Transmisión de una solicitud en asp.net (Reenviar una solicitud)

Tengo un método de extensión en HttpResponseBase para copiar una solicitud entrante a una solicitud saliente.

Uso:

    var externalRequest = (HttpWebRequest)WebRequest.Create("http://stackoverflow.com");
    this.Request.CopyTo(externalRequest);
    var externalResponse = (HttpWebResponse)externalRequest.GetResponse();

Fuente:

/// <summary>
/// Copies all headers and content (except the URL) from an incoming to an outgoing
/// request.
/// </summary>
/// <param name="source">The request to copy from</param>
/// <param name="destination">The request to copy to</param>
public static void CopyTo(this HttpRequestBase source, HttpWebRequest destination)
{
    destination.Method = source.HttpMethod;

    // Copy unrestricted headers (including cookies, if any)
    foreach (var headerKey in source.Headers.AllKeys)
    {
        switch (headerKey)
        {
            case "Connection":
            case "Content-Length":
            case "Date":
            case "Expect":
            case "Host":
            case "If-Modified-Since":
            case "Range":
            case "Transfer-Encoding":
            case "Proxy-Connection":
                // Let IIS handle these
                break;

            case "Accept":
            case "Content-Type":
            case "Referer":
            case "User-Agent":
                // Restricted - copied below
                break;

            default:
                destination.Headers[headerKey] = source.Headers[headerKey];
                break;
        }
    }

    // Copy restricted headers
    if (source.AcceptTypes.Any())
    {
        destination.Accept = string.Join(",", source.AcceptTypes);
    }
    destination.ContentType = source.ContentType;
    destination.Referer = source.UrlReferrer.AbsoluteUri;
    destination.UserAgent = source.UserAgent;

    // Copy content (if content body is allowed)
    if (source.HttpMethod != "GET"
        && source.HttpMethod != "HEAD"
        && source.ContentLength > 0)
    {
        var destinationStream = destination.GetRequestStream();
        source.InputStream.CopyTo(destinationStream);
        destinationStream.Close();
    }
}

Aquí hay un buen código de retransmisión en VB.NET usando MVC.

GLOBAL.ASAX.VB

Public Class MvcApplication
    Inherits System.Web.HttpApplication

    Shared Sub RegisterRoutes(ByVal routes As RouteCollection)
        routes.MapRoute("Default", "{*s}", New With {.controller = "Home", .action = "Index"})
    End Sub

    Sub Application_Start()
        RegisterRoutes(RouteTable.Routes)
    End Sub
End Class

HomeController.vb

Option Explicit On
Option Strict On

Imports System.Net

<HandleError()> _
Public Class HomeController
    Inherits System.Web.Mvc.Controller

    Function Index(ByVal s As String) As ActionResult
        Server.ScriptTimeout = 60 * 60
        If Request.QueryString.ToString <> "" Then s = s + "?" + Request.QueryString.ToString
        Dim req As HttpWebRequest = CType(WebRequest.Create("http://stackoverflow.com/" + s), HttpWebRequest)
        req.AllowAutoRedirect = False
        req.Method = Request.HttpMethod
        req.Accept = Request.Headers("Accept")
        req.Referer = Request.Headers("Referer")
        req.UserAgent = Request.UserAgent
        For Each h In Request.Headers.AllKeys
            If Not (New String() {"Connection", "Accept", "Host", "User-Agent", "Referer"}).Contains(h) Then
                req.Headers.Add(h, Request.Headers(h))
            End If
        Next
        If Request.HttpMethod <> "GET" Then
            Using st = req.GetRequestStream
                StreamCopy(Request.InputStream, st)
            End Using
        End If
        Dim resp As WebResponse = Nothing
        Try
            Try
                resp = req.GetResponse()
            Catch ex As WebException
                resp = ex.Response
            End Try

            If resp IsNot Nothing Then
                Response.StatusCode = CType(resp, HttpWebResponse).StatusCode
                For Each h In resp.Headers.AllKeys
                    If Not (New String() {"Content-Type"}).Contains(h) Then
                        Response.AddHeader(h, resp.Headers(h))
                    End If
                Next
                Response.ContentType = resp.ContentType

                Using st = resp.GetResponseStream
                    StreamCopy(st, Response.OutputStream)
                End Using
            End If
        Finally
            If resp IsNot Nothing Then resp.Close()
        End Try
        Return Nothing
    End Function
    Sub StreamCopy(ByVal input As IO.Stream, ByVal output As IO.Stream)
        Dim buf(0 To 16383) As Byte
        Using br = New IO.BinaryReader(input)
            Using bw = New IO.BinaryWriter(output)
                Do
                    Dim rb = br.Read(buf, 0, buf.Length)
                    If rb = 0 Then Exit Do
                    bw.Write(buf, 0, rb)
                Loop
            End Using
        End Using
    End Sub
End Class

HttpContext incluye la propiedad Request, que a su vez contiene la colección Headers. Debería ser toda la información que necesitas.

Posiblemente algo como:

HttpWebRequest request = (HttpWebRequest)WebRequest.Create("www.testing.test");
request.Headers = (WebHeaderCollection)Request.Headers;

Luego llame a la respuesta get

HttpWebResponse response  = (HttpWebResponse)request.GetResponse();

Esto tendrá los mismos encabezados HTTP que la solicitud original.