Using foreach with index in C#

Just a quick tip today! for and foreach loops are among the most useful constructs in a C# developer’s toolbox. To iterate a collection, foreach is, in my opinion, more convenient than for in most cases. It works with all collection types, including those that are not indexable such as IEnumerable<T>, and doesn’t require to access the current element by its index. But sometimes, you do need the index of the current item; this usually leads to one of these patterns:

Handling type hierarchies in Cosmos DB (part 2)

This is the second post in a series of 2: Handling type hierarchies in Cosmos DB (part 1) Handling type hierarchies in Cosmos DB (part 2) (this post) In the previous post, I talked about the difficulty of handling type hierarchies in Cosmos DB, showed that the problem was actually with the JSON serializer, and proposed a solution using JSON.NET’s TypeNameHandling feature. In this post, I’ll show another approach based on custom converters, and how to integrate the solution with the Cosmos DB .

Handling type hierarchies in Cosmos DB (part 1)

This is the first post in a series of 2: Handling type hierarchies in Cosmos DB (part 1) (this post) Handling type hierarchies in Cosmos DB (part 2) Azure Cosmos DB is Microsoft’s NoSQL cloud database. In Cosmos DB, you store JSON documents in containers. This makes it very easy to model data, because you don’t need to split complex objects into multiple tables and use joins like in relational databases.

Using TypeScript to write Cosmos DB stored procedures with async/await

Disclaimer: I am by no mean a TypeScript expert. In fact, I know very little about JS, npm, gulp, etc. So it’s entirely possible I said something really stupid in this article, or maybe I missed a much simpler way of doing things. Don’t hesitate to let me know in the comments! Azure Cosmos DB (formerly known as Azure Document DB) is a NoSQL, multi-model, globally-distributed database hosted in Azure. If you come from relational SQL databases, it’s a very different world.

Scaling out ASP.NET Core SignalR using Azure Service Bus

ASP.NET Core SignalR is a super easy way to establish two-way communication between an ASP.NET Core app and its clients, using WebSockets, Server-Sent Events, or long polling, depending on the client’s capabilities. For instance, it can be used to send a notification to all connected clients. However, if you scale out your application to multiple server instances, it no longer works out of the box: only the clients connected to the instance that sent the notification will receive it.

Google+ shutdown: fixing Google authentication in ASP.NET Core

A few months ago, Google decided to shutdown Google+, due to multiple data leaks. More recently, they announced that the Google+ APIs will be shutdown on March 7, 2019, which is pretty soon! In fact, calls to these APIs might start to fail as soon as January 28, which is less than 3 weeks from now. You might think that it doesn’t affect you as a developer; but if you’re using Google authentication in an ASP.

Multitenant Azure AD issuer validation in ASP.NET Core

If you use Azure AD authentication and want to allow users from any tenant to connect to your ASP.NET Core application, you need to configure the Azure AD app as multi-tenant, and use a “wildcard” tenant id such as organizations or common in the authority URL: openIdConnectOptions.Authority = "https://login.microsoftonline.com/organizations/v2.0"; The problem when you do that is that with the default configuration, the token validation will fail because the issuer in the token won’t match the issuer specified in the OpenID metadata.

Making a WPF app using a SDK-style project with MSBuildSdkExtras

Ever since the first stable release of the .NET Core SDK, we’ve enjoyed a better C# project format, often called “SDK-style” because you specify a SDK to use in the project file. It’s still a .csproj XML file, it’s still based on MSBuild, but it’s much more lightweight and much easier to edit by hand. Personally, I love it and use it everywhere I can. However, out of the box, it’s only usable for some project types: ASP.

Asynchronous initialization in ASP.NET Core, revisited

Initialization in ASP.NET Core is a bit awkward. There are well defined places for registering services (the Startup.ConfigureServices method) and for building the middleware pipeline (the Startup.Configure method), but not for performing other initialization steps (e.g. pre-loading data, seeding a database, etc.). Using a middleware: not such a good idea Two months ago I published a blog post about asynchronous initialization of an ASP.NET Core app using a custom middleware. At the time I was rather pleased with my solution, but a comment from Frantisek made me realize it wasn’t such a good approach.

Handling multipart requests with JSON and file uploads in ASP.NET Core

Suppose we’re writing an API for a blog. Our “create post” endpoint should receive the title, body, tags and an image to display at the top of the post. This raises a question: how do we send the image? There are at least 3 options: Embed the image bytes as base64 in the JSON payload, e.g. { "title": "My first blog post", "body": "This is going to be the best blog EVER!