Translate UniqueKey to TopicID in attributes on Import()

Some types of attributes—such as `TokenizedTopicList`, `TopicList`, and `TopicReference`—create pointers to other topics. These can be stored in a variety of formats, including topic key, unique key, or topic ID. If the latter, that can introduce problems when exporting the data, as those IDs won't be maintained when importing them into a new database.

To mitigate this, these are translated from `TopicID` to `UniqueKey` on `Export()` (0993ea3). To complement this, I've introduced a new `GetTopicID()` helper function and corresponding `getAttributeValue()` local function into the `Import()` extension method. If an attribute ends with `ID`, begins with `Root`, and maps to a topic with the same `UniqueKey` in the topic graph, then the value is replaced with the topic's `Id` on import.

There's a _very_ minor risk of false positives during this process, and we'd need to come up with pretty contrived scenarios where that would occur (e.g., an attribute with the key `Kid` and value `Root`  would have the value replaced with the `TopicID` of the root topic). The far greater risk remains in the `Export()` scenario (as discussed in 0993ea3).

Author: JeremyCaney

OnTopic.Data.Transfer.Tests/TopicExtensionsTest.cs

@@ -583,5 +583,46 @@ public void Import_TopicDataWithChild_SkipsOrphanedChild() {
 
     }
 
+    /*==========================================================================================================================
+    | TEST: IMPORT: TOPIC DATA WITH TOPIC POINTER: MAPS TOPIC ID
+    \-------------------------------------------------------------------------------------------------------------------------*/
+    /// <summary>
+    ///   Creates a <see cref="TopicData"/> with an arbitrary <see cref="AttributeData"/> that points to another topic. Confirms
+    ///   that it is converted to a <c>TopicID</c> if valid, and otherwise left as is.
+    /// </summary>
+    [TestMethod]
+    public void Import_TopicDataWithTopicPointer_MapsTopicID() {
+
+      var rootTopic             = TopicFactory.Create("Root", "Container");
+      var topic                 = TopicFactory.Create("Topic", "Container", rootTopic);
+      var siblingTopic          = TopicFactory.Create("SiblingTopic", "Container", 5, rootTopic);
+
+      var topicData             = new TopicData() {
+        Key                     = topic.Key,
+        UniqueKey               = topic.GetUniqueKey(),
+        ContentType             = topic.ContentType
+      };
+
+      topicData.Attributes.Add(
+        new AttributeData() {
+          Key                   = "SomeId",
+          Value                 = siblingTopic.GetUniqueKey()
+        }
+      );
+
+      topicData.Attributes.Add(
+        new AttributeData() {
+          Key                   = "InitialBid",
+          Value                 = "6"
+        }
+      );
+
+      topic.Import(topicData);
+
+      Assert.AreEqual<string>("5", topic.Attributes.GetValue("SomeId"));
+      Assert.AreEqual<string>("6", topic.Attributes.GetValue("InitialBid"));
+
+    }
+
   } //Class
 } //Namespace

OnTopic.Data.Transfer/Interchange/TopicExtensions.cs

@@ -212,7 +212,7 @@ public static void Import(this Topic topic, TopicData topicData, [NotNull]Import
         if (matchedAttribute?.LastModified >= attribute.LastModified && isStrategy(ImportStrategy.Merge)) continue;
         topic.Attributes.SetValue(
           attribute.Key,
-          attribute.Value
+          getAttributeValue(attribute)
         );
       }
 
@@ -305,6 +305,16 @@ bool useCustomMergeRules(AttributeData attribute) =>
         (attribute.Key == "LastModified" && !options!.LastModifiedStrategy.Equals(LastModifiedImportStrategy.Inherit)) ||
         (attribute.Key == "LastModifiedBy" && !options!.LastModifiedByStrategy.Equals(LastModifiedImportStrategy.Inherit));
 
+      /*------------------------------------------------------------------------------------------------------------------------
+      | Get attribute value
+      \-----------------------------------------------------------------------------------------------------------------------*/
+      string? getAttributeValue(AttributeData attribute) =>
+        attribute.Key.EndsWith("ID", StringComparison.InvariantCultureIgnoreCase)?
+          GetTopicId(topic, attribute.Value) :
+          attribute.Value;
+
+    }
+
     /*==========================================================================================================================
     | GET UNIQUE KEY
     \-------------------------------------------------------------------------------------------------------------------------*/
@@ -322,6 +332,20 @@ bool useCustomMergeRules(AttributeData attribute) =>
       return uniqueKey;
     }
 
+    /*==========================================================================================================================
+    | GET TOPIC ID
+    \-------------------------------------------------------------------------------------------------------------------------*/
+    /// <summary>
+    ///   Given a <c>UniqueKey</c>, lookup the topic in the topic graph and return the <c>TopicID</c>. If no value can be
+    ///   found, the original <c>UniqueKey</c> is returned.
+    /// </summary>
+    /// <param name="topic">The source <see cref="Topic"/> to operate off of.</param>
+    /// <param name="uniqueKey">The <see cref="Topic.GetUniqueKey"/> to retrieve the <see cref="Topic.Id"/> for.</param>
+    private static string? GetTopicId(Topic topic, string? uniqueKey) {
+      if (!String.IsNullOrEmpty(uniqueKey) && uniqueKey!.StartsWith("Root", StringComparison.InvariantCultureIgnoreCase)) {
+        return topic.GetByUniqueKey(uniqueKey)?.Id.ToString(CultureInfo.CurrentCulture)?? uniqueKey;
+      }
+      return uniqueKey;
     }
 
   } //Class