Function getServer

src/examples/server/ssePollingExample.ts:26–109

()

// Factory to create a new MCP server per session.
// Each session needs its own server+transport pair to avoid cross-session contamination.
const getServer = () => {
    const server = new McpServer(
        {
            name: 'sse-polling-example',
            version: '1.0.0'
        },
        {
            capabilities: { logging: {} }
        }
    );

    // Register a long-running tool that demonstrates server-initiated disconnect
    server.tool(
        'long-task',
        'A long-running task that sends progress updates. Server will disconnect mid-task to demonstrate polling.',
        {},
        async (_args, extra): Promise<CallToolResult> => {
            const sleep = (ms: number) => new Promise(resolve => setTimeout(resolve, ms));

            console.log(`[${extra.sessionId}] Starting long-task...`);

            // Send first progress notification
            await server.sendLoggingMessage(
                {
                    level: 'info',
                    data: 'Progress: 25% - Starting work...'
                },
                extra.sessionId
            );
            await sleep(1000);

            // Send second progress notification
            await server.sendLoggingMessage(
                {
                    level: 'info',
                    data: 'Progress: 50% - Halfway there...'
                },
                extra.sessionId
            );
            await sleep(1000);

            // Server decides to disconnect the client to free resources
            // Client will reconnect via GET with Last-Event-ID after the transport's retryInterval
            // Use extra.closeSSEStream callback - available when eventStore is configured
            if (extra.closeSSEStream) {
                console.log(`[${extra.sessionId}] Closing SSE stream to trigger client polling...`);
                extra.closeSSEStream();
            }

            // Continue processing while client is disconnected
            // Events are stored in eventStore and will be replayed on reconnect
            await sleep(500);
            await server.sendLoggingMessage(
                {
                    level: 'info',
                    data: 'Progress: 75% - Almost done (sent while client disconnected)...'
                },
                extra.sessionId