I want to connect to the Push API of Poloniex. On their page they write the following:
In order to use the push API, connect to wss://api.poloniex.com and subscribe to the desired feed.
wss = WebSocket Secure -> SSL Protected
They also give an example for Node.js and Autobahn|JS:
var autobahn = require('autobahn');
var wsuri = "wss://api.poloniex.com";
var connection = new autobahn.Connection({
url: wsuri,
realm: "realm1"
});
connection.onopen = function (session) {
function marketEvent (args,kwargs) {
console.log(args);
}
function tickerEvent (args,kwargs) {
console.log(args);
}
function trollboxEvent (args,kwargs) {
console.log(args);
}
session.subscribe('BTC_XMR', marketEvent);
session.subscribe('ticker', tickerEvent);
session.subscribe('trollbox', trollboxEvent);
}
connection.onclose = function () {
console.log("Websocket connection closed");
}
connection.open();
However, I do not want to use JavaScript, instead I use C++. There's also a Autobahn-Library for C++, called Autobahn|CPP. I've installed it and tried to run their subscriber example code with little modifications (basically just hardcoded the adress and port):
#include <autobahn/autobahn.hpp>
#include <boost/asio.hpp>
#include <iostream>
#include <memory>
#include <tuple>
void topic1(const autobahn::wamp_event& event)
{
std::cerr << "received event: " << event.argument<uint64_t>(0) << std::endl;
}
using namespace boost;
using namespace boost::asio;
using namespace boost::asio::ip;
int main()
{
try {
boost::asio::io_service io;
boost::asio::ip::tcp::socket socket(io);
bool debug = true;
auto session = std::make_shared<
autobahn::wamp_session<boost::asio::ip::tcp::socket,
boost::asio::ip::tcp::socket>>(io, socket, socket, debug);
boost::future<void> start_future;
boost::future<void> join_future;
boost::asio::ip::tcp::endpoint rawsocket_endpoint( boost::asio::ip::address::from_string("173.236.42.218"), 443/*8000=standard*/);
socket.async_connect(rawsocket_endpoint,
[&](boost::system::error_code ec) {
if (!ec) {
std::cerr << "connected to server" << std::endl;
start_future = session->start().then([&](boost::future<bool> started) {
if (started.get()) {
std::cerr << "session started" << std::endl;
join_future = session->join("realm1").then([&](boost::future<uint64_t> s) {
std::cerr << "joined realm: " << s.get() << std::endl;
session->subscribe("ticker", &topic1);
});
} else {
std::cerr << "failed to start session" << std::endl;
io.stop();
}
});
} else {
std::cerr << "connect failed: " << ec.message() << std::endl;
io.stop();
}
}
);
std::cerr << "starting io service" << std::endl;
io.run();
std::cerr << "stopped io service" << std::endl;
}
catch (std::exception& e) {
std::cerr << e.what() << std::endl;
return 1;
}
return 0;
}
There are a few things to explain here: I found out the IP-Adress 173.236.42.218 by simply pinging api.poloniex.com.
Port 443 is the standard SSL-Port. I've tried using the standard WAMP/WebSocket port which is 8000, but the server does not accept that. 80 is also not accepted.
So if I start the program, the output is the following:
starting io service
connected to server
Then, nothing happens. So the code must be stuck at session_start(), where the WS handshake is performed, what you can see when you look into wamp_session.ipp at line 80.
In my opinion the problem is that the API wants to use a secure connection (wss://). It seems like this piece of code does not try to create a SSL-encrypted connection and I don't know how to tell the session that I need a secure one.
Edit: In this question the Author says that Autobahn can't handle mixed http/wamp servers where and upgrade http-request is required first before using the WebSocket protocol. I know Poloniex uses such a mixed type, but I've tried to access the API with Autobahn|JS already and there it works fine, also sending the upgrade request. So maybe this is a Autobahn|CPP issue?
Edit 2: If the above is true, is it possible to send the Http-Update-Request myself and maybe even put a SSL-encryption onto the connection? I'm not sure because maybe that would interfere the library.