up

src/Attestor/StellaOps.Attestation/DsseEnvelopeExtensions.cs

@@ -0,0 +1,73 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using StellaOps.Attestor.Envelope;
+
+namespace StellaOps.Attestation;
+
+/// <summary>
+/// Extension methods for converting between <see cref="DsseEnvelope"/> domain types
+/// and API DTO representations.
+/// </summary>
+public static class DsseEnvelopeExtensions
+{
+    /// <summary>
+    /// Converts a <see cref="DsseEnvelope"/> to a JSON-serializable dictionary
+    /// suitable for API responses.
+    /// </summary>
+    public static Dictionary<string, object> ToSerializableDict(this DsseEnvelope envelope)
+    {
+        ArgumentNullException.ThrowIfNull(envelope);
+
+        return new Dictionary<string, object>
+        {
+            ["payloadType"] = envelope.PayloadType,
+            ["payload"] = Convert.ToBase64String(envelope.Payload.Span),
+            ["signatures"] = envelope.Signatures.Select(s => new Dictionary<string, object?>
+            {
+                ["keyid"] = s.KeyId,
+                ["sig"] = s.Signature
+            }).ToList()
+        };
+    }
+
+    /// <summary>
+    /// Creates a <see cref="DsseEnvelope"/> from base64-encoded payload and signature data.
+    /// </summary>
+    /// <param name="payloadType">The DSSE payload type URI.</param>
+    /// <param name="payloadBase64">Base64-encoded payload bytes.</param>
+    /// <param name="signatures">Collection of signature data as (keyId, signatureBase64) tuples.</param>
+    /// <returns>A new <see cref="DsseEnvelope"/> instance.</returns>
+    public static DsseEnvelope FromBase64(
+        string payloadType,
+        string payloadBase64,
+        IEnumerable<(string? KeyId, string SignatureBase64)> signatures)
+    {
+        ArgumentException.ThrowIfNullOrWhiteSpace(payloadType);
+        ArgumentException.ThrowIfNullOrWhiteSpace(payloadBase64);
+        ArgumentNullException.ThrowIfNull(signatures);
+
+        var payloadBytes = Convert.FromBase64String(payloadBase64);
+        var dsseSignatures = signatures.Select(s => new DsseSignature(s.SignatureBase64, s.KeyId));
+
+        return new DsseEnvelope(payloadType, payloadBytes, dsseSignatures);
+    }
+
+    /// <summary>
+    /// Gets the payload as a UTF-8 string.
+    /// </summary>
+    public static string GetPayloadString(this DsseEnvelope envelope)
+    {
+        ArgumentNullException.ThrowIfNull(envelope);
+        return System.Text.Encoding.UTF8.GetString(envelope.Payload.Span);
+    }
+
+    /// <summary>
+    /// Gets the payload as a base64-encoded string.
+    /// </summary>
+    public static string GetPayloadBase64(this DsseEnvelope envelope)
+    {
+        ArgumentNullException.ThrowIfNull(envelope);
+        return Convert.ToBase64String(envelope.Payload.Span);
+    }
+}

src/Attestor/StellaOps.Attestation/DsseHelper.cs

@@ -50,6 +50,7 @@ public static class DsseHelper
         var keyId = await signer.GetKeyIdAsync(cancellationToken).ConfigureAwait(false);
 
         var dsseSignature = DsseSignature.FromBytes(signatureBytes, keyId);
-        return new DsseEnvelope(statement.Type, payloadBytes, new[] { dsseSignature });
+        var payloadType = statement.Type ?? "https://in-toto.io/Statement/v1";
+        return new DsseEnvelope(payloadType, payloadBytes, new[] { dsseSignature });
     }
 }