/// <summary>
/// Initiates an asynchronous call to the HTTP handler.
/// </summary>
/// <param name="context">An <see cref="T:System.Web.HttpContext"></see> object that provides references to intrinsic server objects (for example, Request, Response, Session, and Server) used to service HTTP requests.</param>
/// <param name="cb">The <see cref="T:System.AsyncCallback"></see> to call when the asynchronous method call is complete. If cb is null, the delegate is not called.</param>
/// <param name="extraData">Any extra data needed to process the request.</param>
/// <returns>
/// An <see cref="T:System.IAsyncResult"></see> that contains information about the status of the process.
/// </returns>
public IAsyncResult BeginProcessRequest(HttpContext context, AsyncCallback cb, object extraData)
{
Log.Debug(typeof(ProxyHandler), "BeginProcessRequest()");
// Request URL Format: http://<load-balancer>:<port>/<tenant>/<application>
Uri requestedUrl = context.Request.Url;
Log.Debug(typeof(ProxyHandler), "Request: " + requestedUrl);
ReverseProxyContext rpContext = new ReverseProxyContext();
rpContext.RequestedHostName = requestedUrl.Host;
rpContext.RequestedPort = requestedUrl.Port;
rpContext.RequestedPathAndQuery = requestedUrl.PathAndQuery;
rpContext.TenantName = findTenantName(rpContext.RequestedPathAndQuery);
rpContext.ApplicationName = findApplicationName(rpContext.RequestedPathAndQuery);
if ((!string.IsNullOrEmpty(rpContext.TenantName)) && (!string.IsNullOrEmpty(rpContext.ApplicationName)))
{
rpContext.ApplicationInstance = LoadBalancerControllerWebUtil.GetApplicationInstance(rpContext.TenantName, rpContext.ApplicationName);
if (rpContext.ApplicationInstance != null)
{
// Asynchronously add request to the load balancer request queue
rpContext.AddReqCaller = new ASyncAddRequestToQueue(AddRequestToQueue);
addReqResult = rpContext.AddReqCaller.BeginInvoke(context, rpContext.ApplicationInstance.NodeId,
rpContext.ApplicationInstance.ApplicationId,
rpContext.ApplicationInstance.Id,
rpContext.ApplicationInstance.Tenant.Id, null, null);
}
}
delegate_ = new AsyncProcessorDelegate(ReverseProxyRequest);
return(delegate_.BeginInvoke(context, rpContext, cb, extraData));
}
/// <summary>
/// Initiates an asynchronous call to the HTTP handler.
/// </summary>
/// <param name="context">An <see cref="T:System.Web.HttpContext"></see> object that provides references to intrinsic server objects (for example, Request, Response, Session, and Server) used to service HTTP requests.</param>
/// <param name="cb">The <see cref="T:System.AsyncCallback"></see> to call when the asynchronous method call is complete. If cb is null, the delegate is not called.</param>
/// <param name="extraData">Any extra data needed to process the request.</param>
/// <returns>
/// An <see cref="T:System.IAsyncResult"></see> that contains information about the status of the process.
/// </returns>
public IAsyncResult BeginProcessRequest(HttpContext context, AsyncCallback cb, object extraData)
{
Log.Debug(typeof(ProxyHandler), "BeginProcessRequest()");
// Request URL Format: http://<load-balancer>:<port>/<tenant>/<application>
Uri requestedUrl = context.Request.Url;
Log.Debug(typeof(ProxyHandler), "Request: " + requestedUrl);
ReverseProxyContext rpContext = new ReverseProxyContext();
rpContext.RequestedHostName = requestedUrl.Host;
rpContext.RequestedPort = requestedUrl.Port;
rpContext.RequestedPathAndQuery = requestedUrl.PathAndQuery;
rpContext.TenantName = findTenantName(rpContext.RequestedPathAndQuery);
rpContext.ApplicationName = findApplicationName(rpContext.RequestedPathAndQuery);
if ((!string.IsNullOrEmpty(rpContext.TenantName)) && (!string.IsNullOrEmpty(rpContext.ApplicationName)))
{
rpContext.ApplicationInstance = LoadBalancerControllerWebUtil.GetApplicationInstance(rpContext.TenantName, rpContext.ApplicationName);
if (rpContext.ApplicationInstance != null)
{
// Asynchronously add request to the load balancer request queue
rpContext.AddReqCaller = new ASyncAddRequestToQueue(AddRequestToQueue);
addReqResult = rpContext.AddReqCaller.BeginInvoke(context, rpContext.ApplicationInstance.NodeId,
rpContext.ApplicationInstance.ApplicationId,
rpContext.ApplicationInstance.Id,
rpContext.ApplicationInstance.Tenant.Id, null, null);
}
}
delegate_ = new AsyncProcessorDelegate(ReverseProxyRequest);
return delegate_.BeginInvoke(context, rpContext, cb, extraData);
}
//private bool IncrementRequestCount(ApplicationInstance instance)
//{
// LbIncrementRequestCountRequest request = new LbIncrementRequestCountRequest(Settings.Credentials);
// request.ApplicationId = instance.ApplicationId;
// request.InstanceId = instance.Id;
// EndPoints.LoadBalancerWebService.IncrementRequestCount(request);
// return true;
//}
//private void DecrementRequestCount(ApplicationInstance instance)
//{
// LbDecrementRequestCountRequest request = new LbDecrementRequestCountRequest(Settings.Credentials);
// request.ApplicationId = instance.ApplicationId;
// request.InstanceId = instance.Id;
// EndPoints.LoadBalancerWebService.DecrementRequestCount(request);
//}
/// <summary>
/// Sends the request to server
/// Implemented using Managed Fusion URL Rewriter
/// Reference: http://www.managedfusion.com/products/url-rewriter/
/// </summary>
/// <param name="context">The context.</param>
/// <returns></returns>
private WebResponse SendRequestToTarget(HttpContext context, Uri requestUrl, ReverseProxyContext rpContext, out bool incremented)
{
incremented = false;
// get the request
WebRequest request = WebRequest.CreateDefault(requestUrl);
if (request == null)
throw new HttpException((int)HttpStatusCode.BadRequest, "The requested url, <" + requestUrl + ">, could not be found.");
// keep the same HTTP request method
request.Method = context.Request.HttpMethod;
var knownVerb = KnownHttpVerb.Parse(request.Method);
// depending on the type of this request specific values for an HTTP request
if (request is HttpWebRequest)
{
var httpRequest = request as HttpWebRequest;
httpRequest.AllowAutoRedirect = false;
httpRequest.ServicePoint.Expect100Continue = false;
// add all the headers from the other proxied session to this request
foreach (string name in context.Request.Headers.AllKeys)
{
// add the headers that are restricted in their supported manor
switch (name)
{
case "User-Agent":
httpRequest.UserAgent = context.Request.UserAgent;
break;
case "Connection":
string connection = context.Request.Headers[name];
if (connection.IndexOf("Keep-Alive", StringComparison.OrdinalIgnoreCase) > 0)
httpRequest.KeepAlive = true;
List<string> list = new List<string>();
foreach (string conn in connection.Split(','))
{
string c = conn.Trim();
if (!c.Equals("Keep-Alive", StringComparison.OrdinalIgnoreCase) && !c.Equals("Close", StringComparison.OrdinalIgnoreCase))
list.Add(c);
}
if (list.Count > 0)
httpRequest.Connection = String.Join(", ", list.ToArray());
break;
case "Transfer-Encoding":
httpRequest.SendChunked = true;
httpRequest.TransferEncoding = context.Request.Headers[name];
break;
case "Expect":
httpRequest.ServicePoint.Expect100Continue = true;
break;
case "If-Modified-Since":
DateTime ifModifiedSince;
if (DateTime.TryParse(context.Request.Headers[name], out ifModifiedSince))
httpRequest.IfModifiedSince = ifModifiedSince;
break;
case "Content-Length":
httpRequest.ContentLength = context.Request.ContentLength;
break;
case "Content-Type":
httpRequest.ContentType = context.Request.ContentType;
break;
case "Accept":
httpRequest.Accept = String.Join(", ", context.Request.AcceptTypes);
break;
case "Referer":
httpRequest.Referer = context.Request.UrlReferrer.OriginalString;
break;
}
// add to header if not restricted
if (!WebHeaderCollection.IsRestricted(name, false))
{
// it is nessisary to get the values for headers that are allowed to specifiy
// multiple values in an instance (i.e. Cookie)
string[] values = context.Request.Headers.GetValues(name);
foreach (string value in values)
request.Headers.Add(name, value);
}
}
}
// Add Proxy Standard Protocol Headers
// http://en.wikipedia.org/wiki/X-Forwarded-For
request.Headers.Add("X-Forwarded-For", context.Request.UserHostAddress);
// Add Server Variables
// http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.45
string currentServerName = context.Request.ServerVariables["SERVER_NAME"];
string currentServerPort = context.Request.ServerVariables["SERVER_PORT"];
string currentServerProtocol = context.Request.ServerVariables["SERVER_PROTOCOL"];
if (currentServerProtocol.IndexOf("/") >= 0)
currentServerProtocol = currentServerProtocol.Substring(currentServerProtocol.IndexOf("/") + 1);
string currentVia = String.Format("{0} {1}:{2} ({3})", currentServerProtocol, currentServerName, currentServerPort, "Monoscape.LoadBalancerController");
request.Headers.Add("Via", currentVia);
//
// ContentLength is set to -1 if their is no data to send
if ((request.ContentLength >= 0) && (!knownVerb.ContentBodyNotAllowed))
{
int bufferSize = 64 * 1024;
using (Stream requestStream = request.GetRequestStream(), bufferStream = new BufferedStream(context.Request.InputStream, bufferSize))
{
byte[] buffer = new byte[bufferSize];
try
{
while (true)
{
// make sure that the stream can be read from
if (!bufferStream.CanRead)
break;
int bytesReturned = bufferStream.Read(buffer, 0, bufferSize);
// if not bytes were returned the end of the stream has been reached
// and the loop should exit
if (bytesReturned == 0)
break;
// write bytes to the response
requestStream.Write(buffer, 0, bytesReturned);
}
}
catch (Exception e)
{
Log.Error(typeof(ProxyHandler), "", e);
}
}
}
WebResponse response;
try
{
// Increment application instance request count
//incremented = IncrementRequestCount(rpContext.ApplicationInstance);
if (addReqResult != null)
{
int requestId = rpContext.AddReqCaller.EndInvoke(addReqResult);
// Remove request from load balancer request queue
ASyncRemoveRequestFromQueue caller = new ASyncRemoveRequestFromQueue(RemoveRequestFromQueue);
caller.BeginInvoke(requestId, null, null);
}
// Send request to the proxy target
response = request.GetResponse();
}
catch (WebException e)
{
Log.Error(typeof(ProxyHandler), "Error received from " + request.RequestUri + ": " + e.Message, e);
response = e.Response;
}
if (response == null)
{
Log.Error(typeof(ProxyHandler), "The requested url " + requestUrl + " could not be found.");
throw new HttpException((int)HttpStatusCode.NotFound, "The requested url could not be found.");
}
Log.Info(typeof(ProxyHandler), response.GetType().ToString());
if (response is HttpWebResponse)
{
HttpWebResponse httpResponse = response as HttpWebResponse;
Log.Info(typeof(ProxyHandler), "Received '" + ((int)httpResponse.StatusCode) + " " + httpResponse.StatusDescription + "'");
}
return response;
}
private void ReverseProxyRequest(HttpContext context, ReverseProxyContext rpContext)
{
Log.Debug(typeof(ProxyHandler), "ReverseProxyRequest()");
// Request URL Format: http://<load-balancer>:<port>/<tenant>/<application>
Uri requestedUrl = context.Request.Url;
Log.Debug(typeof(ProxyHandler), "Request: " + requestedUrl);
if ((!string.IsNullOrEmpty(rpContext.TenantName)) && (!string.IsNullOrEmpty(rpContext.ApplicationName)))
{
var appInstance = rpContext.ApplicationInstance;
if (appInstance == null)
{
context.Response.Write("Application or the tenant not found");
context.Response.StatusCode = (int)HttpStatusCode.NotFound;
context.Response.End();
return;
}
else
{
Uri proxyRequestUrl = null;
Uri proxyResponseUrl = null;
WebResponse response = null;
bool incremented = false;
try
{
// Use same path and query for the reverse proxy
string pathAndQuery = rpContext.RequestedPathAndQuery;
// Set Proxy Host Name/Port
string proxyHostName = appInstance.IpAddress;
int proxyPort = appInstance.Port;
UriBuilder requestUrlBuilder = new UriBuilder(requestedUrl.Scheme, proxyHostName, proxyPort, pathAndQuery);
proxyRequestUrl = requestUrlBuilder.Uri;
Log.Debug(typeof(ProxyHandler), "Proxy Request: " + proxyRequestUrl);
UriBuilder responseUrlBuilder = new UriBuilder(requestedUrl.Scheme, rpContext.RequestedHostName, rpContext.RequestedPort, rpContext.RequestedPathAndQuery);
proxyResponseUrl = responseUrlBuilder.Uri;
// Send the request to the selected application instance
response = SendRequestToTarget(context, proxyRequestUrl, rpContext, out incremented);
}
catch (HttpException e)
{
Log.Error(this, "Http Error: " + e.GetHttpCode(), e);
context.Response.Write(e.Message);
context.Response.StatusCode = e.GetHttpCode();
context.Response.End();
return;
}
catch (Exception e)
{
Log.Error(this, e);
context.Response.Write("An internal error occurred");
context.Response.StatusCode = (int)HttpStatusCode.InternalServerError;
context.Response.End();
return;
}
finally
{
//if (incremented)
//{
// // Decrement application instance request count
// DecrementRequestCount(appInstance);
//}
if (response != null)
{
// Send the response to the client
SendResponseToClient(context, response, proxyRequestUrl, proxyResponseUrl);
}
}
}
}
else
{
context.Response.Write(String.Format("Invalid request URL, expected: http://{0}:{1}/tenant/application", rpContext.RequestedHostName, rpContext.RequestedPort));
context.Response.StatusCode = (int)HttpStatusCode.NotFound;
context.Response.End();
return;
}
}
//private bool IncrementRequestCount(ApplicationInstance instance)
//{
// LbIncrementRequestCountRequest request = new LbIncrementRequestCountRequest(Settings.Credentials);
// request.ApplicationId = instance.ApplicationId;
// request.InstanceId = instance.Id;
// EndPoints.LoadBalancerWebService.IncrementRequestCount(request);
// return true;
//}
//private void DecrementRequestCount(ApplicationInstance instance)
//{
// LbDecrementRequestCountRequest request = new LbDecrementRequestCountRequest(Settings.Credentials);
// request.ApplicationId = instance.ApplicationId;
// request.InstanceId = instance.Id;
// EndPoints.LoadBalancerWebService.DecrementRequestCount(request);
//}
/// <summary>
/// Sends the request to server
/// Implemented using Managed Fusion URL Rewriter
/// Reference: http://www.managedfusion.com/products/url-rewriter/
/// </summary>
/// <param name="context">The context.</param>
/// <returns></returns>
private WebResponse SendRequestToTarget(HttpContext context, Uri requestUrl, ReverseProxyContext rpContext, out bool incremented)
{
incremented = false;
// get the request
WebRequest request = WebRequest.CreateDefault(requestUrl);
if (request == null)
{
throw new HttpException((int)HttpStatusCode.BadRequest, "The requested url, <" + requestUrl + ">, could not be found.");
}
// keep the same HTTP request method
request.Method = context.Request.HttpMethod;
var knownVerb = KnownHttpVerb.Parse(request.Method);
// depending on the type of this request specific values for an HTTP request
if (request is HttpWebRequest)
{
var httpRequest = request as HttpWebRequest;
httpRequest.AllowAutoRedirect = false;
httpRequest.ServicePoint.Expect100Continue = false;
// add all the headers from the other proxied session to this request
foreach (string name in context.Request.Headers.AllKeys)
{
// add the headers that are restricted in their supported manor
switch (name)
{
case "User-Agent":
httpRequest.UserAgent = context.Request.UserAgent;
break;
case "Connection":
string connection = context.Request.Headers[name];
if (connection.IndexOf("Keep-Alive", StringComparison.OrdinalIgnoreCase) > 0)
{
httpRequest.KeepAlive = true;
}
List <string> list = new List <string>();
foreach (string conn in connection.Split(','))
{
string c = conn.Trim();
if (!c.Equals("Keep-Alive", StringComparison.OrdinalIgnoreCase) && !c.Equals("Close", StringComparison.OrdinalIgnoreCase))
{
list.Add(c);
}
}
if (list.Count > 0)
{
httpRequest.Connection = String.Join(", ", list.ToArray());
}
break;
case "Transfer-Encoding":
httpRequest.SendChunked = true;
httpRequest.TransferEncoding = context.Request.Headers[name];
break;
case "Expect":
httpRequest.ServicePoint.Expect100Continue = true;
break;
case "If-Modified-Since":
DateTime ifModifiedSince;
if (DateTime.TryParse(context.Request.Headers[name], out ifModifiedSince))
{
httpRequest.IfModifiedSince = ifModifiedSince;
}
break;
case "Content-Length":
httpRequest.ContentLength = context.Request.ContentLength;
break;
case "Content-Type":
httpRequest.ContentType = context.Request.ContentType;
break;
case "Accept":
httpRequest.Accept = String.Join(", ", context.Request.AcceptTypes);
break;
case "Referer":
httpRequest.Referer = context.Request.UrlReferrer.OriginalString;
break;
}
// add to header if not restricted
if (!WebHeaderCollection.IsRestricted(name, false))
{
// it is nessisary to get the values for headers that are allowed to specifiy
// multiple values in an instance (i.e. Cookie)
string[] values = context.Request.Headers.GetValues(name);
foreach (string value in values)
{
request.Headers.Add(name, value);
}
}
}
}
// Add Proxy Standard Protocol Headers
// http://en.wikipedia.org/wiki/X-Forwarded-For
request.Headers.Add("X-Forwarded-For", context.Request.UserHostAddress);
// Add Server Variables
// http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.45
string currentServerName = context.Request.ServerVariables["SERVER_NAME"];
string currentServerPort = context.Request.ServerVariables["SERVER_PORT"];
string currentServerProtocol = context.Request.ServerVariables["SERVER_PROTOCOL"];
if (currentServerProtocol.IndexOf("/") >= 0)
{
currentServerProtocol = currentServerProtocol.Substring(currentServerProtocol.IndexOf("/") + 1);
}
string currentVia = String.Format("{0} {1}:{2} ({3})", currentServerProtocol, currentServerName, currentServerPort, "Monoscape.LoadBalancerController");
request.Headers.Add("Via", currentVia);
//
// ContentLength is set to -1 if their is no data to send
if ((request.ContentLength >= 0) && (!knownVerb.ContentBodyNotAllowed))
{
int bufferSize = 64 * 1024;
using (Stream requestStream = request.GetRequestStream(), bufferStream = new BufferedStream(context.Request.InputStream, bufferSize))
{
byte[] buffer = new byte[bufferSize];
try
{
while (true)
{
// make sure that the stream can be read from
if (!bufferStream.CanRead)
{
break;
}
int bytesReturned = bufferStream.Read(buffer, 0, bufferSize);
// if not bytes were returned the end of the stream has been reached
// and the loop should exit
if (bytesReturned == 0)
{
break;
}
// write bytes to the response
requestStream.Write(buffer, 0, bytesReturned);
}
}
catch (Exception e)
{
Log.Error(typeof(ProxyHandler), "", e);
}
}
}
WebResponse response;
try
{
// Increment application instance request count
//incremented = IncrementRequestCount(rpContext.ApplicationInstance);
if (addReqResult != null)
{
int requestId = rpContext.AddReqCaller.EndInvoke(addReqResult);
// Remove request from load balancer request queue
ASyncRemoveRequestFromQueue caller = new ASyncRemoveRequestFromQueue(RemoveRequestFromQueue);
caller.BeginInvoke(requestId, null, null);
}
// Send request to the proxy target
response = request.GetResponse();
}
catch (WebException e)
{
Log.Error(typeof(ProxyHandler), "Error received from " + request.RequestUri + ": " + e.Message, e);
response = e.Response;
}
if (response == null)
{
Log.Error(typeof(ProxyHandler), "The requested url " + requestUrl + " could not be found.");
throw new HttpException((int)HttpStatusCode.NotFound, "The requested url could not be found.");
}
Log.Info(typeof(ProxyHandler), response.GetType().ToString());
if (response is HttpWebResponse)
{
HttpWebResponse httpResponse = response as HttpWebResponse;
Log.Info(typeof(ProxyHandler), "Received '" + ((int)httpResponse.StatusCode) + " " + httpResponse.StatusDescription + "'");
}
return(response);
}
private void ReverseProxyRequest(HttpContext context, ReverseProxyContext rpContext)
{
Log.Debug(typeof(ProxyHandler), "ReverseProxyRequest()");
// Request URL Format: http://<load-balancer>:<port>/<tenant>/<application>
Uri requestedUrl = context.Request.Url;
Log.Debug(typeof(ProxyHandler), "Request: " + requestedUrl);
if ((!string.IsNullOrEmpty(rpContext.TenantName)) && (!string.IsNullOrEmpty(rpContext.ApplicationName)))
{
var appInstance = rpContext.ApplicationInstance;
if (appInstance == null)
{
context.Response.Write("Application or the tenant not found");
context.Response.StatusCode = (int)HttpStatusCode.NotFound;
context.Response.End();
return;
}
else
{
Uri proxyRequestUrl = null;
Uri proxyResponseUrl = null;
WebResponse response = null;
bool incremented = false;
try
{
// Use same path and query for the reverse proxy
string pathAndQuery = rpContext.RequestedPathAndQuery;
// Set Proxy Host Name/Port
string proxyHostName = appInstance.IpAddress;
int proxyPort = appInstance.Port;
UriBuilder requestUrlBuilder = new UriBuilder(requestedUrl.Scheme, proxyHostName, proxyPort, pathAndQuery);
proxyRequestUrl = requestUrlBuilder.Uri;
Log.Debug(typeof(ProxyHandler), "Proxy Request: " + proxyRequestUrl);
UriBuilder responseUrlBuilder = new UriBuilder(requestedUrl.Scheme, rpContext.RequestedHostName, rpContext.RequestedPort, rpContext.RequestedPathAndQuery);
proxyResponseUrl = responseUrlBuilder.Uri;
// Send the request to the selected application instance
response = SendRequestToTarget(context, proxyRequestUrl, rpContext, out incremented);
}
catch (HttpException e)
{
Log.Error(this, "Http Error: " + e.GetHttpCode(), e);
context.Response.Write(e.Message);
context.Response.StatusCode = e.GetHttpCode();
context.Response.End();
return;
}
catch (Exception e)
{
Log.Error(this, e);
context.Response.Write("An internal error occurred");
context.Response.StatusCode = (int)HttpStatusCode.InternalServerError;
context.Response.End();
return;
}
finally
{
//if (incremented)
//{
// // Decrement application instance request count
// DecrementRequestCount(appInstance);
//}
if (response != null)
{
// Send the response to the client
SendResponseToClient(context, response, proxyRequestUrl, proxyResponseUrl);
}
}
}
}
else
{
context.Response.Write(String.Format("Invalid request URL, expected: http://{0}:{1}/tenant/application", rpContext.RequestedHostName, rpContext.RequestedPort));
context.Response.StatusCode = (int)HttpStatusCode.NotFound;
context.Response.End();
return;
}
}
