Best Practices for Building Async APIs with ASP.NET Core

Did you know the main driver for async isn't performance but scalability? Ever wondered why it makes sense to async I/O-bound tasks, but why doing the same with a long-running algorithm can actually hurt scalability? Or why using .Result on a Task in ASP.NET can result in a deadlock but perfectly works in ASP.NET Core - yet you still shouldn't use it? For answers to all of that and more, watch this recorded webinar session on async best practices for ASP.NET Core.

0:06 Intro
2:36 Why write asynchronous code?
15:12 The async/await keywords
20:20 Async return types
26:00 Demo time
42:30 I/O bound vs. computational bound work
57:40 What about legacy code?
1:01:16 What about the synchronization context?
1:22:20 Wrap up and Q&A

About the Presenter:
Kevin Dockx is a freelance solution architect, Pluralsight author & consultant, living in Antwerp (Belgium). These days he's mainly focused on RESTful architectures & security for web applications and mobile applications. He's a Microsoft MVP, and a keen proponent of open-source software.

[benleonard]

Totally agree. I liked the structure and the flow. Everything was explained to make it easy to understand.

[CodeSbyAniz]

GREAT TUTORIAL AS ALWAYS! This channel is providing so much value. Keep up the good work!

[sridharpatnayak]

Kevin, Good Stuff and great video, I am a big fan for your videos. I watched your Pluralsight videos. Great.,

[PlerbyMcFlerb]

at 35:30 you mention "leakage" by not using async/await on the repository. Could you expand on this? I'm struggling to see how this is "leaking implementation details". Seems like a "task" is a prefectly good abstraction regardless of if it originated from an async method or not.

[mr.anderson]

I found this *really* helpful and it answered many question I had beforehand. Thank you very much for sharing.

[RajaKajiev]

If you are not a newbie it is now worth spending 1+ hour on this talk IMHO.

[kuroki_suzume]

Very detailed lesson. Thanks !
P.S. only one remark - it would be nice if you could increase zoom. It was little bit hard to read code :)

[argelpamintuango]

thanks for introducing us the good usage of async and synchronous types. but I'm still curious of how do you implement it when the data you will pull is large that will make the api too long to get it

[mrnkhlblv]

But what if controller is marked as async but nothing inside awaiting

[howtospeakamharic]

Please increase the font size and use dark theme when presenting

[haythamhegab]

Please I would like to download source code for api

[honestcommenter]

At 33:45 you checked if id is Guid.Empty to throw null exception, but that is wrong. If id is null you throw that exception. In fact, Guid.Empty should be valid value, and you shouldn't throw for it even the normal argument exception.

[haljohnson]

i could make this a very short video... 90 minutes later still watching

[olegshevchenko]

You are saying that if we just return the task, we will expose repository implementation (get leaky abstraction).
But from the caller perspective, the is no difference, it even doesn't know if the method is async/await or not, because the caller will operate the interface only.


Could you please explain your point in more detail?

[thiruvetti]

Hmm, a little complex explanation. Could have been more simpler. Lot of lose ends like "dont use async in server" but you showed only one case of 2 Threads being used. I still couldnt understand whats wrong.. Hmm!

[TanvirAnowar]

Thank you very much for clarifying the async stuffs and when to use it!

[kuttikrishnankodoth]

Kevins materials will always have a guarantee.. Thank you Kevin..!!!

[benjaminsehic]

Thank you very much for these tips, they were quite helpful and explained my dilemmas around when to use async and where exactly to and no to use it

[BurundukXP]

looks like the author is mixing up "asynchronous execution" and "parallel execution" terms. also mentioning "leakage of your repository" is a bit misleading. I think it comes from the lack of .net async state machine explanation in this presentation (it was just only mentioned without many details...).

[locduonghuu]

Can you share your slide show ? Thanks in advance.