From 45de39193238ab4263eca6238192c73beb8eb1f9 Mon Sep 17 00:00:00 2001
From: George Katsikas <giorgakis.katsikas@gmail.com>
Date: Wed, 13 Nov 2024 14:11:13 +0100
Subject: [PATCH] create mailgun webhook endpoint

send message to slack channel on failure
---
 scipost_django/SciPost_v1/settings/base.py    |  4 ++
 scipost_django/apimail/api/views/__init__.py  |  2 +
 .../apimail/api/views/integrations.py         | 71 +++++++++++++++++++
 scipost_django/apimail/urls.py                |  1 +
 4 files changed, 78 insertions(+)
 create mode 100644 scipost_django/apimail/api/views/integrations.py

diff --git a/scipost_django/SciPost_v1/settings/base.py b/scipost_django/SciPost_v1/settings/base.py
index 24da99a92..e3b4407f4 100644
--- a/scipost_django/SciPost_v1/settings/base.py
+++ b/scipost_django/SciPost_v1/settings/base.py
@@ -632,3 +632,7 @@ GITLAB_KEY = get_secret("GITLAB_KEY")
 # ORCID API
 ORCID_CLIENT_ID = get_secret("ORCID_CLIENT_ID")
 ORCID_CLIENT_SECRET = get_secret("ORCID_CLIENT_SECRET")
+
+
+# SLACK API
+SLACK_WEBHOOK_URL_MAILGUN_ALERTS = get_secret("SLACK_WEBHOOK_URL_MAILGUN_ALERTS")
diff --git a/scipost_django/apimail/api/views/__init__.py b/scipost_django/apimail/api/views/__init__.py
index a0aa6dfa0..49109cb7c 100644
--- a/scipost_django/apimail/api/views/__init__.py
+++ b/scipost_django/apimail/api/views/__init__.py
@@ -25,3 +25,5 @@ from .stored_message import (
     StoredMessageUpdateReadAPIView,
     StoredMessageUpdateTagAPIView,
 )
+
+from .integrations import mailgun_webhook
diff --git a/scipost_django/apimail/api/views/integrations.py b/scipost_django/apimail/api/views/integrations.py
new file mode 100644
index 000000000..2918d96de
--- /dev/null
+++ b/scipost_django/apimail/api/views/integrations.py
@@ -0,0 +1,71 @@
+__copyright__ = "Copyright © Stichting SciPost (SciPost Foundation)"
+__license__ = "AGPL v3"
+
+import json
+from django.conf import settings
+from django.http import HttpResponse
+from django.views.decorators.csrf import csrf_exempt
+
+
+def mailgun_webhook_is_signed(timestamp, token, signature):
+    """
+    Verify the signature of a mailgun webhook.
+    """
+    import hmac
+
+    encoded_token = hmac.new(
+        settings.MAILGUN_API_KEY.encode(),
+        (timestamp + token).encode(),
+        "sha256",
+    ).hexdigest()
+
+    return encoded_token == signature
+
+
+def send_mailgun_alert_slack_message(event_data: dict):
+    """
+    Format mailgun event data and send an alert to Slack
+    """
+    import requests
+
+    event = event_data.get("event", "unknown")
+    reason = event_data.get("reason", "unknown")
+    recipient = event_data.get("message", {}).get("headers", {}).get("to", "unknown")
+    sender = event_data.get("message", {}).get("headers", {}).get("from", "unknown")
+    subject = event_data.get("message", {}).get("headers", {}).get("subject", "unknown")
+
+    message = f"[{event.upper()}] {recipient} -> {sender}\nSubject: {subject}\nReason: {reason}"
+
+    response = requests.post(
+        settings.SLACK_WEBHOOK_URL_MAILGUN_ALERTS,
+        json={"text": message},
+        headers={"Content-type": "application/json"},
+    )
+
+    return response
+
+
+@csrf_exempt
+def mailgun_webhook(request):
+    """
+    Endpoint to receive POST requests for mailgun webhook.
+    Executes custom integrations upon reception.
+    """
+
+    if request.method != "POST":
+        return HttpResponse(status=405)
+
+    data = json.loads(request.body)
+
+    if "signature" not in data:
+        return HttpResponse(status=400)
+
+    # Verify signature, return 403 if invalid
+    if not mailgun_webhook_is_signed(**data.get("signature")):
+        return HttpResponse(status=403)
+
+    # Apply custom integrations here
+    event_data = data.get("event-data", {})
+    send_mailgun_alert_slack_message(event_data)
+
+    return HttpResponse(status=200)
diff --git a/scipost_django/apimail/urls.py b/scipost_django/apimail/urls.py
index 725f95ba8..f4846154a 100644
--- a/scipost_django/apimail/urls.py
+++ b/scipost_django/apimail/urls.py
@@ -117,5 +117,6 @@ urlpatterns = [
     path(  # /mail/attachment_file/<uuid>
         "attachment_file/<uuid:uuid>", views.attachment_file, name="attachment_file"
     ),
+    path("mailgun_webhook", apiviews.mailgun_webhook, name="mailgun_webhook"),
     path("", views.mail, name="mail"),  # /mail
 ]
-- 
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