Added option to set a temporary user id in ICurrentUserProvider

Author: Felix-CodingClimber

src/DotNetElements.AppFramework.Abstractions/Auth/ICurrentUserProvider.cs

@@ -3,4 +3,5 @@
 public interface ICurrentUserProvider
 {
     Guid GetCurrentUserId();
+    void SetTemporaryUserId(Guid userId);
 }

src/DotNetElements.AppFramework.AspNet/CurrentUserProvider.cs

@@ -1,11 +1,14 @@
 using System.Security.Claims;
 using DotNetElements.AppFramework.Abstractions.Auth;
+using DotNetElements.Core.Extensions;
 using Microsoft.AspNetCore.Http;
 
 namespace DotNetElements.AppFramework.AspNet;
 
 public class CurrentUserProvider : ICurrentUserProvider
 {
+    private Guid? temporaryUserId;
+
     private readonly IHttpContextAccessor contextAccessor;
 
     public CurrentUserProvider(IHttpContextAccessor contextAccessor)
@@ -15,12 +18,16 @@ public CurrentUserProvider(IHttpContextAccessor contextAccessor)
 
     public Guid GetCurrentUserId()
     {
-        string? userId = contextAccessor.HttpContext?.User.FindFirstValue(ClaimTypes.NameIdentifier);
+        if (temporaryUserId is not null)
+            return temporaryUserId.Value;
+
+        ArgumentNullException.ThrowIfNull(contextAccessor.HttpContext);
 
-        // todo better error handling
-        if (userId is null)
-            throw new ArgumentNullException(nameof(userId));
+        return contextAccessor.HttpContext.User.GetRequiredValue<Guid>(ClaimTypes.NameIdentifier);
+    }
 
-        return new Guid(userId);
+    public void SetTemporaryUserId(Guid userId)
+    {
+        temporaryUserId = userId;
     }
 }

src/DotNetElements.AppFramework.Development/FakeCurrentUserProvider.cs

@@ -4,6 +4,8 @@ namespace DotNetElements.AppFramework.Development;
 
 public sealed class FakeCurrentUserProvider : ICurrentUserProvider
 {
+    private Guid? temporaryUserId;
+
     private readonly Guid fakeUserId;
 
     public FakeCurrentUserProvider(Guid fakeUserId)
@@ -13,6 +15,14 @@ public FakeCurrentUserProvider(Guid fakeUserId)
 
     public Guid GetCurrentUserId()
     {
+        if (temporaryUserId is not null)
+            return temporaryUserId.Value;
+
         return fakeUserId;
     }
+
+    public void SetTemporaryUserId(Guid userId)
+    {
+        temporaryUserId = userId;
+    }
 }

src/DotNetElements.Core/Extensions/PrincipalExtensions.cs

@@ -0,0 +1,49 @@
+using System.Security.Claims;
+
+namespace DotNetElements.Core.Extensions;
+
+/// <summary>
+/// Claims related extensions for <see cref="ClaimsPrincipal"/>.
+/// </summary>
+public static class PrincipalExtensions
+{
+    /// <summary>
+    /// Retrieves a required claim value from the given <see cref="ClaimsPrincipal"/>.
+    /// </summary>
+    /// <param name="principal">The <see cref="ClaimsPrincipal"/> from which to retrieve the claim value.</param>
+    /// <param name="claimType">The type of the claim to retrieve.</param>
+    /// <returns>The value of the specified claim.</returns>
+    /// <exception cref="InvalidOperationException">Thrown if the specified claim type is not present in the <paramref name="principal"/>.</exception>
+    public static string GetRequiredValue(this ClaimsPrincipal principal, string claimType)
+    {
+        Claim? claim = principal.FindFirst(claimType);
+
+        if (claim is null)
+            throw new InvalidOperationException($"Claim '{claimType}' is required but not present in the principal.");
+
+        return claim.Value;
+    }
+
+    /// <summary>
+    /// Retrieves and parses a required claim value from the specified <see cref="ClaimsPrincipal"/>.
+    /// </summary>
+    /// <typeparam name="T">The type to which the claim value should be parsed. Must implement <see cref="IParsable{T}"/>.</typeparam>
+    /// <param name="principal">The <see cref="ClaimsPrincipal"/> from which to retrieve the claim.</param>
+    /// <param name="claimType">The type of the claim to retrieve.</param>
+    /// <returns>The parsed claim value of type <typeparamref name="T"/>.</returns>
+    /// <exception cref="InvalidOperationException">Thrown if the claim of the specified <paramref name="claimType"/> is not present in the <paramref
+    /// name="principal"/> or if the claim value cannot be parsed to type <typeparamref name="T"/>.</exception>
+    public static T GetRequiredValue<T>(this ClaimsPrincipal principal, string claimType)
+        where T : IParsable<T>
+    {
+        Claim? claim = principal.FindFirst(claimType);
+
+        if (claim is null)
+            throw new InvalidOperationException($"Claim '{claimType}' is required but not present in the principal.");
+
+        if (!T.TryParse(claim.Value, null, out T? value))
+            throw new InvalidOperationException($"Claim '{claimType}' has an invalid value: '{claim.Value}'.");
+
+        return value;
+    }
+}