asp.net core defaultProxy

Question

In net 4.5 we are working with proxy like this:

<system.net>
    <!-- -->
    <defaultProxy enabled="true" useDefaultCredentials="false">
        <proxy usesystemdefault="True" proxyaddress="http://192.168.1.1:8888" bypassonlocal="True" autoDetect="False" />
        <module type="CommonLibrary.Proxy.MyProxy, CommonLibrary, Version=1.0.0.0, Culture=neutral" />
    </defaultProxy>

    <settings>
        <httpWebRequest useUnsafeHeaderParsing="true" />
        <servicePointManager expect100Continue="false" />
    </settings>
</system.net>

but in asp.net core or test we can't found a solution like the above Could someone please help me?

I really appreciate your help

Thanks, Regards

Answer 1

To use an HTTP proxy in .net core, you have to implement IWebProxy interface.This is from the System.Net.Primitives.dll assembly. You can add it to project.json if not already there

e.g.

"frameworks": {
    "dotnet4.5": {
      "dependencies": {
        "System.Net.Primitives": "4.3.0"
      }
    }
}

Implementation is very trivial

public class MyHttpProxy : IWebProxy
    {

        public MyHttpProxy()
        {
           //here you can load it from your custom config settings 
            this.ProxyUri = new Uri(proxyUri);
        }

        public Uri ProxyUri { get; set; }

        public ICredentials Credentials { get; set; }

        public Uri GetProxy(Uri destination)
        {
            return this.ProxyUri;
        }

        public bool IsBypassed(Uri host)
        {
            //you can proxy all requests or implement bypass urls based on config settings
            return false; 

        }
    }


var config = new HttpClientHandler
{
    UseProxy = true,
    Proxy = new MyHttpProxy()
};

//then you can simply pass the config to HttpClient
var http = new HttpClient(config)

checkout https://msdn.microsoft.com/en-us/library/system.net.iwebproxy(v=vs.100).aspx

Answer 2

Whilst manually setting the proxy works when it's possible to use a HttpClientHander, defaulting all requests to do so without code, like you could do in the .NET Framework is currently not possible. Which is bummer if you're using a library that doesn't expose this functionality.

Thankfully, from .NET Core 3.0, this will be possible simply by setting environment variables (i.e. behaves exactly as Linux has worked forever): https://github.com/dotnet/corefx/issues/37187

Alternatively, https://github.com/dotnet/corefx/issues/36553 added a new static DefaultWebProxy property on HttpClient that will allow you to accomplish the same thing via code. This will also be available in Core 3.0.

Answer 3

You should use a middleware. Did you have a look at this one:

https://github.com/aspnet/Proxy

there's a 'samples' folder: https://github.com/aspnet/Proxy/tree/dev/samples/Microsoft.AspNetCore.Proxy.Samples

Other resources on the topic: http://josephwoodward.co.uk/2016/07/proxying-http-requests-asp-net-core-using-kestrel

http://overengineer.net/creating-a-simple-proxy-server-middleware-in-asp-net-core

Does a middleware works for you?

Answer 4

Another incompleted work around is:

After you deploy .NET Core app to a web server(mine is IIS). There is actually a web.config file in the root folder.

Manually add

 <system.net>
 <defaultProxy useDefaultCredentials="true">
 </defaultProxy>
 </system.net>

or your specific setting will do the magic

Only works on the server though. Your local build still won't work.