Rohlik MCP Proxy Server

A Docker-based proxy MCP (Model Context Protocol) server for the Rohlik MCP service that forwards requests to https://mcp.rohlik.cz/mcp while automatically injecting authentication headers from a base64url token in the URL path (or optional env fallback).

Features

• Transparent Proxying: Forwards MCP protocol messages between clients and the Rohlik MCP server

• Authentication Injection: Automatically injects rhl-email and rhl-pass headers from a base64url path token (env fallback optional)

• SSE/Streaming Support: Streams GET responses for real-time MCP sessions

• Docker-based: Easy deployment with Docker and Docker Compose

• Health Monitoring: Built-in health check endpoint

• CORS Enabled: Allows browser-based and desktop MCP clients to connect

Related MCP server: trundler

Prerequisites

• Docker and Docker Compose installed

• Rohlik account credentials (email and password)

Quick Start

1. Generate a base64url token

Create a base64url-encoded token for email:password:

python - <<'PY'
import base64
print(base64.urlsafe_b64encode(b"email@gmail.com:password").decode())
PY

2. Build and Run with Docker Compose

Note: docker-compose.yml expects an external network named cloudflare. Create it with docker network create cloudflare or remove the networks section if you don't need it.

# Build and start the proxy server
docker-compose up -d

# View logs
docker-compose logs -f rohlik-mcp-proxy

# Stop the server
docker-compose down

The proxy server will be available at:

• MCP Endpoint: http://localhost:8000/mcp/<base64url-token>

• Health Check: http://localhost:8000/health

• Info: http://localhost:8000/

3. Alternative: Run with Docker

# Build the image
docker build -t rohlik-mcp-proxy .

# Run the container
docker run -d \
  --name rohlik-mcp-proxy \
  -p 8000:8000 \
  rohlik-mcp-proxy

# View logs
docker logs -f rohlik-mcp-proxy

# Stop the container
docker stop rohlik-mcp-proxy
docker rm rohlik-mcp-proxy

Configuration

Environment Variables

Base64url Path Token

The proxy expects a URL path like /mcp/<base64url(email:password)>. Padding (=) is optional. If you set RHL_EMAIL and RHL_PASS, you can also use /mcp without a token.

MCP Client Configuration

Configure your MCP client (e.g., Claude Desktop, ChatGPT) to connect to the proxy. Use the base64url token in the URL path:

{
  "mcpServers": {
    "rohlik": {
      "url": "http://localhost:8000/mcp/<base64url-token>",
      "transport": "streamable-http"
    }
  }
}

Or for fastmcp client:

Or using MCP Inspector:

npx @modelcontextprotocol/inspector http://localhost:8000/mcp/<base64url-token>

Development

Local Development (Without Docker)

# Install uv package manager
pip install uv

# Install dependencies
uv pip install -e .

# Run the proxy server
python proxy_server.py

Project Structure

rohlik-mcp-proxy/
├── proxy_server.py       # Main proxy server implementation
├── pyproject.toml        # Python project configuration
├── Dockerfile            # Docker image definition
├── docker-compose.yml    # Docker Compose configuration
├── .env.example          # Environment variables template
├── .gitignore           # Git ignore rules
└── README.md            # This file

How It Works

1. Client Connection: MCP client connects to the proxy at /mcp/<base64url-token> (GET for streaming, POST for calls)

2. Request Forwarding: Proxy receives MCP requests from the client

3. Header Injection: Proxy decodes the path token and adds authentication headers (rhl-email, rhl-pass)

4. Backend Communication: Proxy forwards the authenticated request to Rohlik MCP server

5. Response Handling: Proxy streams GET responses and returns POST/other responses

6. Bidirectional Flow: Process repeats for all subsequent requests

┌─────────────┐         ┌──────────────────┐         ┌─────────────────┐
│             │         │                  │         │                 │
│ MCP Client  │ <-----> │  Rohlik Proxy    │ <-----> │ Rohlik MCP      │
│             │  HTTP   │  (adds headers)  │  HTTPS  │ Backend Server  │
│             │         │                  │         │                 │
└─────────────┘         └──────────────────┘         └─────────────────┘
                        Port 8000                    mcp.rohlik.cz

Health Check

The proxy includes a built-in health check endpoint:

curl http://localhost:8000/health
# Returns: OK

Docker Compose automatically monitors this endpoint and restarts the container if it becomes unhealthy.

Security Considerations

• Credentials Storage: Never commit your .env file with real credentials to version control

• Network Security: For production use, consider running the proxy behind a reverse proxy with HTTPS

• Access Control: No additional authentication is enforced by the proxy; restrict access at the network or reverse proxy level

• Password Safety: Credentials are passed via URL path and HTTP headers (ensure HTTPS and avoid logging full URLs in production)

Troubleshooting

Container won't start

# Check logs
docker-compose logs rohlik-mcp-proxy

# Common issues:
# - Port 8000 already in use
# - Invalid or missing base64 token in the URL path

Connection refused

# Verify the container is running
docker-compose ps

# Check if port is accessible
curl http://localhost:8000/health

Rohlik authentication errors

# Verify your base64url token decodes to email:password
python - <<'PY'
import base64
print(base64.urlsafe_b64decode(b"<base64url-token>").decode())
PY

License

This project is provided as-is for integration with the Rohlik MCP service.

Related Documentation

• Model Context Protocol (MCP)

• FastMCP Documentation

• Rohlik MCP Service