Add support for optional attributes

descriptions.go

@@ -77,6 +77,7 @@ func (ct *CredentialType) ContainsAttribute(ai AttributeTypeIdentifier) bool {
 // AttributeDescription is a description of an attribute within a credential type.
 type AttributeDescription struct {
 	ID          string `xml:"id,attr"`
+	Optional    string `xml:"optional,attr"`
 	Name        TranslatedString
 	Description TranslatedString
 }

irmaclient/session_test.go

@@ -137,6 +137,32 @@ func getIssuanceRequest(defaultValidity bool) *irma.IssuanceRequest {
 	}
 }
 
+func getNameIssuanceRequest(prefix bool) *irma.IssuanceRequest {
+	expiry := irma.Timestamp(irma.NewMetadataAttribute().Expiry())
+	credid := irma.NewCredentialTypeIdentifier("irma-demo.MijnOverheid.fullName")
+
+	req := &irma.IssuanceRequest{
+		Credentials: []*irma.CredentialRequest{
+			{
+				Validity:         &expiry,
+				CredentialTypeID: &credid,
+				Attributes: map[string]string{
+					"firstnames": "Johan Pieter",
+					"firstname":  "Johan",
+					"familyname": "Stuivezand",
+					"prefix":     "",
+				},
+			},
+		},
+	}
+
+	if (prefix) {
+		req.Credentials[0].Attributes["prefix"] = "van"
+	}
+
+	return req
+}
+
 func getIssuanceJwt(name string, defaultValidity bool) interface{} {
 	return irma.NewIdentityProviderJwt(name, getIssuanceRequest(defaultValidity))
 }
@@ -191,6 +217,16 @@ func TestDefaultCredentialValidity(t *testing.T) {
 	sessionHelper(t, jwtcontents, "issue", client)
 }
 
+func TestIssuanceOptionalEmptyAttributes(t *testing.T) {
+	jwt := irma.NewIdentityProviderJwt("testip", getNameIssuanceRequest(false))
+	sessionHelper(t, jwt, "issue", nil)
+}
+
+func TestIssuanceOptionalSetAttributes(t *testing.T) {
+	jwt := irma.NewIdentityProviderJwt("testip", getNameIssuanceRequest(true))
+	sessionHelper(t, jwt, "issue", nil)
+}
+
 func TestLargeAttribute(t *testing.T) {
 	client := parseStorage(t)
 	require.NoError(t, client.RemoveAllCredentials())

requests.go

@@ -142,21 +142,36 @@ func (cr *CredentialRequest) AttributeList(conf *Configuration) (*AttributeList,
 		return nil, err
 	}
 
-	attrs := make([]*big.Int, len(cr.Attributes)+1, len(cr.Attributes)+1)
 	credtype := conf.CredentialTypes[*cr.CredentialTypeID]
 	if credtype == nil {
 		return nil, errors.New("Unknown credential type")
 	}
-	if len(credtype.Attributes) != len(cr.Attributes) {
-		return nil, errors.New("Received unexpected amount of attributes")
+
+	// Check that there are no attributes in the credential request that aren't
+	// in the credential descriptor.
+	for crName := range cr.Attributes {
+		found := false
+		for _, ad := range credtype.Attributes {
+			if ad.ID == crName {
+				found = true
+				break
+			}
+		}
+		if !found {
+			return nil, errors.New("Unknown CR attribute")
+		}
 	}
 
+	attrs := make([]*big.Int, len(credtype.Attributes)+1)
 	attrs[0] = meta.Int
 	for i, attrtype := range credtype.Attributes {
+		attrs[i+1] = new(big.Int)
 		if str, present := cr.Attributes[attrtype.ID]; present {
-			attrs[i+1] = new(big.Int).SetBytes([]byte(str))
+			attrs[i+1].SetBytes([]byte(str))
 		} else {
-			return nil, errors.New("Unknown attribute")
+			if (attrtype.Optional != "true") {
+				return nil, errors.New("Required attribute not provided")
+			}
 		}
 	}
 

testdata/irma_configuration/irma-demo/MijnOverheid/Issues/fullName/description.xml

+<IssueSpecification version="4">
+	<Name>
+		<en>Name</en>
+		<nl>Naam</nl>
+	</Name>
+	<ShortName>
+		<en>Name</en>
+		<nl>Naam</nl>
+	</ShortName>
+	<SchemeManager>irma-demo</SchemeManager>
+	<IssuerID>MijnOverheid</IssuerID>
+	<CredentialID>fullName</CredentialID>
+	<Description>
+		<en>Your full name, as it is known to the government</en>
+		<nl>Uw volledige naam, zoals bekend bij de overheid</nl>
+	</Description>
+	<ShouldBeSingleton>true</ShouldBeSingleton>
+
+	<Attributes>
+		<Attribute id="firstnames">
+			<Name>
+				<en>First names</en>
+				<nl>Voornamen</nl>
+			</Name>
+			<Description>
+				<en>All of your first names</en>
+				<nl>Al uw voornamen</nl>
+			</Description>
+		</Attribute>
+		<Attribute id="firstname">
+			<Name>
+				<en>First name</en>
+				<nl>Voornaam</nl>
+			</Name>
+			<Description>
+				<en>Your first name</en>
+				<nl>Uw voornaam</nl>
+			</Description>
+		</Attribute>
+		<Attribute id="familyname">
+			<Name>
+				<en>Family name</en>
+				<nl>Achternaam</nl>
+			</Name>
+			<Description>
+				<en>Your family name</en>
+				<nl>Uw achternaam</nl>
+			</Description>
+		</Attribute>
+		<Attribute id="prefix" optional="true">
+			<Name>
+				<en>Prefix</en>
+				<nl>Tussenvoegsel</nl>
+			</Name>
+			<Description>
+				<en>Family name prefix</en>
+				<nl>Tussenvoegsel van uw achternaam</nl>
+			</Description>
+		</Attribute>
+
+	</Attributes>
+</IssueSpecification>

testdata/irma_configuration/irma-demo/index

+230ce9f61beca5f52a6a241592c290baff9bae1066385e4b9bcf3a030f4a3b47 irma-demo/MijnOverheid/Issues/fullName/description.xml
 5cef2de223075ea192407d66de274f8bc7104ab3537b455df14aca306b4809f7 irma-demo/MijnOverheid/Issues/root/description.xml
 3571e30777cdf5b97acbb0820f1b69983d2dc2b6bae91c8fb67cfc79ef4e2543 irma-demo/MijnOverheid/PublicKeys/0.xml
 115bd71b738cd2ba10e832559fc5d35ee8222f4049a0fc10fc18d0853c4aa4d9 irma-demo/MijnOverheid/PublicKeys/1.xml