feat(ConfigurationExtension): Hinzufügen der Klasse ConfigurationExtension mit der Methode GetOrDefault zum sichereren Abrufen von Konfigurationen

- Einführung einer neuen statischen Klasse ConfigurationExtension im Namespace DigitalData.Core.Abstractions.
- Hinzufügen der GetOrDefault-Erweiterungsmethode zu IConfiguration, die eine einfachere Abfrage von Konfigurationswerten mit Standardverhalten ermöglicht, wenn diese nicht gefunden werden.
- Aktualisierung der Versionsnummern auf 3.5.0 in den Projektdateien.

DigitalData.Core.Abstractions/ConfigurationExtension.cs

@@ -0,0 +1,30 @@
+using Microsoft.Extensions.Configuration;
+
+namespace DigitalData.Core.Abstractions
+{
+    /// <summary>
+    /// Extension methods for the <see cref="IConfiguration"/> interface, providing 
+    /// additional functionality for retrieving configuration values with default behavior.
+    /// </summary>
+    public static class ConfigurationExtension
+    {
+        /// <summary>
+        /// Retrieves a configuration value for the specified key, or returns a default value 
+        /// of type <typeparamref name="T"/> if the configuration is not found or the key is null.
+        /// </summary>
+        /// <typeparam name="T">The type of the object to retrieve from the configuration.</typeparam>
+        /// <param name="configuration">The <see cref="IConfiguration"/> instance.</param>
+        /// <param name="key">The optional key to look for in the configuration. If null, the method 
+        /// retrieves the root configuration.</param>
+        /// <returns>
+        /// An instance of <typeparamref name="T"/> populated from the configuration values, or 
+        /// a new instance of <typeparamref name="T"/> if no matching configuration is found.
+        /// </returns>
+        public static T GetOrDefault<T>(this IConfiguration configuration, string? key = null)
+            where T : new()
+            => (key is null
+                ? configuration.Get<T>()
+                : configuration.GetSection(key).Get<T>())
+            ?? new T();
+    }
+}

DigitalData.Core.Abstractions/DeferredServiceProvider.cs

@@ -0,0 +1,40 @@
+namespace DigitalData.Core.Abstractions;
+
+/// <summary>
+/// A deferred implementation of <see cref="IServiceProvider"/> that allows the <see cref="IServiceProvider"/> instance 
+/// to be provided at a later time via a factory callback.
+/// </summary>
+/// <remarks>
+/// This is particularly useful when service registration requires an <see cref="IServiceProvider"/> instance,
+/// but the service provider is not yet available at registration time. 
+/// By using <see cref="DeferredServiceProvider"/>, a service can safely resolve dependencies once
+/// the application's service provider has been built, ensuring a single consistent scope.
+/// </remarks>
+public class DeferredServiceProvider : IServiceProvider
+{
+    private Lazy<IServiceProvider>? _serviceProvider;
+
+    /// <summary>
+    /// Sets the factory that will be used to lazily initialize the <see cref="IServiceProvider"/> instance.
+    /// </summary>
+    public Func<IServiceProvider> Factory
+    {
+        set => _serviceProvider = new(value);
+    }
+
+    /// <summary>
+    /// Retrieves the requested service object from the deferred <see cref="IServiceProvider"/>.
+    /// </summary>
+    /// <param name="serviceType">The type of service object to retrieve.</param>
+    /// <returns>The requested service object, or <c>null</c> if the service is not available.</returns>
+    /// <exception cref="InvalidOperationException">
+    /// Thrown if the service provider factory has not been set before calling <see cref="GetService"/>.
+    /// </exception>
+    public object? GetService(Type serviceType)
+    {
+        if (_serviceProvider is null)
+            throw new InvalidOperationException("The service provider has not been initialized. Make sure 'Factory' is set before calling 'GetService'.");
+
+        return _serviceProvider.Value.GetService(serviceType);
+    }
+}

DigitalData.Core.Abstractions/DigitalData.Core.Abstractions.csproj

@@ -17,9 +17,9 @@
 		<RepositoryUrl>http://git.dd:3000/AppStd/WebCoreModules.git</RepositoryUrl>
 		<PackAsTool>False</PackAsTool>
 		<PackageIcon>core_icon.png</PackageIcon>
-		<Version>3.4.3</Version>
-		<AssemblyVersion>3.4.3</AssemblyVersion>
-		<FileVersion>3.4.3</FileVersion>
+		<Version>3.5.0</Version>
+		<AssemblyVersion>3.5.0</AssemblyVersion>
+		<FileVersion>3.5.0</FileVersion>
 	</PropertyGroup>
 
 	<ItemGroup>