auth selection: cookie with optional domain parameter

loops/server/auth.py

@@ -49,12 +49,17 @@ class LoginPageSelect(LoginPage):
     def showSelection(self):
         return getConfigAuthMethod() == 'cookie'
 
+    def authMethodCookieString(self):
+        domain = getattr(config, 'authentication_method_cookie_domain', None)
+        return 'document.cookie=`loops_auth_method=${this.value}; path=/; expires=Sun, 31 Jan 2027 12:00:00 UTC%s`' % (domain and f'; domain={domain}' or '')
+
 
 def getConfigAuthMethod():
     return getattr(config, 'authentication_method', 'legacy')
 
 def getAuthMethodCookieValue(request):
-    return request.cookies.get('loops_auth_method') or 'legacy'
+    default = getattr(config, 'authentication_method_cookie_default', 'legacy')
+    return request.cookies.get('loops_auth_method') or default
 
 
 # OIDC authentication

loops/server/loginform.pt

@@ -31,7 +31,8 @@
         <select name="auth_method"
                 onchange="document.cookie=`loops_auth_method=${this.value}; path=/; expires=Sun, 31 Jan 2027 12:00:00 UTC`"
                 tal:define="meth view/authMethod"
-                tal:attributes="value meth">
+                tal:attributes="value meth;
+                                onchange view/authMethodCookieString">
            <option value="legacy" i18n:translate="authentication-method-legacy"
                    tal:attributes="selected python:meth=='legacy'">Legacy</option>
            <option value="oidc" i18n:translate="authentication-method-oidc"