Golang JSON Custom Marshal

GolangJSONCustomMarshal.go

/*
In a fairly typical webapp data model you often want to send
the client different "views" of the data model.

Many database and caching tools require the base model to be quite
standard with json tags and types, so the following approach is
ideal:

Based on this blog post and SO question:

http://choly.ca/post/go-json-marshalling/
http://stackoverflow.com/questions/23695479/format-timestamp-in-outgoing-json-in-golang

Note there are quirks with this method, so test throughly. Also define json names for each base field and 
the override fields
*/


type DataModel struct {
	Created time.Time `json:"created"`
	FirstName string `json:"first_name"`
  LastName string `json:"last_name"`
	Password string `json:"pw"`
}

func (d *DataModel) PublicJSON() []byte {
	type Alias DataModel
	bys, err := json.Marshal(&struct {
		*Alias
		Password string `json:"pw,omitempty"`
		Created string `json:"created"`
	}{
		Alias: (*Alias)(d),
		Created: d.Format("2006-01-02"),
	})
	if err != nil {
		panic(err)
	}
	return bys

}