Add simulated latency middleware

A new middleware, SimulatedLatencyMiddleware, has been added to simulate latency in a designated range. This can be used for testing purposes by delaying a request for a random amount of time. Additionally, an extension method for IApplicationBuilder has been implemented to conveniently add this functionality to the application's pipeline.

src/bundles/Elsa.Server.Web/Middleware/SimulatedLatencyMiddleware.cs

@@ -0,0 +1,56 @@
+using JetBrains.Annotations;
+
+namespace Elsa.Server.Web.Middleware;
+
+/// <summary>
+/// Simulates latency by delaying the request for a random amount of time between the specified minimum and maximum durations.
+/// </summary>
+/// <param name="next"></param>
+/// <param name="min"></param>
+/// <param name="max"></param>
+[UsedImplicitly]
+public class SimulatedLatencyMiddleware(
+ RequestDelegate next,
+ TimeSpan min,
+ TimeSpan max)
+{
+ private readonly int _minDelayInMs = (int)min.TotalMilliseconds;
+ private readonly int _maxDelayInMs = (int)max.TotalMilliseconds;
+ private readonly ThreadLocal<Random> _random = new(() => new Random());
+
+ /// <summary>
+ /// Invokes the middleware.
+ /// </summary>
+ /// <param name="context"></param>
+ [UsedImplicitly]
+ public async Task Invoke(HttpContext context)
+ {
+ int delayInMs = _random.Value!.Next(
+ _minDelayInMs,
+ _maxDelayInMs
+ );
+
+ await Task.Delay(delayInMs);
+ await next(context);
+ }
+}
+
+/// <summary>
+/// Provides extension methods for the <see cref="IApplicationBuilder"/> interface.
+/// </summary>
+public static class AppBuilderExtensions
+{
+ /// <summary>
+ /// Adds the <see cref="SimulatedLatencyMiddleware"/> to the application's request pipeline.
+ /// </summary>
+ /// <param name="app"></param>
+ /// <param name="min"></param>
+ /// <param name="max"></param>
+ public static IApplicationBuilder UseSimulatedLatency(
+ this IApplicationBuilder app,
+ TimeSpan min,
+ TimeSpan max)
+ {
+ return app.UseMiddleware<SimulatedLatencyMiddleware>(min, max);
+ }
+}

src/bundles/Elsa.Server.Web/Program.cs

@@ -16,6 +16,7 @@
 using Elsa.MongoDb.Modules.Management;
 using Elsa.MongoDb.Modules.Runtime;
 using Elsa.Server.Web;
+using Elsa.Server.Web.Middleware;
 using Elsa.Workflows.Management.Compression;
 using Microsoft.Data.Sqlite;
 using Microsoft.Extensions.Options;
@@ -249,6 +250,11 @@
 // Build the web application.
 var app = builder.Build();
 
+// app.UseSimulatedLatency(
+// TimeSpan.FromMilliseconds(1000),
+// TimeSpan.FromMilliseconds(3000)
+// );
+
 // Configure the pipeline.
 if (app.Environment.IsDevelopment())
  app.UseDeveloperExceptionPage();