How can I use proxies for web requests in Flurl?

Question

I have a simple post request using the Flurl client, and I was wondering how to make this request using a proxy using information like the IP, port, username, and password.

string result = await atc.Request(url)
    .WithHeader("Accept", "application/json")
    .WithHeader("Content-Type", "application/x-www-form-urlencoded")
    .WithHeader("Host", "www.website.com")
    .WithHeader("Origin", "http://www.website.com")
    .PostUrlEncodedAsync(new { st = colorID, s = sizeID, qty = 1 })
    .ReceiveString();

Answer 1

I was looking for a similar answer and found this: https://github.com/tmenier/Flurl/issues/228

Here is a copy of the contents of that link. It worked for me!

You can do this with a custom factory:

using Flurl.Http.Configuration;

public class ProxyHttpClientFactory : DefaultHttpClientFactory {
    private string _address;

    public ProxyHttpClientFactory(string address) {
        _address = address;
    }

    public override HttpMessageHandler CreateMessageHandler() {
        return new HttpClientHandler {
            Proxy = new WebProxy(_address),
            UseProxy = true
        };
    }
} 

To register it globally on startup:

FlurlHttp.Configure(settings => {
    settings.HttpClientFactory = new ProxyHttpClientFactory("http://myproxyserver");
});