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copied!<p>This is an ASP.Net MVC 3.0 AsyncController which accepts requests, converts the inbound HttpRequestBase MVC object to a System.Web.HttpWebRequest. It then sends the request asynchronously. When the response comes back, it converts the System.Web.HttpWebResponse back into an MVC HttpResponseBase object which can be returned via the MVC controller. </p> <p>To answer this question explicitly, I guess you'd only be interested in the BuildWebRequest() function. However, it demonstrates how to move through the whole pipeline - converting from BaseRequest > Request and then Response > BaseResponse. I thought sharing both would be useful.</p> <p>Through these classes, you can have an MVC server which acts as a web proxy. </p> <p>Hope this helps!</p> <p><strong>Controller:</strong></p> <pre><code>[HandleError] public class MyProxy : AsyncController { [HttpGet] public void RedirectAsync() { AsyncManager.OutstandingOperations.Increment(); var hubBroker = new RequestBroker(); hubBroker.BrokerCompleted += (sender, e) => { this.AsyncManager.Parameters["brokered"] = e.Response; this.AsyncManager.OutstandingOperations.Decrement(); }; hubBroker.BrokerAsync(this.Request, redirectTo); } public ActionResult RedirectCompleted(HttpWebResponse brokered) { RequestBroker.BuildControllerResponse(this.Response, brokered); return new HttpStatusCodeResult(Response.StatusCode); } } </code></pre> <p><strong>This is the proxy class which does the heavy lifting:</strong></p> <pre><code>namespace MyProxy { /// <summary> /// Asynchronous operation to proxy or "broker" a request via MVC /// </summary> internal class RequestBroker { /* * HttpWebRequest is a little protective, and if we do a straight copy of header information we will get ArgumentException for a set of 'restricted' * headers which either can't be set or need to be set on other interfaces. This is a complete list of restricted headers. */ private static readonly string[] RestrictedHeaders = new string[] { "Accept", "Connection", "Content-Length", "Content-Type", "Date", "Expect", "Host", "If-Modified-Since", "Range", "Referer", "Transfer-Encoding", "User-Agent", "Proxy-Connection" }; internal class BrokerEventArgs : EventArgs { public DateTime StartTime { get; set; } public HttpWebResponse Response { get; set; } } public delegate void BrokerEventHandler(object sender, BrokerEventArgs e); public event BrokerEventHandler BrokerCompleted; public void BrokerAsync(HttpRequestBase requestToBroker, string redirectToUrl) { var httpRequest = BuildWebRequest(requestToBroker, redirectToUrl); var brokerTask = new Task(() => this.DoBroker(httpRequest)); brokerTask.Start(); } private void DoBroker(HttpWebRequest requestToBroker) { var startTime = DateTime.UtcNow; HttpWebResponse response; try { response = requestToBroker.GetResponse() as HttpWebResponse; } catch (WebException e) { Trace.TraceError("Broker Fail: " + e.ToString()); response = e.Response as HttpWebResponse; } var args = new BrokerEventArgs() { StartTime = startTime, Response = response, }; this.BrokerCompleted(this, args); } public static void BuildControllerResponse(HttpResponseBase httpResponseBase, HttpWebResponse brokeredResponse) { if (brokeredResponse == null) { PerfCounters.ErrorCounter.Increment(); throw new GriddleException("Failed to broker a response. Refer to logs for details."); } httpResponseBase.Charset = brokeredResponse.CharacterSet; httpResponseBase.ContentType = brokeredResponse.ContentType; foreach (Cookie cookie in brokeredResponse.Cookies) { httpResponseBase.Cookies.Add(CookieToHttpCookie(cookie)); } foreach (var header in brokeredResponse.Headers.AllKeys .Where(k => !k.Equals("Transfer-Encoding", StringComparison.InvariantCultureIgnoreCase))) { httpResponseBase.Headers.Add(header, brokeredResponse.Headers[header]); } httpResponseBase.StatusCode = (int)brokeredResponse.StatusCode; httpResponseBase.StatusDescription = brokeredResponse.StatusDescription; BridgeAndCloseStreams(brokeredResponse.GetResponseStream(), httpResponseBase.OutputStream); } private static HttpWebRequest BuildWebRequest(HttpRequestBase requestToBroker, string redirectToUrl) { var httpRequest = (HttpWebRequest)WebRequest.Create(redirectToUrl); if (requestToBroker.Headers != null) { foreach (var header in requestToBroker.Headers.AllKeys) { if (RestrictedHeaders.Any(h => header.Equals(h, StringComparison.InvariantCultureIgnoreCase))) { continue; } httpRequest.Headers.Add(header, requestToBroker.Headers[header]); } } httpRequest.Accept = string.Join(",", requestToBroker.AcceptTypes); httpRequest.ContentType = requestToBroker.ContentType; httpRequest.Method = requestToBroker.HttpMethod; if (requestToBroker.UrlReferrer != null) { httpRequest.Referer = requestToBroker.UrlReferrer.AbsoluteUri; } httpRequest.UserAgent = requestToBroker.UserAgent; /* This is a performance change which I like. * If this is not explicitly set to null, the CLR will do a registry hit for each request to use the default proxy. */ httpRequest.Proxy = null; if (requestToBroker.HttpMethod.Equals("POST", StringComparison.InvariantCultureIgnoreCase)) { BridgeAndCloseStreams(requestToBroker.InputStream, httpRequest.GetRequestStream()); } return httpRequest; } /// <summary> /// Convert System.Net.Cookie into System.Web.HttpCookie /// </summary> private static HttpCookie CookieToHttpCookie(Cookie cookie) { HttpCookie httpCookie = new HttpCookie(cookie.Name); foreach (string value in cookie.Value.Split('&')) { string[] val = value.Split('='); httpCookie.Values.Add(val[0], val[1]); } httpCookie.Domain = cookie.Domain; httpCookie.Expires = cookie.Expires; httpCookie.HttpOnly = cookie.HttpOnly; httpCookie.Path = cookie.Path; httpCookie.Secure = cookie.Secure; return httpCookie; } /// <summary> /// Reads from stream into the to stream /// </summary> private static void BridgeAndCloseStreams(Stream from, Stream to) { try { int read; do { read = from.ReadByte(); if (read != -1) { to.WriteByte((byte)read); } } while (read != -1); } finally { from.Close(); to.Close(); } } } } </code></pre>

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