delegation: use the fancy Meta

delegation/delegation.go

@@ -5,12 +5,12 @@ import (
 	"fmt"
 	"time"
 
-	"github.com/ipld/go-ipld-prime/datamodel"
 	"github.com/libp2p/go-libp2p/core/crypto"
 
 	"github.com/ucan-wg/go-ucan/capability/command"
 	"github.com/ucan-wg/go-ucan/capability/policy"
 	"github.com/ucan-wg/go-ucan/did"
+	"github.com/ucan-wg/go-ucan/pkg/meta"
 )
 
 type Token struct {
@@ -27,7 +27,7 @@ type Token struct {
 	// A unique, random nonce
 	nonce []byte
 	// Arbitrary Metadata
-	meta map[string]datamodel.Node
+	meta *meta.Meta
 	// "Not before" UTC Unix Timestamp in seconds (valid from), 53-bits integer
 	notBefore *time.Time
 	// The timestamp at which the Invocation becomes invalid
@@ -47,6 +47,7 @@ func New(privKey crypto.PrivKey, aud did.DID, cmd *command.Command, pol policy.P
 		subject:  did.Undef,
 		command:  cmd,
 		policy:   pol,
+		meta:     meta.NewMeta(),
 		nonce:    nonce,
 	}
 
@@ -109,7 +110,7 @@ func (t *Token) Nonce() []byte {
 }
 
 // Meta returns the Token's metadata.
-func (t *Token) Meta() map[string]datamodel.Node {
+func (t *Token) Meta() *meta.Meta {
 	return t.meta
 }
 
@@ -165,13 +166,13 @@ func WithExpiration(exp time.Time) Option {
 	}
 }
 
-// WithMetadata sets the Token's optional "meta" field to the provided
+// WithMeta adds a key/value pair in the "meta" field.
-// value.
+// WithMeta can be used multiple times in the same call.
-func WithMetadata(meta map[string]datamodel.Node) Option {
+// Accepted types for the value are: bool, string, int, int32, int64, []byte,
+// and ipld.Node.
+func WithMeta(key string, val any) Option {
 	return func(t *Token) error {
-		t.meta = meta
+		return t.meta.Add(key, val)
-
-		return nil
 	}
 }
 
@@ -246,8 +247,7 @@ func tokenFromModel(m tokenPayloadModel) (*Token, error) {
 	}
 	tkn.nonce = m.Nonce
 
-	// TODO: copy?
+	tkn.meta = &m.Meta
-	tkn.meta = m.Meta.Values
 
 	if m.Nbf != nil {
 		t := time.Unix(*m.Nbf, 0)

delegation/delegation_test.go

@@ -5,15 +5,14 @@ import (
 	"testing"
 	"time"
 
-	"github.com/ipld/go-ipld-prime/datamodel"
-	"github.com/ipld/go-ipld-prime/node/basicnode"
 	"github.com/libp2p/go-libp2p/core/crypto"
 	"github.com/stretchr/testify/require"
+	"gotest.tools/v3/golden"
+
 	"github.com/ucan-wg/go-ucan/capability/command"
 	"github.com/ucan-wg/go-ucan/capability/policy"
 	"github.com/ucan-wg/go-ucan/delegation"
 	"github.com/ucan-wg/go-ucan/did"
-	"gotest.tools/v3/golden"
 )
 
 const (
@@ -86,13 +85,13 @@ func TestConstructors(t *testing.T) {
 	exp, err := time.Parse(time.RFC3339, "2200-01-01T00:00:00Z")
 	require.NoError(t, err)
 
-	meta := map[string]datamodel.Node{
-		"foo": basicnode.NewString("fooo"),
-		"bar": basicnode.NewString("barr"),
-	}
-
 	t.Run("New", func(t *testing.T) {
-		dlg, err := delegation.New(privKey, aud, cmd, pol, []byte(nonce), delegation.WithSubject(sub), delegation.WithExpiration(exp), delegation.WithMetadata(meta))
+		dlg, err := delegation.New(privKey, aud, cmd, pol, []byte(nonce),
+			delegation.WithSubject(sub),
+			delegation.WithExpiration(exp),
+			delegation.WithMeta("foo", "fooo"),
+			delegation.WithMeta("bar", "barr"),
+		)
 		require.NoError(t, err)
 
 		data, err := dlg.ToDagJson(privKey)
@@ -106,7 +105,11 @@ func TestConstructors(t *testing.T) {
 	t.Run("Root", func(t *testing.T) {
 		t.Parallel()
 
-		dlg, err := delegation.Root(privKey, aud, cmd, pol, []byte(nonce), delegation.WithExpiration(exp), delegation.WithMetadata(meta))
+		dlg, err := delegation.Root(privKey, aud, cmd, pol, []byte(nonce),
+			delegation.WithExpiration(exp),
+			delegation.WithMeta("foo", "fooo"),
+			delegation.WithMeta("bar", "barr"),
+		)
 		require.NoError(t, err)
 
 		data, err := dlg.ToDagJson(privKey)

delegation/ipld.go

@@ -68,14 +68,6 @@ func (t *Token) ToIPLD(privKey crypto.PrivKey) (datamodel.Node, error) {
 		return nil, err
 	}
 
-	metaKeys := make([]string, len(t.meta))
-	i := 0
-
-	for k := range t.meta {
-		metaKeys[i] = k
-		i++
-	}
-
 	var nbf *int64
 	if t.notBefore != nil {
 		u := t.notBefore.Unix()
@@ -95,12 +87,9 @@ func (t *Token) ToIPLD(privKey crypto.PrivKey) (datamodel.Node, error) {
 		Cmd:   t.command.String(),
 		Pol:   pol,
 		Nonce: t.nonce,
-		Meta: metaModel{
+		Meta:  *t.meta,
-			Keys:   metaKeys,
+		Nbf:   nbf,
-			Values: t.meta,
+		Exp:   exp,
-		},
-		Nbf: nbf,
-		Exp: exp,
 	}
 
 	return envelope.ToIPLD(privKey, model)

delegation/schema.go

@@ -9,7 +9,9 @@ import (
 	"github.com/ipld/go-ipld-prime/datamodel"
 	"github.com/ipld/go-ipld-prime/node/bindnode"
 	"github.com/ipld/go-ipld-prime/schema"
+
 	"github.com/ucan-wg/go-ucan/internal/envelope"
+	"github.com/ucan-wg/go-ucan/pkg/meta"
 )
 
 const Tag = "ucan/dlg@1.0.0-rc.1"
@@ -58,8 +60,7 @@ type tokenPayloadModel struct {
 	Nonce []byte
 
 	// Arbitrary Metadata
-	// optional: can be nil
+	Meta meta.Meta
-	Meta metaModel
 
 	// "Not before" UTC Unix Timestamp in seconds (valid from), 53-bits integer
 	// optional: can be nil
@@ -76,8 +77,3 @@ func (e *tokenPayloadModel) Prototype() schema.TypedPrototype {
 func (*tokenPayloadModel) Tag() string {
 	return Tag
 }
-
-type metaModel struct {
-	Keys   []string
-	Values map[string]datamodel.Node
-}

delegation/schema_test.go

@@ -7,8 +7,9 @@ import (
 
 	"github.com/ipld/go-ipld-prime"
 	"github.com/stretchr/testify/require"
-	"github.com/ucan-wg/go-ucan/delegation"
 	"gotest.tools/v3/golden"
+
+	"github.com/ucan-wg/go-ucan/delegation"
 )
 
 //go:embed delegation.ipldsch

pkg/meta/meta.go

@@ -26,7 +26,7 @@ func NewMeta() *Meta {
 // GetBool retrieves a value as a bool.
 // Returns ErrNotFound if the given key is missing.
 // Returns datamodel.ErrWrongKind if the value has the wrong type.
-func (m Meta) GetBool(key string) (bool, error) {
+func (m *Meta) GetBool(key string) (bool, error) {
 	v, ok := m.Values[key]
 	if !ok {
 		return false, ErrNotFound
@@ -37,7 +37,7 @@ func (m Meta) GetBool(key string) (bool, error) {
 // GetString retrieves a value as a string.
 // Returns ErrNotFound if the given key is missing.
 // Returns datamodel.ErrWrongKind if the value has the wrong type.
-func (m Meta) GetString(key string) (string, error) {
+func (m *Meta) GetString(key string) (string, error) {
 	v, ok := m.Values[key]
 	if !ok {
 		return "", ErrNotFound
@@ -48,7 +48,7 @@ func (m Meta) GetString(key string) (string, error) {
 // GetInt64 retrieves a value as an int64.
 // Returns ErrNotFound if the given key is missing.
 // Returns datamodel.ErrWrongKind if the value has the wrong type.
-func (m Meta) GetInt64(key string) (int64, error) {
+func (m *Meta) GetInt64(key string) (int64, error) {
 	v, ok := m.Values[key]
 	if !ok {
 		return 0, ErrNotFound
@@ -59,7 +59,7 @@ func (m Meta) GetInt64(key string) (int64, error) {
 // GetFloat64 retrieves a value as a float64.
 // Returns ErrNotFound if the given key is missing.
 // Returns datamodel.ErrWrongKind if the value has the wrong type.
-func (m Meta) GetFloat64(key string) (float64, error) {
+func (m *Meta) GetFloat64(key string) (float64, error) {
 	v, ok := m.Values[key]
 	if !ok {
 		return 0, ErrNotFound
@@ -70,7 +70,7 @@ func (m Meta) GetFloat64(key string) (float64, error) {
 // GetBytes retrieves a value as a []byte.
 // Returns ErrNotFound if the given key is missing.
 // Returns datamodel.ErrWrongKind if the value has the wrong type.
-func (m Meta) GetBytes(key string) ([]byte, error) {
+func (m *Meta) GetBytes(key string) ([]byte, error) {
 	v, ok := m.Values[key]
 	if !ok {
 		return nil, ErrNotFound
@@ -81,7 +81,7 @@ func (m Meta) GetBytes(key string) ([]byte, error) {
 // GetNode retrieves a value as a raw IPLD node.
 // Returns ErrNotFound if the given key is missing.
 // Returns datamodel.ErrWrongKind if the value has the wrong type.
-func (m Meta) GetNode(key string) (ipld.Node, error) {
+func (m *Meta) GetNode(key string) (ipld.Node, error) {
 	v, ok := m.Values[key]
 	if !ok {
 		return nil, ErrNotFound
@@ -92,7 +92,7 @@ func (m Meta) GetNode(key string) (ipld.Node, error) {
 // Add adds a key/value pair in the meta set.
 // Accepted types for the value are: bool, string, int, int32, int64, []byte,
 // and ipld.Node.
-func (m Meta) Add(key string, val any) error {
+func (m *Meta) Add(key string, val any) error {
 	switch val := val.(type) {
 	case bool:
 		m.Values[key] = basicnode.NewBool(val)