Source Code for Module npsgd.email_manager

  1  # Author: Thomas Dimson [tdimson@gmail.com] 
  2  # Date:   January 2011 
  3  # For distribution details, see LICENSE 
  4  """NPSGD e-mail related module for blocking/non-blocking sends.""" 
  5  import smtplib 
  6  import Queue 
  7  from email.mime.audio import MIMEAudio 
  8  from email.mime.base import MIMEBase 
  9  from email.mime.image import MIMEImage 
 10  from email.mime.multipart import MIMEMultipart 
 11  from email.mime.text import MIMEText 
 12  from email.Utils import formatdate 
 13  from email import Encoders 
 14  from threading import Thread 
 15  import mimetypes 
 16  import logging 
 17  import socket 
 18  from config import config 
 19   
 20 -class EmailSendError(RuntimeError): pass 
 21   
 22 -def blockingEmailSend(email): 
 23      """Attempt to send an e-mail synchronously, reporting an error if we fail.""" 
 24      try: 
 25          s = smtpServer() 
 26      except socket.gaierror, e: 
 27          raise EmailSendError("Unable to connect to smtp server") 
 28       
 29   
 30      try: 
 31          logging.info("Connected to SMTP server, sending email") 
 32          email.sendThrough(s) 
 33      finally: 
 34          s.close() 
 35   
 36  email_manager_thread = None 
 37 -def backgroundEmailSend(email): 
 38      """Attempt to send an e-mail asynchronously, spawning a background thread if necesarry. 
 39   
 40      This method sends an e-mail in the background using an e-mail thread. Note that 
 41      this has a side effect of actually spawning an e-mail thread if none exists already. 
 42      """ 
 43   
 44      global email_manager_thread 
 45      if email_manager_thread == None: 
 46          email_manager_thread = EmailManagerThread() 
 47          email_manager_thread.start() 
 48   
 49      email_manager_thread.addEmail(email) 
 50   
 51 -def smtpServer(): 
 52      smtpserver = smtplib.SMTP(config.smtpServer, config.smtpPort) 
 53      smtpserver.ehlo() 
 54      if config.smtpUseTLS: 
 55          smtpserver.starttls() 
 56      if config.smtpUseAuth: 
 57          smtpserver.ehlo() 
 58          smtpserver.login(config.smtpUsername, config.smtpPassword) 
 59   
 60      return smtpserver 
 61   
 62 -class EmailManagerThread(Thread): 
 63      """Thread for sending e-mail in the background (using a queue of e-mails).""" 
 64   
 65 -    def __init__(self): 
 66          Thread.__init__(self) 
 67          self.daemon = True 
 68          self.queue = Queue.Queue() 
 69   
 70 -    def addEmail(self, email): 
 71          self.queue.put(email) 
 72   
 73 -    def run(self): 
 74          """Blocks on the queue until it has an e-mail in it, then send it.""" 
 75          while True: 
 76              try: 
 77                  email = self.queue.get(True) 
 78                  logging.info("Email Manager: Found email in the queue, attempting to send") 
 79                  blockingEmailSend(email) 
 80              except Exception: 
 81                  logging.exception("Unhandled exception in email thread!") 
 82                  self.queue.put(email) 
 83   
 84 -class Email(object): 
 85      """Actual e-mail object containing all information needed to send an e-mail. 
 86   
 87      The e-mail object includes the recipient, subject, body, attachments and 
 88      also contains a method to send through a given smtp server.""" 
 89   
 90 -    def __init__(self, recipient, subject, body, binaryAttachments=[], textAttachments=[]): 
 91          self.recipient         = recipient 
 92          self.subject           = subject 
 93          self.body              = body 
 94          self.binaryAttachments = binaryAttachments 
 95          self.textAttachments   = textAttachments 
 96   
 97 -    def sendThrough(self, smtpServer): 
 98          """Sends this e-mail through a given smtp server (blocking).""" 
 99          msg = MIMEMultipart() 
100          #headers 
101          msg['To']      = self.recipient  
102          if len(config.cc) > 0: 
103              msg['Cc'] = ",".join(config.cc) 
104          msg['From']    = config.fromAddress 
105          msg['Subject'] = self.subject 
106   
107          #actual recipients 
108          recipients = [self.recipient] + config.cc + config.bcc 
109   
110          msg.attach(MIMEText(self.body)) 
111   
112          for (name, attach) in self.textAttachments: 
113              part = MIMEText(attach, 'plain', 'UTF-8') 
114              part.add_header("Content-Disposition", "attachment; filename=%s" % name) 
115              msg.attach(part) 
116   
117          for (name, attach) in self.binaryAttachments: 
118              ctype, encoding = mimetypes.guess_type(name) 
119              if ctype is None or encoding is not None: 
120                  ctype = 'application/octet-stream' 
121   
122              maintype, subtype = ctype.split('/', 1) 
123              if maintype == 'text': 
124                  part = MIMEText(attach,  _subtype=subtype) 
125              elif maintype == 'image': 
126                  part = MIMEImage(attach, _subtype=subtype) 
127              elif maintype == 'audio': 
128                  part = MIMEAudio(attach, _subtype=subtype) 
129              else: 
130                  part = MIMEBase(maintype, subtype) 
131                  part.set_payload(attach) 
132                  Encoders.encode_base64(part) 
133   
134              part.add_header("Content-Disposition", "attachment; filename=%s" % name) 
135              msg.attach(part) 
136   
137          logging.info("Email: constructed email object, sending to %s", ", ".join(recipients)) 
138          smtpServer.sendmail(config.fromAddress, recipients, msg.as_string()) 
139          logging.info("Email: sent") 
140