private async Task ProcessNegotiate(HttpContext context, HttpConnectionDispatcherOptions options, ConnectionLogScope logScope)
{
context.Response.ContentType = "application/json";
string error = null;
int clientProtocolVersion = 0;
if (context.Request.Query.TryGetValue("NegotiateVersion", out var queryStringVersion))
{
// Set the negotiate response to the protocol we use.
var queryStringVersionValue = queryStringVersion.ToString();
if (!int.TryParse(queryStringVersionValue, out clientProtocolVersion))
{
error = $"The client requested an invalid protocol version '{queryStringVersionValue}'";
Log.InvalidNegotiateProtocolVersion(_logger, queryStringVersionValue);
}
else if (clientProtocolVersion < options.MinimumProtocolVersion)
{
error = $"The client requested version '{clientProtocolVersion}', but the server does not support this version.";
Log.NegotiateProtocolVersionMismatch(_logger, clientProtocolVersion);
}
else if (clientProtocolVersion > _protocolVersion)
{
clientProtocolVersion = _protocolVersion;
}
}
else if (options.MinimumProtocolVersion > 0)
{
// NegotiateVersion wasn't parsed meaning the client requests version 0.
error = $"The client requested version '0', but the server does not support this version.";
Log.NegotiateProtocolVersionMismatch(_logger, 0);
}
// Establish the connection
HttpConnectionContext connection = null;
if (error == null)
{
connection = CreateConnection(options, clientProtocolVersion);
}
// Set the Connection ID on the logging scope so that logs from now on will have the
// Connection ID metadata set.
logScope.ConnectionId = connection?.ConnectionId;
// Don't use thread static instance here because writer is used with async
var writer = new MemoryBufferWriter();
try
{
// Get the bytes for the connection id
WriteNegotiatePayload(writer, connection?.ConnectionId, connection?.ConnectionToken, context, options, clientProtocolVersion, error);
Log.NegotiationRequest(_logger);
// Write it out to the response with the right content length
context.Response.ContentLength = writer.Length;
await writer.CopyToAsync(context.Response.Body);
}
finally
{
writer.Reset();
}
}
private async Task <bool> EnsureConnectionStateAsync(HttpConnectionContext connection, HttpContext context, HttpTransportType transportType, HttpTransportType supportedTransports, ConnectionLogScope logScope, HttpConnectionDispatcherOptions options)
{
if ((supportedTransports & transportType) == 0)
{
context.Response.ContentType = "text/plain";
context.Response.StatusCode = StatusCodes.Status404NotFound;
Log.TransportNotSupported(_logger, transportType);
await context.Response.WriteAsync($"{transportType} transport not supported by this end point type");
return(false);
}
// Set the IHttpConnectionFeature now that we can access it.
connection.Features.Set(context.Features.Get <IHttpConnectionFeature>());
if (connection.TransportType == HttpTransportType.None)
{
connection.TransportType = transportType;
}
else if (connection.TransportType != transportType)
{
context.Response.ContentType = "text/plain";
context.Response.StatusCode = StatusCodes.Status400BadRequest;
Log.CannotChangeTransport(_logger, connection.TransportType, transportType);
await context.Response.WriteAsync("Cannot change transports mid-connection");
return(false);
}
// Configure transport-specific features.
if (transportType == HttpTransportType.LongPolling)
{
connection.HasInherentKeepAlive = true;
// For long polling, the requests come and go but the connection is still alive.
// To make the IHttpContextFeature work well, we make a copy of the relevant properties
// to a new HttpContext. This means that it's impossible to affect the context
// with subsequent requests.
var existing = connection.HttpContext;
if (existing == null)
{
var httpContext = CloneHttpContext(context);
connection.HttpContext = httpContext;
}
else
{
// Set the request trace identifier to the current http request handling the poll
existing.TraceIdentifier = context.TraceIdentifier;
// Don't copy the identity if it's a windows identity
// We specifically clone the identity on first poll if it's a windows identity
// If we swapped the new User here we'd have to dispose the old identities which could race with the application
// trying to access the identity.
if (!(context.User.Identity is WindowsIdentity))
{
existing.User = context.User;
}
}
}
else
{
connection.HttpContext = context;
}
// Setup the connection state from the http context
connection.User = connection.HttpContext.User;
// Set the Connection ID on the logging scope so that logs from now on will have the
// Connection ID metadata set.
logScope.ConnectionId = connection.ConnectionId;
return(true);
}
private static void CloneHttpContext(HttpContext context, HttpConnectionContext connection)
{
// The reason we're copying the base features instead of the HttpContext properties is
// so that we can get all of the logic built into DefaultHttpContext to extract higher level
// structure from the low level properties
var existingRequestFeature = context.Features.Get <IHttpRequestFeature>();
var requestFeature = new HttpRequestFeature();
requestFeature.Protocol = existingRequestFeature.Protocol;
requestFeature.Method = existingRequestFeature.Method;
requestFeature.Scheme = existingRequestFeature.Scheme;
requestFeature.Path = existingRequestFeature.Path;
requestFeature.PathBase = existingRequestFeature.PathBase;
requestFeature.QueryString = existingRequestFeature.QueryString;
requestFeature.RawTarget = existingRequestFeature.RawTarget;
var requestHeaders = new Dictionary <string, StringValues>(existingRequestFeature.Headers.Count, StringComparer.OrdinalIgnoreCase);
foreach (var header in existingRequestFeature.Headers)
{
requestHeaders[header.Key] = header.Value;
}
requestFeature.Headers = new HeaderDictionary(requestHeaders);
var existingConnectionFeature = context.Features.Get <IHttpConnectionFeature>();
var connectionFeature = new HttpConnectionFeature();
if (existingConnectionFeature != null)
{
connectionFeature.ConnectionId = existingConnectionFeature.ConnectionId;
connectionFeature.LocalIpAddress = existingConnectionFeature.LocalIpAddress;
connectionFeature.LocalPort = existingConnectionFeature.LocalPort;
connectionFeature.RemoteIpAddress = existingConnectionFeature.RemoteIpAddress;
connectionFeature.RemotePort = existingConnectionFeature.RemotePort;
}
// The response is a dud, you can't do anything with it anyways
var responseFeature = new HttpResponseFeature();
var features = new FeatureCollection();
features.Set <IHttpRequestFeature>(requestFeature);
features.Set <IHttpResponseFeature>(responseFeature);
features.Set <IHttpResponseBodyFeature>(new StreamResponseBodyFeature(Stream.Null));
features.Set <IHttpConnectionFeature>(connectionFeature);
// REVIEW: We could strategically look at adding other features but it might be better
// if we expose a callback that would allow the user to preserve HttpContext properties.
var newHttpContext = new DefaultHttpContext(features);
newHttpContext.TraceIdentifier = context.TraceIdentifier;
var endpointFeature = context.Features.Get <IEndpointFeature>();
newHttpContext.SetEndpoint(endpointFeature?.Endpoint);
CloneUser(newHttpContext, context);
connection.ServiceScope = context.RequestServices.CreateScope();
newHttpContext.RequestServices = connection.ServiceScope.ServiceProvider;
// REVIEW: This extends the lifetime of anything that got put into HttpContext.Items
newHttpContext.Items = new Dictionary <object, object>(context.Items);
connection.HttpContext = newHttpContext;
}
