/// <summary>
/// default init
/// </summary>
public ProxyMiddleware()
{
_defaultOptions = new InternalProxyOptions()
{
SendChunked = false
};
// if port is not specified default one is taken
if (!_defaultOptions.Port.HasValue)
{
if (string.Equals(_defaultOptions.Scheme, "https", StringComparison.OrdinalIgnoreCase))
{
_defaultOptions.Port = 443;
}
else
{
_defaultOptions.Port = 80;
}
}
//if no scheme is choosen, http is taken
if (string.IsNullOrEmpty(_defaultOptions.Scheme))
{
_defaultOptions.Scheme = "http";
}
_httpClient = new HttpClient(_defaultOptions.BackChannelMessageHandler ?? new HttpClientHandler());
}
/// <summary>
/// Handle also Web socket, calling pump method inside
/// </summary>
/// <param name="context"></param>
/// <param name="_options"></param>
/// <param name="destination"></param>
/// <param name="host"></param>
/// <param name="port"></param>
/// <param name="scheme"></param>
/// <returns></returns>
private async Task HandleWebSocketRequest(HttpContext context, InternalProxyOptions _options, Node destination, string host, int port, string scheme)
{
using (var client = new ClientWebSocket())
{
foreach (var headerEntry in context.Request.Headers)
{
if (!NotForwardedWebSocketHeaders.Contains(headerEntry.Key, StringComparer.OrdinalIgnoreCase))
{
client.Options.SetRequestHeader(headerEntry.Key, headerEntry.Value);
}
}
var wsScheme = string.Equals(destination.Scheme, "https", StringComparison.OrdinalIgnoreCase) ? "wss" : "ws";
string url = GetUri(context, host, port, scheme);
if (_options.WebSocketKeepAliveInterval.HasValue)
{
client.Options.KeepAliveInterval = _options.WebSocketKeepAliveInterval.Value;
}
try
{
await client.ConnectAsync(new Uri(url), context.RequestAborted);
}
catch (WebSocketException)
{
context.Response.StatusCode = 400;
return;
}
using (var server = await context.WebSockets.AcceptWebSocketAsync(client.SubProtocol))
{
await Task.WhenAll(PumpWebSocket(context, client, server, _options, context.RequestAborted), PumpWebSocket(context, server, client, _options, context.RequestAborted));
}
}
}
/// <summary>
/// Handle a simple http request dumping remote content to the client
/// </summary>
/// <param name="context"></param>
/// <param name="_options"></param>
/// <param name="destination"></param>
/// <param name="host"></param>
/// <param name="port"></param>
/// <param name="scheme"></param>
/// <returns></returns>
private async Task HandleHttpRequest(HttpContext context, InternalProxyOptions _options, Node destination, string host, int port, string scheme)
{
var requestMessage = new HttpRequestMessage();
var requestMethod = context.Request.Method;
if (!HttpMethods.IsGet(requestMethod) && !HttpMethods.IsHead(requestMethod) && !HttpMethods.IsDelete(requestMethod) && !HttpMethods.IsTrace(requestMethod))
{
var streamContent = new StreamContent(context.Request.Body);
requestMessage.Content = streamContent;
}
// All request headers and cookies must be transferend to remote server. Some headers will be skipped
foreach (var header in context.Request.Headers)
{
if (!requestMessage.Headers.TryAddWithoutValidation(header.Key, header.Value.ToArray()) && requestMessage.Content != null)
{
requestMessage.Content?.Headers.TryAddWithoutValidation(header.Key, header.Value.ToArray());
}
}
requestMessage.Headers.Host = host;
//recreate remote url
string uriString = GetUri(context, host, port, scheme);
requestMessage.RequestUri = new Uri(uriString);
requestMessage.Method = new HttpMethod(context.Request.Method);
using (var responseMessage = await _httpClient.SendAsync(requestMessage, HttpCompletionOption.ResponseHeadersRead, context.RequestAborted))
{
context.Response.StatusCode = (int)responseMessage.StatusCode;
foreach (var header in responseMessage.Headers)
{
context.Response.Headers[header.Key] = header.Value.ToArray();
}
foreach (var header in responseMessage.Content.Headers)
{
context.Response.Headers[header.Key] = header.Value.ToArray();
}
if (!_options.SendChunked)
{
//tell to the browser that response is not chunked
context.Response.Headers.Remove("transfer-encoding");
await responseMessage.Content.CopyToAsync(context.Response.Body);
}
else
{
var buffer = new byte[_options.BufferSize ?? DefaultBufferSize];
using (var responseStream = await responseMessage.Content.ReadAsStreamAsync())
{
//long pos = responseStream.Position;
//if (pos > 0)
//{
// responseStream.Seek(0, SeekOrigin.Begin);
//}
//context.Response.Body = new MemoryStream();
int len = 0;
int full = 0;
while ((len = await responseStream.ReadAsync(buffer, 0, buffer.Length)) > 0)
{
await context.Response.Body.WriteAsync(buffer, 0, buffer.Length);
// await context.Response.Body.FlushAsync();
full += buffer.Length;
}
// context.Response.ContentLength = full;
context.Response.Headers.Remove("transfer-encoding");
}
}
}
}
/// <summary>
/// Core pump method
/// </summary>
/// <param name="context"></param>
/// <param name="source"></param>
/// <param name="destination"></param>
/// <param name="_options"></param>
/// <param name="cancellationToken"></param>
/// <returns></returns>
private async Task PumpWebSocket(HttpContext context, WebSocket source, WebSocket destination, InternalProxyOptions _options, CancellationToken cancellationToken)
{
var buffer = new byte[_options.BufferSize ?? DefaultBufferSize];
while (true)
{
WebSocketReceiveResult result;
try
{
result = await source.ReceiveAsync(new ArraySegment <byte>(buffer), cancellationToken);
}
catch (OperationCanceledException)
{
await destination.CloseOutputAsync(WebSocketCloseStatus.EndpointUnavailable, null, cancellationToken);
return;
}
if (result.MessageType == WebSocketMessageType.Close)
{
await destination.CloseOutputAsync(source.CloseStatus.Value, source.CloseStatusDescription, cancellationToken);
return;
}
await destination.SendAsync(new ArraySegment <byte>(buffer, 0, result.Count), result.MessageType, result.EndOfMessage, cancellationToken);
}
}
