random port

[qwertzui11]

hi. Thx for your great on this awesome framework.

I'd like to host the server on a random port. Aka using port 0 and then call some method like get_port(). asio::*::acceptor assigns on port 0 a random port.
This is useful when it comes to unittests, that may run in parallel.
I could not find any information on that topic. Is there a possibility to set the port to 0 and then retreive it?

so far I got:

using server_t = restinio::http_server_t<>;
using settings_t = restinio::server_settings_t<>;

server_t srv1{
    restinio::external_io_context(*context),
    settings_t{}.port(0).address("localhost").request_handler([](auto) {
      return restinio::request_accepted();
    })};
#if 0
srv1.get_port(); // does not work. desperate experiment ;-)
#endif

thx for ur time!

[eao197]

Hi! Thanks for reporting this use-case.

We've never used RESTinio in such scenarios. I'll investigate the behavior of RESTinio's acceptor and reply to you back later.

[eao197]

At this time I don't see an easy way to pass the actual local_endpoint of the acceptor to the outside of http_server_t instance. One of the reasons is the fact that that local_endpoint will be known only after completion of http_server_t::open_sync method, but this moment is hard to detect from the outside of http_server_t instance.

One of the current ideas is to add another callback to server_settings_t. Something like:

asio::ip::tcp::endpoint server_endpoint;
...
server_t srv1{
    restinio::external_io_context(*context),
    settings_t{}.port(0).address("localhost")
      .post_acceptor_bind_hook([&server_endpoint](asio::ip::tcp::acceptor & acceptor) {
            server_endpoint = acceptor.local_endpoint();
         })
      .request_handler([](auto) {
         return restinio::request_accepted();
      })};
...

But I'm not sure that's a good idea yet. Will think further.

[qwertzui11]

I don't know this library well enough, nor its design.

hoooowever some ideas 😆

• inject a factory for asio::ip::tcp::acceptor, and more? like for resolver and more.
• open_sync could return a result that contains a port and maybe some other information thats available after the open. like the resolved bind endpoint?

[eao197]

Hi @qwertzui11 !

A new post-bind callback is added to RESTinio. You can see an example of its usage here:

restinio/dev/test/handle_requests/acceptor_post_bind_hook/main.cpp

Lines 23 to 66 in f3bdbfc

	std::promise<unsigned short> server_port_promise;
	auto server_port_future = server_port_promise.get_future();
	namespace asio_ns = restinio::asio_ns;
	http_server_t http_server{
	restinio::own_io_context(),
	[&server_port_promise]( auto & settings ){
	settings
	.port( 0u )
	.address( "127.0.0.1" )
	.acceptor_post_bind_hook(
	[&server_port_promise]( asio_ns::ip::tcp::acceptor & acceptor ) {
	server_port_promise.set_value(
	acceptor.local_endpoint().port() );
	} )
	.request_handler(
	[]( auto req ){
	req->create_response()
	.append_header( "Server", "RESTinio utest server" )
	.append_header_date_field()
	.append_header( "Content-Type", "text/plain; charset=utf-8" )
	.set_body(
	restinio::const_buffer( req->header().method().c_str() ) )
	.done();
	return restinio::request_accepted();
	} );
	} };
	other_work_thread_for_server_t<http_server_t> other_thread(http_server);
	other_thread.run();
	std::string response;
	const char * request_str =
	"GET / HTTP/1.1\r\n"
	"Host: 127.0.0.1\r\n"
	"User-Agent: unit-test\r\n"
	"Accept: */*\r\n"
	"Connection: close\r\n"
	"\r\n";
	REQUIRE_NOTHROW( response = do_request(
	request_str, "127.0.0.1", server_port_future.get() ) );

The new functionality is in 0.6-dev-0.6.11 branch now. I plan to add yet more functionality into v.0.6.11 before the public release of that version. Hope I can complete it in a week, but it hard to predict. So if you can't wait please let us know.

[qwertzui11]

excellent. I'll wait and try it out as soon as it's available on conan. Thx for the great work! 😍

[eao197]

It seems that the scope of v.0.6.11 is completed. We have to update to docs and then the release will be published.

[qwertzui11]

works! awesome, thx!