Overview

@queryleaf/postgres-server provides a PostgreSQL wire protocol compatible server for QueryLeaf, allowing you to connect to MongoDB using standard PostgreSQL clients and drivers. It implements the PostgreSQL wire protocol and leverages the core @queryleaf/lib package to translate SQL queries into MongoDB commands.

Key Features

• Connect to MongoDB using any PostgreSQL client (pgAdmin, psql, etc.)
• Full SQL support for querying MongoDB collections
• Transparent authentication passthrough
• Compatible with any tool that uses PostgreSQL drivers
• Convert MongoDB documents to PostgreSQL-compatible row format

Installation

# Global installation
npm install -g @queryleaf/postgres-server
# or
yarn global add @queryleaf/postgres-server

# Local installation
npm install @queryleaf/postgres-server
# or
yarn add @queryleaf/postgres-server

Usage

Running the Server

# Start the server with default settings
queryleaf-pg-server

# With specific MongoDB URI and port
queryleaf-pg-server --uri mongodb://localhost:27017 --port 5432

# With authentication
queryleaf-pg-server --uri mongodb://user:pass@localhost:27017

# Help
queryleaf-pg-server --help

Connecting with PostgreSQL Clients

Connect using any PostgreSQL client with these connection parameters:

• Host: localhost (or wherever the server is running)
• Port: 5432 (or your configured port)
• Database: your MongoDB database name
• Username/Password: if required by your MongoDB deployment

Example with psql:

psql -h localhost -p 5432 -d mydatabase

Example connection string:

postgresql://localhost:5432/mydatabase

SQL Query Examples

Once connected, you can use SQL syntax to query MongoDB:

-- Basic SELECT with WHERE
SELECT name, email FROM users WHERE age > 21;

-- Nested field access
SELECT name, address.city FROM users WHERE address.zip = '10001';

-- Array access
SELECT items[0].name FROM orders WHERE items[0].price > 100;

-- GROUP BY with aggregation
SELECT status, COUNT(*) as count FROM orders GROUP BY status;

-- JOIN between collections
SELECT u.name, o.total FROM users u JOIN orders o ON u._id = o.userId;

Configuration

You can configure the server using command-line arguments or environment variables:

| Argument | Environment Variable | Description | |----------------|-------------------------|----------------------------------| | --uri | MONGODB_URI | MongoDB connection URI | | --port | POSTGRES_PORT | Server port (default: 5432) | | --host | POSTGRES_HOST | Server host (default: 0.0.0.0) | | --auth | ENABLE_AUTH | Enable authentication passthrough| | --debug | DEBUG | Enable debug output |

Links

• Website
• Documentation
• GitHub Repository

License

QueryLeaf is dual-licensed:

• AGPL-3.0 for open source use
• Commercial license for commercial use

For commercial licensing options, visit queryleaf.com.