add is_valid_email()

app/email_utils.py

@@ -11,6 +11,7 @@ from smtplib import SMTP
 import arrow
 import dkim
 from jinja2 import Environment, FileSystemLoader
+from validate_email import validate_email
 
 from app.config import (
     SUPPORT_EMAIL,
@@ -645,3 +646,10 @@ def should_add_dkim_signature(domain: str) -> bool:
         return True
 
     return False
+
+
+def is_valid_email(email_address: str) -> bool:
+    """Used to check whether an email address is valid"""
+    return validate_email(
+        email_address=email_address, check_mx=False, use_blacklist=False
+    )

tests/test_email_utils.py

@@ -13,6 +13,7 @@ from app.email_utils import (
     copy,
     get_spam_from_header,
     get_header_from_bounce,
+    is_valid_email,
 )
 from app.extensions import db
 from app.models import User, CustomDomain
@@ -286,3 +287,10 @@ DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=simplelogin.co;
     assert (
         get_header_from_bounce(email.message_from_string(msg_str), "Not-exist") is None
     )
+
+
+def test_is_valid_email():
+    assert is_valid_email("abcd@gmail.com")
+    assert not is_valid_email("with space@gmail.com")
+    assert not is_valid_email("strange char !ç@gmail.com")
+    assert not is_valid_email("emoji👌@gmail.com")