ASP.NET Core - Service Scope - Singleton vs Scoped vs Transient

Want to know the difference between different service scope in dotnet core? Well today you can learn the difference between Singleton, Scoped and Transient servoce types.
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Amaizing Stackoverflow post:
stackoverflow.com/questions/3...
Why not dispose of Http Client?
/ c-httpclient-should-no...

[@taraspelenio8259]

I'd like to say, that it's very informative video without any secondary constructions. 1)Lifetime of services defined as singleton - is equal to lifetime of application, 2)lifetime of scoped services is equal to lifetime of request, 3)lifetime of transient services is equal to lifetime of variable which represent the service object.
I think it's great idea to explain these concepts with Guid as example, it's simple and clear. Nice job.

[@RawCoding]

Cheers glad you liked it!

[@andyshen689]

Very helpful video, not only explains the differences but also talks about the usage!

[@RawCoding]

Cheers!

[@katerynamalova4933]

This is the best explanation on this topic I've seen so far. Finally I understand when each of them should be used (not just theoretical difference). Many thanks!

[@proguru7790]

Same thoughts love u too

[@badrulhussain5545]

Thanks, this is the only video that I have seen that details out on the 3 DI.

[@RawCoding]

Glad I could help

[@AlphaMatt1000]

Thank you as a fellow .NET Developer; excellent video. Subscribed my friend.

[@RawCoding]

Thank you

[@anjanobalesh8046]

relating addscoped to real world example would be to maintain same context and access that context from different parts of your application everywhere in the same request without creating different context objects in different parts. This also can be achieved by passsing the context as a parameter of your method call but if you want to achieve this through dependency injection this is the use case for addscoped.

[@aseneda]

Great content, thanks for sharing. Congratulations.

[@Kamil0289]

Very good to use GUID as example, helped to understand Service Scoped quicker :)

[@thirumanitheivarajan7295]

Thank you so much, excellent information.

[@RawCoding]

Cheers

[@az1nn]

Very informative, thanks man!

[@monugupta3508]

Thanks bro,Easy to understand.

[@letitbe1259]

thanks, excellent explanation

[@RawCoding]

Thank you))

[@intechligence4112]

Well, very useful and helpful. Thanks

[@RawCoding]

Glad I could be of help : )

[@ashutoshmishra2170]

you just cleared my doubts .thanks a lot

[@RawCoding]

Awesome!

[@esnatzea]

Awesome into man!

[@shahzain009]

You can use Service Scope, scoped while using ICurrent User service, that would need to be persistent throughout the request.

[@RawCoding]

Thanks for sharing

[@kristuze1]

awesome explanation, thanks a lot!

[@RawCoding]

Thank you for watching

[@ognjenvojnovic9778]

You f*ng rock ... this is the simplest explanation by far! Thanks man ...

[@julojenis8181]

Great job, thanks a lot.

[@fenchelteefee]

Great video man!

[@RawCoding]

Cheers

[@iancarr3923]

Very helpful, thanks

[@RawCoding]

Glad you found it useful

[@imadabab]

Excellent tutorial. I have subscribed.

[@RawCoding]

Cheers:)

[@timriley1501]

do the timers for Authenticator apps use the "scoped service" model? Seems like after the count down timer ends, you get a new input key...maybe leverage the service for that "feature" (generating some new key every 60 seconds)?

[@RawCoding]

Heya, I think calling them a service is a light statement. It's more of a system rather than a service

[@nunomaster]

Very good and understandable.

[@RawCoding]

Cheers

[@felcoshane5947]

hi, I saw lots of your videos, if I want to download your samples, where can I donwload from?github?

[@RawCoding]

Yes from GitHub

[@this.arunsaini]

This guy has my respect!

[@RawCoding]

Cheers

[@odytrice]

Scoped Services are typically used for objects that need to hold state across injections and are computationally expensive to Instantiate like Database Contexts for example

[@RawCoding]

yesir

[@DEvilParsnip]

best intro ever.

[@RawCoding]

Thank you)

[@auchucknorris]

great explanation and examples, will still take a bit to fully sink in but feel I'm pretty on track after this video, but apparently scoped is better for DB stuff, and is the default for DBContext as it can persist after the initial request for things up updating the context after created

[@RawCoding]

cheers, for the feedback

[@lifeinloop]

I was trying to create a singleton to store the numbers on hold in a queue management program on which i'm using signalR. I would like to use a object in the signalR hub to store those values as a terminal is making the requests. Can't i create a simple singleton without any IService class, and declare it in configure services and then use it in the signalR hub? I'm asking this because here you only have a example with IService class and i would like something like services.addSingleton;

[@RawCoding]

You want to use the IServiceProvider to surface non singletons inside a singleton

[@lifeinloop]

@@RawCoding This is so hard. Why couldn't they(microsoft) make things more easy to do... Sorry, i just don't understand.. Thank you anyway

[@RawCoding]

It’s too hard try, here’s an example stackoverflow.com/questions/61470121/create-scope-using-iserviceprovider-from-singleton-instance

[@akmalbukhariev7932]

thank you very much brother.

[@RawCoding]

Thank you for watching

[@YoungLeaf79]

That intro got me hooked.

[@g-luu]

Hi great content but i have an issue.
So what if you have a swagger code generated apiClient that uses the same baseUrl which is registered in the startup file and i want that same apiClient to get appended with Authorization header(jwt token) on each request but keep the same baseUrl? What do you register for this interface? as Scoped, Transient or Singleton?

[@RawCoding]

Q: What do you register for this interface?
> For what Interface?

[@g-luu]

@@RawCoding Thanks for the swift response, what I register is a custom apiClient from swagger that makes http calls.
It takes a baseUrl so i am passing it as a parameter.

[@RawCoding]

@@g-luu If it's a client that's making http calls, I think you want singleton. However http clients are nutorious for eating ports on a device, have a read through this. docs.microsoft.com/en-us/dotnet/architecture/microservices/implement-resilient-applications/use-httpclientfactory-to-implement-resilient-http-requests

[@g-luu]

@@RawCoding Cool thanks hey i will have a look. i was just worried that a singleton might keep the same auth token for every user who logs in.

[@RawCoding]

That is correct. So you want scoped then, good thinking!

[@lifeinloop]

Caw we put methods to access database in the singleton class, so we can have a thread safe singleton and the application wont crash?

[@RawCoding]

Yes, you’ll have to get the database connection via IServiceProvider

[@lifeinloop]

@@RawCoding thanks

[@achrafelkhamsi]

I had a question about scope validation in .net. Why are we not allowed to inject scoped services into singleton services ? and why it's Ok to do so with transient services ? In the documentation, it's stated that resolving a service from another service with larger lifetime throws an exception...Anyway thanks for the video!

[@RawCoding]

if you put a scoped service inside a singleton service it may live past it's designed life time. if you put it in a transient service, the transient service will be disposed before the scoped one, meaning the scoped one has no chance of surviving past it's life time.

[@jayrao5525]

Beautiful

[@RawCoding]

No you are !

[@arunnayak3342]

Thanks sir

[@RawCoding]

Thank you for watching

[@trustingod0]

I'm new to this so I was wondering where can I find some real world examples? Thanks !

[@RawCoding]

Of what? Real world examples of service lifetimes and when to use which one?

[@trustingod0]

@@RawCoding Yes a real world example of a Singleton and Transient Service and when to use which one. Thanks !!!

[@RawCoding]

Singleton - Memory Cache
Scoped/Transient - Database Repository
When to use which depends on what you are using an in memory cache is a singleton because you want to re-use the cache. Database Repository shouldn’t be a single because we want to free the connection otherwise we would be holding the database hostage.
But if you have a distributed cache you might want a transient service again to break the connection in case you have multiple services using that cache.

[@aimanalnami7655]

@@RawCoding man u are awesome 👌 👏

[@ritwikgupta7540]

Nice intro music 🪨

[@hafidzfairiz8398]

What an opening! lmao

[@RawCoding]

I tried ))

[@bojohannesen4352]

This better solve my problem, because if I don't get something in return for suffering through that intro...

[@kimberlyjacobsen4148]

I use the Scoped for JWT Authorization

[@peymannaji]

For example, I use Transient for services, Scoped for database repositories, Singleton for Database contexts.

[@RawCoding]

> Singleton for Database contexts
nooo, Database Context opens a connection which you don't want to persist if there is no data going over the wire. Make this Scoped incase many services use the context at the same time, you don't have to re-open the connection.
> Scoped for database repositories
same as you database context
> Transient for services
Depends on the service, you don't want your Memory Cache to be transient, otherwise it will get wiped after you are finished using it.

[@peymannaji]

@@RawCoding That's true (regarding what u mentioned about Transient).
I guess AddDBContext middleware in .net core adds the context as singleton if I am not wrong. But also I experience a scenario with Mongo DB recently.
The context just keeps some info regarding connection string and database collection and there is nothing else and I added it as singleton. But If I would have anything like Insert, Update ,... in the context, Definitely it should be added as Scoped, Am I doing right?

[@RawCoding]

Database context is scoped and all interaction with that service should be scoped as well

[@peymannaji]

@@RawCoding Thanks for the video & useful info :)

[@Zhouri]

Transient: Each injection results in a new instance with new state
Scoped: All injections within the same HTTP request share the same instance => same state
Singleton: All injections throughout the application share the same instance and maintain the same state across the entire application runtime.

[@waheedbhatti0]

If a dependency needs access to HttpContext then it is a good candidate to be scoped

[@bhaskarreddy2660]

if i use singleton all the request user will get the same object right

[@RawCoding]

Yes

[@conaxlearn8566]

It is quite clear to understand the three when they don't touch each other. But when one service uses another service that has different life span it starts getting interesting....or frustrating. For example:
Some services are not able to be constructed
(
Error while validating the service descriptor 'ServiceType:
Microsoft.Extensions.Hosting.IHostedService Lifetime:
Singleton ImplementationType:
MyApp.Import.Service.Worker':
Cannot consume scoped service 'MyApp.ImportService.AppDbContext' from singleton Microsoft.Extensions.Hosting.IHostedService'.
)
Have googled for a few hours so far still don't know what that means and how to solve it. 😅

[@RawCoding]

You want to use the IServiceProvider to surface your appdbcontex in a singleton service

[@conaxlearn8566]

@@RawCoding Thank you. That's something I'd never know by myself. I was thinking about to review my services so I can register them as scoped.

[@RawCoding]

I usually use Singletons and Channels to avoid race conditions

[@barscankurt4854]

If you are building an API, you can use Scoped.

[@RawCoding]

For?

[@SayWhaaaaaaaaaaaaaaaaaaaaaaat]

Transient for DB is stupid. It should be scoped.
Requests takes so little time and in that time you may use new db connections like 40 times... it' more logical to use single instance per request instead of many. Not to mention that creating new connections takes time, compared to when you use already initialized db object and no need to reconnect.

[@RawCoding]

Thank you for sharing!

[@godfreyodenigbo95]

he has 26k now

[@RawCoding]

We ain’t stopping here

[@muddyPassenger]

Ahhah, in the beginning you'r sayibg like with that ugly accent?

[@RawCoding]

Hey! I'm getting better at it!

[@alvaromp1106]

Confusing and not good explanation. Sorry.

[@maxshymkiv2200]

how to say in not offensive way to your audience to get better: "GetGuid"

[@RawCoding]

xd

[@wadeatamim3230]

Thanks ! very good explanation

[@RawCoding]

Glad I could help