feat: allow duplicate evidence value keys

Dan.Core/Extensions/HttpExtensions.cs

@@ -1,5 +1,4 @@
-using System.Collections;
-using System.Collections.Specialized;
+using System.Collections.Specialized;
 using System.Net;
 using Newtonsoft.Json;
 using System.Net.Http.Headers;
@@ -10,6 +9,7 @@
 using Dan.Common.Models;
 using Dan.Core.Exceptions;
 using Dan.Core.Helpers;
+using Dan.Core.Helpers.JsonConverters;
 using Dan.Core.Middleware;
 using Microsoft.Azure.Functions.Worker.Http;
 using Newtonsoft.Json.Linq;
@@ -266,8 +266,12 @@ public static async Task SetUnenvelopedEvidenceValuesAsync(this HttpResponseData
         string jsonResult;
         if (evidenceValues.Count > 1)
         {
-            var asHashTable = ConvertToHashtable(evidenceValues);
-            jsonResult = JsonConvert.SerializeObject(asHashTable, new JsonSerializerSettings { ContractResolver = new HiddenPropertyContractResolver() });
+            var kvpList = ConvertToKvpList(evidenceValues);
+            jsonResult = JsonConvert.SerializeObject(kvpList, new JsonSerializerSettings
+            {
+                ContractResolver = new HiddenPropertyContractResolver(),
+                Converters = [new KeyValueListAsObjectConverter<object?>()]
+            });
             JmesPathTransfomer.Apply(jmesExpression, ref jsonResult);
             await response.WriteStringAsync(jsonResult);
             response.Headers.Add("Content-Type", "application/json");
@@ -316,12 +320,10 @@ public static async Task SetEvidenceAsync(this HttpResponseData response, Eviden
         response.Headers.Add("X-Signature-JWT", Jwt.GetDigestJwt(jsonResult));
     }
 
-    private static Hashtable ConvertToHashtable(List<EvidenceValue> evidenceValues)
+    private static List<KeyValuePair<string, object?>> ConvertToKvpList(List<EvidenceValue> evidenceValues)
     {
-        var hashTable = new Hashtable();
-        foreach (var evidenceValue in evidenceValues)
-            hashTable.Add(evidenceValue.EvidenceValueName, evidenceValue.Value);
-
-        return hashTable;
+        return evidenceValues
+            .Select(evidenceValue => new KeyValuePair<string, object?>(evidenceValue.EvidenceValueName, evidenceValue.Value))
+            .ToList();
     }
 }

Dan.Core/Helpers/JsonConverters/KeyValueListAsObjectConverter.cs

@@ -0,0 +1,29 @@
+using Newtonsoft.Json;
+
+namespace Dan.Core.Helpers.JsonConverters;
+
+// Solution found here: https://stackoverflow.com/questions/68069271/how-to-serialize-and-deserialize-a-json-object-with-duplicate-property-names-in
+public class KeyValueListAsObjectConverter<TValue> : JsonConverter<List<KeyValuePair<string, TValue>>>
+{
+    public override List<KeyValuePair<string, TValue>> ReadJson(
+        JsonReader reader,
+        Type objectType,
+        List<KeyValuePair<string, TValue>>? existingValue,
+        bool hasExistingValue,
+        JsonSerializer serializer)
+    {
+        // We don't need to read this format
+        throw new NotImplementedException();
+    }
+
+    public override void WriteJson(JsonWriter writer, List<KeyValuePair<string, TValue>>? value, JsonSerializer serializer)
+    {
+        writer.WriteStartObject();
+        foreach (var pair in value ?? [])
+        {
+            writer.WritePropertyName(pair.Key);
+            serializer.Serialize(writer, pair.Value);
+        }
+        writer.WriteEndObject();
+    }
+}