Beast SSL Stream Shutdown During Handshake

Question

I am using beast for implementation of HTTPS Client. In order to make the handshake I call async_handshake . But if I try to shutdown the stream via async_shutdown , I receive the following assert: boost::beast::detail::stream_base::pending_guard::pending_guard(bool&): Assertion `. b_' failed. boost::beast::detail::stream_base::pending_guard::pending_guard(bool&): Assertion `. b_' failed. Is there a way to correctly shutdown the stream during the handshake?

Answer 1

As far as I can tell the assertion means that a read/write operation is in progress. Make sure you synchronize access to the stream object using a (implicit) strand.

If you have only one thread, you should already have it. Otherwise, post to the strand executor, eg instead of

stream_.async_shutdown(handler);

Do something like

boost::asio::post(stream_.get_executor(),
     [self] { self->stream_.async_shutdown(handler); });

If the containing class has shared ownership you would have auto self = shared_from_this(); . Otherwise self could just be this .

More background on where and why of strands: Asio docs and Why do I need strand per connection when using boost::asio?