=============================
Element **autoServiceCustom**
=============================

The XML configuration file has an element **autoServiceCustom** that can appear under "iocConfiguration/dependencyInjection/autoGeneratedServices" and "iocConfiguration/pluginsSetup/pluginSetup/dependencyInjection/autoGeneratedServices" elements.
 
The **autoServiceCustom** element specifies the interface that needs to be auto-implemented and has a child element **autoServiceCodeGenerator** that specifies an implementation of interface `IoC.Configuration.ConfigurationFile.ICustomAutoServiceCodeGenerator <https://github.com/artakhak/IoC.Configuration/blob/master/IoC.Configuration/ConfigurationFile/ICustomAutoServiceCodeGenerator.cs>`_.

The implementation of interface `IoC.Configuration.ConfigurationFile.ICustomAutoServiceCodeGenerator <https://github.com/artakhak/IoC.Configuration/blob/master/IoC.Configuration/ConfigurationFile/ICustomAutoServiceCodeGenerator.cs>`_ is responsible for validating the auto-generated interface and for providing a code for the auto-generating the interface implementation. 

See the example below or in test project for more details.

Below is the declaration of `IoC.Configuration.ConfigurationFile.ICustomAutoServiceCodeGenerator <https://github.com/artakhak/IoC.Configuration/blob/master/IoC.Configuration/ConfigurationFile/ICustomAutoServiceCodeGenerator.cs>`_.

.. raw:: html

   <details>
   <summary><a>Click to expand IoC.Configuration.ConfigurationFile.ICustomAutoServiceCodeGenerator</a></summary>

.. code-block:: csharp
   :linenos: 

   // Copyright (c) IoC.Configuration Project. All rights reserved.
   // Licensed under the MIT License. See LICENSE in the solution root for license information.

   using JetBrains.Annotations;
   using OROptimizer.DynamicCode;
   using OROptimizer.ServiceResolver;
   using System;

   namespace IoC.Configuration.ConfigurationFile
   {
       /// <summary>
       /// Generates an implementation class for interfaces specified in autoServiceCustom element in configuration file.
       /// </summary>
       public interface ICustomAutoServiceCodeGenerator
       {
           /// <summary>
           /// Validates the configuration of "autoServiceCustom" element.
           /// Throws an exception if the configuration is invalid.
           /// </summary>
           /// <param name="customAutoGeneratedServiceInfo"></param>
           void Validate([NotNull] ICustomAutoGeneratedServiceInfo customAutoGeneratedServiceInfo);
           
           /// <summary>
           /// Generates a C# code for the auto-implemented interface specified in "autoServiceCustom" element.
           /// </summary>
           /// <param name="customAutoGeneratedServiceInfo">Configuration of auto-implemented service configuration.</param>
           /// <param name="dynamicAssemblyBuilder">
           /// An instance of <see cref="IDynamicAssemblyBuilder"/>.
           /// Use methods <see cref="IDynamicAssemblyBuilder.StartDynamicallyGeneratedClass(string, string)"/>,
           /// <see cref="IDynamicAssemblyBuilder.StartDynamicallyGeneratedClass(string, System.Collections.Generic.IEnumerable{string}, string)"/>,
           /// <see cref="IDynamicAssemblyBuilder.AddCSharpFile(string)"/>, etc., to generate the C# code for the implementation. 
           /// </param>
           /// <param name="generatedClassNamespace">The generated class namespace.</param>
           /// <param name="generatedClassName">The generated class name without namespace.</param>
           void GenerateCSharp([NotNull] ICustomAutoGeneratedServiceInfo customAutoGeneratedServiceInfo,
               [NotNull] IDynamicAssemblyBuilder dynamicAssemblyBuilder,
               [NotNull] string generatedClassNamespace, [NotNull] string generatedClassName);

           /// <summary>
           /// Validates the configuration of "autoServiceCustom" element after the IoC container is loaded.
           /// Throws an exception if the configuration is invalid.
           /// </summary>
           /// <param name="diContainer">The IoC container. Use IDiContainer.<see cref="IServiceResolver.Resolve(Type)"/> to resolve types.</param>
           /// <param name="customAutoGeneratedServiceInfo">Information about auto-implemented interface.</param>
           void ValidateOnIoCContainerLoaded([NotNull] DiContainer.IDiContainer diContainer, [NotNull] ICustomAutoGeneratedServiceInfo customAutoGeneratedServiceInfo);
       }
   }


.. raw:: html

   </details>

The motivation for adding **autoServiceCustom** was to provide an auto-implemented interface implementation based on **C#** attributes applied to the interface and in interface and interface methods and properties. 

For example one such scenario when **autoServiceCustom** might be handy is when we want to auto-implement interfaces for object relational mapping, when interfaces represent database tables, and are decorated with metadata attributes that describe the database schema.

In this case, an implementation of `IoC.Configuration.ConfigurationFile.ICustomAutoServiceCodeGenerator <https://github.com/artakhak/IoC.Configuration/blob/master/IoC.Configuration/ConfigurationFile/ICustomAutoServiceCodeGenerator.cs>`_ can scan the attributes applied to an interface and interface methods and properties, and generate an implementation of an interface based on metadata attributes.  

The tests in `IoC.Configuration.Tests.AutoServiceCustom.AutoServiceCustomSuccessfulLoadTests.cs <https://github.com/artakhak/IoC.Configuration/blob/master/IoC.Configuration.Tests/AutoServiceCustom/AutoServiceCustomSuccessfulLoadTests.cs>`_ demonstrate an 
example of auto-generated repository interface implementations based on attributes applied to the interface.

.. note::
    Refer to :doc:`../../sample-files/IoCConfiguration_autoServiceCustom.generated` and tests in `IoC.Configuration.Tests.AutoServiceCustom.AutoServiceCustomSuccessfulLoadTests.cs <https://github.com/artakhak/IoC.Configuration/blob/master/IoC.Configuration.Tests/AutoServiceCustom/AutoServiceCustomSuccessfulLoadTests.cs>`_ for more examples on **autoServiceCustom** element.
    
.. note::
    This wiki uses simpler examples in `IoC.Configuration.Tests.DocumentationTests.AutoServiceCustom.DemoAutoServiceCustom.cs <https://github.com/artakhak/IoC.Configuration/blob/master/IoC.Configuration.Tests/DocumentationTets/AutoServiceCustom/DemoAutoServiceCustom.cs>`_.

Below is a simple example of setting up custom auto-service in configuration file (a segment copied from configuration file
`DemoIoCConfiguration_autoServiceCustom.xml <https://github.com/artakhak/IoC.Configuration/blob/master/IoC.Configuration.Tests/DocumentationTets/AutoServiceCustom/DemoIoCConfiguration_autoServiceCustom.xml>`_.

.. code-block:: xml
    :linenos:
   
    <dependencyInjection>
        <modules>
        </modules>
    		
    	<services>
    	</services>
    	
    	<autoGeneratedServices>
    
    	   <!--Interface specified in autoServiceCustom is auto-implemented by implementation of 
    	   IoC.Configuration.ConfigurationFile.ICustomAutoServiceCodeGenerator IoC.Configuration.Tests.AutoServiceCustom.SimpleDataRepository.RepositoryInterfaceImplementationGenerator
    	   that is specified in autoServiceCodeGenerator element.-->
    		
    	    <autoServiceCustom interface="IoC.Configuration.Tests.DocumentationTests.AutoServiceCustom.ISimpleAutoImplementedInterface1">
    	    	<autoServiceCodeGenerator>
    	    		<constructedValue typeRef="DemoCustomAutoServiceCodeGenerator">
    	    			<parameters>
    	    				<classMember name="connectionString" 
    	    				    classRef="ConnectionStrings" 
    	    				    memberName="ConnectionString1" />						
    	    			</parameters>			
    	    		</constructedValue>
    	    	</autoServiceCodeGenerator>
    	    </autoServiceCustom>
    
    		<autoServiceCustom interface="IoC.Configuration.Tests.DocumentationTests.AutoServiceCustom.ISimpleAutoImplementedInterface2">
    			<autoServiceCodeGenerator>
    				<constructedValue typeRef="DemoCustomAutoServiceCodeGenerator">
    					<parameters>
    						<classMember name="connectionString" 
    						    classRef="ConnectionStrings" 
    						    memberName="ConnectionString1" />
    					</parameters>
    				</constructedValue>
    			</autoServiceCodeGenerator>
    		</autoServiceCustom>
    	</autoGeneratedServices>    
    </dependencyInjection>    
    
This configuration instructs **IoC.Configuration** to generate an implementation of interfaces `IoC.Configuration.Tests.DocumentationTests.AutoServiceCustom.ISimpleAutoImplementedInterface1.cs <https://github.com/artakhak/IoC.Configuration/blob/master/IoC.Configuration.Tests/DocumentationTests/AutoServiceCustom/ISimpleAutoImplementedInterface1.cs>`_ and `IoC.Configuration.Tests.DocumentationTests.AutoServiceCustom.ISimpleAutoImplementedInterface2.cs <https://github.com/artakhak/IoC.Configuration/blob/master/IoC.Configuration.Tests/DocumentationTests/AutoServiceCustom/ISimpleAutoImplementedInterface2.cs>`_ using class 
`IoC.Configuration.Tests.DocumentationTests.AutoServiceCustom.DemoCustomAutoServiceCodeGenerator.cs <https://github.com/artakhak/IoC.Configuration/blob/master/IoC.Configuration.Tests/DocumentationTests/AutoServiceCustom/DemoCustomAutoServiceCodeGenerator.cs>`_ specified in child element **autoServiceCodeGenerator**.

Below is the code in `IoC.Configuration.Tests.DocumentationTests.AutoServiceCustom.DemoCustomAutoServiceCodeGenerator <https://github.com/artakhak/IoC.Configuration/tree/master/IoC.Configuration.Tests/DocumentationTests/AutoServiceCustom/DemoCustomAutoServiceCodeGenerator.cs>`_.

.. code-block:: csharp
   :linenos: 

   using System;
   using System.IO;
   using System.Linq;
   using System.Reflection;
   using IoC.Configuration.ConfigurationFile;
   using IoC.Configuration.DiContainer;
   using IoC.Configuration.Tests.AutoServiceCustom.SimpleDataRepository;
   using NUnit.Framework;
   using OROptimizer;
   using OROptimizer.DynamicCode;
   using SharedServices.Interfaces;

   namespace IoC.Configuration.Tests.DocumentationTests.AutoServiceCustom;

   /// <summary>
   /// This is a simple demo to demonstrate an implementation of <see cref="ICustomAutoServiceCodeGenerator"/>.
   /// For a better example reference <see cref="RepositoryInterfaceImplementationGenerator"/> used in tests
   /// in AutoServiceCustom.
   /// The best use of <see cref="ICustomAutoServiceCodeGenerator"/> is to generate interface implementation based
   /// on attributes applied to interface and interface methods (such as auto-generating entity framework interfaces based on
   /// table names, and column metadata attributes).
   /// </summary>
   public class DemoCustomAutoServiceCodeGenerator : ICustomAutoServiceCodeGenerator
   {
       public DemoCustomAutoServiceCodeGenerator(string connectionString)
       {
           // Demo passing parameters to ICustomAutoServiceCodeGenerator in configuration file.
           Assert.AreEqual(ConnectionStrings.ConnectionString1, connectionString);
       }
       
       /// <inheritdoc />
       public void Validate(ICustomAutoGeneratedServiceInfo customAutoGeneratedServiceInfo)
       {
           var implementedInterfaceType = customAutoGeneratedServiceInfo.ImplementedInterface;
           
           if (!implementedInterfaceType.IsInterface || 
               implementedInterfaceType.GetInterfaces().Length > 0 || 
               implementedInterfaceType.GetMethods().Length != 1 ||
               implementedInterfaceType.GetProperties().Length != 0)
               throw new Exception($"The demo auto-implemented interface should not have a parent interfaces and should have exactly one method.");

           var methodInfo = implementedInterfaceType.GetMethods().First();
           
           if (methodInfo.GetParameters().Length != 0 || methodInfo.ReturnType != typeof(int))
               throw new Exception($"The demo auto-implemented method should be veryyy simple to be short!!.");

           if (methodInfo.GetCustomAttributes().FirstOrDefault(x => x is SimpleMethodMetadataAttribute) == null)
               throw new Exception($"Method should have an attribute of type '{typeof(SimpleMethodMetadataAttribute)}'.");
       }

       /// <inheritdoc />
       public void GenerateCSharp(ICustomAutoGeneratedServiceInfo customAutoGeneratedServiceInfo, IDynamicAssemblyBuilder dynamicAssemblyBuilder, string generatedClassNamespace, string generatedClassName)
       {
           // Use IDynamicAssemblyBuilder.AddReferencedAssembly(string assemblyPath) or 
           // IDynamicAssemblyBuilder.AddReferencedAssembly(Type typeInAssembly) to add assemblies that will be 
           // referenced by auto-generated assembly if types in these assemblies are used in auto-generated code.
           dynamicAssemblyBuilder.AddReferencedAssembly(Path.Combine(Helpers.GetTestFilesFolderPath(), @"DynamicallyLoadedDlls\TestProjects.DynamicallyLoadedAssembly1.dll"));
           dynamicAssemblyBuilder.AddReferencedAssembly(typeof(IInterface1));

           // By now Validate(ICustomAutoGeneratedServiceInfo customAutoGeneratedServiceInfo) already validated 
           // that a single method with attribute is present in interface.
           var methodInfo = customAutoGeneratedServiceInfo.ImplementedInterface.GetMethods().First();

           var attribute = (SimpleMethodMetadataAttribute)methodInfo.GetCustomAttributes().FirstOrDefault(x => x is SimpleMethodMetadataAttribute);

           var dynamicClass = dynamicAssemblyBuilder.StartDynamicallyGeneratedClass(generatedClassName,
               new[]
               {
                   customAutoGeneratedServiceInfo.ImplementedInterface.GetTypeNameInCSharpClass()
               },
               generatedClassNamespace);

           var methodData = dynamicClass.StartInterfaceImplementationMethod(methodInfo, false);
           
           methodData.AddCodeLine("{");
           
           methodData.AddCodeLine("var testReferencedAssembly = new DynamicallyLoadedAssembly1.Dog(40);");
           
           methodData.AddCodeLine($"return {attribute.ReturnedValue};");
           methodData.AddCodeLine("}");
       }

       /// <inheritdoc />
       public void ValidateOnIoCContainerLoaded(IDiContainer diContainer, ICustomAutoGeneratedServiceInfo customAutoGeneratedServiceInfo)
       {
           // At this point the DI container diContainer is loaded. Do validation using some services in container
           // and throw an exception if necessary
           //diContainer.Resolve()
       }
   }

Look at test class below for an example of setting up and initializing the DI container from configuration file, and resolving and using auto-generated interfaces `IoC.Configuration.Tests.DocumentationTests.AutoServiceCustom.ISimpleAutoImplementedInterface1.cs <https://github.com/artakhak/IoC.Configuration/blob/master/IoC.Configuration.Tests/DocumentationTests/AutoServiceCustom/ISimpleAutoImplementedInterface1.cs>`_ and `IoC.Configuration.Tests.DocumentationTests.AutoServiceCustom.ISimpleAutoImplementedInterface2.cs <https://github.com/artakhak/IoC.Configuration/blob/master/IoC.Configuration.Tests/DocumentationTests/AutoServiceCustom/ISimpleAutoImplementedInterface2.cs>`_.
   
.. code-block:: csharp
   :linenos: 

   // Copyright (c) IoC.Configuration Project. All rights reserved.
   // Licensed under the MIT License. See LICENSE in the solution root for license information.

   using System.IO;
   using IoC.Configuration.DiContainerBuilder;
   using IoC.Configuration.DiContainerBuilder.FileBased;
   using NUnit.Framework;
   using OROptimizer.Utilities.Xml;
   using TestsSharedLibrary;

   namespace IoC.Configuration.Tests.DocumentationTests.AutoServiceCustom;

   [TestFixture]
   public class DemoAutoServiceCustom
   {
       private static IContainerInfo _containerInfo;

       [SetUp]
       public static void TestSetUp()
       {
           TestsHelper.SetupLogger();
           
           var fileBasedConfigurationParameters = new FileBasedConfigurationParameters(
               new FileBasedConfigurationFileContentsProvider(
                   Path.Combine(Helpers.TestsEntryAssemblyFolder, @"DocumentationTests\AutoServiceCustom\DemoIoCConfiguration_autoServiceCustom.xml")),
               Helpers.TestsEntryAssemblyFolder,
               // LoadedAssembliesForTests is an implementation of ILoadedAssemblies that has a method 
               // "IEnumerable<Assembly> GetAssemblies()" that returns list of assemblies to add as references to
               // generate dynamic assembly.
               new LoadedAssembliesForTests())
           {
               AdditionalReferencedAssemblies = new []
               {
                   // List additional assemblies that should be added to dynamically generated assembly as references
                   Path.Combine(Helpers.GetTestFilesFolderPath(), @"DynamicallyLoadedDlls\TestProjects.DynamicallyLoadedAssembly1.dll"),
                   Path.Combine(Helpers.GetTestFilesFolderPath(), @"DynamicallyLoadedDlls\TestProjects.DynamicallyLoadedAssembly2.dll")
               },
               AttributeValueTransformers = new[] {new FileFolderPathAttributeValueTransformer()},
               ConfigurationFileXmlDocumentLoaded = (sender, e) => 
                   Helpers.EnsureConfigurationDirectoryExistsOrThrow(e.XmlDocument.SelectElement("/iocConfiguration/appDataDir").GetAttribute("path"))
           };
           
           _containerInfo = new DiContainerBuilder.DiContainerBuilder()
               .StartFileBasedDi(fileBasedConfigurationParameters)
               .WithoutPresetDiContainer()
               .RegisterModules().Start();
       }

       [Test]
       public void Demo()
       {
           var simpleAutoImplementedInterface1 = _containerInfo.DiContainer.Resolve<ISimpleAutoImplementedInterface1>();
           Assert.AreEqual(10, simpleAutoImplementedInterface1.GetValue());
           
           var simpleAutoImplementedInterface2 = _containerInfo.DiContainer.Resolve<ISimpleAutoImplementedInterface2>();
           Assert.AreEqual(20, simpleAutoImplementedInterface2.GetSomeOtherValue());
       }
       
       [TearDown]
       public static void TestTeaDown()
       {
           _containerInfo.Dispose();
       }
   }