Add Get endpoint for Activity descriptors

src/modules/Elsa.Workflows.Api/Endpoints/ActivityDescriptors/Get/Endpoint.cs

@@ -0,0 +1,34 @@
+using Elsa.Abstractions;
+using Elsa.Workflows.Core.Models;
+using Elsa.Workflows.Management.Services;
+
+namespace Elsa.Workflows.Api.Endpoints.ActivityDescriptors.Get;
+
+public class Get : ElsaEndpoint<Request, ActivityDescriptor>
+{
+    private readonly IActivityRegistry _registry;
+
+    /// <inheritdoc />
+    public Get(IActivityRegistry registry)
+    {
+        _registry = registry;
+    }
+
+    /// <inheritdoc />
+    public override void Configure()
+    {
+        Get("/descriptors/activities/{typeName}");
+        ConfigurePermissions("read:*", "read:activity-descriptors");
+    }
+
+    /// <inheritdoc />
+    public override async Task HandleAsync(Request request, CancellationToken cancellationToken)
+    {
+        var descriptor = _registry.Find(request.TypeName);
+
+        if (descriptor == null)
+            await SendNotFoundAsync(cancellationToken);
+        else
+            await SendOkAsync(descriptor, cancellationToken);
+    }
+}

src/modules/Elsa.Workflows.Api/Endpoints/ActivityDescriptors/Get/Models.cs

@@ -0,0 +1,6 @@
+namespace Elsa.Workflows.Api.Endpoints.ActivityDescriptors.Get;
+
+public class Request
+{
+    public string TypeName { get; set; }
+}