Tag Archives: C#

How to integrate Ocelot with Identity Server 4

Published by:

Not so long ago I wrote an article on how we can create our own API gateways using the Ocelot open source library. Since then, I received some questions on how to integrate Ocelot with Identity Server 4 so I thought to share how I managed to achieve this using the Ocelot documentation and some basic Identity Server 4 knowledge. Please note that following these steps I was able to successfully build an API gateway using Ocelot, that used Identity Server 4 JWT tokens to authorize requests and redirect them to the desired downstream path. Continue reading

New Asp.Net Core 2.1 features announced at #MsBuild

Published by:

Last week #MsBuild was underway in Seattle. I have already made some notes on the keynote last Monday and the following days I tried to keep track with different novelties announced for ASP.Net Core 2.1. And I think for some members of the community it might be useful to have them written down, so in this article I’ll try to summarize all the information. Please note, that I was not present at the #MsBuild conference. I just tried to follow the sessions streamed on Channel 9 and some key Twitter accounts.

HttpClientFactory

One of the novelties I am most exciting about is the new HttpClientFactory feature. If you worked with the HttpClient in production software, there is a good chance that you noticed a lot of challenges and head aches. In a services oriented architecture where we might need to have several different connections, the only way to go is to use several HttpClient instances (sure not for every call a new client ūüôā but still a bunch of them).¬† One of the problems is that each HttpClient would maintain its own connection pool to the remote server, so it’s highly inefficient. The second, and most stringent problem, is that in scenarios where an application needs to make a lot of calls to remote servers, you could exhaust all the available sockets from time to time. And this is really not cool at all.¬† Continue reading

The curious case of strings in C#

Published by:

In the last article I tried to describe the difference between value types and reference types in C# and I received some interesting feedback from colleagues and former colleagues as well. And based on discussions I had, it makes a lot of sense to talk a little bit about strings. Strings are very strange, because they are a reference type but behave somehow similar to value types. So, there are some common misconceptions and misunderstanding when it comes to strings that I will try to clarify in this article.

Note: I have also created a video on this topic. If you find it easier to follow the video, then here it is:

Continue reading

Reference types and value types in .NET

Published by:

In .NET (and therefore C#) there are two main sorts of type: reference types and value types! Understanding these sorts of type is crucial in the .Net ecosystem and, more generally, in object oriented programming. There are some clear definitions of these concepts that anybody could learn fairly easy, but really understanding how reference types and value types work is sometimes a little bit harder. And I must confess that it took me some time to achieve a certain level of familiarity. Furthermore, if you really want to understand how reference types and value types work, you need to get your hands dirty an play around with them. In this article I will try to explain reference types and value types as good as I can, starting from some dry (but important) definitions that I will try to make more vivid using code samples.

Note: I also made a YouTube video on this topic with some more graphical representations of these concepts. You might want to check it out:

Continue reading

Sorting lists in C#

Published by:

Working with lists is something developers do almost everyday. One of the most common tasks when we think about lists is sorting them. Fortunately, sorting lists in C# is not very complicated when it comes to primitive types and strings, but are slightly more complicated when we create lists of our own objects. In this tutorial we’ll go through some of the common ways to sort lists in C#.

Update:¬†I have also created a video on this topic so if you think that it’s easier to follow the video, here it is:

Let’s start with a short and simple example. Let’s assume that we create a list of names and we add some names to the list:


List<string> names = new List<string>();
names.Add("John");
names.Add("Dan");
names.Add("Zack");
names.Add("Cristina");

Continue reading

Middleware in ASP.Net Core – part II

Published by:

Few days ago I wrote a short tutorial about middleware in ASP.Net Core and I promised to continue the topic, since there are some concepts that I didn’t cover. In the mentioned first tutorial I tried to describe what a middleware pipeline is, why middleware order is important and the importance of the¬†next()¬†delegate. In the second part I will focus more on the¬†Use(),¬†Run() and¬†Map() methods that we can use when setting up the middleware pipeline of an ASP.Net Core application.

Technically speaking¬†Use(),¬†Run() and¬†Map()¬†are extension methods on¬†Microsoft.AspNetCore.Builder.IApplicationBuilder instances. If you look them up, you’ll see something like this: Continue reading

Middleware in ASP.Net Core – part I

Published by:

Middleware is a very important topic in ASP.Net Core since it enables you to add very important functionality, like adding necessary configuration to deploy ASP.Net Core and Angular together. But at the same time there are a lot of misunderstandings regarding middleware in ASP.Net Core among developers that are new to the platform. That’s why I think it’s a good start to highlight the most important concepts regarding middleware so that new developers can get started much quicker with ASP.Net Core.

The concept of middleware

I won’t try to give a real and exhaustive definition of middleware (you can find this on the Microsoft documentation). Instead, I will try to depict a picture of how middleware in ASP.Net cor relate to the application you’re developing. So let’s imagine that you already have an ASP.Net Core application that is hosted somewhere and I want to make a request to that application. So when I send my GET request, it will first hit Kestrel, the web server built into ASP.Net Core. For the request, that’s the entry point to the application. Continue reading

Do you want to become a software developer? Here’s how!

Published by:

So, do you want to become a software developer and you didn’t graduate computer science? Do you feel that “your time has passed” and you still think that there’s a lot more to achieve? Well, this post is for you, so you might want to keep on reading! If you ask yourself if this is even possible, well…. yes it is! I’ve studied philosophy and theology and still I’m working for almost ten years in the IT industry, I’m playing around with code for around 2 years and now I’m a software developer. Is it easy? Not at all! Or it depends on what “easy” means for you. But it’s achievable and here are a few guidelines on how you can become a software developer.¬† Continue reading

Create your own reusable C# libraries targeting .Net Standard

Published by:

A while back I tried to “demistify” the main concepts around .Net Core, .Net Standard and .Net Framework, since there were (and still are) a lot of questions and concerns regarding these topics on social media. This time, I’ve decided to go one step further and show you all these concepts at work . This article is intended for beginner .Net developers or self-taught developers like me, which struggle to find a clear path in a jungle full of information that is not always accurate.¬† Continue reading

Building SPAs with C#

Published by:

Looking at this title, many developers would say “Are you mad? You can’t build single page applications with C#! You need a front end framework, like Angular, React or Vue”. Right now I can’t say that I can prove them wrong, but I can definitely at least say that building SPAs with C# is in fact possible. For now it’s only experimental, but the ASP.NET team announced an experimental project called Blazor.¬†Blazor is an experimental web UI framework based on C#, Razor, and HTML that runs completely in the browser via WebAssembly. This really opens new perspectives on the fact that you may build modern SPAs using C# and the entire .NET stack.¬† Continue reading