[Tutor] Review my code

[Chanakya Mitra]

I wrote a short script that tries to check if an email address exists or
not.

 

It takes the domain of the inputted email and looks up the registered
mail exchange.

 

It then connects via smtp and attempts the "RCPT TO:<entered email>"
command and based on the response decides if the email exists or not.

 

I was trying to be more OOP in my approach but not sure I've been
entirely successful.

 

Thanks for your time.

 

Chan

 

Code:

 

 

import DNS, socket, string, re, sys

servers = []

myserver = 'mailgate.xxxxxxxx.com'

mymail = 'maywedtuza at xxxxxxxx.com'

CRLF="\r\n"

def mailxch(hname):

    mxhosts = DNS.mxlookup(hname)

    return mxhosts

 

def prompt(prompt):

    return raw_input(prompt).strip()

 

class smtsock(object):

    response = None

    def getmsg(self):

        self.response = self.msock.makefile('rb')

        while 1:

            try:

               line = self.response.readline()

               return line[:3], line[4:]               

            except socket.error:

                self.msock.close()

                return "socket Error"

    def put(self,cmd,args=""):

        if args == "":

            str = '%s%s' % (cmd, CRLF)

        else:

            str = '%s %s%s' % (cmd, args, CRLF)        

        try:

            self.msock.send(str)

        except socket.error:

            self.msock.close()

            return "socket Error"                        

    def pr(self,cmd,args=""):

        self.put(cmd, args) 

        return self.getmsg()

    def conn(self,server):

        try:

            self.msock = socket.create_connection((server,25))

            (hand, msg) = self.getmsg()

            return hand, msg

        except:

            err = sys.exc_info()[1]

            return err

    def helo(self, server):             

        (hand, msg) =  self.pr("HELO",server)

        return hand, msg

    def vrfy(self, hname):

        cstr =  "<%s>"% hname

        (hand, msg) = self.pr("VRFY", cstr)

        return hand, msg

    def mailfrm(self, emf):

        cstr =  "<%s>"% emf        

        (hand, msg) = self.pr("MAIL FROM:", cstr)

        return hand, msg

    def rcptto(self,hname):

        cstr =  "<%s>"% hname        

        (hand, msg) = self.pr("rcpt to:", cstr)

        return hand, msg

    def cls(self):

        self.msock.close()

 

   

 

rcpt_handlers = {

"250":"  \n#------------------------------------------# \n\tE-mail
Exists\n#------------------------------------------# \n",

"251":"  User not local; will forward to <forward-path>",

"550":"  \n#------------------------------------------# \n\tNo Such
Address\n#------------------------------------------# \n",

"551":"  User not local; please try <forward-path>",

"552":"  Requested mail action aborted: exceeded storage allocation",

"553":"  Requested action not taken: mailbox name not allowed",

"450":"  Requested mail action not taken: mailbox unavailable",

"451":"  Requested action aborted: local error in processing",

"452":"  Requested action not taken: insufficient system storage",

"500":"  Syntax error, command unrecognised",

"501":"  Syntax error in parameters or arguments",

"503":"  Bad sequence of commands",

"521":"  <domain> does not accept mail [rfc1846]",

"socket Error":"                Socket Error: Connection closed.",

"421":"  <domain> Service not available, closing transmission channel"

    }

 

    

em =
re.compile(r"(?:^|\s)[-a-z0-9_.]+@(?:[-a-z0-9]+\.)+[a-z]{2,6}(?:\s|$)",r
e.IGNORECASE)

 

while True:

    hname = prompt("E-Mail Address(or XX to quit): ")

    if hname == "XX":

        break

    if em.match(hname) == None:

        print "Email incorrect format"

    else:

        s = smtsock()

        servers = mailxch(hname.split("@")[1])

        print servers        

        i = 0        

        for i in range(len(servers)):

            print "Trying mailserver: %s"% servers[i][1]

            (reply, msg)= s.conn(servers[i][1])

            if reply != '220':

                break

            (reply, msg) = s.helo(myserver)

            if reply != '250':            

                break

            (reply, msg) = s.mailfrm(mymail)

            if reply != '250':                        

                break

            (reply, msg) = s.rcptto(hname)

            print rcpt_handlers.get(reply)

            if reply == '250':                        

                break

            s.cls()

 

    

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