AddHttpClient fails with DefaultHttpClientFactory

Question

At startup of my API, I declare a client for an external API in ConfigureServices:

services.AddTransient<ApiBearerTokenHandler>();
services.AddHttpClient<IExternalApi, ExternalApi>(client =>
{
    client.BaseAddress = new Uri(settings.ApiUrl);
    client.DefaultRequestHeaders.Add("Accept", "application/json");
}).AddHttpMessageHandler<ApiBearerTokenHandler>();

At injection time, I get the folowing error:

System.InvalidOperationException: ValueFactory attempted to access the Value property of this instance

It seems that the DefaultHttpClientFactory doesn't manage to create an HttpClient.

Am I meant to provide a way to create this client or should it be automatically created?

If I declare the client without th handler, injection doesn't fail, but I don't have a token:

        services.AddHttpClient<IExternalApi, ExternalApi>(client =>
        {
            client.BaseAddress = new Uri(settings.ApiUrl);
            client.DefaultRequestHeaders.Add("Accept", "application/json");
        });

Pretty stack:

System.InvalidOperationException: ValueFactory attempted to access the Value property of this instance.
   at System.Lazy`1.ViaFactory(LazyThreadSafetyMode mode)
   at System.Lazy`1.ExecutionAndPublication(LazyHelper executionAndPublication, Boolean useDefaultConstructor)
   at System.Lazy`1.CreateValue()
   at System.Lazy`1.get_Value()
   at Microsoft.Extensions.Http.DefaultHttpClientFactory.CreateHandler(String name)
   at Microsoft.Extensions.Http.DefaultHttpClientFactory.CreateClient(String name)
   at Microsoft.Extensions.DependencyInjection.HttpClientBuilderExtensions.<>c__DisplayClass12_0`2.<AddTypedClientCore>b__0(IServiceProvider s)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitFactory(FactoryCallSite factoryCallSite, RuntimeResolverContext context)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteVisitor`2.VisitCallSiteMain(ServiceCallSite callSite, TArgument argument)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitDisposeCache(ServiceCallSite transientCallSite, RuntimeResolverContext context)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteVisitor`2.VisitCallSite(ServiceCallSite callSite, TArgument argument)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitConstructor(ConstructorCallSite constructorCallSite, RuntimeResolverContext context)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteVisitor`2.VisitCallSiteMain(ServiceCallSite callSite, TArgument argument)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitDisposeCache(ServiceCallSite transientCallSite, RuntimeResolverContext context)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteVisitor`2.VisitCallSite(ServiceCallSite callSite, TArgument argument)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.Resolve(ServiceCallSite callSite, ServiceProviderEngineScope scope)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.DynamicServiceProviderEngine.<>c__DisplayClass1_0.<RealizeService>b__0(ServiceProviderEngineScope scope)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.ServiceProviderEngine.GetService(Type serviceType, ServiceProviderEngineScope serviceProviderEngineScope)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.ServiceProviderEngineScope.GetService(Type serviceType)
   at Microsoft.Extensions.DependencyInjection.ServiceProviderServiceExtensions.GetRequiredService(IServiceProvider provider, Type serviceType)
   at Microsoft.Extensions.DependencyInjection.ServiceProviderServiceExtensions.GetRequiredService[T](IServiceProvider provider)
   at Microsoft.Extensions.DependencyInjection.HttpClientBuilderExtensions.<>c__4`1.<AddHttpMessageHandler>b__4_1(HttpMessageHandlerBuilder b)
   at Microsoft.Extensions.Http.DefaultHttpClientFactory.<>c__DisplayClass17_0.<CreateHandlerEntry>g__Configure|0(HttpMessageHandlerBuilder b)
   at Microsoft.Extensions.Http.LoggingHttpMessageHandlerBuilderFilter.<>c__DisplayClass2_0.<Configure>b__0(HttpMessageHandlerBuilder builder)
   at Microsoft.Extensions.Http.DefaultHttpClientFactory.CreateHandlerEntry(String name)
   at Microsoft.Extensions.Http.DefaultHttpClientFactory.<>c__DisplayClass14_0.<.ctor>b__1()
   at System.Lazy`1.ViaFactory(LazyThreadSafetyMode mode)
   at System.Lazy`1.ExecutionAndPublication(LazyHelper executionAndPublication, Boolean useDefaultConstructor)
   at System.Lazy`1.CreateValue()
   at System.Lazy`1.get_Value()
   at Microsoft.Extensions.Http.DefaultHttpClientFactory.CreateHandler(String name)
   at Microsoft.Extensions.Http.DefaultHttpClientFactory.CreateClient(String name)
   at Microsoft.Extensions.DependencyInjection.HttpClientBuilderExtensions.<>c__DisplayClass12_0`2.<AddTypedClientCore>b__0(IServiceProvider s)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitFactory(FactoryCallSite factoryCallSite, RuntimeResolverContext context)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteVisitor`2.VisitCallSiteMain(ServiceCallSite callSite, TArgument argument)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitDisposeCache(ServiceCallSite transientCallSite, RuntimeResolverContext context)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteVisitor`2.VisitCallSite(ServiceCallSite callSite, TArgument argument)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitConstructor(ConstructorCallSite constructorCallSite, RuntimeResolverContext context)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteVisitor`2.VisitCallSiteMain(ServiceCallSite callSite, TArgument argument)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitCache(ServiceCallSite callSite, RuntimeResolverContext context, ServiceProviderEngineScope serviceProviderEngine, RuntimeResolverLock lockType)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitScopeCache(ServiceCallSite singletonCallSite, RuntimeResolverContext context)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteVisitor`2.VisitCallSite(ServiceCallSite callSite, TArgument argument)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.Resolve(ServiceCallSite callSite, ServiceProviderEngineScope scope)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.DynamicServiceProviderEngine.<>c__DisplayClass1_0.<RealizeService>b__0(ServiceProviderEngineScope scope)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.ServiceProviderEngine.GetService(Type serviceType, ServiceProviderEngineScope serviceProviderEngineScope)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.ServiceProviderEngineScope.GetService(Type serviceType)
   at Microsoft.Extensions.DependencyInjection.ActivatorUtilities.GetService(IServiceProvider sp, Type type, Type requiredBy, Boolean isDefaultParameterRequired)
   at lambda_method(Closure , IServiceProvider , Object[] )
   at Microsoft.AspNetCore.Mvc.Controllers.ControllerActivatorProvider.<>c__DisplayClass4_0.<CreateActivator>b__0(ControllerContext controllerContext)
   at Microsoft.AspNetCore.Mvc.Controllers.ControllerFactoryProvider.<>c__DisplayClass5_0.<CreateControllerFactory>g__CreateController|0(ControllerContext controllerContext)
   at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.Next(State& next, Scope& scope, Object& state, Boolean& isCompleted)
   at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.InvokeInnerFilterAsync()
--- End of stack trace from previous location where exception was thrown ---
   at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.<InvokeNextResourceFilter>g__Awaited|24_0(ResourceInvoker invoker, Task lastTask, State next, Scope scope, Object state, Boolean isCompleted)
   at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.Rethrow(ResourceExecutedContextSealed context)
   at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.Next(State& next, Scope& scope, Object& state, Boolean& isCompleted)
   at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.InvokeFilterPipelineAsync()
--- End of stack trace from previous location where exception was thrown ---
   at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.<InvokeAsync>g__Awaited|17_0(ResourceInvoker invoker, Task task, IDisposable scope)
   at Microsoft.AspNetCore.Routing.EndpointMiddleware.<Invoke>g__AwaitRequestTask|6_0(Endpoint endpoint, Task requestTask, ILogger logger)
   at Microsoft.AspNetCore.Diagnostics.ExceptionHandlerMiddleware.<Invoke>g__Awaited|6_0(ExceptionHandlerMiddleware middleware, HttpContext context, Task task)

sinsedrix · Accepted Answer · 2021-03-17 15:58:21Z

6

In my case, a single API provides authentication and other services.

But I can't use the same HttpClient for both as services need an authentication to get instanciated. So I had to split the HttpClient in two parts:

// 1 - authentication
services.AddHttpClient<IAuthApi, AuthApi>(client =>
{
    client.BaseAddress = new Uri(settings.ApiUrl);
    client.DefaultRequestHeaders.Add("Accept", "application/json");
});

// 2 - other services
services.AddTransient<ApiBearerTokenHandler>();
services.AddHttpClient<IExternalApi, ExternalApi>(client =>
{
    client.BaseAddress = new Uri(settings.ApiUrl);
    client.DefaultRequestHeaders.Add("Accept", "application/json");
}).AddHttpMessageHandler<ApiBearerTokenHandler>();

Where ApiBearerTokenHandler uses IAuthApi to get a token.

Great resource: https://blog.joaograssi.com/typed-httpclient-with-messagehandler-getting-accesstokens-from-identityserver/

answered Mar 17, 2021 at 15:58

sinsedrix

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2 Comments

display-name Over a year ago

I am running into the same problem. Did you try to inject your HttpClient into the ApiBearerTokenHandler or something similar? Could you please share (parts of) the code for your ApiBearerTokenHandler?

sinsedrix Over a year ago

@rm-code The IAuthApi is injected in the ApiBearerTokenHandler with a RequestToken method called in SendAsync override.

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