Forwarding Server

This package is a part of the Flutter MCP.

A WebSocket forwarding server that enables bi-directional communication between Flutter applications and TypeScript clients.

Overview

This package provides a standalone WebSocket server that can:

• Accept connections from both Flutter and TypeScript clients
• Forward messages between different client types
• Prevent message loops by tracking forwarded messages
• Emit events for client connections/disconnections

Installation

npm install

Usage

Starting the Server

# Start with default settings (port 8143, path /forward)
npm start

# Start with custom port
npm start -- --port 9000

# Start with custom WebSocket path
npm start -- --path /ws

# Show help
npm start -- --help

Environment Variables

You can also configure the server using environment variables:

• FORWARDING_SERVER_PORT: Port to run the server on (default: 8143)
• FORWARDING_SERVER_PATH: WebSocket path (default: /forward)

Connecting Clients

Connect to the WebSocket server with the appropriate client type:

ws://localhost:8143/forward?clientType=flutter    # For Flutter clients
ws://localhost:8143/forward?clientType=inspector  # For TypeScript/Inspector clients

Development

# Install dependencies
npm install

# Build the project
npm run build

# Run in development mode (with auto-reload)
npm run dev

# Lint the project
npm run lint

API

The server works by accepting WebSocket connections and forwarding messages between client types.

Client Types

• flutter: For connections from Flutter applications
• inspector: For connections from TypeScript/Inspector applications

Message Forwarding

All messages received from one client type are forwarded to all connected clients of the other type.

The server handles JSON-RPC 2.0 formatted messages, tracking message IDs to prevent circular forwarding.

Architecture

+----------------+                  +-------------------+
|                |                  |                   |
| Flutter Client +<---------------->+ Forwarding Server |
|                |                  |                   |
+----------------+                  |                   |
                                    |                   |
+----------------+                  |                   |
|                |                  |                   |
| Inspector Client +<--------------->+                   |
|                |                  |                   |
+----------------+                  +-------------------+