package authority import ( "encoding/json" "github.com/pkg/errors" ) // multiString represents a type that can be encoded/decoded in JSON as a single // string or an array of strings. type multiString []string // First returns the first element of a multiString. It will return an empty // string if the multistring is empty. func (s multiString) First() string { if len(s) > 0 { return s[0] } return "" } // HasEmpties returns `true` if any string in the array is empty. func (s multiString) HasEmpties() bool { if len(s) == 0 { return true } for _, ss := range s { if len(ss) == 0 { return true } } return false } // MarshalJSON marshals the multistring as a string or a slice of strings . With // 0 elements it will return the empty string, with 1 element a regular string, // otherwise a slice of strings. func (s multiString) MarshalJSON() ([]byte, error) { switch len(s) { case 0: return []byte(`""`), nil case 1: return json.Marshal(s[0]) default: return json.Marshal([]string(s)) } } // UnmarshalJSON parses a string or a slice and sets it to the multiString. func (s *multiString) UnmarshalJSON(data []byte) error { if s == nil { return errors.New("multiString cannot be nil") } if len(data) == 0 { *s = nil return nil } // Parse string if data[0] == '"' { var str string if err := json.Unmarshal(data, &str); err != nil { return errors.Wrapf(err, "error unmarshalling %s", data) } *s = []string{str} return nil } // Parse array var ss []string if err := json.Unmarshal(data, &ss); err != nil { return errors.Wrapf(err, "error unmarshalling %s", data) } *s = ss return nil }