Add helper extension to JsonNode

src/core/EdFi.DataManagementService.Core/ApiSchema/ApiSchemaDocument.cs

@@ -33,19 +33,13 @@ public List<JsonNode> GetAllProjectSchemaNodes()
     {
         JsonNode schema = _apiSchemaRootNode;
 
-        KeyValuePair<string, JsonNode?>[]? projectSchemas = schema["projectSchemas"]?.AsObject().ToArray();
-        if (projectSchemas == null || projectSchemas.Length == 0)
+        var projectSchemasNode = schema["projectSchemas"];
+
+        if (projectSchemasNode == null)
         {
-            string errorMessage = "No projectSchemas found, ApiSchema.json is invalid";
-            _logger.LogCritical(errorMessage);
-            throw new InvalidOperationException(errorMessage);
+            throw new InvalidOperationException("Expected ProjectSchmas node to exist.");
         }
 
-        List<JsonNode> projectSchemaNodes = projectSchemas
-            .Where(x => x.Value != null)
-            .Select(x => x.Value ?? new JsonObject())
-            .ToList();
-
-        return projectSchemaNodes;
+        return projectSchemasNode.SelectNodesFromPropertyValues();
     }
 }

src/core/EdFi.DataManagementService.Core/ApiSchema/Extensions/JsonHelperExtensions.cs

@@ -244,4 +244,23 @@ public static void TryCoerceStringToNumber(this JsonNode jsonNode)
             }
         }
     }
+
+    /// <summary>
+    /// Helper to extract a list of JsonNodes as the values of all the properties of a JsonNode
+    /// </summary>
+    /// <param name="jsonNode"></param>
+    public static List<JsonNode> SelectNodesFromPropertyValues(this JsonNode jsonNode)
+    {
+        KeyValuePair<string, JsonNode?>[]? nodeKeys = jsonNode?.AsObject().ToArray();
+
+        if (nodeKeys == null)
+        {
+            throw new InvalidOperationException("Unexpected null");
+        }
+
+        return nodeKeys
+            .Where(x => x.Value != null)
+            .Select(x => x.Value ?? new JsonObject())
+            .ToList();
+    }
 }