feat: Add support for VCDM 2 - EnvelopedVerifiableCredential type

Signed-off-by: Bob Stasyszyn <bob.stasyszyn@gendigital.com>

verifiable/common.go

@@ -17,6 +17,7 @@ package verifiable
 import (
 	"errors"
 	"fmt"
+	"strings"
 
 	"github.com/piprate/json-gold/ld"
 	util "github.com/trustbloc/did-go/doc/util/time"
@@ -371,3 +372,52 @@ func mapSlice2[T any, U any](slice []T, mapFN func(T) (U, error)) ([]U, error) {
 
 	return result, nil
 }
+
+// MediaType specifies the media type of the data.
+type MediaType string
+
+// Encoding specifies the encoding of the data.
+type Encoding string
+
+// NewDataURL returns a new Data URL given the media type, encoding, and data.
+// The URL will be in the format "data:<media type>[;base64],<data>".
+// See https://www.rfc-editor.org/rfc/rfc2397.
+func NewDataURL(mediaType MediaType, encoding Encoding, data string) string {
+	if encoding == "" {
+		return fmt.Sprintf("data:%s,%s", mediaType, data)
+	}
+
+	return fmt.Sprintf("data:%s;%s,%s", mediaType, encoding, data)
+}
+
+// ParseDataURL parses the given data URL and returns the media type, encoding, and data.
+// The URL must be in the format "data:<media type>[;base64],<data>".
+// See https://www.rfc-editor.org/rfc/rfc2397.
+func ParseDataURL(url string) (MediaType, Encoding, string, error) {
+	if !strings.HasPrefix(url, "data:") {
+		return "", "", "", fmt.Errorf("invalid data URL format: %s", url)
+	}
+
+	url = url[5:] // Remove "data:" prefix
+	commaIndex := strings.Index(url, ",")
+	if commaIndex == -1 {
+		return "", "", "", fmt.Errorf("invalid data URL format: %s", url)
+	}
+
+	fullMediaType := url[:commaIndex]
+	if fullMediaType == "" {
+		return "", "", "", fmt.Errorf("media type is required")
+	}
+
+	data := url[commaIndex+1:]
+
+	semicolonIndex := strings.Index(fullMediaType, ";")
+	if semicolonIndex == -1 {
+		return MediaType(fullMediaType), "", data, nil
+	}
+
+	mediaType := MediaType(fullMediaType[:semicolonIndex])
+	encoding := Encoding(fullMediaType[semicolonIndex+1:])
+
+	return mediaType, encoding, data, nil
+}

verifiable/common_test.go

@@ -236,6 +236,47 @@ func Test_parseLDProof(t *testing.T) {
 	})
 }
 
+func TestParseDataURL(t *testing.T) {
+	t.Run("Valid data URL with media type and encoding", func(t *testing.T) {
+		url := "data:text/plain;base64,SGVsbG8sIFdvcmxkIQ=="
+		mediaType, encoding, data, err := ParseDataURL(url)
+		require.NoError(t, err)
+		require.Equal(t, MediaType("text/plain"), mediaType)
+		require.Equal(t, Encoding("base64"), encoding)
+		require.Equal(t, "SGVsbG8sIFdvcmxkIQ==", data)
+	})
+
+	t.Run("Valid data URL with media type only", func(t *testing.T) {
+		url := "data:text/plain,HelloWorld"
+		mediaType, encoding, data, err := ParseDataURL(url)
+		require.NoError(t, err)
+		require.Equal(t, MediaType("text/plain"), mediaType)
+		require.Empty(t, encoding)
+		require.Equal(t, "HelloWorld", data)
+	})
+
+	t.Run("Invalid data URL without media type", func(t *testing.T) {
+		url := "data:,HelloWorld"
+		_, _, _, err := ParseDataURL(url)
+		require.Error(t, err)
+		require.Contains(t, err.Error(), "media type is required")
+	})
+
+	t.Run("Invalid data URL without comma", func(t *testing.T) {
+		url := "data:text/plain;base64SGVsbG8sIFdvcmxkIQ=="
+		_, _, _, err := ParseDataURL(url)
+		require.Error(t, err)
+		require.Contains(t, err.Error(), "invalid data URL format")
+	})
+
+	t.Run("Invalid data URL without prefix", func(t *testing.T) {
+		url := "text/plain;base64,SGVsbG8sIFdvcmxkIQ=="
+		_, _, _, err := ParseDataURL(url)
+		require.Error(t, err)
+		require.Contains(t, err.Error(), "invalid data URL format")
+	})
+}
+
 // toArray convert array to array of json objects.
 func toArray[T any](v []T) ([]interface{}, error) {
 	maps := make([]interface{}, len(v))