Python program that obfuscates an email address

Question

I decided to resume my (limited) Python skills after not coding for a long time.

Here's a very simple self-contained program to convert the characters of an email address into their HTML entities (the purpose is to make the email invisible to spamrobots).

• Any comment for improvement? (e.g. args parsing, code style, etc.)

• Apart from the -h option in argparse, what is the standard way to add some documentation for it, such as a manpage or some embedded help?

#!/usr/bin/python
#
# mung - Convert a string into its HTML entities
#
import argparse
parser = argparse.ArgumentParser(description = 'Convert a string into its HTML entities.')
parser.add_argument('string_to_mung', help = 'String to convert')
parser.add_argument('-l', '--link', action = 'store_true', help = 'Embed the munged string into a mailto: link')
args = parser.parse_args()
def mung(plain):
 munged = ''
 for c in plain:
 munged = munged + '&#' + str(ord(c)) + ';'
 return munged
string_munged = mung(args.string_to_mung)
if (args.link):
 print('<a href="&#109;&#97;&#105;&#108;&#116;&#111;&#58;')
 print(string_munged + '">')
 print(string_munged + '</a>')
else:
 print(string_munged)

• David Foerster: Spam bots deal rather well with X(HT)ML escape sequences since they often use appropriate parser libraries.
• dr_: Actually my experience suggests otherwise, as an obfuscated email address gets ten times less spam; see bit.ly/2UOuAOA

Answer 1

The code is straightforward and reads well, but:

1. string concatenation is not very efficient, especially in a loop. You'd be better off using str.join on an iterable;
2. encoding the mailto: part yourself impairs readability and maintenance, if only you had a function to do it for you. Oh wait...
3. The comment at the beginning would be better as a module docstrings, you would then be able to use it as the argparse description using __doc__;
4. You should avoid interleaving code and function definition, and protect top level code using an if __name__ == '__main__': guard.

Proposed improvements:

#!/usr/bin/python
"""Convert a string into its HTML entities"""
import argparse
def command_line_parser():
 parser = argparse.ArgumentParser(description=__doc__)
 parser.add_argument('string_to_mung', help='String to convert')
 parser.add_argument('-l', '--link', action='store_true',
 help='Embed the munged string into a mailto: link')
 return parser
def mung(plain):
 return ''.join('&#{};'.format(ord(c)) for c in plain)
if __name__ == '__main__':
 args = command_line_parser().parse_args()
 string_munged = mung(args.string_to_mung)
 if (args.link):
 string_munged = '<a href="{0}{1}">{1}</a>'.format(mung('mailto:'), string_munged)
 print(string_munged)

• Roman Odaisky: Python 3.6+: '&#{};'.format(ord(c)) → f'&#{ord(c)};'
• 301_Moved_Permanently: @RomanOdaisky Given that there is no version tag, I prefer to keep format.