Method StartDetectClientSideShutdown

lib/remote/httpserverconnection.cpp:107–148

* Starts a coroutine that continually reads from the stream to detect a disconnect from the client. * * This can be accessed inside an @c HttpHandler via the HttpResponse::StartStreaming() method by * passing true as the argument, expressing that disconnect detection is desired. */

 * passing true as the argument, expressing that disconnect detection is desired.
 */
void HttpServerConnection::StartDetectClientSideShutdown()
{
	namespace asio = boost::asio;

	m_ConnectionReusable = false;

	HttpServerConnection::Ptr keepAlive (this);

	/* Technically it would be possible to detect disconnects on the TCP-side by setting the
	 * socket to non-blocking and then performing a read directly on the socket with the message_peek
	 * flag. As the TCP FIN message will put the connection into a CLOSE_WAIT even if the kernel
	 * buffer is full, this would technically be reliable way of detecting a shutdown and free
	 * of side-effects.
	 *
	 * However, for detecting the close_notify on the SSL/TLS-side, an async_fill() would be necessary
	 * when the check on the TCP level above returns that there are readable bytes (and no FIN/eof).
	 * If this async_fill() then buffers more application data and not an immediate eof, we could
	 * attempt to read another message before disconnecting.
	 *
	 * This could either be done at the level of the handlers, via the @c HttpApiResponse class, or
	 * generally as a separate coroutine here in @c HttpServerConnection, both (mostly) side-effect
	 * free and without affecting the state of the connection.
	 *
	 * However, due to the complexity of this approach, involving several asio operations, message
	 * flags, synchronous and asynchronous operations in blocking and non-blocking mode, ioctl cmds,
	 * etc., it was decided to stick with a simple reading loop, started conditionally on request by
	 * the handler.
	 */
	IoEngine::SpawnCoroutine(m_IoStrand, [this, keepAlive](asio::yield_context yc) {
		if (!m_ShuttingDown) {
			char buf[128];
			asio::mutable_buffer readBuf (buf, 128);
			boost::system::error_code ec;

			do {
				m_Stream->async_read_some(readBuf, yc[ec]);
			} while (!ec);

			Disconnect(yc);
		}
	});
}

bool HttpServerConnection::Disconnected()
{