Method View

db.go:936–961

View executes a function within the context of a managed read-only transaction. Any error that is returned from the function is returned from the View() method. Attempting to manually rollback within the function will cause a panic.

(fn func(*Tx) error)

//
// Attempting to manually rollback within the function will cause a panic.
func (db *DB) View(fn func(*Tx) error) error {
	t, err := db.Begin(false)
	if err != nil {
		return err
	}

	// Make sure the transaction rolls back in the event of a panic.
	defer func() {
		if t.db != nil {
			t.rollback()
		}
	}()

	// Mark as a managed tx so that the inner function cannot manually rollback.
	t.managed = true

	// If an error is returned from the function then pass it through.
	err = fn(t)
	t.managed = false
	if err != nil {
		_ = t.Rollback()
		return err
	}

	return t.Rollback()
}

// Batch calls fn as part of a batch. It behaves similar to Update,
// except: