Connection Lifecycle

Understanding the connection lifecycle helps you build reliable applications that handle network conditions gracefully.

Connection States

   ┌──────┐
   │ IDLE │◄────────────────────────────┐
   └──┬───┘                             │
      │ connect()                       │
      ▼                                 │
┌────────────┐                          │
│ CONNECTING │◄─────────┐               │
└─────┬──────┘          │               │
      │ success         │ retry         │
      ▼                 │               │
┌───────────┐      ┌────┴───────┐       │
│ CONNECTED │─────▶│RECONNECTING│       │
└─────┬─────┘      └────────────┘       │
      │ disconnect()                    │
      ▼                                 │
   ┌────────┐                           │
   │ CLOSED │───────────────────────────┘
   └────────┘

State	Description
IDLE	Initial state before any connection attempt
CONNECTING	Attempting to establish WebSocket connection
CONNECTED	WebSocket is open and ready
RECONNECTING	Connection lost, attempting to reconnect
CLOSED	Connection closed (gracefully or due to error)

Initialization

The agent must be initialized before use:

const agent = new AiAgent({
  id: "agent-id",
  endpoint: "https://your-endpoint.com",
  auth: { type: "pre-auth", accessToken: "your-token" }
});

// Always await initialize()
await agent.initialize();

// Now you can connect
await agent.connect();

WebSocket Endpoint Resolution

endpoint is the eGain server the SDK bootstraps from (deployment info, agent details, session). The chat WebSocket itself is resolved during initialize(), in this order:

1. wss://<webSocketDomain>, where webSocketDomain comes from the agent details API (GET /core/aiservices/v4/aiagent/details/agent/{agentId}) when the backend returns it. It is the WebSocket host of the deployment that answered the request, so a disaster-recovery region whose chat stack listens on a region-suffixed host is reached without any change on the host page.
2. Otherwise wss://chat.<aiAgentDomain>, derived from /system/deploymentInfo (older backends).

In both cases the SDK appends sessionId and, when set, externalCallId. The resolved endpoint is logged at debug level with its source.

Using Pre-Provided Session ID

If you already have a session ID (e.g., from a previous session or external source), you can provide it in the config to skip fetching from the network:

const agent = new AiAgent({
  id: "agent-id",
  endpoint: "https://your-endpoint.com",
  auth: { type: "pre-auth", accessToken: "your-token" },
  sessionId: "existing-session-id"  // Skip network fetch
});

await agent.initialize();
// SessionId is used directly, no network call made

Auto-Connect

Skip the manual connect step:

const agent = new AiAgent({
  id: "agent-id",
  endpoint: "https://your-endpoint.com",
  auth: { type: "pre-auth", accessToken: "your-token" },
  autoConnect: true  // Connect automatically after initialize
});

await agent.initialize();
// Agent is now connected!

Manual Connection Control

// Check current state
const state = agent.getState();
console.log("Current state:", state);  // "CONNECTED", "IDLE", etc.

// Check if connected
if (agent.isConnected()) {
  await agent.send("Hello!");
}

// Connect manually
await agent.connect();

// Disconnect gracefully (sends disconnect message)
await agent.disconnect();

// Disconnect without graceful message
await agent.disconnect({ skipGracefulDisconnect: true });

Reconnection

The SDK automatically reconnects with exponential backoff:

const agent = new AiAgent({
  id: "agent-id",
  endpoint: "https://your-endpoint.com",
  auth: { type: "pre-auth", accessToken: "your-token" },
  
  // Reconnection settings
  maxReconnectAttempts: Infinity,   // Keep trying forever
  baseReconnectDelay: 1000,         // Start with 1 second
  maxReconnectDelay: 30000          // Cap at 30 seconds
});

Reconnection Timing

Attempt 1: 1s delay
Attempt 2: 2s delay
Attempt 3: 4s delay
Attempt 4: 8s delay
Attempt 5: 16s delay
Attempt 6: 30s delay (capped)
Attempt 7+: 30s delay

Handling Reconnection

agent.on("stateChanged", (event) => {
  const { state, previousState } = event.payload;
  
  if (state === "RECONNECTING") {
    showReconnectingUI();
  } else if (state === "CONNECTED" && previousState === "RECONNECTING") {
    hideReconnectingUI();
    showReconnectedNotification();
  }
});

Connection Restart

Restart with a fresh session (clears queue and transcript):

// Useful when:
// - Starting a new conversation
// - User logs out/in
// - Need fresh session state

// Restart with a new sessionId (fetched from network)
await agent.restartConnection();
// Stored context is sent in the session POST body (v0.2.2+)

// Restart with a specific sessionId
await agent.restartConnection({ sessionId: 'existing-session-id' });
// Compatibility path: stored context is sent over the WebSocket after connect

Updating Session ID After Initialization

You can update the session ID at runtime using setSessionId():

// Update sessionId
agent.setSessionId('new-session-id');

// If connected, restart with the new sessionId
if (agent.isConnected()) {
  await agent.restartConnection({ sessionId: 'new-session-id' });
}

Event Handling

Connection Established

agent.on("connected", (event) => {
  console.log("Connected!", {
    sessionId: event.sessionId,
    agentId: event.agentId,
    at: new Date(event.timestamp)
  });
  
  enableChatInput();
});

Connection Closed

agent.on("closed", (event) => {
  const { code, reason } = event.payload;
  
  console.log(`Closed: ${code} - ${reason}`);
  
  // Common close codes:
  // 1000: Normal closure
  // 1001: Going away (page navigation)
  // 1006: Abnormal closure (network issue)
  // 4000+: Application-specific
  
  if (code === 1006) {
    showNetworkErrorMessage();
  }
});

State Changes

agent.on("stateChanged", (event) => {
  const { state, previousState } = event.payload;
  
  updateConnectionStatus(state);
  
  // Log state transitions
  console.log(`Connection: ${previousState} → ${state}`);
});

Offline Behavior

When offline, messages are queued:

// Send works even when offline
await agent.send("Hello!");  // Queued

// Check queue
console.log("Queued:", agent.getQueueSize());

// Messages sent automatically when reconnected
agent.on("queueFlushed", (event) => {
  console.log(`Sent ${event.payload.count} queued messages`);
});

Graceful Shutdown

Always disconnect properly on application exit:

// Browser
window.addEventListener("beforeunload", () => {
  agent.disconnect();
});

// Node.js
process.on("SIGINT", async () => {
  await agent.disconnect();
  process.exit(0);
});

// React
useEffect(() => {
  return () => {
    agent.disconnect();
  };
}, []);

Error Handling

agent.on("error", (event) => {
  const error = event.payload.error;
  
  if (error instanceof ConnectionError) {
    // Connection-specific errors
    handleConnectionError(error);
  }
});

// Connection errors include:
// - WebSocket connection failures
// - Network timeouts
// - Server rejections

Best Practices

1. Wait for Connection

async function sendWhenReady(message: string) {
  if (!agent.isConnected()) {
    // Wait for connection
    await new Promise<void>((resolve) => {
      agent.once("connected", () => resolve());
    });
  }
  
  await agent.send(message);
}

2. Handle All States

function updateUI(state: ConnectionState) {
  switch (state) {
    case "IDLE":
      showConnectButton();
      break;
    case "CONNECTING":
      showConnectingSpinner();
      break;
    case "CONNECTED":
      showChatInterface();
      break;
    case "RECONNECTING":
      showReconnectingBanner();
      break;
    case "CLOSED":
      showDisconnectedMessage();
      break;
  }
}

3. Monitor Connection Health

let lastHeartbeat = Date.now();

agent.on("heartbeat", () => {
  lastHeartbeat = Date.now();
});

setInterval(() => {
  const elapsed = Date.now() - lastHeartbeat;
  if (elapsed > 60000) {
    console.warn("No heartbeat for 60s");
  }
}, 10000);