example_test.go

package toml_test

import (
	"bytes"
	"fmt"
	"log"
	"time"

	"github.com/lucasbutn/toml"
)

func ExampleEncoder_Encode() {
	date, _ := time.Parse(time.RFC822, "14 Mar 10 18:00 UTC")
	var config = map[string]interface{}{
		"date":   date,
		"counts": []int{1, 1, 2, 3, 5, 8},
		"hash": map[string]string{
			"key1": "val1",
			"key2": "val2",
		},
	}
	buf := new(bytes.Buffer)
	if err := toml.NewEncoder(buf).Encode(config); err != nil {
		log.Fatal(err)
	}
	fmt.Println(buf.String())

	// Output:
	// counts = [1, 1, 2, 3, 5, 8]
	// date = 2010-03-14T18:00:00Z
	//
	// [hash]
	//   key1 = "val1"
	//   key2 = "val2"
}

func ExampleMetaData_PrimitiveDecode() {
	var md toml.MetaData
	var err error

	var tomlBlob = `
ranking = ["Springsteen", "J Geils"]

[bands.Springsteen]
started = 1973
albums = ["Greetings", "WIESS", "Born to Run", "Darkness"]

[bands."J Geils"]
started = 1970
albums = ["The J. Geils Band", "Full House", "Blow Your Face Out"]
`

	type band struct {
		Started int
		Albums  []string
	}
	type classics struct {
		Ranking []string
		Bands   map[string]toml.Primitive
	}

	// Do the initial decode. Reflection is delayed on Primitive values.
	var music classics
	if md, err = toml.Decode(tomlBlob, &music); err != nil {
		log.Fatal(err)
	}

	// MetaData still includes information on Primitive values.
	fmt.Printf("Is `bands.Springsteen` defined? %v\n",
		md.IsDefined("bands", "Springsteen"))

	// Decode primitive data into Go values.
	for _, artist := range music.Ranking {
		// A band is a primitive value, so we need to decode it to get a
		// real `band` value.
		primValue := music.Bands[artist]

		var aBand band
		if err = md.PrimitiveDecode(primValue, &aBand); err != nil {
			log.Fatal(err)
		}
		fmt.Printf("%s started in %d.\n", artist, aBand.Started)
	}
	// Check to see if there were any fields left undecoded.
	// Note that this won't be empty before decoding the Primitive value!
	fmt.Printf("Undecoded: %q\n", md.Undecoded())

	// Output:
	// Is `bands.Springsteen` defined? true
	// Springsteen started in 1973.
	// J Geils started in 1970.
	// Undecoded: []
}

func ExampleDecode() {
	var tomlBlob = `
# Some comments.
[alpha]
ip = "10.0.0.1"

	[alpha.config]
	Ports = [ 8001, 8002 ]
	Location = "Toronto"
	Created = 1987-07-05T05:45:00Z

[beta]
ip = "10.0.0.2"

	[beta.config]
	Ports = [ 9001, 9002 ]
	Location = "New Jersey"
	Created = 1887-01-05T05:55:00Z
`

	type serverConfig struct {
		Ports    []int
		Location string
		Created  time.Time
	}

	type server struct {
		IP     string       `toml:"ip,omitempty"`
		Config serverConfig `toml:"config"`
	}

	type servers map[string]server

	var config servers
	if _, err := toml.Decode(tomlBlob, &config); err != nil {
		log.Fatal(err)
	}

	for _, name := range []string{"alpha", "beta"} {
		s := config[name]
		fmt.Printf("Server: %s (ip: %s) in %s created on %s\n",
			name, s.IP, s.Config.Location,
			s.Config.Created.Format("2006-01-02"))
		fmt.Printf("Ports: %v\n", s.Config.Ports)
	}

	// Output:
	// Server: alpha (ip: 10.0.0.1) in Toronto created on 1987-07-05
	// Ports: [8001 8002]
	// Server: beta (ip: 10.0.0.2) in New Jersey created on 1887-01-05
	// Ports: [9001 9002]
}

type duration struct {
	time.Duration
}

func (d *duration) UnmarshalText(text []byte) error {
	var err error
	d.Duration, err = time.ParseDuration(string(text))
	return err
}

// Example Unmarshaler shows how to decode TOML strings into your own
// custom data type.
func Example_unmarshaler() {
	blob := `
[[song]]
name = "Thunder Road"
duration = "4m49s"

[[song]]
name = "Stairway to Heaven"
duration = "8m03s"
`
	type song struct {
		Name     string
		Duration duration
	}
	type songs struct {
		Song []song
	}
	var favorites songs
	if _, err := toml.Decode(blob, &favorites); err != nil {
		log.Fatal(err)
	}

	// Code to implement the TextUnmarshaler interface for `duration`:
	//
	// type duration struct {
	// 	time.Duration
	// }
	//
	// func (d *duration) UnmarshalText(text []byte) error {
	// 	var err error
	// 	d.Duration, err = time.ParseDuration(string(text))
	// 	return err
	// }

	for _, s := range favorites.Song {
		fmt.Printf("%s (%s)\n", s.Name, s.Duration)
	}
	// Output:
	// Thunder Road (4m49s)
	// Stairway to Heaven (8m3s)
}

// Example StrictDecoding shows how to detect whether there are keys in the
// TOML document that weren't decoded into the value given. This is useful
// for returning an error to the user if they've included extraneous fields
// in their configuration.
func Example_strictDecoding() {
	var blob = `
key1 = "value1"
key2 = "value2"
key3 = "value3"
`
	type config struct {
		Key1 string
		Key3 string
	}

	var conf config
	md, err := toml.Decode(blob, &conf)
	if err != nil {
		log.Fatal(err)
	}
	fmt.Printf("Undecoded keys: %q\n", md.Undecoded())
	// Output:
	// Undecoded keys: ["key2"]
}

type order struct {
	// NOTE `order.parts` is a private slice of type `part` which is an
	// interface and may only be loaded from toml using the UnmarshalTOML()
	// method of the Umarshaler interface.
	parts parts
}

type parts []part

type part interface {
	Name() string
}

type valve struct {
	Type   string
	ID     string
	Size   float32
	Rating int
}

func (v *valve) Name() string {
	return fmt.Sprintf("VALVE: %s", v.ID)
}

type pipe struct {
	Type     string
	ID       string
	Length   float32
	Diameter int
}

func (p *pipe) Name() string {
	return fmt.Sprintf("PIPE: %s", p.ID)
}

type cable struct {
	Type   string
	ID     string
	Length int
	Rating float32
}

func (c *cable) Name() string {
	return fmt.Sprintf("CABLE: %s", c.ID)
}

func (o *order) UnmarshalTOML(data interface{}) error {

	// NOTE the example below contains detailed type casting to show how
	// the 'data' is retrieved. In operational use, a type cast wrapper
	// may be preferred e.g.
	//
	// func AsMap(v interface{}) (map[string]interface{}, error) {
	// 		return v.(map[string]interface{})
	// }
	//
	// resulting in:
	// d, _ := AsMap(data)
	//

	d, _ := data.(map[string]interface{})
	parts, _ := d["parts"].([]map[string]interface{})

	for _, p := range parts {

		typ, _ := p["type"].(string)
		id, _ := p["id"].(string)

		// detect the type of part and handle each case
		switch p["type"] {
		case "valve":

			size := float32(p["size"].(float64))
			rating := int(p["rating"].(int64))

			valve := &valve{
				Type:   typ,
				ID:     id,
				Size:   size,
				Rating: rating,
			}

			o.parts = append(o.parts, valve)

		case "pipe":

			length := float32(p["length"].(float64))
			diameter := int(p["diameter"].(int64))

			pipe := &pipe{
				Type:     typ,
				ID:       id,
				Length:   length,
				Diameter: diameter,
			}

			o.parts = append(o.parts, pipe)

		case "cable":

			length := int(p["length"].(int64))
			rating := float32(p["rating"].(float64))

			cable := &cable{
				Type:   typ,
				ID:     id,
				Length: length,
				Rating: rating,
			}

			o.parts = append(o.parts, cable)

		}
	}

	return nil
}

// Example UnmarshalTOML shows how to implement a struct type that knows how to
// unmarshal itself. The struct must take full responsibility for mapping the
// values passed into the struct. The method may be used with interfaces in a
// struct in cases where the actual type is not known until the data is
// examined.
func Example_unmarshalTOML() {

	var blob = `
[[parts]]
type = "valve"
id = "valve-1"
size = 1.2
rating = 4

[[parts]]
type = "valve"
id = "valve-2"
size = 2.1
rating = 5

[[parts]]
type = "pipe"
id = "pipe-1"
length = 2.1
diameter = 12

[[parts]]
type = "cable"
id = "cable-1"
length = 12
rating = 3.1
`
	o := &order{}
	err := toml.Unmarshal([]byte(blob), o)
	if err != nil {
		log.Fatal(err)
	}

	fmt.Println(len(o.parts))

	for _, part := range o.parts {
		fmt.Println(part.Name())
	}

	// Code to implement UmarshalJSON.

	// type order struct {
	// 	// NOTE `order.parts` is a private slice of type `part` which is an
	// 	// interface and may only be loaded from toml using the
	// 	// UnmarshalTOML() method of the Umarshaler interface.
	// 	parts parts
	// }

	// func (o *order) UnmarshalTOML(data interface{}) error {

	// 	// NOTE the example below contains detailed type casting to show how
	// 	// the 'data' is retrieved. In operational use, a type cast wrapper
	// 	// may be preferred e.g.
	// 	//
	// 	// func AsMap(v interface{}) (map[string]interface{}, error) {
	// 	// 		return v.(map[string]interface{})
	// 	// }
	// 	//
	// 	// resulting in:
	// 	// d, _ := AsMap(data)
	// 	//

	// 	d, _ := data.(map[string]interface{})
	// 	parts, _ := d["parts"].([]map[string]interface{})

	// 	for _, p := range parts {

	// 		typ, _ := p["type"].(string)
	// 		id, _ := p["id"].(string)

	// 		// detect the type of part and handle each case
	// 		switch p["type"] {
	// 		case "valve":

	// 			size := float32(p["size"].(float64))
	// 			rating := int(p["rating"].(int64))

	// 			valve := &valve{
	// 				Type:   typ,
	// 				ID:     id,
	// 				Size:   size,
	// 				Rating: rating,
	// 			}

	// 			o.parts = append(o.parts, valve)

	// 		case "pipe":

	// 			length := float32(p["length"].(float64))
	// 			diameter := int(p["diameter"].(int64))

	// 			pipe := &pipe{
	// 				Type:     typ,
	// 				ID:       id,
	// 				Length:   length,
	// 				Diameter: diameter,
	// 			}

	// 			o.parts = append(o.parts, pipe)

	// 		case "cable":

	// 			length := int(p["length"].(int64))
	// 			rating := float32(p["rating"].(float64))

	// 			cable := &cable{
	// 				Type:   typ,
	// 				ID:     id,
	// 				Length: length,
	// 				Rating: rating,
	// 			}

	// 			o.parts = append(o.parts, cable)

	// 		}
	// 	}

	// 	return nil
	// }

	// type parts []part

	// type part interface {
	// 	Name() string
	// }

	// type valve struct {
	// 	Type   string
	// 	ID     string
	// 	Size   float32
	// 	Rating int
	// }

	// func (v *valve) Name() string {
	// 	return fmt.Sprintf("VALVE: %s", v.ID)
	// }

	// type pipe struct {
	// 	Type     string
	// 	ID       string
	// 	Length   float32
	// 	Diameter int
	// }

	// func (p *pipe) Name() string {
	// 	return fmt.Sprintf("PIPE: %s", p.ID)
	// }

	// type cable struct {
	// 	Type   string
	// 	ID     string
	// 	Length int
	// 	Rating float32
	// }

	// func (c *cable) Name() string {
	// 	return fmt.Sprintf("CABLE: %s", c.ID)
	// }

	// Output:
	// 4
	// VALVE: valve-1
	// VALVE: valve-2
	// PIPE: pipe-1
	// CABLE: cable-1

}