Thank you sponsors

Hi, I am Vedran. 👋

• I freelance, talk and lecture C# / .NET and JavaScript
• currently in insurance industry
• on medium and dev.to by @vekzdran
• on github by @vmandic
• bad at basics, suck at CSS, moderate in C#... jk 🙈

What's this presentation about?

Today's plan?

1. (ASP).NET Core super quick overview
2. No Visual Studio IDE?
3. API Design, REST, DDD, Swagger?
4. demo up a web API with code 👩‍💻
5. host the demo to a CI/CD provider

First a  bit of .NET Core

.NET Core, an overview

• open-source (GitHub) cross-platform Runtime and SDK 
• Current release is 3.1 (Dec 3 2019), started in 2015
• modern, stable, performing, modular, extensible
• you can fix bugs, suggest PRs, report issues, ... FIND ANSWERS :-)
• it is a complete rewrite of .NET Framework; its Core libraries
• introduced .NET Standard, run side by side with Full framework
• integrated DI/IoC, Builder pattern, logging, configuration
• extends with ASP.NET Core, ASP.NET Identity, MVC, Razor Pages, Blazor, EFCore... just search NuGet.org and you got it...
• you can compile for a dedicated OS, e.g. linux-x64
• you can compile the whole framework /w app as single .exe

ASP.NET Core?

ASP.NET Core

• a set of APIs, libraries for building a web apps and services
• APIs come either separately or in AspNetCore Metapackage
• comes with its own new server Kestrel, also HTTP.sys
• can host in IIS, outside it, behind a reverse proxy e.g. Nginx
• expands design on the OWIN architecture
• Startup.cs, ConfigureService(), Configure()
• Go full MVC with filters etc, or go Web API with ControllerBase
• Razor view, Razor pages, Blazor server side-by-side with Razor
• compile the app as self-executable and host on any linux server

by the way... we will be building a web API today

what's to like?

lol, what's not to like?! :-)

what's to like?

• dotnet CLI... and dotnet tools!
• fast builds, logs everything!
• stability, performance and openness for extensiblity
• fantastic docs and GitHub support
• learn from MSDN docs 80%, 10% from blogs, and 10% from XP
• my XP: 1 month for basics, 6 months to feel safe
• great community, lots of books, blogs
• widespread (open-source) NuGet packages, supported
• cross-plat and docker friendly, CI/CD happy
• I learned to appreciate and harness the CLI and linux

Visual Studio IDE?

• there is... Visual Studio 2017, 2019 and they are better then ever
• Instead try the open source community VSCode
• embrace the dotnet CLI, reference projects faster ;-)
• VSCode is an editor with a ton of extensions and C# support
• currently I use Visual Studio IDE only for multi test debugging
• https://visualstudio.microsoft.com/services/visual-studio-online/

Visual Studio Code

Considerations to take when building an API

Some things to consider in API design

• exhaustive logging
• healthcheck API
• REST(ful) (as much as possible...🙈) HATEOAS
• API Documentation (Swagger OpenAPI)
• CORS policy
• full control over in and out HTTP headers
• versioned, rate limited, cached... 
• Authentication with JWT and claims
• Multi-authentication
• Fail unobtrusively and redact error details
• logic independent to scaling (ACS, k8s, OpenShift pods++)
   
• Clean Code, Domain Driven Design layered...
• Open-Closed, SRP, pure as much as possible...
• Testable, Integration testable, CI/CD-able

That's what you should love about .NET Core, all of it's plug and play

Also Luka Gospodnetić had a wonderful great talk about it yesterday:
 

"Through desert and wilderness to .NET Core Enterprise app"

Swagger (OpenAPI)

• solves the problem of API documentation
• it is a .json which describes your API: methods & models
• Swashbuckle.AspNetCore & NSwag solve generating the .json
• Swashbuckle generates a freindly web Swagger-UI to for testing
• https://docs.microsoft.com/en-us/aspnet/core/tutorials/web-api-help-pages-using-swagger
   
• Example: https://petstore.swagger.io/

demo time!

more sort of a code-review than coding :-)

The end! 📸 Questions?

VEDRAN MANDIĆ

mandic.vedran@gmail.com

@vekzdran @vmandic
https://gitlab.com/vmandic/from-dotnet-new-webapi
https://slides.com/vmandic/from-dotnet-new-webapi