C#•2y ago

❔ Resolve a service before the container is built

Is it possible? My use case is that I want to share an object when I'm configuring the services. This question is ungooglable in the way I describe it

33 Replies

Auros•2y ago

If I'm reading this correctly, you want to resolve a service, and then use that service to further configure your services? Can you prove a code example of what you would like to do? (It doesn't have to work)

AntonOP•2y ago

I just did kind of a hack of what I need. But I'm sure there's a better way. https://github.com/AntonC9018/49/blob/auth/source/fourtynine/Utils/KeyedProvider.cs and usage: https://github.com/AntonC9018/49/blob/auth/source/fourtynine/Program.cs#L146-L152 imagine doing this configuration at multiple points in some configuration classes that can't share context directly.

GitHub

49/KeyedProvider.cs at auth · AntonC9018/49

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GitHub

49/Program.cs at auth · AntonC9018/49

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AntonOP•2y ago

@Auros not necessarily a service, some piece of state in this case would suffice

Auros•2y ago

I might be wrong with what you're trying to do, but if the shared object doesn't require a dependency from the built container, you can use the builder.Host.Properties dictionary to store shared objects during the host building process.

AntonOP•2y ago

gotcha are there events that trigger before the container gets built? do you know by any chance?

Auros•2y ago

Not that I know of. If you need to set the shared object, do it after you call WebApplication.CreateBuilder. Technically a lambda provided to ctx.Host.ConfigureServices is called while the container is building, but that's not really an ideal event.

AntonOP•2y ago

it's fine, I can just build that object with the dictionary dynamically, setting it both as a singleton in the DI and on those properties. thanks for the insight

Omnissiah•2y ago

could you just call a surrogate object that initialize the real object for you? or use a hosted service?

AntonOP•2y ago

I don't know what either of these are

mikernet•2y ago

Tbh not entirely sure what you are trying to eliminate or "fix" here What is the part that doesnt work how you want it to and how do you want it to work

AntonOP•2y ago

hosted service can serve as a callback don't know what you mean by surrogate object getting a reference to the same configuration object before the app is built I managed to do this with properties

AntonOP•2y ago

https://github.com/AntonC9018/49/blob/auth/source/fourtynine/Utils/KeyedProvider.cs

GitHub

49/KeyedProvider.cs at auth · AntonC9018/49

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AntonOP•2y ago

tho not sure what key to use, I haven't checked what FullName returns also been asking what's the convention

mikernet•2y ago

This seems like an odd way to do this tbh. I would just register each IUserEmailConfirmationProvider, give that interface a Name or Scheme property, then have the KeyedProvider ctor take an IEnumerable<IUserEmailConfirmationProvider> which it then uses to build its dictionary using the Name/Scheme as the key

AntonOP•2y ago

that won't work, because you'd need to have an instance to get the scheme nane in the first place but it could be scoped or whatever

mikernet•2y ago

You don't need an instance, those instances get passed into the key provider when it is first requested from the container, i.e when the container builds the key provider

AntonOP•2y ago

with abstract statics or with some weird reflection maybe

mikernet•2y ago

It will inject the instances As an IEnumerable<>

AntonOP•2y ago

so all would get instantiated every time I need one?

mikernet•2y ago

It's a singleton, so no

AntonOP•2y ago

the email provider may not be a singleton

mikernet•2y ago

Hmm I see, give me a sec

AntonOP•2y ago

your idea could work if you were to also make email provider factories, but that's a ridiculous amount of extra boilerplate needed or like descriptors

mikernet•2y ago

In KeyedProviderExtensions.AddKeyed you can register this singleton which gets the actual instance:

class KeyedInstanceProvider<TBaseType>
{
    public KeyedInstanceProvider(string schemaName, IServiceProvider serviceProvider)
    {
    }

    public TBaseType? Get() { ... }
}

class KeyedInstanceProvider<TBaseType>
{
    public KeyedInstanceProvider(string schemaName, IServiceProvider serviceProvider)
    {
    }

    public TBaseType? Get() { ... }
}

Then KeyedProvider ctor takes IEnumerable<KeyedInstanceProvider<TBaseType>> as the parameter

AntonOP•2y ago

+ extra anstraction so that would be the conventional way of doing it right?

mikernet•2y ago

That's the "proper" way I would do it using .net DI

AntonOP•2y ago

ok thanks

mikernet•2y ago

Then you can do away with the shared configuration object Also I dont think the return needs to be nullable BaseType AFAICT. If there's a mapping for it then it will return an instance, otherwise it will throw.

AntonOP•2y ago

you mean in your code?

mikernet•2y ago

In yours as well But yes https://github.com/AntonC9018/49/blob/auth/source/fourtynine/Utils/KeyedProvider.cs#L97 I dont see that ever returning null

AntonOP•2y ago

yeah it shouldn't throw there

mikernet•2y ago

Gotcha 🙂

Accord•2y ago

Was this issue resolved? If so, run /close - otherwise I will mark this as stale and this post will be archived until there is new activity.

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❔ Resolve a service before the container is built