Added exists block helper in handlebars.

Author: RoelantVos

ClassLibrary/DataWarehouseAutomation/DataWarehouseAutomation/DataWarehouseAutomation.csproj

@@ -2,7 +2,7 @@
 
   <PropertyGroup>
     <TargetFramework>net7.0</TargetFramework>
-    <Version>1.3.3</Version>
+    <Version>1.3.4</Version>
     <Authors>Roelant Vos</Authors>
     <GeneratePackageOnBuild>True</GeneratePackageOnBuild>
     <Title>Data Warehouse Automation</Title>

ClassLibrary/DataWarehouseAutomation/DataWarehouseAutomation/HandleBarsHelpers.cs

@@ -1,4 +1,5 @@
 using System;
+using System.Collections.Generic;
 using System.Linq;
 using System.Security.Cryptography;
 using System.Text;
@@ -248,6 +249,7 @@ public static void RegisterHandleBarsHelpers()
             }
         });
 
+        // Run at data object mapping level.
         Handlebars.RegisterHelper("targetDataItemExists", (output, options, context, arguments) =>
         {
             if (arguments.Length != 1) throw new HandlebarsException("The {{targetDataItemExists}} function requires only one argument.");
@@ -275,5 +277,73 @@ public static void RegisterHandleBarsHelpers()
                 throw new HandlebarsException($"The {{targetDataItemExists}} helper reported a conversion error, and was unable to deserialize the context into a DataObjectMapping. The reported error is " + exception.Message);
             }
         });
+
+        // Run at data object mapping level.
+        Handlebars.RegisterHelper("exists", (output, options, context, arguments) =>
+        {
+            if (arguments.Length != 1) throw new HandlebarsException("The {{exists}} function must have a single argument, which must be a property of a data object mapping.");
+
+            var property = arguments[0] == null ? "" : arguments[0].ToString();
+
+            // Supported:
+            // - targetDataItemClassification
+            // - targetDataItem
+
+            try
+            {
+                DataObjectMapping dataObjectMapping = JsonSerializer.Deserialize<DataObjectMapping>(context.Value.ToString());
+
+                var outcome = false;
+
+                if (property == "multiActiveKey")
+                {
+                    var targetDataItemsWithClassifications = dataObjectMapping?.DataItemMappings?.Where(x => x.TargetDataItem.DataItemClassification != null).ToList();
+
+                    if (targetDataItemsWithClassifications != null)
+                    {
+                        var dataItemClassifications = targetDataItemsWithClassifications.SelectMany(x => x.TargetDataItem.DataItemClassification).ToList();
+
+                        if (dataItemClassifications != null && dataItemClassifications.Any())
+                        {
+                            foreach (var classification in dataItemClassifications)
+                            {
+                                if (classification.Classification == "MultiActiveKey")
+                                {
+                                    outcome = true;
+                                }
+                            }
+                        }
+                    }
+                }
+                else if (property == "targetDataItem")
+                {
+                    var targetDataItem = dataObjectMapping?.DataItemMappings?.Where(x => x.TargetDataItem != null).FirstOrDefault();
+
+                    if (targetDataItem != null)
+                    {
+                        outcome = true;
+                    }
+                }
+                else
+                {
+                    throw new HandlebarsException($"The {{{property}}} used is not supported by the exist function. Only multiActiveKey and targetDataItem are currently supported.");
+                }
+
+                if (outcome)
+                {
+                    // Regular block
+                    options.Template(output, context);
+                }
+                else
+                {
+                    // Else block
+                    options.Inverse(output, context);
+                }
+            }
+            catch (Exception exception)
+            {
+                throw new HandlebarsException($"The exists helper using the property {{{property}}} reported a conversion error, and was unable to deserialize the context into a DataObjectMapping. The reported error is " + exception.Message);
+            }
+        });
     }
 }

ClassLibrary/DataWarehouseAutomation/Example_Project/Program.cs

@@ -15,14 +15,14 @@ static void Main(string[] args)
             var sampleTemplateDirectory = AppDomain.CurrentDomain.BaseDirectory+@"..\..\..\..\Sample_Templates\";
             var sampleMetadataDirectory = AppDomain.CurrentDomain.BaseDirectory + @"..\..\..\..\Sample_Metadata\";
 
-            DisplayPatternResult(sampleTemplateDirectory + @"TemplateSampleBasic.handlebars", sampleMetadataDirectory + @"sampleBasic.json");
-            DisplayPatternResult(sampleTemplateDirectory + @"TemplateSampleBasicWithExtensions.handlebars", sampleMetadataDirectory + @"sampleBasicWithExtensions.json");
-            DisplayPatternResult(sampleTemplateDirectory + @"TemplateSampleMultipleDataItemMappings.handlebars", sampleMetadataDirectory + @"sampleMultipleDataItemMappings.json");
-            DisplayPatternResult(sampleTemplateDirectory + @"TemplateSampleSourceQuery.handlebars", sampleMetadataDirectory + @"sampleSourceQuery.json");
-            DisplayPatternResult(sampleTemplateDirectory + @"TemplateSampleSimpleDDL.handlebars", sampleMetadataDirectory + @"sampleSimpleDDL.json");
-            DisplayPatternResult(sampleTemplateDirectory + @"TemplateSampleCalculation.handlebars", sampleMetadataDirectory + @"sampleCalculation.json");
-            DisplayPatternResult(sampleTemplateDirectory + @"TemplateSatelliteView.handlebars", sampleMetadataDirectory + @"sampleVDW_Sat_Customer_v161.json");
-            DisplayPatternResult(sampleTemplateDirectory + @"TemplateSampleFreeForm.handlebars", sampleMetadataDirectory + @"sampleFreeForm.json");
+            //DisplayPatternResult(sampleTemplateDirectory + @"TemplateSampleBasic.handlebars", sampleMetadataDirectory + @"sampleBasic.json");
+            //DisplayPatternResult(sampleTemplateDirectory + @"TemplateSampleBasicWithExtensions.handlebars", sampleMetadataDirectory + @"sampleBasicWithExtensions.json");
+            //DisplayPatternResult(sampleTemplateDirectory + @"TemplateSampleMultipleDataItemMappings.handlebars", sampleMetadataDirectory + @"sampleMultipleDataItemMappings.json");
+            //DisplayPatternResult(sampleTemplateDirectory + @"TemplateSampleSourceQuery.handlebars", sampleMetadataDirectory + @"sampleSourceQuery.json");
+            //DisplayPatternResult(sampleTemplateDirectory + @"TemplateSampleSimpleDDL.handlebars", sampleMetadataDirectory + @"sampleSimpleDDL.json");
+            //DisplayPatternResult(sampleTemplateDirectory + @"TemplateSampleCalculation.handlebars", sampleMetadataDirectory + @"sampleCalculation.json");
+            //DisplayPatternResult(sampleTemplateDirectory + @"TemplateSatelliteView.handlebars", sampleMetadataDirectory + @"sampleVDW_Sat_Customer_v161.json");
+            //DisplayPatternResult(sampleTemplateDirectory + @"TemplateSampleFreeForm.handlebars", sampleMetadataDirectory + @"sampleFreeForm.json");
             DisplayPatternResult(sampleTemplateDirectory + @"TemplateSampleCustomFunctions.handlebars", sampleMetadataDirectory + @"sampleCustomFunctions.json");
 
             Console.ReadKey();

ClassLibrary/DataWarehouseAutomation/Sample_Metadata/sampleCustomFunctions.json

@@ -38,7 +38,12 @@
             }
           ],
           "targetDataItem": {
-            "name": "DATE_OF_BIRTH"
+            "name": "DATE_OF_BIRTH",
+            "dataItemClassification": [
+              {
+                "classification": "MultiActiveKey"
+              }
+            ]
           }
         }
       ],

ClassLibrary/DataWarehouseAutomation/Sample_Templates/TemplateSampleCustomFunctions.Handlebars

@@ -23,6 +23,9 @@ Working on mapping {{mappingName}}
 Found a data item mapping from {{sourceDataItems.0.name}} to {{targetDataItem.name}}
 {{/each}}
 
+{{#exists multiActiveKey}}There is a multi-active key!{{else}}No multi-active key in this data object mapping.{{/exists}}
+{{#exists targetDataItem}}There is a target data item in this mapping!{{else}}No target data items are defined in this mapping.{{/exists}}
+
 {{#targetDataItemExists "FIRST_NAME"}}FIRST_NAME exists{{else}}FIRST_NAME does not exist{{/targetDataItemExists}}
 {{#targetDataItemExists "NAME"}}NAME exists{{else}}NAME does not exist{{/targetDataItemExists}}
 {{#targetDataItemExists "DATE_OF_BIRTH"}}NAME exists{{else}}NAME does not exist{{/targetDataItemExists}}