Downloading github files through proxy

Description

Paket does not work with github files from behind proxy.

When building paket.sln:

Severity    Code    Description Project File    Line    Suppression State
Error       Could not download from https://raw.githubusercontent.com/fsharp/FAKE/7f9fe8f546f6adec66febeec31e50821b60814d6/modules/Octokit/Octokit.fsx
 Message: One or more errors occurred.
 Details: The underlying connection was closed: An unexpected error occurred on a send.     C:\Git\Third Party\Paket\integrationtests\Paket.IntegrationTests\paket.references   0   

Repro steps

#r "System.dll"
open System.Net

let https = @"https://raw.githubusercontent.com/fsharp/FAKE/f4024fd5b790485828c1cfc002190716eee97597/modules/Octokit/Octokit.fsx";
let http = @"http://stackoverflow.com/"

let download (url:string) =
    printfn "%s" url;
    try
      use client = new WebClient()
      // client.Proxy.Credentials <- System.Net.CredentialCache.DefaultNetworkCredentials
      client.DownloadString url |> ignore
      printfn "Success!"
    with
    | ex -> printfn "Exception! %s " (ex.Message)

download http
download https

Uncommenting the proxy line gives success for http but exception for https.

Exception! The remote server returned an error: (403) Forbidden.

I don't know much about proxies, been testing a bunch of stackoverflow answers but nothing has worked. If anyone has suggestions please paste a modified script and I'll run it and output the results.

Known workarounds

a) Download the files manually and turn off auto-restore.
b) This is a nasty hack, but it works for downloading the file. It is Windows only and brings in WPF or WinForms references which is not ideal.

Related information

• Win 7
• Latest paket and every version I have tried.
• .NET
• Don't know much about the proxy in use.
• Browsing to the file via browser works.
• Git.exe works from behind the proxy.

Start with the F# reproduction script and the integrationtests/Paket.IntegrationTests/paket.references example. Investigate the Paket download path for raw.githubusercontent.com and compare proxy behavior for HTTP and HTTPS. Done means a Paket restore or build can download the referenced GitHub file through the reported proxy setup.