jsonutil

func Filter ¶

func Filter(v interface{}, fields []string) interface{}

Filter filters an interface given its type and JSON field paths.

func FilterMap ¶

func FilterMap(v interface{}, fields []string) map[string]interface{}

FilterMap filters a map given key paths.

func FilterSlice ¶

func FilterSlice(v interface{}, fields []string) []map[string]interface{}

FilterSlice filters a slice of struct given JSON field paths.

func FilterStruct ¶

func FilterStruct(v interface{}, fields []string) map[string]interface{}

FilterStruct filters a struct given a list of JSON field paths. The return value is a map containing the struct fields matched on the `json` field tag.

It is possible to filter nested structures using a dot as level separator, e.g. "item.sub_item".

Fields are ignored when:

• not tagged with `json`
• tagged with `json:"-"`
• tagged with `omitempty` and set to their default value

Example:

type Service struct {
	ID        string    `json:"id"`
	Name      string    `json:"name"`
	Hostgroup Hostgroup `json:"hostgroup"`
}

type Hostgroup struct {
	ID    string `json:"id"`
	Name  string `json:"name"`
	Hosts []Host `json:"hosts"`
}

type Host struct {
	ID   string `json:"id"`
	Name string `json:"name"`
	Addr string `json:"addr"`
	Port int    `json:"port"`
}

func main() {
	service := Service{
		ID:   "CCDE8419-74BB-4A8C-8AE4-8E2A17B3C3DD",
		Name: "service1",
		Hostgroup: Hostgroup{
			ID:   "48F2F97F-EB85-418B-A05D-63C0A3914AA4",
			Name: "hostgroup1",
			Hosts: []Host{
				Host{
					ID:   "E0011483-5E4A-4A2F-96AA-DADA236E3BD6",
					Name: "host1",
					Addr: "1.2.3.4",
					Port: 9999,
				},
				Host{
					ID:   "C9AFE8C0-1017-4025-B9A3-CBB9901E1F44",
					Name: "host2",
					Addr: "5.6.7.8",
					Port: 9999,
				},
				Host{
					ID:   "E2F99B14-8839-4321-90AF-3877486A68D9",
					Name: "host3",
					Addr: "9.10.11.12",
					Port: 9999,
				},
			},
		},
	}

	j, err := json.MarshalIndent(jsonutil.FilterStruct(service, []string{
		"name",
		"hostgroup.name",
		"hostgroup.hosts.name",
	}), "", "  ")

	fmt.Printf("%s\n", j)

}

...will output the following JSON data:

{
"hostgroup": {
	"hosts": [
	{
		"name": "host1"
	},
	{
		"name": "host2"
	},
	{
		"name": "host3"
	}
	],
	"name": "hostgroup1"
},
"name": "service1"
}

func MarshalFile ¶

func MarshalFile(file string, v interface{}) error

MarshalFile writes the JSON encoded version of v to file.

func UnmarshalFile ¶

func UnmarshalFile(file string, v interface{}) error

UnmarshalFile parses the JSON-encoded data from file and stores the result in the value pointed to by v.