add a token interface

token/interface.go

@@ -0,0 +1,41 @@
+package token
+
+import (
+	"io"
+
+	"github.com/ipfs/go-cid"
+	"github.com/ipld/go-ipld-prime/codec"
+	"github.com/libp2p/go-libp2p/core/crypto"
+
+	"github.com/ucan-wg/go-ucan/did"
+	"github.com/ucan-wg/go-ucan/pkg/meta"
+)
+
+type Token interface {
+	Marshaller
+
+	// Issuer returns the did.DID representing the Token's issuer.
+	Issuer() did.DID
+	// Meta returns the Token's metadata.
+	Meta() *meta.Meta
+}
+
+type Marshaller interface {
+	// ToSealed wraps the token in an envelope, generates the signature, encodes
+	// the result to DAG-CBOR and calculates the CID of the resulting binary data.
+	ToSealed(privKey crypto.PrivKey) ([]byte, cid.Cid, error)
+	// ToSealedWriter is the same as ToSealed but accepts an io.Writer.
+	ToSealedWriter(w io.Writer, privKey crypto.PrivKey) (cid.Cid, error)
+	// Encode marshals a Token to the format specified by the provided codec.Encoder.
+	Encode(privKey crypto.PrivKey, encFn codec.Encoder) ([]byte, error)
+	// EncodeWriter is the same as Encode, but accepts an io.Writer.
+	EncodeWriter(w io.Writer, privKey crypto.PrivKey, encFn codec.Encoder) error
+	// ToDagCbor marshals the Token to the DAG-CBOR format.
+	ToDagCbor(privKey crypto.PrivKey) ([]byte, error)
+	// ToDagCborWriter is the same as ToDagCbor, but it accepts an io.Writer.
+	ToDagCborWriter(w io.Writer, privKey crypto.PrivKey) error
+	// ToDagJson marshals the Token to the DAG-JSON format.
+	ToDagJson(privKey crypto.PrivKey) ([]byte, error)
+	// ToDagJsonWriter is the same as ToDagJson, but it accepts an io.Writer.
+	ToDagJsonWriter(w io.Writer, privKey crypto.PrivKey) error
+}