Can I use HttpClientFactory in a .NET.core app which is not ASP.NET Core?

问题

I have read the popular blog post https://www.stevejgordon.co.uk/introduction-to-httpclientfactory-aspnetcore on using HttpClientFactory

To quote from it

A new HttpClientFactory feature is coming in ASP.NET Core 2.1 which helps to solve some common problems that developers may run into when using HttpClient instances to make external web requests from their applications.

All the examples show wiring it up in startup class of asp.net application e.g.

public void ConfigureServices(IServiceCollection services)
{
            services.AddMvc().SetCompatibilityVersion(CompatibilityVersion.Version_2_1);
            services.AddHttpClient();
}

My question is can you use outside of ASP.NET core? And if so are there examples

I would have thought lots of non web applications(.net core apps) need to make web calls, so why was this not part of .net core api instead of putting into asp.net core api

回答1:

According to the documentation HttpClientFactory is a part of .Net Core 2.1, so you don't need ASP.NET to use it. And there some ways to use are described. The easiest way would be to use Microsoft.Extensions.DependencyInjection with AddHttpClient extension method.

static void Main(string[] args)
{
    var serviceProvider = new ServiceCollection().AddHttpClient().BuildServiceProvider();

    var httpClientFactory = serviceProvider.GetService<IHttpClientFactory>();

    var client = httpClientFactory.CreateClient();
}

回答2:

Thanks for replies.

So it is possible to use in console app.

There are a few ways to do this, depending on what way you want to go. Here are 2:

Directly add to ServiceCollection e.g. services.AddHttpClient()
Use Generic host e.g. Add httpclientFactory in .ConfigureServices() method

See here for blog post using in console app

回答3:

As one of the answers suggests,

you do not need ASP.NET to use it

However, you need a bit of work to get it into your Dependency Injection (DI):

Install microsoft.extensions.http (has nothing to do with ASP.NET)
When configuring your DI, use this extension. it registers builders/httpclientFactory/... (have a look at its source code on github)
```
ServiceCollections.AddHttpClient();
```
if you want register HttpClient with different names/settings to communicate with different web servers (different settings, ex: different base urls)
```
ServiceCollection.AddHttpClient(
"yourClientName", x => x.BaseAddress = new Uri("http://www.mywebserver.com"))
```

In case you want to add DelegateHendlers, you need to add it both to your httpClient and your DI container.

ServiceCollection
        .AddHttpClient(clientName, x => x.BaseAddress = new Uri("http://www.google.com"))
        .AddHttpMessageHandler<DummyDelegateHandler>();
ServiceCollection.AddScoped<DummyDelegateHandler>();

ServiceCollection.AddScoped<HttpClient>(x => 
x.GetService<IHttpClientFactory>().CreateClient("yourClientName"));

To resolve http client:

var client = ServiceProvider.GetService<HttpClient>();

回答4:

Just providing sample code for the first suggested approach in the accepted answer:

services.AddHttpClient<IFoo, Foo>(); // where services is of type IServiceCollection

and your class looks like:

public class Foo : IFoo
{
    private readonly HttpClient httpClient;

    public Consumer(HttpClient httpClient)
    {
        this.httpClient = httpClient;
    }
}

来源：https://stackoverflow.com/questions/52622586/can-i-use-httpclientfactory-in-a-net-core-app-which-is-not-asp-net-core

标签

asp.net-core

.net-core

httpclientfactory