Refactoring C# with Chain of Responsibility

What is the Chain of Responsibility Design Pattern, and how can I apply it in C#.
💎 Be a Patreon to get the source code: / gsferreira
🚨 KEY LINKS
🤝 Support me on Patreon (and get access to source code) here: / gsferreira
👋 HEY FRIEND
If you're new to my Channel, my name is Guilherme, but you can call me Gui if Portuguese pronunciation is not your thing.
I see myself as a Minimalist Software Craftsman. That says a lot of what I talk about here.
So, why this KZbin channel? To share with you to simplify your life as a Developer through knowledge, technology, and practices.
If you are into those things as I do, don't forget to subscribe for new videos.
🔗 GET IN TOUCH
LinkedIn: / gferreira
Twitter: / gsferreira
GitHub: github.com/gsferreira
Visit my blog: gsferreira.com
#dotnet #csharp

[@OrgesKreka]

Please do another video on design patterns!

[@gui.ferreira]

Any Design Pattern, in particular, you would like to see?

[@kostasgkoutis8534]

I would like to see a video on Pipes and Filters pattern and on State Machines. Together with the Chain of Responsibility, Mediator, and Rule Engine patterns, they form (for me) a logical "pipeline patterns" group (maybe with the Monad pattern as well).

[@gui.ferreira]

That's a big list 😁 Thanks for sharing

[@ahmet9424]

Great sample app 👍 Thank you.

[@gui.ferreira]

Glad you like it! Thanks!

[@moab5102]

Thank you that's an excellent video I would like a tutorial about rule engine or specification design pattern keep up the good work

[@gui.ferreira]

Thanks for the suggestion. Added to the content idea list 😉

[@nucasspro1]

Thank you so much, after watching this video, now I realize asp net core pipeline is following this pattern

[@gui.ferreira]

Excellent and accurate observation! I'm happy you find this video useful.

[@starterdev]

Show us all the design patterns 🥰

[@gui.ferreira]

There's a new one comming soon. 😉

[@alexandrgoncharov5074]

thank you for the video. great explanation

[@gui.ferreira]

Glad you liked it 🙏 Thanks for taking the time to write feedback.

[@patbeansoo]

Good stuff. Subscribed :)

[@gui.ferreira]

Thanks, Vince! Welcome aboard!

[@sunnypatel1045]

I be keep to see your experience with observer and visitor design patterns

[@gui.ferreira]

I'm likely doing one on Visitor soon.

[@gui.ferreira]

Here it is the video on the Visitor Design Pattern kzbin.info/www/bejne/r6quo6dtr7igrJI

[@FreeMindInMotion]

Great explanation. Visitor pattern would be interesting

[@gui.ferreira]

Noted 😉 Anything, in particular, you would like to see on the Visitor Pattern?

[@FreeMindInMotion]

For me the visitor use case is difficult to identify. That's why I chose it 😀 Maybe you have a good example pointing out the double polymorphic dispatch.

[@FreeMindInMotion]

Taking your example with the order I think it could be used, if you have IOrder, PriorityOrder and NormalOrder. Both need to be handled by the different Handlers, but differently by each or at least some handlers based on their concrete type without type checking.

[@gui.ferreira]

@@FreeMindInMotion Let me think about it 😁

[@gui.ferreira]

Here it is the video on the Visitor Design Pattern kzbin.info/www/bejne/r6quo6dtr7igrJI

[@saqibali7066]

Good example, Please do explain strategy design pattarn.

[@gui.ferreira]

Added to the pipeline! Anything, in particular, you would like to see on Strategy Pattern?

[@saqibali7066]

@@gui.ferreira how the flow goes ? Is loading web project configuration dynamically is good example mean either I can read configuration from web.config or from dynamoDB

[@gui.ferreira]

@@saqibali7066 I published it weeks ago: kzbin.info/www/bejne/lZy5aJ-GhLF8idk

[@saqibali7066]

@@gui.ferreirathanks

[@ghevisartor6242]

I wonder if this is correct to use in a case where i don't have a commonality like a "discount approval" but regardless i need to check a bunch of conditions, for example for deleting a file. Basically to get those conditions, in one i have to check the database, in another just some of the file properties. By separating these into their own handler, now i have the DbContext for example just in the first handler and not the other. So i end up with "IsFileInUseHandler", "IsFileOlderThanHandler" and then lastly "DeleteFileHandler" where i do File.Delete(filePath). It seems to work fine and simplify the code, but as you can see from the naming it sounds odd, also the last handler is actually having side effects. Am i trying to force a square in a circle?

[@gui.ferreira]

You are building a pipeline, which is a common practice here. As an example, I've seen many implementations similar to the one you mention in MediatR pipelines (which is a Chain of Responsibility).

[@LucasSantos-yw4nh]

Do you see any performance downgrade between Chain Of resposibility and Strategy Pattern? Also, is there any technique to find the the best order to fit the handlers in the chain?

[@gui.ferreira]

To be honest, they solve different problems, so it's not fair to compare them. Regarding the order, it depends on the problem they are solving. In the example from the video, order matters. But, in some cases, the Order can be ignored. For example, if you want to apply Authorization restrictions, you may want to start with the least resource-intensive ones. Long story short, it depends on the domain and business context. Did my answer help? 😅

[@LucasSantos-yw4nh]

@@gui.ferreira Yeah, it helped, thanks. But I still think both design patterns solve the open closed principle in order to create new behaviors without the need to change the class. I would like to know more about your point that it solves different problems.

[@gui.ferreira]

@@LucasSantos-yw4nh When I say that they solve different problems it's because Strategy is about having a generic interface that you can use to provide different implementations. On the other hand, a Chain of responsibility is about having a chain of objects which usually go from more detailed to more generic. So, you may solve the same problem with both, but not all the problems.

[@xmadcode]

The Chain Of Responsibility and the Pipeline Patterns would make a fair comparison, not as with the Strategy Pattern, in my opinion

[@xmadcode]

The strategy pattern

[@gui.ferreira]

Added to the list! 😉 Anything you would like to see on Strategy Pattern?

[@xmadcode]

@@gui.ferreira an overview of the pattern with a simple real life implementation in C#, and how can someone spot a use case for the pattern, would a make a great video ;)

[@gui.ferreira]

@@xmadcode Thanks for the Tip. I will think about it!

[@SimonLomax-qw3dv]

What colour theme are you using?

[@gui.ferreira]

Hi! Dracula for Rider plugins.jetbrains.com/plugin/12275-dracula-theme

[@vagnerwentz1189]

What is this IDE? JetBrains?

[@gui.ferreira]

JetBrains Rider 🤘

[@SteveNgaiCheeWeng]

can we also refactor it with DDD?

[@gui.ferreira]

Not sure what you are thinking about. For sure, the service/application can be modeled using DDD. However, Design Patterns like the Chain of Responsibility are useful even with DDD. Can you detail your question?