PEX: Changed path_nested to be object instead of slice (#2609)

vcr/pe/presentation_submission.go

@@ -71,8 +71,9 @@ type SignInstruction struct {
 	// Holder contains the DID of the holder that should sign the VP.
 	Holder did.DID
 	// VerifiableCredentials contains the VCs that should be included in the VP.
-	VerifiableCredentials         []vc.VerifiableCredential
-	inputDescriptorMappingObjects []InputDescriptorMappingObject
+	VerifiableCredentials []vc.VerifiableCredential
+	// Mappings contains the Input Descriptor that are mapped by this SignInstruction.
+	Mappings []InputDescriptorMappingObject
 }
 
 // Empty returns true if there are no VCs in the SignInstruction.
@@ -100,7 +101,6 @@ func (b *PresentationSubmissionBuilder) Build(format string) (PresentationSubmis
 		Id:           uuid.New().String(),
 		DefinitionId: b.presentationDefinition.Id,
 	}
-	signInstructions := make([]SignInstruction, len(b.wallets))
 
 	// first we need to select the VCs from all wallets that match the presentation definition
 	allVCs := make([]vc.VerifiableCredential, 0)
@@ -115,43 +115,57 @@ func (b *PresentationSubmissionBuilder) Build(format string) (PresentationSubmis
 
 	// next we need to map the selected VCs to the correct wallet
 	// loop over all selected VCs and find the wallet that contains the VC
+	signInstructions := make([]SignInstruction, len(b.wallets))
+	walletCredentialIndex := map[did.DID]int{}
 	for j := range selectedVCs {
 		for i, walletVCs := range b.wallets {
-			var index int
 			for _, walletVC := range walletVCs {
 				// do a JSON equality check
-				if vcEqual(selectedVCs[j], walletVC) {
+				if selectedVCs[j].Raw() == walletVC.Raw() {
 					signInstructions[i].Holder = b.holders[i]
 					signInstructions[i].VerifiableCredentials = append(signInstructions[i].VerifiableCredentials, selectedVCs[j])
 					// remap the path to the correct wallet index
-					inputDescriptorMappingObjectForVC := inputDescriptorMappingObjects[j]
-					inputDescriptorMappingObjectForVC.Path = fmt.Sprintf("$.verifiableCredential[%d]", index)
-					signInstructions[i].inputDescriptorMappingObjects = append(signInstructions[i].inputDescriptorMappingObjects, inputDescriptorMappingObjectForVC)
-					index++
+					mapping := inputDescriptorMappingObjects[j]
+					mapping.Format = selectedVCs[j].Format()
+					mapping.Path = fmt.Sprintf("$.verifiableCredential[%d]", walletCredentialIndex[b.holders[i]])
+					signInstructions[i].Mappings = append(signInstructions[i].Mappings, mapping)
+					walletCredentialIndex[b.holders[i]]++
 				}
 			}
 		}
 	}
 
+	// filter out empty sign instructions
+	nonEmptySignInstructions := make([]SignInstruction, 0)
+	for _, signInstruction := range signInstructions {
+		if !signInstruction.Empty() {
+			nonEmptySignInstructions = append(nonEmptySignInstructions, signInstruction)
+		}
+	}
+
 	index := 0
 	// last we create the descriptor map for the presentation submission
-	// If there's only one sign instruction the Path will be $. If there are multiple sign instructions the Path will be $[0], $[1], etc.
-	for _, signInstruction := range signInstructions {
-		if len(signInstruction.VerifiableCredentials) > 0 {
-			// wrap each InputDescriptorMappingObject for the outer VP
-			nestedDescriptorMap := InputDescriptorMappingObject{
-				Id:         "", // todo what to add here?
-				Format:     format,
-				Path:       "$.",
-				PathNested: signInstruction.inputDescriptorMappingObjects,
-			}
-			if len(signInstructions) > 1 {
-				nestedDescriptorMap.Path = fmt.Sprintf("$[%d]", index)
+	// If there's only one sign instruction the Path will be $.
+	// If there are multiple sign instructions (each yielding a VP) the Path will be $[0], $[1], etc.
+	for _, signInstruction := range nonEmptySignInstructions {
+		if len(signInstruction.Mappings) > 0 {
+			for _, inputDescriptorMapping := range signInstruction.Mappings {
+				// If we have multiple VPs in the resulting submission, wrap each in a nested descriptor map (see path_nested in PEX specification).
+				if len(nonEmptySignInstructions) > 1 {
+					presentationSubmission.DescriptorMap = append(presentationSubmission.DescriptorMap, InputDescriptorMappingObject{
+						Id:         inputDescriptorMapping.Id,
+						Format:     format,
+						Path:       fmt.Sprintf("$[%d]", index),
+						PathNested: &inputDescriptorMapping,
+					})
+				} else {
+					// Just 1 VP, no nesting needed
+					presentationSubmission.DescriptorMap = append(presentationSubmission.DescriptorMap, inputDescriptorMapping)
+				}
 			}
-			presentationSubmission.DescriptorMap = append(presentationSubmission.DescriptorMap, nestedDescriptorMap)
 			index++
 		}
 	}
 
-	return presentationSubmission, signInstructions, nil
+	return presentationSubmission, nonEmptySignInstructions, nil
 }

vcr/pe/presentation_submission_test.go

@@ -46,10 +46,29 @@ func TestPresentationSubmissionBuilder_Build(t *testing.T) {
 	holder2 := did.MustParseDID("did:example:2")
 	id1 := ssi.MustParseURI("1")
 	id2 := ssi.MustParseURI("2")
-	vc1 := vc.VerifiableCredential{ID: &id1}
-	vc2 := vc.VerifiableCredential{ID: &id2}
+	id3 := ssi.MustParseURI("3")
+	vc1 := credentialToJSONLD(vc.VerifiableCredential{ID: &id1})
+	vc2 := credentialToJSONLD(vc.VerifiableCredential{ID: &id2})
+	vc3 := credentialToJSONLD(vc.VerifiableCredential{ID: &id3})
 
-	t.Run("ok - single wallet", func(t *testing.T) {
+	t.Run("1 presentation", func(t *testing.T) {
+		expectedJSON := `
+		{
+		 "id": "for-test",
+		 "definition_id": "",
+		 "descriptor_map": [
+		   {
+		     "format": "ldp_vc",
+		     "id": "Match ID=1",
+		     "path": "$.verifiableCredential[0]"
+		   },
+		   {
+		     "format": "ldp_vc",
+		     "id": "Match ID=2",
+		     "path": "$.verifiableCredential[1]"
+		   }
+		 ]
+		}`
 		presentationDefinition := PresentationDefinition{}
 		_ = json.Unmarshal([]byte(test.All), &presentationDefinition)
 		builder := presentationDefinition.PresentationSubmissionBuilder()
@@ -60,12 +79,42 @@ func TestPresentationSubmissionBuilder_Build(t *testing.T) {
 		require.NoError(t, err)
 		require.NotNil(t, signInstructions)
 		assert.Len(t, signInstructions, 1)
-		assert.Len(t, submission.DescriptorMap, 1)
-		assert.Equal(t, "$.", submission.DescriptorMap[0].Path)
-		require.Len(t, submission.DescriptorMap[0].PathNested, 2)
-		assert.Equal(t, "$.verifiableCredential[0]", submission.DescriptorMap[0].PathNested[0].Path)
+		require.Len(t, submission.DescriptorMap, 2)
+
+		submission.Id = "for-test" // easier assertion
+		actualJSON, _ := json.MarshalIndent(submission, "", "  ")
+		println(string(actualJSON))
+		assert.JSONEq(t, expectedJSON, string(actualJSON))
 	})
-	t.Run("ok - two wallets", func(t *testing.T) {
+	t.Run("2 presentations", func(t *testing.T) {
+		expectedJSON := `
+{
+  "id": "for-test",
+  "definition_id": "",
+  "descriptor_map": [
+    {
+      "format": "ldp_vp",
+      "id": "Match ID=1",
+      "path": "$[0]",
+      "path_nested": {
+        "format": "ldp_vc",
+        "id": "Match ID=1",
+        "path": "$.verifiableCredential[0]"
+      }
+    },
+    {
+      "format": "ldp_vp",
+      "id": "Match ID=2",
+      "path": "$[1]",
+      "path_nested": {
+        "format": "ldp_vc",
+        "id": "Match ID=2",
+        "path": "$.verifiableCredential[0]"
+      }
+    }
+  ]
+}
+`
 		presentationDefinition := PresentationDefinition{}
 		_ = json.Unmarshal([]byte(test.All), &presentationDefinition)
 		builder := presentationDefinition.PresentationSubmissionBuilder()
@@ -78,11 +127,58 @@ func TestPresentationSubmissionBuilder_Build(t *testing.T) {
 		require.NotNil(t, signInstructions)
 		assert.Len(t, signInstructions, 2)
 		assert.Len(t, submission.DescriptorMap, 2)
-		assert.Equal(t, "$[0]", submission.DescriptorMap[0].Path)
-		require.Len(t, submission.DescriptorMap[0].PathNested, 1)
-		assert.Equal(t, "$.verifiableCredential[0]", submission.DescriptorMap[0].PathNested[0].Path)
-		assert.Equal(t, "$[1]", submission.DescriptorMap[1].Path)
-		require.Len(t, submission.DescriptorMap[1].PathNested, 1)
-		assert.Equal(t, "$.verifiableCredential[0]", submission.DescriptorMap[1].PathNested[0].Path)
+
+		submission.Id = "for-test" // easier assertion
+		actualJSON, _ := json.MarshalIndent(submission, "", "  ")
+		assert.JSONEq(t, expectedJSON, string(actualJSON))
+	})
+	t.Run("2 wallets, but 1 VP", func(t *testing.T) {
+		expectedJSON := `
+		{
+		 "id": "for-test",
+		 "definition_id": "",
+		 "descriptor_map": [
+		   {
+		     "format": "ldp_vc",
+		     "id": "Match ID=1",
+		     "path": "$.verifiableCredential[0]"
+		   },
+		   {
+		     "format": "ldp_vc",
+		     "id": "Match ID=2",
+		     "path": "$.verifiableCredential[1]"
+		   }
+		 ]
+		}`
+		presentationDefinition := PresentationDefinition{}
+		_ = json.Unmarshal([]byte(test.All), &presentationDefinition)
+		builder := presentationDefinition.PresentationSubmissionBuilder()
+		builder.AddWallet(holder1, []vc.VerifiableCredential{vc1, vc2})
+		builder.AddWallet(holder2, []vc.VerifiableCredential{vc3})
+
+		submission, signInstructions, err := builder.Build("ldp_vp")
+
+		require.NoError(t, err)
+		require.NotNil(t, signInstructions)
+		assert.Len(t, signInstructions, 1)
+		assert.Len(t, submission.DescriptorMap, 2)
+
+		submission.Id = "for-test" // easier assertion
+		actualJSON, _ := json.MarshalIndent(submission, "", "  ")
+		println(string(actualJSON))
+		assert.JSONEq(t, expectedJSON, string(actualJSON))
 	})
 }
+
+func credentialToJSONLD(credential vc.VerifiableCredential) vc.VerifiableCredential {
+	bytes, err := credential.MarshalJSON()
+	if err != nil {
+		panic(err)
+	}
+	var result vc.VerifiableCredential
+	err = json.Unmarshal(bytes, &result)
+	if err != nil {
+		panic(err)
+	}
+	return result
+}

vcr/pe/test/test_definitions.go

@@ -183,7 +183,7 @@ const All = `
   ],
   "input_descriptors": [
 	{
-	  "name": "Match ID=1",
+	  "id": "Match ID=1",
       "group": ["A"],
 	  "constraints": {
 		"fields": [
@@ -200,7 +200,7 @@ const All = `
 	  }
     },
     {
-	  "name": "Match ID=2",
+	  "id": "Match ID=2",
       "group": ["A"],
 	  "constraints": {
 		"fields": [

vcr/pe/types.go

@@ -34,10 +34,10 @@ type PresentationSubmission struct {
 
 // InputDescriptorMappingObject
 type InputDescriptorMappingObject struct {
-	Format     string                         `json:"format"`
-	Id         string                         `json:"id"`
-	Path       string                         `json:"path"`
-	PathNested []InputDescriptorMappingObject `json:"path_nested,omitempty"`
+	Format     string                        `json:"format"`
+	Id         string                        `json:"id"`
+	Path       string                        `json:"path"`
+	PathNested *InputDescriptorMappingObject `json:"path_nested,omitempty"`
 }
 
 // Constraints