smtp: allow sending email using an smtp queue

1 files changed, 207 insertions, 0 deletions

diff --git a/src/acit/smtpplugin.py b/src/acit/smtpplugin.py
new file mode 100644
index 0000000..3b9cc81
--- /dev/null
+++ b/src/acit/smtpplugin.py
@@ -0,0 +1,207 @@
+
+import cherrypy
+import threading
+from os import getenv
+from queue import Queue, Empty
+from imap_tools import MailMessage as IMAP_Message
+from email.message import Message
+from email import message_from_bytes, utils
+from smtplib import SMTP_SSL as SMTP
+from smtplib import (
+	SMTPResponseException,
+	SMTPDataError,
+	SMTPConnectError,
+	SMTPServerDisconnected,
+	SMTPHeloError,
+	SMTPAuthenticationError
+	)
+
+from datetime import datetime
+
+class SmtpPlugin():
+	def __init__(self):
+		self.smtp_server=getenv("ACIT_SMTP_SERVER")
+		self.smtp_user=getenv("ACIT_SMTP_USER")
+		self.smtp_pass=getenv("ACIT_SMTP_PASS")
+		self.smtp_port=int(getenv("ACIT_SMTP_PORT",0))
+
+		self.domain="whyisthisattributeunset.example.com"
+
+		self.thread:threading.Thread=None
+		self.stopping=threading.Event()
+		self.que=Queue()
+
+	def sendmail(self,
+			from_:str=None,
+			to:str|list[str]=[],
+			subject:str=None,
+			body:str=None,
+			cc:list[str]=[],
+			bcc:list[str]=[],
+			replyto:IMAP_Message=None,
+			tosend:IMAP_Message|Message=None,
+			save=False,
+			):
+		"""
+		Required arguments:
+		
+		if ``tosend`` is unset:
+			- body, from_
+			- if ``replyto`` is also unset, also:
+				- to, subject
+
+		if ``tosend`` is set:
+			- from_
+
+		from_ (str): the email address to use for the ``From`` header. if ``tosend`` is set, used for ``Resent-From`` instead, and added to ``Cc``.
+		to (list|str): the email address(es) to send to. when specifying multiple addrs, use a list.
+		subject (str): the subject for the email. not needed when ``replyto`` is set, though when both are set, ``subject`` is used.
+		body (str): the email body
+		cc (list): email addresses to put in the cc
+
+		save (bool): force adding from_ to the cclist, making ImapPlugin store the email in ``Sent`` on arrival
+		"""
+
+		if type(to)==str:
+			to=[to]
+
+		if tosend:
+			if type(tosend)==IMAP_Message:
+				tosend=tosend.obj
+			tosend=message_from_bytes(tosend.as_bytes(), policy=tosend.policy) # copy message object
+			tosend["Resent-From"]=from_
+			tosend["Resent-Date"]=utils.format_datetime(datetime.now())
+			tosend["Resent-To"]=", ".join(to)
+			if bcc:
+				tosend["Resent-Bcc"]=", ".join(bcc)
+			if cc:
+				tosend["Resent-Cc"]=", ".join(bcc)
+
+			if not from_ in tosend["to"]+tosend.get("cc","")+tosend.get("resent-to",""):
+				if "cc" in tosend:
+					tosend["cc"]+=", "+from_
+				else:
+					tosend["cc"]=from_
+
+			tosend["x-acit-delete-when-sender"]=from_
+
+		else:
+
+			if replyto:
+				cc.extend(replyto.cc)
+				cc.extend(replyto.to)
+				to.append(replyto.headers["reply-to"] if "reply-to" in replyto.headers else replyto.from_)
+
+				if not subject:
+					subject="Re: "+replyto.subject
+
+
+			for addr in to:
+				if addr in cc:
+					cc.remove(addr)
+			for addr in cc:
+				if addr in bcc:
+					bcc.remove(addr)
+
+			if not (to and body and from_ and subject):
+				raise ValueError("Missing to, from_, body, or subject")
+
+			tosend=Message()
+			tosend["From"]=from_
+			tosend["To"]=", ".join(set(to)) # set()s can't have duplicates
+			tosend["Subject"]=subject
+			tosend["Cc"]=", ".join(set(cc))
+			tosend["Bcc"]=", ".join(set(bcc))
+
+			if replyto:
+				if "references" in replyto.headers:
+					tosend["References"]=replyto.obj["references"]
+				elif "in-reply-to" in replyto.headers:
+					tosend["References"]=replyto.obj["in-reply-to"]
+
+				if "message-id" in replyto.headers:
+					tosend["In-Reply-To"]=replyto.obj["message-id"]
+
+					if "References" in tosend:
+						tosend["References"]+=" "+replyto.obj["message-id"]
+					else:
+						tosend["References"]=replyto.obj["message-id"]
+
+			tosend.set_payload(body)
+
+
+		tosend["Sender"]=from_
+		tosend["X-Acit-Is-Outgoing"]=from_
+		if not "Message-ID" in tosend:
+			tosend["Message-ID"]="<"+datetime.now().strftime("%d%m%Y%H%M%S%j")+"@"+self.domain+">"
+
+		if save and not from_ in tosend["Cc"]:
+			tosend["Cc"]+=" "+from_
+
+		self.que.put(tosend)
+
+		return tosend["Message-ID"]
+
+	
+	def start(self):
+		self.thread=threading.Thread(target=self.runner)
+		self.thread.start()
+ 
+	def runner(self):
+		threading.current_thread().name="SendMailRunner"
+		smtp=None
+		while True:
+			try:
+				item=self.que.get(timeout=1)
+				if not item:
+					continue
+			except Empty:
+				if smtp:
+					smtp.quit()
+					smtp=None
+				if self.stopping.is_set():
+					break
+				continue
+
+			try:
+				if not smtp:
+					self.mlog("Connecting and logging in to smtp server")
+					smtp=SMTP(host=self.smtp_server,port=self.smtp_port)
+					smtp.ehlo()
+					smtp.login(user=self.smtp_user,password=self.smtp_pass)
+
+				self.mlog("Sending message %s '%s'"%(item.get("message-id"),item.get("subject")))
+
+				smtp.send_message(item)
+
+			except SMTPAuthenticationError:
+				self.mlog("!!! AUTH ERROR !!! please check your config. Discarding email.")
+
+			except (SMTPHeloError,SMTPResponseException,SMTPDataError,SMTPServerDisconnected,SMTPConnectError) as e:
+				self.mlog("Error occured: %s"%repr(e))
+				self.que.put(item)
+				self.mlog("Sending rescheduled.")
+
+			except Exception:
+				if smtp:
+					smtp.quit()
+					smtp=None
+				import traceback
+				self.mlog("An error occured in the SMTP runner:\n",traceback.format_exc())
+				self.mlog("As a result, the following email was discarded: %s '%s'"%(item.get("message-id"),item.get("subject")))
+
+			finally:
+				self.que.task_done()
+
+	
+	def stop(self,block=True):
+		self.mlog("Signaling stop to sendmail")
+		self.stopping.set()
+		if block:
+			self.thread.join()
+
+	def mlog(self,*msg,**kwargs):
+		import traceback
+		function=traceback.extract_stack(limit=2)[0].name
+		cherrypy.log(context="%s>>SENDMAIL:%s"%(threading.current_thread().name, function), msg=" ".join([str(i) for i in msg]),**kwargs)
+