CreateClient<TClient> Naming Issue

[gorillapower]

I encountered an issue when my Typed HttpClient was using a generic type. In my example .AddHttpClient<GenericClient<MyName>> produced "GenericClient`1" in the IContextualHttpClientFactory.CreateClient<TClient>(string handlerContext)) method

This caused issues as I was expecting the name to be GenericClient<MyName>. It looks like in .NET there is an internal method that resolves the TClient name string. See this code string name = TypeNameHelper.GetTypeDisplayName(typeof(TClient), fullName: false);

I resolved the issue by creating my own IContextualHttpClientFactory and creating the CreateClient to look like this

    public TClient CreateClient<TClient>(string handlerContext)
    {
        var client = CreateClient(typeof(TClient).FullName, handlerContext);
        return _serviceProvider.GetRequiredService<ITypedHttpClientFactory<TClient>>().CreateClient(client);
    }

This resolved the FullName with the generic type included.

UPDATE: This solution did not work, the TClient needs to resemble the exact name that the internal AddHttpClient would create, being GenericClient<MyName>.

What did end up working was to replicate the TypeNameHelper.GetTypeDisplayName() code referenced above. Working Example.

    public TClient CreateClient<TClient>(string handlerContext)
    {
         string name = TypeNameHelper.GetTypeDisplayName(typeof(TClient), fullName: false);
         var client = CreateClient(name, handlerContext);
        return _serviceProvider.GetRequiredService<ITypedHttpClientFactory<TClient>>().CreateClient(client);
    }

[agertenbach]

Thanks for the report, issue confirmed.

I have a pending branch and PR to address this issue along with additions to properly handle typed clients with interfaces and some other small quality of life updates.

[agertenbach]

3.0.0-rc is available here and as a pre-release package on Nuget. It has a major version increment due to some small changes on interfaces.

The issue you reported is addressed by a new wrapper type called TypedClientSignature that uses an internal implementation of TypeNameHelper and has implicit conversion to and from a string to maintain existing comparison logic.

In addition to resolving issues with typed clients with a generic parameter, the handler factory logic now supports

client.IsTypedClient<TypedClient>()

in favor of (but optionally in addition to the potentially inaccurate)

client == typeof(TypedClient).Name

Let me know if you have any issues with the RC, will plan to merge this week.