Add AddHttpClientDefaults

[JamesNK]

Fixes #87914

The AddHttpClientDefaults method supports adding configuration to all created HttpClients.

The method:

• Creates a builder with a null name. Microsoft.Extensions.Configuration automatically applies configuration with a null name to all named configuration.
• Ensures that default configuration is added before named configuration in the IServiceCollection. This is to make it so the order of AddHttpClientDefaults and AddHttpClient doesn't matter. Default config is always applied first, then named config is applied after. This is done by wrapping the IServiceCollection in an implementation that modifies the order that IConfigureOptions<HttpClientFactoryOptions> values are added.

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Issue Details

---

Fixes #87914

The AddHttpClientDefaults method supports adding configuration to all created HttpClients.

The method:

• Creates a builder with a null name. Microsoft.Extensions.Configuration automatically applies configuration with a null name to all named configuration.
• Ensures that default configuration is added before named configuration in the IServiceCollection. This is to make it so the order of AddHttpClientDefaults and AddHttpClient doesn't matter. Default config is always applied first, then named config is applied after. This is done by wrapping the IServiceCollection in an implementation that modifies the order that IConfigureOptions<HttpClientFactoryOptions> values are added.

Author:	JamesNK
Assignees:	-
Labels:	area-Extensions-HttpClientFactory
Milestone:	-

[davidfowl]

Ensures that default configuration is added before named configuration in the IServiceCollection. This is to make it so the order of AddHttpClientDefaults and AddHttpClient doesn't matter. Default config is always applied first, then named config is applied after. This is done by wrapping the IServiceCollection in an implementation that modifies the order that IConfigureOptions values are added.

This feels pretty bad.

[JamesNK]

@noahfalk @joperezr @geeknoid @davidfowl

The AddHttpClientDefaults is designed to make it easy to apply configuration to all clients configured with AddHttpClient using one extension method on IHttpClientBuilder.

The goal is to avoid having two methods:

• Add config to one builder - extension method on IHttpClientBuilder.
• Add config to all builders - extension method on IServiceCollection.

For example, methods in dotnet/extensions below will no longer be needed:

https://github.com/dotnet/extensions/blob/52ebc1b123613254f9dfe250515027c1332fba35/src/Libraries/Microsoft.Extensions.Http.Telemetry/Logging/HttpClientLoggingExtensions.cs#L31-L122

It will be possible to do:

// Add HttpClientLogging to all clients.
services.AddHttpClientDefaults().AddHttpClientLogging();

// Is configured with HttpClientLogging from the defaults.
services.AddHttpClient();

[davidfowl]

I've also been thinking about an API like this and was hoping we could add an overload to AddHttpClient so it wasnt 2 different calls.

services.AddHttpClient(IHttpClientBuilder clientBuilder =>
{
     clientBuilder.AddHttpMessageHandler<MyAuthHandler>();
});  

[JamesNK]

Ensures that default configuration is added before named configuration in the IServiceCollection. This is to make it so the order of AddHttpClientDefaults and AddHttpClient doesn't matter. Default config is always applied first, then named config is applied after. This is done by wrapping the IServiceCollection in an implementation that modifies the order that IConfigureOptions values are added.

This feels pretty bad.

It's not the best, but it works well. It hits these important requirements:

• AddHttpClientDefaults config is overridden by named client configuration.
• The order AddHttpClientDefaults and AddHttpClient are called doesn't matter. Named client configuration always wins.
• It automatically works for people who have written their own IHttpClientBuilder extension methods that call services.Configure<HttpClientFactoryOptions>(...).

The extra logic is only applied to IOptionsConfiguration<HttpClientFactoryOptions> to ensure they have the right order. It won't interfere with or break other DI extension methods.

[geeknoid]

@dpk83 FYI

[dpk83]

@xakep139

[stephentoub]

Let's please agree on the API via discussion on the issue and API review before opening PRs. I spoke with @CarnaViire at length about this and other related APIs yesterday and I know she was going to be following up with you.

[CarnaViire]

LGTM for @JamesNK 's changes

[CarnaViire]

@dotnet/ncl can someone pls review as well? Since I've taken over the PR.

[ManickaP]

@CarnaViire changes LGTM.

[lewing]

This change appears to be breaking flow into aspnetcore in dotnet/aspnetcore#49433

[joperezr]

@CarnaViire can you please take a look?

[CarnaViire]

I've pushed the fix to the branch dotnet/aspnetcore#49433

[davidfowl]

So we have a problem here. I tried to use ConfigureHttpClientDefaults and noticed it isn't an extension method in the reference assembly.

[joperezr]

Can you elaborate? This change seems to suggest that the reference assembly was edited and that the extension was properly added: https://github.com/dotnet/runtime/pull/87953/files#diff-06e422c9663ed696b723dc56832cbdb53b9f9c3e6d0a98e52a1cb081b7c9dc7aR50

[karelz]

@joperezr the this is missing -- see #90911 which David filed and which was just fixed :)

[joperezr]

Oh, completely missed it! Good catch @davidfowl and thanks for the quick fix 😃