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Websocket server connection control

Since SFU SDK build 2.0.194 it is possible to check a websocket server connection consistency. WCS server sends a special ping packets periodically (every 5 seconds by default). The ping packets are received and counted by SFU SDK. If more than a certain number of consequent packets are missed, the websocket connection is supposed to be lost, and the client receives SfuEvent.CONNECTION_FAILED event.

Connection control parameters setup in config.json file

If the example reads the connection parameters from config.json file, the maximum number of pings missing and pings checking interval may be set in the file:

code

{
  "room": {
    ...,
    "failedProbesThreshold": 5,
    "pingInterval": 5000
  },
  ...
}

Where:

  • failedProbesThreshold - the maximum number of pings missing
  • pingInterval - pings checking interval in ms

Connection control parameters setup in a source code

  1. roomConfig object creation
    code

    let roomConfig = {
    url: config.room.url || "ws://127.0.0.1:8080",
    roomName: config.room.name || "ROOM1",
    pin: config.room.pin || "1234",
    nickname: config.room.nickName || "User1"
};
if (config.room.failedProbesThreshold !== undefined) {
    roomConfig.failedProbesThreshold = config.room.failedProbesThreshold;
}
if (config.room.pingInterval !== undefined) {
    roomConfig.pingInterval = config.room.pingInterval;
}

  2. Connection establishing and the room creation
    code

    const session = await sfu.createRoom(roomConfig);

  3. SfuEvent.CONNECTION_FAILED event handling
    code

    session.on(constants.SFU_EVENT.DISCONNECTED, function() {
    ...
}).on(constants.SFU_EVENT.FAILED, function(e) {
    ...
    setStatus(state.statusId(), "FAILED", "red");
    if (e.status && e.statusText) {
        ...
    } else if (e.type && e.info) {
        setStatus(state.errInfoId(), e.type + ": " + e.info, "red");
    }
});

Disabling connection control at client side

Sometimes pings sending may be disabled at server side

keep_alive.algorithm=NONE

In this case, pings checking at client side should also be disabled

{
  "room": {
    ...,
    "failedProbesThreshold": 0,
    "pingInterval": 0
  },
  ...
}