Need Example WebSocket ping

[shakor0]

Hello,

Some websockets are not compliant and we need to be able to sendPings once in a while manually.
Please show an example on how to do this for a connectWebSocket (Client) stream.

Thank you.

[s-ludwig]

A simple ping can be sent like this:

ws.send((msg) { msg.write([]); }, FrameOpcode.ping);

This will send a ping message and should trigger a matching pong on the remote side. However, it will not count as a regular ping/pong within vibe.d's logic, so all it does is generate some network activity.

Do you know what exactly goes wrong on the connection? Are no pings generated at all by the server?

[shakor0]

It looks like some websocket servers expect the client to start pinging before sending an pong back, if the client does not send a ping the connection will get dropped.

What is msg in your example?

[s-ludwig]

Okay, sounds like this should work then, no idea whether the server expects any actual payload in the ping message. Maybe it also makes sense to add a new field HTTPClientSettings.webSocketPingInterval that would optionally enable the same ping logic as the WebSocket server currently performs.

msg is an OutgoingWebSocketMessage instance.

[shakor0]

Adding HTTPClientSettings.webSocketPingInterval for the client would indeed solve these issues.

[MrX273]

Does not work for me, could you show me a working example?

import vibe.core.core;
import vibe.core.log;
import vibe.http.fileserver : serveStaticFiles;
import vibe.http.router : URLRouter;
import vibe.http.server;
import vibe.web.web;
import vibe.http.websockets;
import vibe.vibe;


int main(string[] args)
{
	string WS_URL= "wss://echo.websocket.org";
	auto ws_url = URL(WS_URL);
	const use_tls = (ws_url.schema == "wss" || ws_url.schema == "https") ? true : false;
    ws_url.schema = use_tls ? "https" : "http";
    auto receiver = connectWebSocket(ws_url);
	
	
	ConnectionStream m_conn;
	RandomNumberStream m_rng;
	
	auto message = new OutgoingWebSocketMessage(m_conn, FrameOpcode.ping, m_rng);

	while (receiver.waitForData())
	 {
			auto msg = parseJsonString(receiver.receiveText());
			
			try {
					receiver.send((message) { message.write([]); }, FrameOpcode.ping);
				}
				catch (Exception ex)
				{
					logInfo("error %s", ex.msg);
				}
			logInfo("%s", msg);
	    }
	
	return 0;
}

[s-ludwig]

Cross-posting from forum: https://forum.rejectedsoftware.com/groups/rejectedsoftware.vibed/thread/279955/#post-279961