From 6bf191a028e6571316ebd83703328ae4c39d005f Mon Sep 17 00:00:00 2001
From: Alireza Lotfi <alotfitakami@archinsurance.com>
Date: Tue, 13 Sep 2022 10:23:04 -0400
Subject: [PATCH] django-mailbox-oauth-imap: support office365 oauth

---
 django_mailbox/models.py               | 10 ++++-
 django_mailbox/transports/__init__.py  |  1 +
 django_mailbox/transports/office365.py | 58 ++++++++++++++++++++++++++
 3 files changed, 68 insertions(+), 1 deletion(-)
 create mode 100644 django_mailbox/transports/office365.py

diff --git a/django_mailbox/models.py b/django_mailbox/models.py
index 616a132..5531624 100644
--- a/django_mailbox/models.py
+++ b/django_mailbox/models.py
@@ -31,7 +31,7 @@ from django_mailbox import utils
 from django_mailbox.signals import message_received
 from django_mailbox.transports import Pop3Transport, ImapTransport, \
     MaildirTransport, MboxTransport, BabylTransport, MHTransport, \
-    MMDFTransport, GmailImapTransport
+    MMDFTransport, GmailImapTransport, Office365ImapTransport
 
 logger = logging.getLogger(__name__)
 
@@ -216,6 +216,14 @@ class Mailbox(models.Model):
                 archive=self.archive
             )
             conn.connect(self.username, self.password)
+        elif self.type == 'office365':
+            conn = Office365ImapTransport(
+                self.location,
+                port=self.port if self.port else None,
+                ssl=True,
+                archive=self.archive
+            )
+            conn.connect(self.username, self.password)
         elif self.type == 'pop3':
             conn = Pop3Transport(
                 self.location,
diff --git a/django_mailbox/transports/__init__.py b/django_mailbox/transports/__init__.py
index 7aeef95..6e31435 100644
--- a/django_mailbox/transports/__init__.py
+++ b/django_mailbox/transports/__init__.py
@@ -8,3 +8,4 @@ from django_mailbox.transports.babyl import BabylTransport
 from django_mailbox.transports.mh import MHTransport
 from django_mailbox.transports.mmdf import MMDFTransport
 from django_mailbox.transports.gmail import GmailImapTransport
+from django_mailbox.transports.office365 import Office365ImapTransport
diff --git a/django_mailbox/transports/office365.py b/django_mailbox/transports/office365.py
new file mode 100644
index 0000000..91278ad
--- /dev/null
+++ b/django_mailbox/transports/office365.py
@@ -0,0 +1,58 @@
+import logging
+import urllib3
+import json
+
+from django_mailbox.transports.imap import ImapTransport
+from django.conf import settings
+
+
+logger = logging.getLogger(__name__)
+
+
+class Office365ImapTransport(ImapTransport):
+    def connect(self, username, password):
+        # Try to use oauth2 first.  It's much safer
+        try:
+            self._connect_oauth(username)
+        except (TypeError, ValueError) as e:
+            logger.warning("Couldn't do oauth2 because %s" % e)
+            self.server = self.transport(self.hostname, self.port)
+            typ, msg = self.server.login(username, password)
+            self.server.select()
+
+    def _connect_oauth(self, username):
+        # username should be an email address that has already been authorized
+        # for gmail access
+
+        access_token = None
+        while access_token is None:
+            try:
+                access_token = self.get_office365_access_token()
+            except Exception as e:
+                raise ValueError(
+                    f"Could not acquire the access token for {username} exception details={e}"
+                )
+
+        auth_string = f"user={username}\1auth=Bearer {access_token}\1\1"
+        self.server = self.transport(self.hostname, self.port)
+        self.server.authenticate("XOAUTH2", lambda x: auth_string)
+        self.server.select()
+
+    def get_office365_access_token():
+        url = f"https://login.microsoftonline.com/{settings.MICROSOFT_0365_TENENT_ID}/oauth2/v2.0/token"
+        oauth_params = {
+            "client_id": settings.MICROSOFT_0365_CLIENT_ID,
+            "client_secret": settings.MICROSOFT_0365_CLIENT_SECRET,
+            "grant_type": "client_credentials",
+            "scope": "https://graph.microsoft.com/.default",
+        }
+        http = urllib3.PoolManager()
+        response = http.request("POST", url, oauth_params)
+        if response.status == 200:
+            token = json.loads(response.data).get("access_token")
+            logger.info(f"[get_office365_access_token] token aquired")
+            return token
+        else:
+            raise Exception(
+                f"[get_office365_access_token] Failed to authenticate with O365 {response.data}"
+            )