reduce code duplication

Former-commit-id: fa4946eff4f979e8fd3550a0b11f3ab147177b8f [formerly cd071c220157452a095325c049d801e99d2f8a94] [formerly 7a619be88fb162ddbf897387a31577fd3e94bfec [formerly ef56112711]]
Former-commit-id: 692897eac98f1d8d4a916d0ef0aa342b994a186b [formerly 69d9f127de2deadbbcaa0174fc1a4613ce2cb93d]
Former-commit-id: 49c5aef77aa74ec8352368627c98b9e50d417228

storage/bolt/users.go

@@ -12,32 +12,29 @@ type usersBackend struct {
 	db *storm.DB
 }
 
-func (st usersBackend) GetByID(id uint) (*users.User, error) {
-	user := &users.User{}
-	err := st.db.One("ID", id, user)
-	if err == storm.ErrNotFound {
-		return nil, errors.ErrNotExist
+func (st usersBackend) GetBy(i interface{}) (user *users.User, err error) {
+	user = &users.User{}
+
+	var arg string
+	switch i.(type) {
+	case uint:
+		arg = "ID"
+	case string:
+		arg = "Username"
+	default:
+		return nil, errors.ErrInvalidDataType
 	}
 
+	err = st.db.One(arg, i, user)
+
 	if err != nil {
+		if err == storm.ErrNotFound {
+			return nil, errors.ErrNotExist
+		}
 		return nil, err
 	}
 
-	return user, nil
-}
-
-func (st usersBackend) GetByUsername(username string) (*users.User, error) {
-	user := &users.User{}
-	err := st.db.One("Username", username, user)
-	if err == storm.ErrNotFound {
-		return nil, errors.ErrNotExist
-	}
-
-	if err != nil {
-		return nil, err
-	}
-
-	return user, nil
+	return
 }
 
 func (st usersBackend) Gets() ([]*users.User, error) {
@@ -82,7 +79,7 @@ func (st usersBackend) DeleteByID(id uint) error {
 }
 
 func (st usersBackend) DeleteByUsername(username string) error {
-	user, err := st.GetByUsername(username)
+	user, err := st.GetBy(username)
 	if err != nil {
 		return err
 	}

users/storage.go

@@ -9,8 +9,7 @@ import (
 
 // StorageBackend is the interface to implement for a users storage.
 type StorageBackend interface {
-	GetByID(uint) (*User, error)
-	GetByUsername(string) (*User, error)
+	GetBy(interface{}) (*User, error)
 	Gets() ([]*User, error)
 	Save(u *User) error
 	Update(u *User, fields ...string) error
@@ -36,27 +35,13 @@ func NewStorage(back StorageBackend) *Storage {
 // Get allows you to get a user by its name or username. The provided
 // id must be a string for username lookup or a uint for id lookup. If id
 // is neither, a ErrInvalidDataType will be returned.
-func (s *Storage) Get(baseScope string, id interface{}) (*User, error) {
-	var (
-		user *User
-		err  error
-	)
-
-	switch id.(type) {
-	case string:
-		user, err = s.back.GetByUsername(id.(string))
-	case uint:
-		user, err = s.back.GetByID(id.(uint))
-	default:
-		return nil, errors.ErrInvalidDataType
-	}
-
+func (s *Storage) Get(baseScope string, id interface{}) (user *User, err error) {
+	user, err = s.back.GetBy(id)
 	if err != nil {
-		return nil, err
+		return
 	}
-
 	user.Clean(baseScope)
-	return user, err
+	return
 }
 
 // Gets gets a list of all users.