[Zope] Email address validator?

[Jim Washington]

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Barry A. Warsaw wrote:

>>>>>>"BE" == Bruce Eckel <Bruce@EckelObjects.com> writes:
>>>>>>
>
>    BE> Worked like a charm! It turns out I was handing it an invalid
>    BE> "from" email address.
>
>    BE> Which brings up another question -- is there a piece of code
>    BE> that will validate email addresses somewhere? Seems like it
>    BE> would be a common tool (I'll bet the spammers have it!).
>
>Do you mean you want to find out if a string looks like a valid email
>address, or that it actually successfully delivers to some end
>destination?  The former is doable, the latter is exceedingly
>difficult!
>
>Mailman has the following bit of code, which accomplishes the goal set
>out in its docstring <wink>:
>
I hadn't thought of looking through mailman.  Here's one I put together 
a couple of weeks ago that seems a bit more thorough...  

-- Jim Washington



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# This is hacked from an existing script written in perl, licensed "public domain"
# The original perl script:  http://aspn.activestate.com/ASPN/Cookbook/Rx/Recipe/68432 2Nov2001
# author e-mail: tbyte@bolehmail.com

"""
Text of the perl script:

sub ValidEmailAddr { #check if e-mail address format is valid

my $mail = shift;                                                  #in form name@host

return 0 if ( $mail !~ /^[0-9a-zA-Z\.\-\_]+\@[0-9a-zA-Z\.\-]+$/ ); #characters allowed on name: 0-9a-Z-._ on host: 0-9a-Z-. on between: @
return 0 if ( $mail =~ /^[^0-9a-zA-Z]|[^0-9a-zA-Z]$/);             #must start or end with alpha or num
return 0 if ( $mail !~ /([0-9a-zA-Z]{1})\@./ );                    #name must end with alpha or num
return 0 if ( $mail !~ /.\@([0-9a-zA-Z]{1})/ );                    #host must start with alpha or num
return 0 if ( $mail =~ /.\.\-.|.\-\..|.\.\..|.\-\-./g );           #pair .- or -. or -- or .. not allowed
return 0 if ( $mail =~ /.\.\_.|.\-\_.|.\_\..|.\_\-.|.\_\_./g );    #pair ._ or -_ or _. or _- or __ not allowed
return 0 if ( $mail !~ /\.([a-zA-Z]{2,3})$/ );                     #host must end with '.' plus 2 or 3 alpha for TopLevelDomain (MUST be modified in future!)

return 1;
}

e-mail checker, checks whether an e-mail address is formatted properly.
usage:

from email_checker import valid_email

s = "string to be tested"
if valid_email(s):
  do_something()
else:
  do something_else()

"""

import re

rega = re.compile("^[0-9a-zA-Z\.\-\_]+\@[0-9a-zA-Z\.\-]+$") #failure a
regb = re.compile("^[^0-9a-zA-Z]|[^0-9a-zA-Z]$")            #failure b
regc = re.compile("([0-9a-zA-Z]{1})\@.")                    #failure c
regd = re.compile(".\@([0-9a-zA-Z]{1})")                    #failure d
rege = re.compile(".\.\-.|.\-\..|.\.\..|.\-\-.")            #failure e
regf = re.compile(".\.\_.|.\-\_.|.\_\..|.\_\-.|.\_\_.")     #failure f
regg = re.compile(".\.([a-zA-Z]{2,3})$|.\.([a-zA-Z]{2,4})$")#failure g

def valid_email(address, debug=None):
    fail = None
    if rega.search(address) is None:
        fail = 'a'
    elif regb.search(address) is not None:
        fail = 'b'
    elif regc.search(address) is None:
        fail = 'c'
    elif regd.search(address) is None:
        fail = 'd'
    elif rege.search(address) is not None:
        fail = 'e'
    elif regf.search(address) is not None:
        fail = 'f'
    elif regg.search(address) is None:
        fail = 'g'
    if fail is not None:
        if debug:
            return address,fail,None
        else:
            return None
    if debug:
        return address,1,1
    else:
        return 1

if __name__ == '__main__':
  #test a few:
  print valid_email('z+z.e@bun.org', debug=1)
  print valid_email('z.e@.org', debug=1)
  print valid_email('_az.e@bun.org', debug=1)
  print valid_email('e@b.g', debug=1)
  print valid_email('a_-.e@bun.org', debug=1)
  print valid_email('ok.computer@-bun.org', debug=1)
  print valid_email('ok.e@bun.org', debug=1)
  print valid_email('OK@bun.org', debug=1)
  print valid_email('t@bun.info', debug=1)
  print valid_email('my friend@bun.org', debug=1)
  print valid_email('my.friend.bun.org', debug=1)

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