How to configure web proxy for HttpClient created directly via HttpClientFactory?

Question

• By directly I mean without Asp.Net Core IoC/DI helpers.

I didn't find docs about it and I think my current solution isn't optimal because the handler lifecyle isn't managed by the HttpClientFactory:

var proxiedHttpClientHandler = new HttpClientHandler() { Proxy = httpProxy };
_createHttpClient = () => HttpClientFactory.Create(proxiedHttpClientHandler);

Is there a better solution?

Answer 1

You can do something like this:

private HttpClient ClientFactory()
{
    var proxiedHttpClientHandler = new HttpClientHandler(){ UseProxy = true};
    proxiedHttpClientHandler.Proxy = new WebProxy("proxy address");
    var httpClient = new HttpClient(proxiedHttpClientHandler)
    {
        BaseAddress = new Uri("uri");
        Timeout = 2000; //if you need timeout;
    }
}
_createHttpClient = () => ClientFactory();

There's a good discussion here about using factory vs. manually instantiating an httpClient object.

Answer 2

When adding the client to the service collection you should be able to configure the handler there

Using the named client approach I'll use a constant to hold the client name.

public static class NamedHttpClients {
    public const string ProxiedClient = "ProxiedClient";
}

From there it is just a matter of configuring the client

//...
var serviceCollection = new ServiceCollection();

serviceCollection
    .AddHttpClient(NamedHttpClients.ProxiedClient)
    .ConfigurePrimaryHttpMessageHandler(() => new HttpClientHandler() { 
        Proxy = httpProxy 
    });

var services = serviceCollection.BuildServiceProvider();

So that when calling the client via a resolved IHttpClientFactory

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

var client = httpClientFactory.CreateClient(NamedHttpClients.ProxiedClient);

the returned client will use the handler with the proxy.