feat(client): add periodic ping support for connection health monitoring

[Br1an67]

Fixes #1000

Summary

This PR implements the missing periodic ping functionality for the MCP TypeScript SDK Client, as specified in the MCP protocol. The implementation allows automatic connection health monitoring by sending ping requests at a configurable interval.

Changes

• Added PingConfig interface to configure periodic ping options
• Added ping configuration option to ClientOptions
• Implemented _startPeriodicPing() method to begin periodic ping after connection
• Implemented _stopPeriodicPing() method to stop periodic ping on close
• Override close() method to ensure periodic ping is stopped when disconnecting
• Default configuration: disabled (opt-in), 30 second interval when enabled
• Ping failures are reported via the onerror callback without stopping the interval

Usage

const client = new Client(
    { name: 'my-client', version: '1.0.0' },
    {
        ping: {
            enabled: true,
            intervalMs: 60000 // Ping every 60 seconds
        }
    }
);

// Handle ping errors
client.onerror = (error) => {
    if (error.message.includes('Periodic ping failed')) {
        console.warn('Connection health check failed:', error);
    }
};

await client.connect(transport);
// Periodic pings will start automatically after connection

Testing

Added comprehensive test suite covering:

• Periodic ping disabled by default
• Periodic ping starts when enabled after connection
• Periodic ping stops on client close
• Custom interval configuration
• Graceful error handling with onerror callback
• Configuration defaults

Diff Stats

 packages/client/src/client/client.ts     |  90 +++++++++++++
 packages/client/test/client/ping.test.ts | 214 +++++++++++++++++++++++++++++++
 2 files changed, 304 insertions(+)

[changeset-bot]

⚠️ No Changeset found

Latest commit: 5d290c3

Merging this PR will not cause a version bump for any packages. If these changes should not result in a new version, you're good to go. If these changes should result in a version bump, you need to add a changeset.

This PR includes no changesets

When changesets are added to this PR, you'll see the packages that this PR includes changesets for and the associated semver types

Click here to learn what changesets are, and how to add one.

Click here if you're a maintainer who wants to add a changeset to this PR

[pkg-pr-new]

Open in StackBlitz

@modelcontextprotocol/client

npm i https://pkg.pr.new/modelcontextprotocol/typescript-sdk/@modelcontextprotocol/client@1645

@modelcontextprotocol/server

npm i https://pkg.pr.new/modelcontextprotocol/typescript-sdk/@modelcontextprotocol/server@1645

@modelcontextprotocol/express

npm i https://pkg.pr.new/modelcontextprotocol/typescript-sdk/@modelcontextprotocol/express@1645

@modelcontextprotocol/hono

npm i https://pkg.pr.new/modelcontextprotocol/typescript-sdk/@modelcontextprotocol/hono@1645

@modelcontextprotocol/node

npm i https://pkg.pr.new/modelcontextprotocol/typescript-sdk/@modelcontextprotocol/node@1645

commit: f00103b