Python by Example
Mailing List Utility
import sys import string import rfc822 import smtplib
Note the use of modules to package related functions and classes, similar to Delphi's units.
def usage():
print "Usage: newsletter [-t] body-file [addr-file]"
sys.exit( 1 )
def main():
if( len( sys.argv ) < 2 or len( sys.argv ) > 4 ):
usage()
args = sys.argv[:]
doSendMail = 1
if( args[ 1 ] == "-t" ):
args = args[ 1:]
doSendMail = 0
msgfile = args[ 1 ]
if( len( args ) < 3 ):
addrfile = "HADPemail.txt"
else:
addrfile = args[ 2 ]
Arrays and lists are first-class citizens in Python, and have powerful built-in operations (note the "slicing" of the argv array).
mf = open( msgfile, 'r' )
af = open( addrfile, 'r' )
if( not mf or not af ):
usage()
fromaddr = "Tres Seaver "
CRLF = "\r\n"
toaddrs = []
toaddrs.append( fromaddr )
for line in af.readlines():
toaddrs.append( '<' + line[:-1] + '>' )
Build up a list from the address file. Note the "clean" syntax:
- Indentation replaces "noise" words / symbols, leaving "executable pseudo-code."
- Variables are always declared by being defined, increasing their cognitive "locality of reference."
msg = 'From: ' + fromaddr + CRLF
msg = msg + 'To: "HADP members"' + CRLF
msg = msg + 'Subject: HADP Meeting announcment' + CRLF + CRLF
for line in mf.readlines():
msg = msg + line[:-1] + CRLF
print "Message length: " + `len( msg )`
print "Number of addresses: " + `len( toaddrs )`
Read the body of the message.
if( doSendMail ):
server = smtplib.SMTP( 'smtp.neosoft.com' )
server.set_debuglevel(1)
server.sendmail( fromaddr, toaddrs, msg )
server.quit()
else :
print "Testing: "
print fromaddr
for addr in toaddrs: print addr
print
print msg
if __name__ == '__main__':
main()
VOILA! As one speaker at the recent International Python Conference noted, "Python comes with batteries included" (I didn't have to write the SMTP code!).