feat: able to login via email (close #921)

model/user.go

@@ -141,7 +141,15 @@ func (user *User) ValidateAndFill() (err error) {
 	if user.Username == "" || password == "" {
 		return errors.New("用户名或密码为空")
 	}
-	DB.Where(User{Username: user.Username}).First(user)
+	err = DB.Where("username = ?", user.Username).First(user).Error
+	if err != nil {
+		// we must make sure check username firstly
+		// consider this case: a malicious user set his username as other's email
+		err := DB.Where("email = ?", user.Username).First(user).Error
+		if err != nil {
+			return errors.New("用户名或密码错误，或用户已被封禁")
+		}
+	}
 	okay := common.ValidatePasswordAndHash(password, user.Password)
 	if !okay || user.Status != common.UserStatusEnabled {
 		return errors.New("用户名或密码错误，或用户已被封禁")