type Item struct {
	Foo string
}

b, err := msgpack.Marshal(&Item{Foo: "bar"})
if err != nil {
	panic(err)
}

var item Item
err = msgpack.Unmarshal(b, &item)
if err != nil {
	panic(err)
}
fmt.Println(item.Foo)

Output:

bar

type Item struct {
	_msgpack struct{} `msgpack:",as_array"`
	Foo      string
	Bar      string
}

var buf bytes.Buffer
enc := msgpack.NewEncoder(&buf)
err := enc.Encode(&Item{Foo: "foo", Bar: "bar"})
if err != nil {
	panic(err)
}

dec := msgpack.NewDecoder(&buf)
v, err := dec.DecodeInterface()
if err != nil {
	panic(err)
}
fmt.Println(v)

Output:

[foo bar]

og := map[string]interface{}{
	"something:special": uint(123),
	"hello, world":      "hello!",
}
raw, err := msgpack.Marshal(og)
if err != nil {
	panic(err)
}

type Item struct {
	SomethingSpecial uint   `msgpack:"'something:special'"`
	HelloWorld       string `msgpack:"'hello, world'"`
}
var item Item
if err := msgpack.Unmarshal(raw, &item); err != nil {
	panic(err)
}
fmt.Printf("%#v\n", item)

Output:

msgpack_test.Item{SomethingSpecial:0x7b, HelloWorld:"hello!"}

var t1 T
raw, err := msgpack.Marshal(t1)
if err != nil {
	panic(err)
}
var t2 T
if err = msgpack.Unmarshal(raw, &t2); err != nil {
	panic(err)
}
fmt.Printf("%#v\n", t2)

t2.I.Set(42)
t2.S.hidden = true // won't be included because it is a hidden field
raw, err = msgpack.Marshal(t2)
if err != nil {
	panic(err)
}
var t3 T
if err = msgpack.Unmarshal(raw, &t3); err != nil {
	panic(err)
}
fmt.Printf("%#v\n", t3)

Output:

msgpack_test.T{I:msgpack_test.NullInt{Valid:false, Int:0}, J:msgpack_test.NullInt{Valid:true, Int:0}, S:msgpack_test.Secretive{Visible:false, hidden:false}}
msgpack_test.T{I:msgpack_test.NullInt{Valid:true, Int:42}, J:msgpack_test.NullInt{Valid:true, Int:0}, S:msgpack_test.Secretive{Visible:false, hidden:false}}

in := map[string]interface{}{"foo": 1, "hello": "world"}
b, err := msgpack.Marshal(in)
if err != nil {
	panic(err)
}

var out map[string]interface{}
err = msgpack.Unmarshal(b, &out)
if err != nil {
	panic(err)
}

fmt.Println("foo =", out["foo"])
fmt.Println("hello =", out["hello"])

Output:

foo = 1
hello = world

type Item struct {
	Foo string
	Bar string
}

item := &Item{
	Foo: "hello",
}
b, err := msgpack.Marshal(item)
if err != nil {
	panic(err)
}
fmt.Printf("item: %q\n", b)

type ItemOmitEmpty struct {
	_msgpack struct{} `msgpack:",omitempty"`
	Foo      string
	Bar      string
}

itemOmitEmpty := &ItemOmitEmpty{
	Foo: "hello",
}
b, err = msgpack.Marshal(itemOmitEmpty)
if err != nil {
	panic(err)
}
fmt.Printf("item2: %q\n", b)

Output:

item: "\x82\xa3Foo\xa5hello\xa3Bar\xa0"
item2: "\x81\xa3Foo\xa5hello"

t := time.Unix(123456789, 123)

{
	msgpack.RegisterExt(1, (*EventTime)(nil))
	b, err := msgpack.Marshal(&EventTime{t})
	if err != nil {
		panic(err)
	}

	var v interface{}
	err = msgpack.Unmarshal(b, &v)
	if err != nil {
		panic(err)
	}
	fmt.Println(v.(*EventTime).UTC())

	tm := new(EventTime)
	err = msgpack.Unmarshal(b, &tm)
	if err != nil {
		panic(err)
	}
	fmt.Println(tm.UTC())
}

{
	msgpack.RegisterExt(1, (*EventTime)(nil))
	b, err := msgpack.Marshal(&EventTime{t})
	if err != nil {
		panic(err)
	}

	// override ext
	msgpack.RegisterExt(1, (*OneMoreSecondEventTime)(nil))

	var v interface{}
	err = msgpack.Unmarshal(b, &v)
	if err != nil {
		panic(err)
	}
	fmt.Println(v.(*OneMoreSecondEventTime).UTC())
}

{
	msgpack.RegisterExt(1, (*OneMoreSecondEventTime)(nil))
	b, err := msgpack.Marshal(&OneMoreSecondEventTime{
		EventTime{t},
	})
	if err != nil {
		panic(err)
	}

	// override ext
	msgpack.RegisterExt(1, (*EventTime)(nil))
	var v interface{}
	err = msgpack.Unmarshal(b, &v)
	if err != nil {
		panic(err)
	}
	fmt.Println(v.(*EventTime).UTC())
}

Output:

1973-11-29 21:33:09.000000123 +0000 UTC
1973-11-29 21:33:09.000000123 +0000 UTC
1973-11-29 21:33:10.000000123 +0000 UTC
1973-11-29 21:33:10.000000123 +0000 UTC

t := time.Unix(123456789, 123)

{
	msgpack.RegisterExt(1, (*EventTime)(nil))
	b, err := msgpack.Marshal(&EventTime{t})
	if err != nil {
		panic(err)
	}

	msgpack.UnregisterExt(1)

	var v interface{}
	err = msgpack.Unmarshal(b, &v)
	wanted := "msgpack: unknown ext id=1"
	if err.Error() != wanted {
		panic(err)
	}

	msgpack.RegisterExt(1, (*OneMoreSecondEventTime)(nil))
	err = msgpack.Unmarshal(b, &v)
	if err != nil {
		panic(err)
	}
	fmt.Println(v.(*OneMoreSecondEventTime).UTC())
}

{
	msgpack.RegisterExt(1, (*OneMoreSecondEventTime)(nil))
	b, err := msgpack.Marshal(&OneMoreSecondEventTime{
		EventTime{t},
	})
	if err != nil {
		panic(err)
	}

	msgpack.UnregisterExt(1)
	var v interface{}
	err = msgpack.Unmarshal(b, &v)
	wanted := "msgpack: unknown ext id=1"
	if err.Error() != wanted {
		panic(err)
	}

	msgpack.RegisterExt(1, (*EventTime)(nil))
	err = msgpack.Unmarshal(b, &v)
	if err != nil {
		panic(err)
	}
	fmt.Println(v.(*EventTime).UTC())
}

Output:

1973-11-29 21:33:10.000000123 +0000 UTC
1973-11-29 21:33:10.000000123 +0000 UTC

package main

import (
	"fmt"

	"github.com/vmihailenco/msgpack/v5"
)

type customStruct struct {
	S string
	N int
}

var _ msgpack.CustomEncoder = (*customStruct)(nil)
var _ msgpack.CustomDecoder = (*customStruct)(nil)

func (s *customStruct) EncodeMsgpack(enc *msgpack.Encoder) error {
	return enc.EncodeMulti(s.S, s.N)
}

func (s *customStruct) DecodeMsgpack(dec *msgpack.Decoder) error {
	return dec.DecodeMulti(&s.S, &s.N)
}

func main() {
	b, err := msgpack.Marshal(&customStruct{S: "hello", N: 42})
	if err != nil {
		panic(err)
	}

	var v customStruct
	err = msgpack.Unmarshal(b, &v)
	if err != nil {
		panic(err)
	}
	fmt.Printf("%#v", v)
}

Output:

msgpack_test.customStruct{S:"hello", N:42}