feat(user): user can't use reserved username

configs/config.go

@@ -7,3 +7,6 @@ var Config []byte
 
 //go:embed  path_ignore.yaml
 var PathIgnore []byte
+
+//go:embed  reserved-usernames.json
+var ReservedUsernames []byte

internal/service/user_common/user.go

@@ -126,6 +126,10 @@ func (us *UserCommon) MakeUsername(ctx context.Context, displayName string) (use
 		return "", errors.BadRequest(reason.UsernameInvalid)
 	}
 
+	if checker.IsReservedUsername(username) {
+		return "", errors.BadRequest(reason.UsernameInvalid)
+	}
+
 	for {
 		_, has, err := us.userRepo.GetByUsername(ctx, username+suffix)
 		if err != nil {

pkg/checker/reserved_username.go

@@ -0,0 +1,26 @@
+package checker
+
+import (
+	"encoding/json"
+
+	"github.com/answerdev/answer/configs"
+	"github.com/segmentfault/pacman/log"
+)
+
+var (
+	reservedUsernameMapping = make(map[string]bool)
+)
+
+func init() {
+	var usernames []string
+	_ = json.Unmarshal(configs.ReservedUsernames, &usernames)
+	log.Debugf("get reserved usernames %d", len(usernames))
+	for _, username := range usernames {
+		reservedUsernameMapping[username] = true
+	}
+}
+
+// IsReservedUsername checks whether the username is reserved
+func IsReservedUsername(username string) bool {
+	return reservedUsernameMapping[username]
+}