What I've Learned Over The Past Year (And A Pandemic!) - Part 1 - Services

A while back, I wrote a blog post about my new job. In my new role, there was a lot of new technology and a whole new backend framework that I would need to learn (.NET Core). In that post I detailed what all I didn’t know. I intended to write a quick follow up after a short time but we all know what life has been like lately. Now, a year and a half (and a whole pandemic!) later, I’ve learned a lot and I finally feel productive and self-sufficient in this new stack!

I wanted to go back and answer some of my own questions, in the hopes that others could compare the two posts and see how much growth is possible, even when you start with so many unanswered questions!

Hopefully this post won’t be too much of a laundry list. I’ve chosen to take some of the initial questions instead of all of them so as to cut down on the word count. 😄

C#  

What is C#?

• C# is an object oriented, strongly typed programming language created by Microsoft. The current stable C# version is 9.0. Being an object oriented language, there are a lot of commonalities with a language like Java, such as abstraction and inheritance.

What types does the language have?

• When I asked this question, I was coming from JavaScript which has the primitive types and Objects, and covers everything that you need. In C#, there are primitives of course, but also named derived types. We know types such as Arrays and Classes, but there’s also user-defined types that are domain-specific. I realized that JavaScript covers these types with anonymous {} objects, whereas in C# it’s good practice to use named types to give you type safety.

Is there a similar concept to a prototype function in C#?

• In JavaScript, methods on the primitive types are called prototype functions, like Array.Map() for instance. In C# the classes that you’re operating on will have public functions to provide functionality. Of course, the primitive types provided in C# have functions already written, like List<T>.Add(T) method to add objects of type T to a list.

Is there an equivalent of Async/Await? Or is that not necessary?

• Yep, C# has the concept of Task<T> which is similar to a JavaScript Promise, as well as Async/Await in functions. “Helper” functions like Promise.All() also have counterparts in C#, such as Task.WhenAll(IEnumerable<Task>). So a lot of this knowledge transfers over very well!

What sort of syntactic sugar do we get?

• I don’t think it’s quite what I expected, but when you add in .NET Core and other libraries there is quite a lot of annotations that add in functionality, like HTTP endpoints and data validation.

What is LINQ?

• LINQ is a way to apply SQL-like queries against lists and other IEnumerables in C#. This lets you write powerful statements against collections in-memory and helps bridge the gap between writing SQL stored procedures and writing queries in-memory.

Are there versions of the language, like the JavaScript ECMAScript progression?

• Yep, there is a language release cadence that aligns with .NET releases.

Package managers? What’s Nuget? How does this relate to the NPM model?

• The NuGet package manager is what pulls libraries into your projects. NuGet.org is a repository for public and private compiled C# code that you can use in your projects, all very similar to the NPM model in JavaScript!

_How is C# compiled? I see c#_.dll and other files too that get built. How are these related?*

• By default, C# projects are compiled into .dll files when running dotnet build on a project. The C# runtime reads the .dll files to run the program. The compiler will provide type errors and other build-time warnings before attempting to run the code itself.

.NET

What is .NET? Is this the same thing as ASP.NET?

• .NET is a free and open-source framework for developing applications that are able to run on multiple different hosts. ASP.NET is a (now dated) framework that is also used to write applications for the web. Both are created by Microsoft

.NET vs .NET core? What’s new? What’s the difference between all these .NET and other 3-letter abbreviations?

• As far as I know, .NET Core was a recent fork of functionality from .NET Framework, specifically aimed at building web applications that can run on multiple host environments. Both of these frameworks compile down to .dll files that are run by the CLR (Common Language Runtime), which allows the code to be run across multiple platforms. Think Java and the JRE.
• A lot of developers use the modern .NET Core framework to write backends. These can be consumed by whatever frontend you want.

Do I have to use Visual Studio on Windows? Are there alternative tools? Anything on Mac? (I’m gonna miss my iMessage on Mac 😄)

• The JetBrains team has a full-featured cross-platform IDE named Rider, which is pretty great. Visual Studio for Mac exists, but is thin in features and not heavily supported. You can always write in plaintext or an editor like VS Code, since you can run the .NET compiler via CLI.

_What’s a c#_.csprojfile?c#_.slnfile? How does everything “get connected” with one another? (My new codebase has a lot ofc#_.csproj files that seem to be connected.)*

• The .csproj file is the declaration file for dependencies, build configurations, and versioning for a specific project. The .sln file helps pull map projects together, so that you can run dotnet build x.sln and the whole program will build, instead of only some code.

What is the MVC pattern, and how does it apply when we use Vue as a frontend framework?

• In .NET land, you can write frontends via Razor pages that are a part of your backend solutions. If you want, you can also embed your frontend code as a Web project in your solution, which can be built and served up by a thread from the same server as your backend.
• While frontend and backend can be served by the same server, it often makes more sense to compile frontends and serve them up from a CDN or static storage, instead of relying on your backend to handle the full workload. This also makes it cleaner to split into microservices/containers and scale with Kubernetes.

What prevents us from breaking up our monorepo into separate apps for backend and frontend (and then easily containerize)?

• Nothing. In the legacy codebase I was initially onboarded onto, the web frontend was served from the same C# process. Others may only use .NET Core as a performant backend, and serve the frontend as they wish.

Vue

• Unfortunately, I haven’t used Vue much! I know a great use case for Vue is “sprinkling in” some MVC logic when you don’t need a full fledged app. The frontend I (occasionally) work on is a modern Angular application.

Summary

Hopefully this gives you an idea of how much you can really learn and flex your skills when onboarding onto a new tech stack. This covers just about every question I had about the “service” tech. While I initially was hesitant about .NET Core world… I think the pros might outweigh the cons with .NET Core. The jury is still out, though. 😁

My next post will cover the infrastructure and code management side of things, which Firebend delegates to Azure. Stay tuned!