@queryleaf/postgres-server NPM

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