Q: urlopen() and "file:///c:/mypage.html" ??

[MAK]

I'm stumped.

I'm trying to use Python 2.3's urllib2.urlopen() to open an HTML file
on the local harddrive of my WinXP box.

If I were to use, say, Netscape to open this file, I'd specify it as
"file:///c:/mypage.html", and it would open it just fine. But
urlopen() won't accept it as a valid URL. I get an OSError exception
with the error message "No such file or directory:
'\\C:\\mypage.html'".

I've tried variations on the URL, such as "file://c:/mypage.html",
too, without luck. That one gives me a 'socket.gaierror' exception
with the message "'getaddrinfo failed'".

Upon diving into the code, I found that, in the first case, the third
'/' is left as part of the filename, and in the second case, it ends
up thinking that 'C:' is the hostname of the machine.

Can anyone point out the error of my ways?
Thanks.

 

[Joe Francia]

I'm stumped.

I'm trying to use Python 2.3's urllib2.urlopen() to open an HTML file
on the local harddrive of my WinXP box.

If I were to use, say, Netscape to open this file, I'd specify it as
"file:///c:/mypage.html", and it would open it just fine. But
urlopen() won't accept it as a valid URL. I get an OSError exception
with the error message "No such file or directory:
'\\C:\\mypage.html'".

I've tried variations on the URL, such as "file://c:/mypage.html",
too, without luck. That one gives me a 'socket.gaierror' exception
with the message "'getaddrinfo failed'".

Upon diving into the code, I found that, in the first case, the third
'/' is left as part of the filename, and in the second case, it ends
up thinking that 'C:' is the hostname of the machine.

Can anyone point out the error of my ways?
Thanks.

This works:

f = urllib2.urlopen(r'file:///c|\mypage.html')

But, if you're only opening local files, what's wrong with:

f = file(r'c:/mypage.html', 'r')

jf

 

[Michael Geary]

This works:

f = urllib2.urlopen(r'file:///c|\mypage.html')

But, if you're only opening local files, what's wrong with:

f = file(r'c:/mypage.html', 'r')

Just to add to that, the significant thing in the working example isn't that
it uses backslash instead of forward slash, but that it uses vertical bar
instead of colon. This works just as well:

f = urllib2.urlopen( 'file:///c|/mypage.html' )

-Mike

 

[MAK]

Wow, thanks guys. A vertical bar instead of a colon... I'da never
figured on that...

 

[John J. Lee]

MAK wrote: [...]

If I were to use, say, Netscape to open this file, I'd specify it as
"file:///c:/mypage.html", and it would open it just fine. But
urlopen() won't accept it as a valid URL. I get an OSError
exception with the error message "No such file or directory:
'\\C:\\mypage.html'".

[...]
f = urllib2.urlopen( 'file:///c|/mypage.html' )

Why does Python use a different syntax to the rest of the Windows
world?


John

 

[Mike Brown]

MAK wrote: [...]
If I were to use, say, Netscape to open this file, I'd specify it as
"file:///c:/mypage.html", and it would open it just fine. But
urlopen() won't accept it as a valid URL. I get an OSError
exception with the error message "No such file or directory:
'\\C:\\mypage.html'".

[...]
f = urllib2.urlopen( 'file:///c|/mypage.html' )

Why does Python use a different syntax to the rest of the Windows
world?

On Windows, if I open a local file in Netscape 4, the Location bar shows a
"file" URL with the "|". If I open a local file in Internet Explorer (or the
file Explorer with the Address bar turned on), the Address bar shows a
"file" URL with a ":". The resolver used by both Netscape and Explorer will
accept either one, if you type it in the address bar. So who is to say what
is canon? The 'file' URI scheme is, by definition, OS dependent. If the OS
likes the URL, then it's good enough.

For 4Suite running on Windows, we were thinking of making a Python wrapper
to the Windows resolver for maximum compatibility, but haven't gotten around
to it. For now, we avoid the bug-ridden urllib as much as we can, and do
some voodoo on 'file' URLs to convert them to OS-specific paths that are
safe to pass to open() on the (win32 or posix) OS we're running on. It's not
foolproof yet, and won't handle the colon case, but does a round-trip from
an OS path to a URI and back pretty well. See the UriToOsPath() and
OsPathToUri() work in the Ft.Lib.Uri module here:
http://cvs.4suite.org/cgi-bin/viewc...rev=1.49&content-type=text/vnd.viewcvs-markup