WIP: Validator

ucan/capability.go

@@ -1,5 +1,15 @@
 package ucan
 
+import (
+	"encoding/json"
+)
+
+type jsonModel struct {
+	With Resource    `json:"with"`
+	Can  Ability     `json:"can"`
+	Nb   interface{} `json:"nb,omitempty"`
+}
+
 type capability[T any] struct {
 	can  Ability
 	nb   T
@@ -20,6 +30,14 @@ func (c *capability[T]) With() Resource {
 	return c.with
 }
 
+func (c *capability[T]) MarshalJSON() ([]byte, error) {
+	return json.Marshal(jsonModel{
+		With: c.with,
+		Can:  c.can,
+		Nb:   c.nb,
+	})
+}
+
 func NewCapability[Caveats any](can Ability, with Resource, nb Caveats) Capability[Caveats] {
 	return &capability[Caveats]{
 		can:  can,

ucan/ucan.go

@@ -1,6 +1,8 @@
 package ucan
 
 import (
+	"encoding/json"
+
 	"github.com/ipld/go-ipld-prime"
 	"github.com/web3-storage/go-ucanto/did"
 	"github.com/web3-storage/go-ucanto/ucan/crypto"
@@ -15,11 +17,17 @@ type Resource = string
 // It MUST have format `${string}/${string}` | "*"
 type Ability = string
 
+// UnknownCapability is a capability whose Nb type is unknown
+type UnknownCapability interface {
+	json.Marshaler
+	Can() Ability
+	With() Resource
+}
+
 // Capability represents an ability that a UCAN holder can perform with some
 // resource.
 type Capability[Caveats any] interface {
-	Can() Ability
-	With() Resource
+	UnknownCapability
 	Nb() Caveats
 }
 
@@ -35,7 +43,7 @@ type Link = ipld.Link
 // It MUST have format `${number}.${number}.${number}`
 type Version = string
 
-// UTCUnixTimestamp is a timestamp in seconds since the Unix epoch.
+// UTCUnixTimestamp is a timestamp in milliseconds since the Unix epoch.
 type UTCUnixTimestamp = uint64
 
 // https://github.com/ucan-wg/spec/#324-nonce

validator/datamodel/errors.go

@@ -0,0 +1,63 @@
+package datamodel
+
+import (
+	// for go:embed
+	_ "embed"
+	"fmt"
+
+	"github.com/ipld/go-ipld-prime"
+	"github.com/ipld/go-ipld-prime/schema"
+)
+
+//go:embed errors.ipldsch
+var errorsch []byte
+
+var (
+	errorTypeSystem *schema.TypeSystem
+)
+
+func init() {
+	ts, err := ipld.LoadSchemaBytes(errorsch)
+	if err != nil {
+		panic(fmt.Errorf("failed to load IPLD schema: %s", err))
+	}
+	errorTypeSystem = ts
+}
+
+func InvalidAudienceType() schema.Type {
+	return errorTypeSystem.TypeByName("InvalidAudience")
+}
+
+type Delegation struct {
+	Audience string
+}
+
+type InvalidAudienceModel struct {
+	Name       *string
+	Audience   string
+	Delegation Delegation
+	Message    string
+	Stack      *string
+}
+
+type ExpiredModel struct {
+	Name      *string
+	Message   string
+	ExpiredAt int64
+	Stack     *string
+}
+
+func ExpiredType() schema.Type {
+	return errorTypeSystem.TypeByName("Expired")
+}
+
+type NotValidBeforeModel struct {
+	Name    *string
+	Message string
+	ValidAt int64
+	Stack   *string
+}
+
+func NotValidBeforeType() schema.Type {
+	return errorTypeSystem.TypeByName("NotValidBefore")
+}

validator/datamodel/errors.ipldsch

@@ -0,0 +1,25 @@
+type Delegation struct {
+	Audience String
+}
+
+type InvalidAudience struct {
+	Name       optional String
+	Audience   String
+	Delegation Delegation
+	Message    String
+	Stack      optional Sstring
+}
+
+type Expired struct {
+	Name      optional String
+	Message   String
+	ExpiredAt Integer
+	Stack     optional String
+}
+
+type NotValidBefore struct {
+	Name      optional String
+	Message   String
+	ValidAt   Integer
+	Stack     optional String
+}