[.NET] Add new OnDeserializingMissingVersion callback

Fixes #3376
microsoft · Sep 17, 2019 · 45a4b1b · 45a4b1b
1 parent 302b0d8
commit 45a4b1b
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Showing 4 changed files with 53 additions and 13 deletions.
diff --git a/source/dotnet/Library/AdaptiveCards/AdaptiveCard.cs b/source/dotnet/Library/AdaptiveCards/AdaptiveCard.cs
@@ -217,6 +217,14 @@ public bool ShouldSerializeJsonSchema()
 
  public bool ShouldSerializeHeight() => this.Height?.ShouldSerializeAdaptiveHeight() == true;
 
+ /// <summary>
+ /// Callback that will be invoked should a null or empty version string is encountered. The callback may return an alternate version to use for parsing.
+ /// </summary>
+ /// <example>
+ /// AdaptiveCard.OnDeserializingMissingVersion = () => new AdaptiveSchemaVersion(0, 5);
+ /// </example>
+ public static Func<AdaptiveSchemaVersion> OnDeserializingMissingVersion { get; set; }
+
  /// <summary>
  /// Parse an AdaptiveCard from a JSON string
  /// </summary>

diff --git a/source/dotnet/Library/AdaptiveCards/AdaptiveCardConverter.cs b/source/dotnet/Library/AdaptiveCards/AdaptiveCardConverter.cs
@@ -20,29 +20,52 @@ public override void WriteJson(JsonWriter writer, object value, JsonSerializer s
 
  public override bool CanWrite => false;
 
+ private void ValidateJsonVersion(ref JObject jObject)
+ {
+ string exceptionMessage = "";
+ if (jObject.Value<string>("version") == null)
+ {
+ exceptionMessage = "Could not parse required key: version. It was not found.";
+ }
+
+ // If this is the root AdaptiveCard and missing a version we fail parsing.
+ // The depth checks that cards within a Action.ShowCard don't require the version
+ if (jObject.Value<string>("version") == "")
+ {
+ exceptionMessage = "Property is required but was found empty: version";
+ }
+
+ if (!String.IsNullOrEmpty(exceptionMessage))
+ {
+ if (AdaptiveCard.OnDeserializingMissingVersion == null)
+ {
+ // no handler registered for dealing with missing/empty version. best just throw...
+ throw new AdaptiveSerializationException(exceptionMessage);
+ }
+ else
+ {
+ // caller wants to override version semantics
+ var overriddenVersion = AdaptiveCard.OnDeserializingMissingVersion();
+ jObject["version"] = overriddenVersion.ToString();
+ }
+ }
+ }
+
  public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
  {
  var jObject = JObject.Load(reader);
 
  if (jObject.Value<string>("type") != AdaptiveCard.TypeName)
+ {
  throw new AdaptiveSerializationException($"Property 'type' must be '{AdaptiveCard.TypeName}'");
+ }
 
  if (reader.Depth == 0)
  {
  // Needed for ID collision detection after fallback was introduced
  ParseContext.Initialize();
 
- if (jObject.Value<string>("version") == null)
- {
- throw new AdaptiveSerializationException("Could not parse required key: version. It was not found.");
- }
-
- // If this is the root AdaptiveCard and missing a version we fail parsing.
- // The depth checks that cards within a Action.ShowCard don't require the version
- if (jObject.Value<string>("version") == "")
- {
- throw new AdaptiveSerializationException("Property is required but was found empty: version");
- }
+ ValidateJsonVersion(ref jObject);
 
  if (new AdaptiveSchemaVersion(jObject.Value<string>("version")) > AdaptiveCard.KnownSchemaVersion)
  {

diff --git a/source/dotnet/Samples/WPFVisualizer/MainWindow.xaml.cs b/source/dotnet/Samples/WPFVisualizer/MainWindow.xaml.cs
@@ -67,7 +67,6 @@ public MainWindow()
  });
  }
 
-
  Renderer = new AdaptiveCardRenderer()
  {
  Resources = Resources
@@ -122,7 +121,6 @@ private void RenderCard()
 
  try
  {
-
  AdaptiveCardParseResult parseResult = AdaptiveCard.FromJson(CardPayload);
 
  AdaptiveCard card = parseResult.Card;

diff --git a/source/dotnet/Test/AdaptiveCards.Test/AdaptiveCardApiTests.cs b/source/dotnet/Test/AdaptiveCards.Test/AdaptiveCardApiTests.cs
@@ -94,7 +94,18 @@ public void TestParsingInvalidCardMissingVersion()
  }
  ]
 }";
+ // By default we should be throwing an exception when no version present.
  Assert.ThrowsException<AdaptiveSerializationException>(() => AdaptiveCard.FromJson(json));
+
+ // Or we can supply a replacement version to use
+ AdaptiveCard.OnDeserializingMissingVersion = () => new AdaptiveSchemaVersion(0, 5);
+ var card = AdaptiveCard.FromJson(json);
+ Assert.AreEqual(new AdaptiveSchemaVersion(0, 5), card.Card.Version);
+
+ // But make sure that if the callback throws an exception that it is allowed through
+ AdaptiveCard.OnDeserializingMissingVersion = () => throw new Exception("test exception");
+ Assert.ThrowsException<Exception>(() => AdaptiveCard.FromJson(json));
+ AdaptiveCard.OnDeserializingMissingVersion = null;
  }
 
  [TestMethod]