refactor(Extensions): move to common

EnvelopeGenerator.Application/Common/Extensions/TaskExtensions.cs

@@ -0,0 +1,78 @@
+using DigitalData.Core.Exceptions;
+
+namespace EnvelopeGenerator.Application.Common.Extensions;
+
+/// <summary>
+/// Extension methods for tasks
+/// </summary>
+public static class TaskExtensions
+{
+    /// <summary>
+    /// Awaits the specified task and ensures that the result is not <c>null</c>.
+    /// If the result is <c>null</c>, the exception created by factory-method is thrown.
+    /// </summary>
+    /// <typeparam name="T">The type of the result.</typeparam>
+    /// <typeparam name="TException">The type of the exception.</typeparam>
+    /// <param name="task">The task to await.</param>
+    /// <param name="factory">Exception provider</param>
+    /// <returns>The awaited result if not <c>null</c>.</returns>
+    /// <exception>Thrown if the result is <c>null</c>.</exception>
+    public static async Task<T> ThrowIfNull<T, TException>(this Task<T?> task, Func<TException> factory) where TException : Exception
+    {
+        var result = await task;
+        return result ?? throw factory();
+    }
+
+    /// <summary>
+    /// Awaits the specified task and ensures that the result is not <c>empty</c>.
+    /// If the result contains no elements, the exception created by factory-method is thrown.
+    /// </summary>
+    /// <typeparam name="T">The element type of the collection.</typeparam>
+    /// <typeparam name="TException">The type of the exception.</typeparam>
+    /// <param name="task">The task to await.</param>
+    /// <param name="factory">Exception provider</param>
+    /// <returns>The awaited collection if it is not <c>null</c> or empty.</returns>
+    /// <exception cref="NotFoundException">Thrown if the result is <c>null</c> or empty.</exception>
+    public static async Task<IEnumerable<T>> ThrowIfEmpty<T, TException>(this Task<IEnumerable<T>> task, Func<TException> factory) where TException : Exception
+    {
+        var result = await task;
+        return result?.Any() ?? false ? result : throw factory();
+    }
+
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <typeparam name="T"></typeparam>
+    /// <typeparam name="I"></typeparam>
+    /// <param name="task"></param>
+    /// <param name="act"></param>
+    /// <returns></returns>
+    public static async Task<I> Then<T, I>(this Task<T> task, Func<T, I> act)
+    {
+        var res = await task;
+        return act(res);
+    }
+}
+
+/// <summary>
+/// 
+/// </summary>
+public static class Exceptions
+{
+    /// <summary>
+    /// 
+    /// </summary>
+    public static NotFoundException NotFound() => new();
+
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <returns></returns>
+    public static BadRequestException BadRequest() => new();
+
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <returns></returns>
+    public static ForbiddenException Forbidden() => new();
+}