feat: support webauthn login (#4945)

* feat: support webauthn login

* manually merge

* fix: clear user cache after updating authn

* decrease db size of Authn

* change authn type to text

* simplify code structure

---------

Co-authored-by: Andy Hsu <i@nn.ci>

internal/db/user.go

@@ -1,7 +1,11 @@
 package db
 
 import (
+	"encoding/base64"
+
 	"github.com/alist-org/alist/v3/internal/model"
+	"github.com/alist-org/alist/v3/pkg/utils"
+	"github.com/go-webauthn/webauthn/webauthn"
 	"github.com/pkg/errors"
 )
 
@@ -59,3 +63,40 @@ func GetUsers(pageIndex, pageSize int) (users []model.User, count int64, err err
 func DeleteUserById(id uint) error {
 	return errors.WithStack(db.Delete(&model.User{}, id).Error)
 }
+
+func UpdateAuthn(userID uint, authn string) error {
+	return db.Model(&model.User{ID: userID}).Update("authn", authn).Error
+}
+
+func RegisterAuthn(u *model.User, credential *webauthn.Credential) error {
+	if u == nil {
+		return errors.New("user is nil")
+	}
+	exists := u.WebAuthnCredentials()
+	if credential != nil {
+		exists = append(exists, *credential)
+	}
+	res, err := utils.Json.Marshal(exists)
+	if err != nil {
+		return err
+	}
+	return UpdateAuthn(u.ID, string(res))
+}
+
+func RemoveAuthn(u *model.User, id string) error {
+	exists := u.WebAuthnCredentials()
+	for i := 0; i < len(exists); i++ {
+		idEncoded := base64.StdEncoding.EncodeToString(exists[i].ID)
+		if idEncoded == id {
+			exists[len(exists)-1], exists[i] = exists[i], exists[len(exists)-1]
+			exists = exists[:len(exists)-1]
+			break
+		}
+	}
+
+	res, err := utils.Json.Marshal(exists)
+	if err != nil {
+		return err
+	}
+	return UpdateAuthn(u.ID, string(res))
+}