[feature] allow blocking of multiple user sessions #884:

frappe/auth.py

@@ -53,6 +53,15 @@ class HTTPRequest:
 		# run login triggers
 		if frappe.form_dict.get('cmd')=='login':
 			frappe.local.login_manager.run_trigger('on_session_creation')
+			self.clear_active_sessions()
+
+	def clear_active_sessions(self):
+		if not frappe.conf.get("deny_multiple_sessions"):
+			return
+
+		if frappe.session.user != "Guest":
+			clear_sessions(frappe.session.user, keep_current=True)
+
 
 	def set_lang(self, lang):
 		from frappe.translate import guess_language_from_http_header

frappe/change_log/v5_0/v5_0_0.md

@@ -1,3 +1,7 @@
 ### Custom DocTypes
 
 The user can add Custom DocTypes (Forms) without creating a new app by setting **Custom** property.
+
+### Site Configuration
+
+- Stop multiple logins for a user by setting `deny_multiple_sessions` in `site_config.json`. [Help on `site_config.json`](https://frappe.io/docs/user-guide/site_config).