feat: Implementierung von CSPMiddleware zur Hinzufügung von CSP-Headern mit Nonce für verbesserte Sicherheit.

DigitalData.Core.API/DIExtensions.cs

@@ -0,0 +1,23 @@
+using Microsoft.AspNetCore.Builder;
+
+namespace DigitalData.Core.API
+{
+    /// <summary>
+    /// Provides extension methods for adding middleware to the application's request pipeline.
+    /// </summary>
+    public static class DIExtensions
+    {
+        /// <summary>
+        /// Adds the <see cref="CSPMiddleware"/> to the application's request pipeline to include 
+        /// Content Security Policy (CSP) headers in the HTTP response.
+        /// </summary>
+        /// <param name="app">The application builder.</param>
+        /// <param name="policy">
+        /// The CSP policy string with placeholders. The first format parameter {0} will be replaced 
+        /// by the nonce value.
+        /// </param>
+        /// <returns>The application builder with the CSP middleware added.</returns>
+        public static IApplicationBuilder UseCSPMiddleware(this IApplicationBuilder app, string policy)
+            => app.UseMiddleware<CSPMiddleware>(policy);
+    }
+}