Add rate limiting for error emails, adjust error message and get them shown in frontend.

Author: wbobeirne

backend/boltathon/app.py

@@ -53,12 +53,12 @@ def handle_notfound_error(err):
 
   @app.errorhandler(RequestError)
   def handle_request_error(err):
-    return jsonify({"message": err.message}), err.code
+    return jsonify({"error": err.message}), err.code
 
   @app.errorhandler(Exception)
   def handle_exception(err):
       app.logger.debug(traceback.format_exc())
       app.logger.debug("Uncaught exception at {} {}, see above for traceback".format(request.method, request.path))
-      return jsonify({"message": "Something went wrong"}), 500
+      return jsonify({"error": "Something went wrong"}), 500
 
   return app

backend/boltathon/util/mail.py

@@ -35,7 +35,7 @@ def tip_error_info(email_args):
 }
 
 
-def generate_email(type, email_args, user=None):
+def generate_email(user, type, email_args):
     info = get_info_lookup[type](email_args)
     body_text = render_template(
         'emails/%s.txt' % (type),
@@ -88,7 +88,7 @@ def send_email(user, type, email_args):
         return
 
     try:
-        email = generate_email(type, email_args)
+        email = generate_email(user, type, email_args)
         sg = SendGridAPIClient(SENDGRID_API_KEY)
         print(SENDGRID_DEFAULT_FROM)
         print(user.email)
@@ -107,3 +107,20 @@ def send_email(user, type, email_args):
     except Exception as e:
         current_app.logger.info('An unknown error occured while sending an email to %s - %s: %s' % (user.email, e.__class__.__name__, e))
         current_app.logger.error(e)
+
+# Sends an email once and only once this session of the app. This is pretty
+# low-stakes, so it's OK that it rests on restart. Mostly meant to avoid spam.
+send_once_map = {}
+
+def send_email_once(user, type, email_args, extra_key='default'):
+    if not user or not user.email:
+        return
+
+    key = '%s - %s - %s' % (user.id, type, extra_key)
+
+    if send_once_map.get(key):
+        current_app.logger.debug('Already sent with key `%s`' % (key))
+        return
+
+    send_once_map[key] = True
+    return send_email(user, type, email_args)

backend/boltathon/views/api.py

@@ -7,7 +7,7 @@
 from boltathon.util.auth import requires_auth
 from boltathon.util.node import get_pubkey_from_credentials, make_invoice, lookup_invoice
 from boltathon.util.errors import RequestError
-from boltathon.util.mail import send_email
+from boltathon.util.mail import send_email_once
 from boltathon.models.user import User, self_user_schema, public_user_schema, public_users_schema
 from boltathon.models.connection import Connection, public_connections_schema
 from boltathon.models.tip import Tip, tip_schema, tips_schema
@@ -125,12 +125,12 @@ def post_invoice(args, user_id, **kwargs):
     current_app.logger.error(e)
 
   if err:
-    send_email(user, 'tip_error', {
+    send_email_once(user, 'tip_error', {
       'error': err,
       'config_url': frontend_url('/user/me?tab=config'),
       'support_url': 'https://github.com/tiphub-io/tiphub/issues',
-    })
-    raise RequestError(code=500, message='Failed to generate a tip invoice')
+    }, err)
+    raise RequestError(code=500, message='Failed to generate a tip invoice, their node may be offline or otherwise inaccessible')
 
 
 @blueprint.route('/users/search/<query>', methods=['GET'])