Some futher thoughts:
On Thu, Jun 16, 2016 at 10:38:13AM -0500, boB Stepp wrote:
> class FTPFiles(FTP, object):
> """FTP files to Windows server location(s)."""
>
> def __init__(self, host=server_ip, user=user, passwd=passwd):
> """Initialize FTPFiles object. Normally the defaults will be used."""
>
> super(FTPFiles, self).__init__(host, user, passwd)
> self.host = host
> self.user = user
> self.passwd = passwd
Do you actually need to record these? Once they're used to establish a
connection and login, what are they for?
> def print_welcome_msg(self):
> """Print welcome message sent by FTP server."""
> print self.getwelcome()
The getwelcome method already prints the message, which is a bad design.
But only if debugging is true. So I would approach this in one of two
ways:
(1) Delegate to the existing getwelcome method:
def print_welcome_msg(self):
save_flag = self.debugging
self.debugging = True
try:
x = self.getwelcome() # prints the msg
finally:
self.debugging = save_flag
(2) Re-implement the print functionality.
def print_welcome_msg(self):
print "*welcome*", self.welcome
(3) If you really want to be paranoid, use:
print "*welcome*", self.sanitize(self.welcome)
although I don't think it's likely to make any real difference in
practice.
(The sanitize method makes a feeble attempt to hide the password.)
> if __name__ == '__main__':
> ftp = FTPFiles()
> ftp.print_welcome_msg()
> ftp.quit()
This appears to be equivalent to:
ftp = FTP(host, user, passwd)
ftp.debugging = True
x = ftp.getwelcome()
ftp.quit()
> What I learned today:
>
> 1) FTP from ftplib appears to be an old-style class.
>
> 2) I can't just use "class FTPFiles(FTP)" or I will be using old-style
> classes.
Is this a problem? Old-style classes are good enough for many purposes.
> 3) I need to use "class FTPFiles(FTP, object)" to use new-style
> classes and "object" must come AFTER "FTP".
>
> 4) I have to use "super(FTPFiles, self).__init__(host, user, passwd)"
> or I cannot successfully inherit from the FTP() class. Also, "self"
> apparently must come AFTER "FTPFiles" in the super expression.
For old-style classes, don't use super because it doesn't work. Instead
just write:
FTP.__init__(self, host, user, passwd)
That means that you cannot engage in multiple inheritence with new-style
classes, but MI is a serious pain to get right, and 99% of the time it
is overkill, so you're not missing much.
--
Steve
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