feat: add email scope to OAuth configuration and update documentation

server/internal/config/member.go

@@ -152,7 +152,7 @@ func (Member) Init(cmd *cobra.Command) error {
 		return err
 	}
 
-	cmd.PersistentFlags().StringSlice("member.oauth.scopes", []string{"openid", "profile"}, "OAuth 2.0 scopes")
+	cmd.PersistentFlags().StringSlice("member.oauth.scopes", []string{"openid", "profile", "email"}, "OAuth 2.0 scopes")
 	if err := viper.BindPFlag("member.oauth.scopes", cmd.PersistentFlags().Lookup("member.oauth.scopes")); err != nil {
 		return err
 	}

server/internal/member/oauth/service.go

@@ -13,6 +13,8 @@ import (
 	"sync"
 	"time"
 
+	"github.com/rs/zerolog/log"
+
 	"github.com/m1k1o/neko/server/pkg/types"
 )
 
@@ -166,6 +168,10 @@ func (service *Service) Complete(ctx context.Context, stateToken, code string) (
 		email = claim(idClaims, "email")
 	}
 
+	if email == "" && (len(config.AdminEmails) > 0 || len(config.UserEmails) > 0) {
+		log.Warn().Msg("OAuth admin_emails/user_emails are configured but the provider did not return an 'email' claim; request the 'email' scope")
+	}
+
 	isAdmin := boolClaim(claims, "isAdmin") || boolClaim(idClaims, "isAdmin")
 	admin := administrator(email, isAdmin, config.AdminEmails)
 

webpage/docs/configuration/authentication.md

@@ -196,7 +196,7 @@ member:
     client_id: "<client-id>"
     client_secret: "<client-secret>"
     issuer_url: "https://id.example.com"
-    scopes: ["openid", "profile"]
+    scopes: ["openid", "profile", "email"]
     # Configure these to match the JSON returned by userinfo_url.
     subject_field: "sub"
     username_field: "name"
@@ -230,6 +230,10 @@ The sign-in endpoint is `GET /api/oauth/login`; the callback endpoint is `GET /a
 
 `user_emails` restricts non-admin login to a list of allowed emails, matched the same way as `admin_emails`. If `user_emails` is empty (the default), any authenticated user is allowed to log in. Administrators (matched by `admin_emails` or `isAdmin: true`) can always log in regardless of `user_emails`. Users whose email is not allowed receive an HTTP 403 response and no session is created.
 
+:::warning
+`admin_emails` and `user_emails` are matched against the `email` claim. Most providers only include that claim if the `email` scope is requested, so `scopes` must include `"email"` (in addition to `"openid"`) or the claim will be empty and these lists will never match.
+:::
+
 For OAuth sessions, `GET /api/whoami` includes `extra_data`: the merged userinfo and ID-token claims, with userinfo values taking precedence. It is returned only to the authenticated session owner and is intended for profile-field troubleshooting. Do not place secrets in provider profile claims.
 
 For non-OIDC providers, set `authorization_url`, `token_url`, `userinfo_url`, and optionally `redirect_url` directly. For GitHub, for example, use `read:user` as a scope and set `subject_field: id`, `username_field: login`, and `avatar_field: avatar_url`.