Running .NET code in an isolated sandbox

Steve Sanderson is experimenting again, and when Steve plays with his toys, I pay attention. In a new video on his YouTube channel, Steve introduces an experimental new .NET package that allows the creation of isolated instances of the .NET runtime that will safely run code in a sandbox. Watch it, and get your mind blown away by the possibilities this could open up. Subscribe to the newsletter, the RSS feed, or follow me on Mastodon »

Making the latest C# language features available in older .NET versions

In a C# library I’ve been working on, I wanted to use C# 9.0’s init keyword. Quoting the documentation: The init keyword defines an accessor method in a property or indexer. An init-only setter assigns a value to the property or the indexer element only during object construction. This enforces immutability so that once the object is initialized, it can’t be changed again. Consider the following class: public class Person { public string FirstName { get; init; } } You can initialize it like this: »

A quick preview of the Blazor United prototype for .NET8

Steve Sanderson, the original creator of Blazor, recently posted a quick peek at some of the new Blazor prototypes they are experimenting with for .NET 8. I think this looks great. Mixing client and server is a brilliant concept. Essentially one would be served with server-side Blazor on the first landing. While using the app, a background task would download the client-side stuff, ready to be consumed at any subsequent access. »

On implementing the ASP.NET Core 7 rate-limiting middleware

Today, my last self-assigned duty before the Christmas break was to migrate our in-house rate-limiting implementation (based on the AspNetCoreRateLimiting third-party package) to the new, shiny rate-limiting middleware introduced by ASP.NET Core 7. While the process was relatively straightforward, I stumbled upon a few quirks I want to annotate here. Our use case is simple. We use what the ASP.NET Core 7 documentation defines as a “fixed window limiter.” It uses a specified time window to limit requests. »

First impressions on JetBrains Rider 2022.3 update

Today I upgraded to JetBrains’ Rider 2022.3. Startup speed has been enhanced, and full .NET 7 and C# 11 support is included. So far, my favorite feature is the conversion of regular and verbatim strings into their raw counterparts (it’s often the small, simple things.) My second best is the fulls upport for WSL2 remote development. This one took a good while to come out of the trenches, but better late than never, I’d say. »

My Top 7 New Features in .NET 7

The other day we did a .NET 7 Spotlight event at this month’s DevRomagna meetup. The speakers were Ugo Lattanzi and me. In my session, I chose to talk about my top 7 new features in .NET 7 (pun intended.) What follows is a mix of my preparation notes and what I ended up really saying1. 1. Performance Since the initial release of “new dotnet” (.NET Core), performance has always been a critical goal for the . »

FatturaElettronica v3.4 released

Today I released v3.4 of FatturaElettronica, a .NET open source project that allows validation and de/serialization of electronic invoices adhering to the standard defined by the Italian “Agenzia delle Entrate”. It’s doing very well for such a niche project, with downloads now well beyond the one hundred thousand mark. Be aware that this release anticipates support for v1.7.1 of the specification going into effect on October 1, 2022. For more information, see the appropriate ticket and the changelog. »

I'm a Microsoft MVP once again

I am happy and humbled to have been awarded the Microsoft MVP Award for the seventh consecutive year. July 1, the award assignation day, always comes with curiosity and a bit of trepidation. Being a member of the MVP community has been a very positive experience for me, especially in the years before COVID, when the MVP Summit, the main MVP event, was held in person in Seattle at the Microsoft HQ. »

My Playwright session at WebDay 2022

If you understand Italian, the recording of my Playwright session at UGIdotNET’s WebDay 2022 is now available on YouTube1. Playwright is a phenomenal cross-browser, cross-platform, cross-language, single-API, mobile-friendly front-end testing tool. I’m looking forward to giving the same session in English sooner or later, but I should first win my laziness and start looking for exciting events with open CFPs. If you happen to know one, please let me know. »

Parameter null-checking added to C# 11 Preview

The first preview of C# 11 is out, and well, I think I like what I see. I dig the new List patterns and am a fan of allowing newlines in the “holes” of interpolated strings. Parameter null-checking is a bit contentious, and it’s good that they are releasing it in preview one and asking for feedback. In a nutshell, they want to spare us a lot of boilerplate. Code like this: »

My ASP.NET 5 migration to .NET 6

I spent the last few days migrating our ASP.NET REST services, MVC web applications and Blazor server apps to .NET 6. Overall the process was pretty straightforward. The few issues I went through were easy to solve and well documented. Things got more involved with the EF Core 6 transition, especially with the Npgsql Entity Framework Core Provider. The official ASP.NET Core 5.0 to 6.0 migration guide was my first stop. »

Drama going on at the .NET Foundation

A few months after I released my first .NET open source project (a niche one targeting the Italian fintech world), I was contacted by a representative of Team Digitale, the digital innovation branch of the Italian Public Administration. He suggested joining the Developers Italia initiative and moving my project to the their organization on GitHub “to enjoy enhanced visibility and broaden the audience”. I politely refused. I did not doubt my counterpart’s good faith. »

ASP.NET 6 Migration Cheatsheet and FAQ

David Fowler has a very informative gist up on GitHub. It’s titled Migration to ASP.NET Core. NET6 and it’s filled with details, recipes and FAQs on migrating an ASP.NET Core 5 web app to ASP.NET Core 61. The focus is on the new, streamlined hosting model, also known as Minimal APIs2. To be clear, You don’t have to move to the new model. As the FAQ section emphasizes: Do I have to migrate to the new hosting model »

Performance improvements in .NET6

I’m pretty psyched about the upcoming .NET6 release. I’ve already touched on ASP.NET 6 Minimal APIs. Continuing on the long-established tradition, the team has also worked hard on the performance side of things. File IO, for example, is seeing impressive gains: For .NET 6, we have made FileStream much faster and more reliable, thanks to an almost entire re-write. For same cases, the async implementation is now a few times faster! »

How to read Windows-1252 encoded files with .NETCore and .NET5+

Another day, another lesson learned: modern .NET does not support the Windows-1252 encoding out of the box. Today my colleague was happily porting a legacy NET4+ app to NET6. As usual, the port was super-easy; it would compile and run just fine, so he was surprised when the app crashed reading a few specific XML files. That’s when I was called in. A closer inspection revealed a pattern: all those crashing files were Windows 1252-encoded (the rest, a vast majority, were UTF-8. »

Will .NET 6 Minimal APIs turn heads?

I am pretty excited about the Minimal APIs feature that is coming with .NET 6. Three lines of code will be enough to build a fully functional REST microservice1: var app = WebApplication.Create(args); app.MapGet("/", () => "Hello World!"); await app.RunAsync(); If you’re a seasoned ASP.NET MVC/WebApi developer, the snippet caught your attention because, pre-.NET 6, achieving the same result will have you messing with a lot of extra cruft2. I suspect, however, that this feature is not primarily targeted at existing . »

My DotNetPodcast interview

Today I was interviewed by Mauro Servienti on the DotNetPodcast. The theme was my experience as an open-source maintainer on both the Python and C# stacks. We also discussed the ongoing evolution of the dotNET ecosystem, touching on a few tangent topics. The recording is in Italian and is available below here. Listen to “Python, Eve, open source e fattura elettronica. Con Nicola Iarocci” on Spreaker. Subscribe to the newsletter, the RSS feed, or follow @nicolaiarocci on Twitter »

Custom default values for not existing dictionary items (and a lesson learned)

When dealing with dictionaries, a typical problem is when an operation attempts to retrieve an element using a key that does not exist in the dictionary. In .NET, a KeyNotFoundException is raised, and that’s the desired behaviour in most circumstances. Sometimes, however, you know that your program will frequently try to retrieve keys that do not exist. In such cases, it is more efficient to use the TryGetValue method: This method returns the value associated with the specified key, if the key is found; otherwise, the default value for the type of the value parameter is returned (source) »

dotnet SmtpClient should not be used

I am very late to the party, but today I learned that the good old dotnet SmptClient is considered obsolete and should not be used. Quoting the documentation: We don’t recommend using the SmtpClient class for new development because SmtpClient doesn’t support many modern protocols. Use MailKit or other libraries instead. (source) Interestingly, Microsoft is recommending a third-party open-source library as an alternative. I hope we’ll see more of that in the future. »