socket.makefile raises ValueError when mode = 'rt'

Dave Angel d at davea.name
Wed Jan 9 14:54:53 CET 2013


On 01/09/2013 08:22 AM, Antoon Pardon wrote:
> This is using python 3.2.
>
> I am writing somekind of wrapper around the ftplib. So
> that you can work with it as if you are working with
> local files.
>
> The idea is that you start with making a connection like
>
> rmt = FTP(...)
>
> and then do something like the following
>
> rmtfl = rmt.open("rmtfilename", "rt")
> for ln in rmtfl:
>     treat(ln)
>
> This is part of the code:
>
> class ftpfile:
>     def __init__(self, cn, rfn, mode, bound = False):
>         self.ftp = cn
>         self.bound = bound
>         if 'b' in mode:
>             self.ftp.voidcmd('TYPE I')
>         else:
>             self.ftp.voidcmd('TYPE A')
>         if 'r' in mode:
>             self.cnct =  self.ftp.transfercmd("RETR %s" % rfn)
>             self.fl = self.cnct.makefile(mode)
>         elif 'w' in mode:
>             self.cnct =  self.ftp.transfercmd("STOR %s" % rfn)
>             self.fl = self.cnct.makefile(mode, newline = '\r\n')
>         else:
>             raise ValueError("%s: invalide mode" % mode)
>
> The problem is with makefile. If mode contains a "t" I get
> the following traceback:
>
> Traceback (most recent call last):
>   File "ftputil.tpy", line 14, in test_textftp
>     rmtfl1 = rmt.open('ftp1.py', 'wt')
>   File "/local/home/apardon/src/projecten/py3lib/ftputil.py", line 76,
> in open
>     return ftpfile(ftp, fn, mode, True)
>   File "/local/home/apardon/src/projecten/py3lib/ftputil.py", line 15,
> in __init__
>     self.fl = self.cnct.makefile(mode, newline = '\r\n')
>   File "/usr/lib/python3.2/socket.py", line 151, in makefile
>     raise ValueError("invalid mode %r (only r, w, b allowed)")
> ValueError: invalid mode %r (only r, w, b allowed)
>
> But the documentation states:
> socket.makefile(mode='r', buffering=None, *, encoding=None, errors=None,
> newline=None)
>     Return a file object associated with the socket. The exact returned
> type depends on the arguments given to makefile(). These arguments are
> interpreted the same way as by the built-in open() function.
>
> And since 't' is allowed in the mode of the built-in open() function I
> would consider this a bug.
> Unless I am missing something?

I believe that 't' was a new addition to mode, for Python 3.x     So
perhaps the socket library hasn't kept consistent with it.

I don't really know the socket library.  Does it even support text
mode?  Does that make sense?  Remember that text mode means a different
thing in 3.x than it did in 2.x



-- 

DaveA




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