Error Handling

Errors happen. PaindaProtocol captures server-side logic and validation errors and safely transmits them back to the client.

1. Acknowledgement Errors

When using Request/Response patterns (Acknowledgements), the first argument in the callback is reserved for the Error, following the standard Node.js convention (error-first callbacks).

// Client
client.send({ type: "authenticate", payload: "fake-jwt" }, (err, data) => {
  if (err) {
    // The server called ack(new Error("..."))
    console.error("Auth Error:", err.message); 
    return;
  }
  console.log("Welcome!", data);
});

// Server
server.on("authenticate", (client, token, ack) => {
  if (!isValid(token)) {
    // Sending a standard Error object will be serialized automatically
    ack(new Error("Invalid authorization token provided")); 
  } else {
    ack(null, { status: "success" });
  }
});

2. Global Client Errors

Some errors don't belong to a specific callback. For example: malformed message frames, connection timeouts, or protocol version mismatches.

client.on("error", (err) => {
  // Global catch for connection and parsing errors
  console.error("PaindaProtocol exception:", err);
});

3. Disconnect Reasons

When a connection drops, the disconnect event emits a reason string. This helps you distinguish between network issues and intentional kicks.

client.on("disconnect", (reason) => {
  if (reason === "transport close") {
    console.log("Server crashed or network dropped.");
  } else if (reason === "Ping timeout") {
    console.log("Client failed to respond to server pings.");
  } else if (reason === "forced server disconnect") {
    console.log("You were kicked by the server-side logic.");
  }
});