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server.py
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server.py
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#! /usr/bin/env python
# -*- coding: utf-8 -*-
# Libraries
import smtpd
import asyncore
import sys
import io
import os
import re
import PyPDF2
import StringIO
import datetime
from outgoing_email import EmailUtils
from flask import Flask, render_template, request
from email.parser import Parser
from encryption import f_decrypt
def timeStamped(fname, fmt='%Y-%m-%d-%H-%M-%S_{fname}'):
return datetime.datetime.now().strftime(fmt).format(fname=fname)
app = Flask(__name__)
print 'Starting custom mail server'
#Regexes for processing email
#-negation of typically forbidden characters, as well as quotation marks, which we stipulate are ridiculous and do not belong in email addresses.
emailchar = r"[^@ \n\(\)\,\:\;\<\>\[\\\]\"]"
#-the actual regex for an address
email = re.compile(emailchar + r"+@" + emailchar + r"+\." + emailchar + r"+")
#-address with capture group for the recipient
recip = re.compile(r"(" + emailchar + r"+)@" + emailchar + r"+\." + emailchar + r"+")
#EMAIL HANDLERS
def admin_handler(data,log):
EmailUtils.forward_message(data,'[email protected]')
log.write(u'Forwarded.\r\n')
return
#Forwards emails sent to [email protected] from permitted senders to blastlist
def list_handler(data,log,replyadr):
sl = io.open('authorized', 'r', encoding='utf-8')
auth = 0
for line in sl:
if replyadr.lower() in line.lower():
auth = 1
sl.close
if auth == 0:
EmailUtils.text_message('[email protected]',replyadr,'Unauthorized','You are not authorized to use this list.')
elif auth == 1:
bl = io.open('blastlist.txt','r', encoding='utf-8')
for addr in bl:
EmailUtils.forward_message(data,addr)
bl.close
#Replies with an error if the mailto code is too short or has no underscore, and adds address to strikelist (for potential blacklisting)
def too_short_handler(replyadr,recipient,log):
bl = io.open('blacklist', 'a+', encoding="utf-8")
sl = io.open('strikelist', 'r', encoding="utf-8")
strikes = 0
for line in sl: #checks if address already strikelisted
if replyadr.lower() in line.lower():
strikes += 1
sl.close()
if strikes >= 2: #blacklists on third strike
log.write(u'Strikelisted address ' + replyadr + u' added to blacklist.\r\n')
bl.write(replyadr + '\r\n')
sl = io.open('strikelist', 'r+', encoding="utf-8")
slcont = sl.readlines()
sl.seek(0)
for entry in slcont:
if replyadr.lower() not in entry.lower():
sl.write(entry)
sl.truncate()
sl.close()
else:
log.write(u'Strike for ' + replyadr + u'.\r\n')
sl = io.open('strikelist', 'a+', encoding="utf-8")
sl.write(replyadr + u'\r\n')
sl.close()
bl.close()
with app.app_context():
shorttxt = render_template('code_failure.txt',code=recipient)
short = render_template('code_failure.html',code=recipient)
EmailUtils.rich_message('[email protected]',replyadr,'Letter Delivery Failure',shorttxt,short)
log.write(recipient + u' too short or no underscore.\r\n')
return
#Replies with an error if no match is found for the mailto code in metadata.txt
def no_match_handler(replyadr,recipient,log):
with app.app_context():
errortxt = render_template('code_failure.txt',code=recipient)
error = render_template('code_failure.html',code=recipient)
EmailUtils.rich_message('[email protected]',replyadr,'Letter Delivery Failure',errortxt,error)
log.write(recipient + u' not in metadata.\r\n')
return
#Replies with an error if no such file is found in letters/
def no_such_file_handler(replyadr,cfn,log):
with app.app_context():
nofiletxt = render_template('file_failure.txt',cfn=cfn)
nofile = render_template('file_failure.html',cfn=cfn)
EmailUtils.rich_message('[email protected]',replyadr,'Letter Delivery Failure',nofiletxt,nofile)
log.write(recipient + u': File not found.\r\n')
return
#Replies with an error if the file is corrupt
def corrupt_file_handler(replyadr,cfn,log):
with app.app_context():
corrupttxt = render_template('corrupt_failure.txt',file=cfn)
corrupt = render_template('corrupt_failure.html',file=cfn)
EmailUtils.rich_message('[email protected]',replyadr,'Letter Delivery Failure',corrupttxt,corrupt)
log.write(recipient + u': Corrupt file.\r\n')
return
#Delivers the letter to a whitelisted address
def delivery_handler(match,rfn,rln,afn,aln,attach,cfn,log):
applicant = afn + ' ' + aln
recs = rfn + ' ' + rln
with app.app_context():
toedutxt = render_template('delivery.txt',recs=recs,app=applicant,email=match)
toedu = render_template('delivery.html',recs=recs,rln=rln,app=applicant,email=match)
subject = 'Letter Delivery for ' + applicant
EmailUtils.rich_message('[email protected]',match,subject,toedutxt,toedu,attach,cfn)
log.write(u'Delivery made to ' + match + u'.\r\n')
return
#Replies with an error if there are no whitelisted addresses present
def not_whitelisted_handler(replyadr,log):
with app.app_context():
wlfailtxt = render_template('wl_failure.txt')
wlfail = render_template('wl_failure.html')
EmailUtils.rich_message('[email protected]',replyadr,'Letter Delivery Failure',wlfailtxt,wlfail)
log.write(u'No whitelisted addresses present.\r\n')
return
#Sends the applicant a confirmation noting whitelisted addresses sent to and any requested addresses not sent to
def applicant_confirmation_handler(aem,rfn,rln,afn,aln,cfn,sentto,fsent,log):
recs = rfn + ' ' + rln
applicant = afn + ' ' + aln
with app.app_context():
toapptxt = render_template('del_confirm.txt',recs=recs,app=applicant,cfn=cfn,sentto=sentto,failed=fsent)
toapp = render_template('del_confirm.html',recs=recs,app=applicant,cfn=cfn,sentto=sentto,failed=fsent)
EmailUtils.rich_message('[email protected]',aem,'Letter Delivery Confirmation',toapptxt,toapp)
log.write(u'Confirmation sent.\r\n')
return
#Replies with a confirmation noting whitelisted addresses sent to and any requested addresses not sent to
def sender_confirmation_handler(replyadr,rfn,rln,afn,aln,cfn,sentto,fsent,log):
recs = rfn + ' ' + rln
applicant = afn + ' ' + aln
with app.app_context():
tosendertxt = render_template('del_confirm.txt',recs=recs,app=applicant,cfn=cfn,sentto=sentto,failed=fsent)
tosender = render_template('del_confirm.html',recs=recs,app=applicant,cfn=cfn,sentto=sentto,failed=fsent)
EmailUtils.rich_message('[email protected]',replyadr,'Letter Delivery Confirmation',tosendertxt,tosender)
log.write(u'Confirmation sent.\r\n')
return
#SERVER
class MargySMTPServer(smtpd.SMTPServer):
def process_message(self, peer, mailfrom, rcpttos, data):
now = datetime.datetime.now().strftime("%m.%d.%Y %H:%M:%S")
log = io.open('serverlog.txt', 'a', encoding="utf-8")
log.write(u'\r\n' + now + u'\r\n')
print '\r\n' + now + '\r\nReceiving...'
parser = Parser()
msg = parser.parsestr(data)
matches = [] #initialize matches for accumulation
for part in msg.walk(): #get matches only from text/html and text/plain parts of an email
if part.get_content_type() in ['text/plain','text/html']:
charset = part.get_content_charset()
if charset is None:
decoded = unicode(part.get_payload(decode=True),'latin1','replace')
else:
decoded = unicode(part.get_payload(decode=True), str(charset), 'replace')
matches = matches + re.findall(email,decoded)
matches = list(set(matches)) #deduplicate match list
if 'reply-to' in msg: replyadr = msg['reply-to']
else: replyadr = str(mailfrom).decode('utf-8') #checks for a reply-to address; if not present, assigns sender as reply-to address
bl = io.open('blacklist', 'r', encoding="utf-8") #open blacklist (spam avoidance)
blisted = 0
for line in bl: #checks reply-to address against blacklist
if replyadr.lower() in line.lower():
log.write(u'Email blocked from blacklisted address ' + replyadr + u'.\r\n')
print 'Blacklisted.'
blisted = 1
bl.close()
if blisted == 1: #handles emails from blacklisted addresses
warned = io.open('warned', 'r', encoding="utf-8") #checks whether this address has already been warned it was blacklisted
wrn = 0
for line in warned:
if replyadr.lower() in line.lower():
wrn = 1
if wrn == 0: #warns previously unwarned blacklisted addresses
EmailUtils.text_message('[email protected]',replyadr,'BLACKLISTED','You have sent too many nonstandard emails to this system; further emails from your address will not be processed. If you believe this is an error, please contact MARGY adminstration.')
warned = io.open('warned', 'a+', encoding="utf-8") #adds reply-to address to list of warned addresses
warned.write(replyadr + u'\r\n')
warned.close()
if blisted == 0:
for addr in rcpttos: #handle multiple addresses
recipient = re.match(recip, addr).group(1)
if recipient.lower() == 'list':
list_handler(data,log,replyadr)
elif ( recipient.lower() == 'admin' or recipient.lower() == 'postmaster' or recipient.lower() == 'abuse' ): #for emails sent to admin@ or postmaster@ or abuse@ or [email protected]
admin_handler(data,log)
else:
if ( recipient.lower() != 'sales' and recipient.lower() != 'info' and recipient.lower() != 'xderia' and recipient.lower() != 'margy' ): #ignores emails to sales@, info@, xderia@, and margy@ (the last to maintain confidentiality)
if ( len(recipient) < 11 or '_' not in recipient ): #makes sure the mailto code isn't too short and includes an underscore
too_short_handler(replyadr,recipient,log)
else:
filecode = recipient[:-10] #scrapes all but the last 10 characters of the mailto code to serve as filecode (e.g., 'Test' from Test_123456789)
key = recipient[-9:] #scrapes the final 9 characters of the mailto code to serve as key (e.g., '123456789' from Test_123456789)
f = io.open('metadata.txt', 'r', encoding="utf-8") #opens the file containing the metadata
mdata = 'empty' #set in case there is no metadata for the filecode
for line in f: #checks whether the filecode matches the first entry on each line of metadata and, if so, scrapes the line
if filecode.lower() == line.rstrip().lower()[:len(filecode)]:
mdata = line
break
f.close()
if mdata == 'empty': #deals with cases where there is no metadata for the filecode
no_match_handler(replyadr,recipient,log)
else:
array = mdata.split() #creates a list out of the relevant line of metadata
cfn = array[0] + '.pdf' #assigns the first item in the metadata list as the file name (should be the same as filecode)
cfnl = [cfn] #creates a list with just that one element, to compensate for changes due to new web delivery system
path = 'letters/' + cfn + '.aes' #the path to the file to be attached should be letters/[value of cfn].aes
if not os.path.isfile(path): #checks whether there is such a file
no_such_file_handler(replyadr,cfn,log)
else:
attach = [f_decrypt(path, key)] #assigns decrypted file as attachment
maybepdf = StringIO.StringIO(attach[0]) #checks to make sure the file isn't corrupt
try:
PyPDF2.PdfFileReader(maybepdf)
except PyPDF2.utils.PdfReadError:
corrupt_file_handler(replyadr,cfn,log)
maybepdf.close()
else:
maybepdf.close()
rfn = array[1].replace('_', ' ') #assigns the items of the metadata list to variables; this is recommender's first name
rln = array[2].replace('_', ' ') #recommender's last name
afn = array[3].replace('_', ' ') #applicant's first name
aln = array[4].replace('_', ' ') #applicant's last name
aem = array[5] #applicant's email address
failed = [] #creates an empty list for non-whitelisted addresses that will not receive attachment
sentto = "" #creates an empty variable for whitelisted addresses that will receive attachment
for match in matches:
if ( key == 'B8NUTB85i' ): #allows for test deliveries of test letter file to any address
delivery_handler(match,rfn,rln,afn,aln,attach,cfnl,log)
sentto += match + ' ' #adds to the variable that contains whitelisted addresses that have been sent attachment
for match in matches + [replyadr]: #checks each email address in the body and the reply-to address against the whitelist
wl = io.open('static/whitelist.txt', 'r', encoding="utf-8")
for line in wl:
if ( match.lower() == line.rstrip().lower() and match not in sentto.strip().lower() ):
delivery_handler(match,rfn,rln,afn,aln,attach,cfnl,log)
sentto += match + ' ' #adds to the variable that contains whitelisted addresses that have been sent attachment
else:
failed.append(match) #adds to the list of non-whitelisted addresses that have not been sent attachment
wl.close()
fsent = "" #creates an empty variable for...
for miss in failed: #...deduplication and removal of reply-to address from the list of failed recipients
if ( miss.lower() != replyadr.lower() and miss.lower() not in sentto.strip().lower() and miss.lower() not in fsent.strip().lower() ):
fsent += miss + ' '
log.write(u'Delivery failed to ' + miss + u'.\r\n')
if sentto == "": #deals with cases where there were no whitelisted addresses
not_whitelisted_handler(replyadr,log)
else: #sends confirmations to the applicant and the reply-to address (if attachment was sent anywhere)
applicant_confirmation_handler(aem,rfn,rln,afn,aln,cfn,sentto,fsent,log)
if ( replyadr.lower() != aem.lower()):
sender_confirmation_handler(replyadr,rfn,rln,afn,aln,cfn,sentto,fsent,log)
log.write(u'End of log entry.\r\n')
log.close()
print 'Done.'
return
#Listen to port 25 ( 0.0.0.0 can be replaced by the ip of your server but that will work with 0.0.0.0 )
server = MargySMTPServer((sys.argv[1], 25), None)
# Wait for incoming emails
asyncore.loop()