Persistent connections even if client disconnects

This commit is contained in:
2025-07-25 14:18:40 +01:00
parent 1d39818127
commit 5c9b4e151f
7 changed files with 307 additions and 109 deletions
+142 -15
View File
@@ -4,8 +4,11 @@ import * as tls from 'tls';
import http from 'http';
import { parse } from 'url';
// Configuration for connection persistence
const CONNECTION_PERSISTENCE_TIMEOUT = 5 * 60 * 1000; // 5 minutes in milliseconds
// Default configuration for connection persistence (fallback values)
const DEFAULT_PERSISTENCE_TIMEOUT = 5 * 60 * 1000; // 5 minutes in milliseconds
const DEFAULT_MAX_BUFFER_MESSAGES = 100; // Maximum number of messages to buffer
const DEFAULT_MAX_BUFFER_SIZE_KB = 10; // Maximum buffer size in KB
const HEARTBEAT_INTERVAL = 30 * 1000; // 30 seconds
// Create HTTP server
@@ -15,17 +18,113 @@ const server = http.createServer();
const wss = new WebSocketServer({ noServer: true });
// Active connections and their proxies
// Key: connectionId, Value: { ws, socket, sessionId, settings }
const connections = new Map();
// Persistent connections waiting for reconnection
// Key: sessionId, Value: { socket, mudHost, mudPort, useSSL, timeoutId, lastActivity }
// Key: sessionId, Value: { socket, mudHost, mudPort, useSSL, timeoutId, lastActivity, messageBuffer, settings }
const persistentConnections = new Map();
// Parse connection settings from URL parameters with defaults
function parseConnectionSettings(urlParts) {
const persistenceTimeoutParam = urlParts.searchParams.get('persistenceTimeout');
const maxBufferMessagesParam = urlParts.searchParams.get('maxBufferMessages');
const maxBufferSizeKBParam = urlParts.searchParams.get('maxBufferSizeKB');
return {
persistenceTimeoutMs: persistenceTimeoutParam ?
parseInt(persistenceTimeoutParam) * 60 * 1000 : // Convert minutes to milliseconds
DEFAULT_PERSISTENCE_TIMEOUT,
maxBufferMessages: maxBufferMessagesParam ?
parseInt(maxBufferMessagesParam) :
DEFAULT_MAX_BUFFER_MESSAGES,
maxBufferSizeKB: maxBufferSizeKBParam ?
parseInt(maxBufferSizeKBParam) :
DEFAULT_MAX_BUFFER_SIZE_KB
};
}
// Generate a unique session ID for persistent connections
function generateSessionId() {
return `session-${Date.now()}-${Math.random().toString(36).substr(2, 9)}`;
}
// Buffer a message for a persistent connection
function bufferMessage(sessionId, data) {
const persistentConn = persistentConnections.get(sessionId);
if (!persistentConn) {
return; // No persistent connection to buffer for
}
if (!persistentConn.messageBuffer) {
persistentConn.messageBuffer = [];
persistentConn.bufferSize = 0;
}
// Add timestamp to the message
const bufferedMessage = {
data: data,
timestamp: Date.now()
};
persistentConn.messageBuffer.push(bufferedMessage);
persistentConn.bufferSize += data.length;
// Use this connection's specific settings for buffer limits
const settings = persistentConn.settings || {
maxBufferMessages: DEFAULT_MAX_BUFFER_MESSAGES,
maxBufferSizeKB: DEFAULT_MAX_BUFFER_SIZE_KB
};
// Trim buffer if it gets too large
while (persistentConn.messageBuffer.length > settings.maxBufferMessages ||
persistentConn.bufferSize > settings.maxBufferSizeKB * 1000) {
const removed = persistentConn.messageBuffer.shift();
if (removed) {
persistentConn.bufferSize -= removed.data.length;
}
}
console.log(`Buffered ${data.length} bytes for session ${sessionId} (${persistentConn.messageBuffer.length} messages, ${persistentConn.bufferSize} bytes total, limits: ${settings.maxBufferMessages} msgs/${settings.maxBufferSizeKB}KB)`);
}
// Replay buffered messages to a reconnected client
function replayBufferedMessages(ws, sessionId) {
const persistentConn = persistentConnections.get(sessionId);
if (!persistentConn || !persistentConn.messageBuffer) {
return 0; // No messages to replay
}
const messages = persistentConn.messageBuffer;
console.log(`Replaying ${messages.length} buffered messages for session ${sessionId}`);
// Send a notification about message replay
const replayNotification = `[SYSTEM]${JSON.stringify({
type: 'message_replay_start',
messageCount: messages.length,
timespan: messages.length > 0 ? Date.now() - messages[0].timestamp : 0
})}`;
ws.send(replayNotification);
// Send all buffered messages
for (const message of messages) {
if (ws.readyState === 1) { // WebSocket.OPEN
ws.send(message.data);
}
}
// Send replay complete notification
const replayComplete = `[SYSTEM]${JSON.stringify({ type: 'message_replay_complete' })}`;
ws.send(replayComplete);
// Clear the buffer since messages have been replayed
const messageCount = messages.length;
persistentConn.messageBuffer = [];
persistentConn.bufferSize = 0;
return messageCount;
}
// Clean up a persistent connection
function cleanupPersistentConnection(sessionId) {
const persistentConn = persistentConnections.get(sessionId);
@@ -54,11 +153,16 @@ wss.on('connection', (ws, req, mudHost, mudPort, useSSL) => {
// Create a unique ID for this connection
const connectionId = `${Date.now()}-${Math.random().toString(36).substr(2, 9)}`;
// Check for session ID in query parameters for reconnection
// Check for session ID and settings in query parameters
const url = req.url || '';
const urlParts = new URL(`http://localhost${url}`);
const sessionId = urlParts.searchParams.get('sessionId');
// Parse connection settings for this specific connection
const connectionSettings = parseConnectionSettings(urlParts);
console.log(`Connection settings for ${connectionId}: timeout=${connectionSettings.persistenceTimeoutMs/1000/60}min, maxMessages=${connectionSettings.maxBufferMessages}, maxSizeKB=${connectionSettings.maxBufferSizeKB}`);
// Special handling for test connections
if (mudHost === 'example.com' && mudPort === '23') {
console.log('Test connection detected - using echo server mode');
@@ -98,11 +202,18 @@ wss.on('connection', (ws, req, mudHost, mudPort, useSSL) => {
clearTimeout(persistentConn.timeoutId);
}
// Remove from persistent connections (now active again)
// Replay any buffered messages first
const replayedCount = replayBufferedMessages(ws, sessionId);
// Remove from persistent connections (now active again) - do this after replay
persistentConnections.delete(sessionId);
// Send reconnection notification with session ID in proper JSON format
ws.send(`[SYSTEM]${JSON.stringify({ type: 'session_resumed', sessionId: sessionId })}`);
ws.send(`[SYSTEM]${JSON.stringify({
type: 'session_resumed',
sessionId: sessionId,
messagesReplayed: replayedCount
})}`);
} else {
// Create new connection
currentSessionId = generateSessionId();
@@ -142,8 +253,13 @@ wss.on('connection', (ws, req, mudHost, mudPort, useSSL) => {
}
}
// Store the connection
connections.set(connectionId, { ws, socket, sessionId: currentSessionId });
// Store the connection with its settings
connections.set(connectionId, {
ws,
socket,
sessionId: currentSessionId,
settings: connectionSettings
});
// Handle data from the MUD server - only in regular mode, not test mode
if (socket) {
@@ -163,6 +279,11 @@ wss.on('connection', (ws, req, mudHost, mudPort, useSSL) => {
if (ws.readyState === 1) { // WebSocket.OPEN
ws.send(data);
console.log(`WebSocket server: Sent ${data.length} bytes to client${isGmcp ? ' (contains GMCP data)' : ''}`);
} else {
// WebSocket is not open, buffer the message if we have a session
if (currentSessionId) {
bufferMessage(currentSessionId, data);
}
}
});
}
@@ -276,13 +397,14 @@ wss.on('connection', (ws, req, mudHost, mudPort, useSSL) => {
const conn = connections.get(connectionId);
if (conn && !conn.testMode && conn.socket && !conn.socket.destroyed) {
console.log(`Moving connection to persistent state for ${CONNECTION_PERSISTENCE_TIMEOUT / 1000} seconds`);
console.log(`Moving connection to persistent state for ${conn.settings.persistenceTimeoutMs / 1000} seconds`);
// Move the connection to persistent storage instead of closing it
// Use this connection's specific timeout setting
const timeoutId = setTimeout(() => {
console.log(`Session ${currentSessionId} timed out, closing MUD connection`);
cleanupPersistentConnection(currentSessionId);
}, CONNECTION_PERSISTENCE_TIMEOUT);
}, conn.settings.persistenceTimeoutMs);
persistentConnections.set(currentSessionId, {
socket: conn.socket,
@@ -290,10 +412,13 @@ wss.on('connection', (ws, req, mudHost, mudPort, useSSL) => {
mudPort,
useSSL,
timeoutId,
lastActivity: Date.now()
lastActivity: Date.now(),
messageBuffer: [],
bufferSize: 0,
settings: conn.settings // Store the connection's settings
});
console.log(`Session ${currentSessionId} will persist for ${CONNECTION_PERSISTENCE_TIMEOUT / 1000} seconds`);
console.log(`Session ${currentSessionId} will persist for ${conn.settings.persistenceTimeoutMs / 1000} seconds with settings: ${conn.settings.maxBufferMessages} msgs/${conn.settings.maxBufferSizeKB}KB`);
} else if (conn && conn.socket) {
// Fallback to immediate cleanup if needed
conn.socket.end();
@@ -347,18 +472,20 @@ setInterval(() => {
const now = Date.now();
for (const [sessionId, persistentConn] of persistentConnections.entries()) {
// Clean up connections that have been inactive for too long
if (now - persistentConn.lastActivity > CONNECTION_PERSISTENCE_TIMEOUT * 2) {
// Use double the connection's specific timeout or default
const timeoutThreshold = (persistentConn.settings?.persistenceTimeoutMs || DEFAULT_PERSISTENCE_TIMEOUT) * 2;
if (now - persistentConn.lastActivity > timeoutThreshold) {
console.log(`Cleaning up abandoned session: ${sessionId}`);
cleanupPersistentConnection(sessionId);
}
}
}, CONNECTION_PERSISTENCE_TIMEOUT);
}, DEFAULT_PERSISTENCE_TIMEOUT); // Run cleanup every default timeout period
// Start the WebSocket server
const PORT = process.env.WS_PORT || 3001;
server.listen(PORT, () => {
console.log(`WebSocket server is running on port ${PORT}`);
console.log(`Connection persistence timeout: ${CONNECTION_PERSISTENCE_TIMEOUT / 1000} seconds`);
console.log(`Default connection persistence timeout: ${DEFAULT_PERSISTENCE_TIMEOUT / 1000} seconds (configurable per connection)`);
});
export default server;