Merge pull request #60 from ucan-wg/wip

feat(invocation): add token validation prior to execution

pkg/args/args.go

@@ -6,11 +6,13 @@ package args
 import (
 	"fmt"
 	"sort"
+	"strings"
 
 	"github.com/ipld/go-ipld-prime"
 	"github.com/ipld/go-ipld-prime/datamodel"
 	"github.com/ipld/go-ipld-prime/fluent/qp"
 	"github.com/ipld/go-ipld-prime/node/basicnode"
+	"github.com/ipld/go-ipld-prime/printer"
 
 	"github.com/ucan-wg/go-ucan/pkg/policy/literal"
 )
@@ -70,6 +72,7 @@ func (a *Args) Include(other *Args) {
 // ToIPLD wraps an instance of an Args with an ipld.Node.
 func (a *Args) ToIPLD() (ipld.Node, error) {
 	sort.Strings(a.Keys)
+
 	return qp.BuildMap(basicnode.Prototype.Any, int64(len(a.Keys)), func(ma datamodel.MapAssembler) {
 		for _, key := range a.Keys {
 			qp.MapEntry(ma, key, qp.Node(a.Values[key]))
@@ -92,3 +95,43 @@ func (a *Args) Equals(other *Args) bool {
 	}
 	return true
 }
+
+func (a *Args) String() string {
+	sort.Strings(a.Keys)
+
+	buf := strings.Builder{}
+	buf.WriteString("{")
+
+	for _, key := range a.Keys {
+		buf.WriteString("\n\t")
+		buf.WriteString(key)
+		buf.WriteString(": ")
+		buf.WriteString(strings.ReplaceAll(printer.Sprint(a.Values[key]), "\n", "\n\t"))
+		buf.WriteString(",")
+	}
+
+	if len(a.Keys) > 0 {
+		buf.WriteString("\n")
+	}
+	buf.WriteString("}")
+
+	return buf.String()
+}
+
+// ReadOnly returns a read-only version of Args.
+func (a *Args) ReadOnly() ReadOnly {
+	return ReadOnly{args: a}
+}
+
+// Clone makes a deep copy.
+func (a *Args) Clone() *Args {
+	res := &Args{
+		Keys:   make([]string, len(a.Keys)),
+		Values: make(map[string]ipld.Node, len(a.Values)),
+	}
+	copy(res.Keys, a.Keys)
+	for k, v := range a.Values {
+		res.Values[k] = v
+	}
+	return res
+}

pkg/args/readonly.go

@@ -0,0 +1,23 @@
+package args
+
+import "github.com/ipld/go-ipld-prime"
+
+type ReadOnly struct {
+	args *Args
+}
+
+func (r ReadOnly) ToIPLD() (ipld.Node, error) {
+	return r.args.ToIPLD()
+}
+
+func (r ReadOnly) Equals(other *Args) bool {
+	return r.args.Equals(other)
+}
+
+func (r ReadOnly) String() string {
+	return r.args.String()
+}
+
+func (r ReadOnly) WriteableClone() *Args {
+	return r.args.Clone()
+}

pkg/container/reader.go

@@ -2,6 +2,7 @@ package container
 
 import (
 	"encoding/base64"
+	"errors"
 	"fmt"
 	"io"
 	"iter"
@@ -34,13 +35,16 @@ func (ctn Reader) GetToken(cid cid.Cid) (token.Token, error) {
 // GetDelegation is the same as GetToken but only return a delegation.Token, with the right type.
 func (ctn Reader) GetDelegation(cid cid.Cid) (*delegation.Token, error) {
 	tkn, err := ctn.GetToken(cid)
+	if errors.Is(err, ErrNotFound) {
+		return nil, delegation.ErrDelegationNotFound
+	}
 	if err != nil {
 		return nil, err
 	}
 	if tkn, ok := tkn.(*delegation.Token); ok {
 		return tkn, nil
 	}
-	return nil, fmt.Errorf("not a delegation token")
+	return nil, delegation.ErrDelegationNotFound
 }
 
 // GetAllDelegations returns all the delegation.Token in the container.

pkg/meta/meta.go

@@ -12,9 +12,7 @@ import (
 	"github.com/ucan-wg/go-ucan/pkg/policy/literal"
 )
 
-var ErrUnsupported = errors.New("failure adding unsupported type to meta")
-
-var ErrNotFound = errors.New("key-value not found in meta")
+var ErrNotFound = errors.New("key not found in meta")
 
 var ErrNotEncryptable = errors.New("value of this type cannot be encrypted")
 
@@ -193,18 +191,19 @@ func (m *Meta) String() string {
 	buf := strings.Builder{}
 	buf.WriteString("{")
 
-	var i int
 	for key, node := range m.Values {
-		if i > 0 {
-			buf.WriteString(", ")
-		}
-		i++
+		buf.WriteString("\n\t")
 		buf.WriteString(key)
-		buf.WriteString(":")
-		buf.WriteString(printer.Sprint(node))
+		buf.WriteString(": ")
+		buf.WriteString(strings.ReplaceAll(printer.Sprint(node), "\n", "\n\t"))
+		buf.WriteString(",")
 	}
 
+	if len(m.Values) > 0 {
+		buf.WriteString("\n")
+	}
 	buf.WriteString("}")
+
 	return buf.String()
 }
 

pkg/policy/policy_test.go

@@ -37,6 +37,37 @@ func ExamplePolicy() {
 	// ]
 }
 
+func ExamplePolicy_accumulate() {
+	var statements []policy.Constructor
+
+	statements = append(statements, policy.Equal(".status", literal.String("draft")))
+
+	statements = append(statements, policy.All(".reviewer",
+		policy.Like(".email", "*@example.com"),
+	))
+
+	statements = append(statements, policy.Any(".tags", policy.Or(
+		policy.Equal(".", literal.String("news")),
+		policy.Equal(".", literal.String("press")),
+	)))
+
+	pol := policy.MustConstruct(statements...)
+
+	fmt.Println(pol)
+
+	// Output:
+	// [
+	//   ["==", ".status", "draft"],
+	//   ["all", ".reviewer",
+	//     ["like", ".email", "*@example.com"]],
+	//   ["any", ".tags",
+	//     ["or", [
+	//       ["==", ".", "news"],
+	//       ["==", ".", "press"]]]
+	//     ]
+	// ]
+}
+
 func TestConstruct(t *testing.T) {
 	pol, err := policy.Construct(
 		policy.Equal(".status", literal.String("draft")),