I encountered what seems like an incompatibility between urllib and urllib2 in the way they handle file:// URLs. Here's a console session to illustrate:
vinay <at> eta-karmic:/tmp$ echo Hello, world! >hello.txt
vinay <at> eta-karmic:/tmp$ cat hello.txt
Hello, world!
vinay <at> eta-karmic:/tmp$ python
Python 2.6.4 (r264:75706, Dec 7 2009, 18:45:15)
[GCC 4.4.1] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> import urllib,urllib2
>>> s = 'file:////tmp/hello.txt'
>>> f1 = urllib.urlopen(s)
>>> f1.read()
'Hello, world!\n'
>>> f2 = urllib2.urlopen(s)
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "/usr/lib/python2.6/urllib2.py", line 124, in urlopen
return _opener.open(url, data, timeout)
File "/usr/lib/python2.6/urllib2.py", line 389, in open
response = self._open(req, data)
File "/usr/lib/python2.6/urllib2.py", line 407, in _open
'_open', req)
File "/usr/lib/python2.6/urllib2.py", line 367, in _call_chain
result = func(*args)
File "/usr/lib/python2.6/urllib2.py", line 1240, in file_open
return self.parent.open(req)
File "/usr/lib/python2.6/urllib2.py", line 389, in open
response = self._open(req, data)
File "/usr/lib/python2.6/urllib2.py", line 407, in _open
'_open', req)
File "/usr/lib/python2.6/urllib2.py", line 367, in _call_chain
result = func(*args)
File "/usr/lib/python2.6/urllib2.py", line 1287, in ftp_open
raise URLError('ftp error: no host given')
urllib2.URLError: <urlopen error ftp error: no host given>
>>>
The problem appears to be that urllib allows a badly-formed file URL (with file://// rather than file:///) when it shouldn't (errors should not pass silently).
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