Well, if you want to apply object orientatation techniques to your work
you would get something like this. Polymorphism is used to distinct
between the ftp method. Another concept is data encapsulation, see the
filedescription class . A third technique is inheritance - ftp is
derived from an existing object, the get classes are derived from my
ftp class.
But most of all it is a different way of organizing your work, for your
code I think it makes sense to split the work between an ftp class and
a filedescrition class - where you can add methods to record the status
of the retrieval.
#!/usr/bin/env python
import ftplib
import os.path
import sys
class ftp_err(Exception):
pass
class ftp(ftplib.FTP):
def __init__(self, address, filedescription, user = None, password
= None):
ftplib.FTP.__init__(self, address)
self.login(user, password)
self.filedescription = filedescription
def list(self):
return self.nlst()
def cd(self, directory):
self.cwd(directory)
def quit(self):
self.quit()
class ftp_get(ftp):
def get(self):
cmd = 'RETR %s' % self.filedescription.name
self.retrlines(cmd, open(self.filedescription.name, 'w').write)
class ftp_get_binary(ftp):
def get(self):
cmd = 'RETR %s' % self.filedescription.name
self.retrbinary(cmd, open(self.filedescription.name,
'wb').write)
class filedescription(object):
def set_name(self, name):
self.__name = name
def get_name(self):
return self.__name
name = property(get_name, set_name)
def _get_texttype(self):
ext = os.path.splitext(self.name)[1]
if ext in ('.txt', '.htm', '.html'):
return True
else:
return False
def get_texttype(self):
return self._get_texttype()
text = property(get_texttype)
def get_binarytype(self):
return not self._get_texttype()
binary = property(get_binarytype)
f1 = filedescription()
f1.name = 'download.ht'
f2 = filedescription()
f2.name = 'download.html'
ftp_site = 'ftp.python.org'
ftp_dir = 'pub/docs.python.org'
for i in (f1, f2):
try:
f = None
if i.text:
f = ftp_get(ftp_site, i)
elif i.binary:
f = ftp_get_binary(ftp_site, i)
f.cd(ftp_dir)
f.get()
except Exception, e:
print >> sys.stderr, '%s: %s' % (e.__class__.__name__, e)
--
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