EF Core – Apply migrations programmatically

DbContext.Database has a few methods you can call to manage migrations programmatically. To apply any pending migrations: If the database doesn’t exist, MigrateAsync() will create it and then apply the migrations. To check if there are any pending migrations: To check which migrations have been applied: To apply a specific migration: This migrates up or … Read more

Adding your own feature flags in ASP.NET

In ASP.NET, you can add your own feature flags by using the feature management functionality. In this article, I’ll show how to configure and use feature management in ASP.NET and how to use this to feature gate an endpoint using your own feature flag. Configure feature management You need to do a few configuration steps … Read more

C# – Handle a faulted Task’s exception

When a Task throws an exception and stops running, it has faulted. The question is, how do you get the exception that was thrown from the faulted Task? This depends on if you’re awaiting the Task or not. This article shows how to handle a faulted Task’s exception in two scenarios: when you’re awaiting the … Read more

C# – Switch from using HttpWebRequest to HttpClient

There are many reasons to use HttpClient instead of HttpWebRequest. For one, the MSDN docs strongly recommends against using HttpWebRequest, and using HttpClient instead. That should be enough, but if you need a little more convincing, take a look at the Practical reasons to not use HttpWebRequest section below. In addition to explaining why not … Read more

ASP.NET – How to use a BackgroundService for long-running and periodic tasks

In ASP.NET, when you need a long-running background task, or need to run a task periodically, you can implement IHostedService or BackgroundService and register your class as a hosted service in Startup. As you may have already encountered, if you try to run a long-running background task, the web server will randomly kill your task … Read more

ASP.NET – InvalidOperationException: Synchronous operations are disallowed

Problem You’re trying to do synchronous IO operations in ASP.NET and you get the following exception: System.InvalidOperationException: ‘Synchronous operations are disallowed. Call WriteAsync or set AllowSynchronousIO to true The reason you’re getting this is because server option AllowSynchronousIO is false. Starting in ASP.NET Core 3.0, this is false by default. Solution Microsoft turned this setting … Read more

Event-driven .NET: Concurrent Producer/Consumer using a non-blocking, async queue

In a previous article I wrote about how to implement concurrent producer/consumer using a BlockingCollection. This is a thread-safe, event-driven approach that uses high-level concurrent constructs. The only downside is that the consumer uses a blocking call to dequeue messages. In other words, it wastes a thread. Is there a way to implement this using … Read more

ASP.NET – Async SSE endpoint

Server-Sent Events (SSE) allow a client to subscribe to messages on a server. The server pushes new messages to the client as they happen. This is an alternative to the client polling the server for new messages. In this article I’ll show how to implement the messaging system shown in the diagram below. This uses … Read more

Event-driven .NET: How to consume an SSE endpoint with HttpClient

Server-Sent Events (SSE) allow a client to subscribe to messages from the server. It creates a one-way stream from the server to the client. When the server has new messages for the client, it writes them to the stream. This is an alternative to the client polling the server for updates. Use the following to … Read more