr/lib/python2.6/urllib2.py", line` `409,` `in` `_open`

`20`	`'_open', req)`

`21`	`File` `"/usr/lib/python2.6/urllib2.py", line` `369,` `in` `_call_chain`

`22`	`result` `=` `func(*args)`

`23`	`File` `"/usr/lib/python2.6/urllib2.py", line` `1170,` `in` `http_open`

`24`	`return` `self.do_open(httplib.HTTPConnection, req)`

`25`	`File` `"/usr/lib/python2.6/urllib2.py", line` `1142,` `in` `do_open`

`26`	`h.request(req.get_method(), req.get_selector(), req.data, headers)`

`27`	`File` `"/usr/lib/python2.6/httplib.py", line` `914,` `in` `request`

`28`	`self._send_request(method, url, body, headers)`

`29`	`File` `"/usr/lib/python2.6/httplib.py", line` `951,` `in` `_send_request`

`30`	`self.endheaders()`

`31`	`File` `"/usr/lib/python2.6/httplib.py", line` `908,` `in` `endheaders`

`32`	`self._send_output()`

`33`	`File` `"/usr/lib/python2.6/httplib.py", line` `780,` `in` `_send_output`

`34`	`self.send(msg)`

`35`	`File` `"/usr/lib/python2.6/httplib.py", line` `759,` `in` `send`

`36`	`self.sock.sendall(str)`

`37`	`File` `"<string>", line` `1,` `in` `sendall`

`38`	`UnicodeEncodeError:` `'ascii'` `codec can't encode characters` `in` `position` `7-8: ordinal` `not` `in` `range(128)`

这个测试说明， urllib2.urlopen() 可以接受ascii/unicode的英文，也可以接受ascii的中文，但是一旦是unicode的中文url，就会报转码错误。

so，请尽量英文url，非要用中文，请记得转码。