Postgres Driver from Scratch (Node.js)

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Overview

This project is a PostgreSQL driver for Node.js, written entirely from scratch.
It aims to provide a minimal, transparent, and educational implementation of the PostgreSQL Protocol It demonstrates how to connect, handle authentication, parse protocol messages, and execute SQL queries without using any external libraries for PostgreSQL.

Features

• Connects to a PostgreSQL server using Node.js's net module
• Authenticates using cleartext password
• Parses key protocol messages:
  • AuthenticationOk
  • ParameterStatus
  • BackendKeyData
  • ReadyForQuery
  • RowDescription
  • DataRow
• Sends basic SQL queries (e.g., SELECT now();)
• Decodes and prints result rows and column descriptions

How It Works

The client follows these steps:

1. Startup: Sends a startup message with user and database.
2. Authentication: Handles cleartext password authentication.
3. Session Setup: Receives server parameters (ParameterStatus) and backend info (BackendKeyData). (NOTE: we are not using as of NOW)
4. Ready State: Waits for ReadyForQuery before sending SQL queries.
5. Query: Sends a SQL query and parses the response (column info and data row).
6. Result Parsing: Extracts and prints column names and result values.

Usage

1. Clone the repository:

   git clone https://github.com/sanjay-xdr/pg-driver
   cd pg-driver
   npm i

2. Edit connection settings: Open pg-protocol.ts and set your PostgreSQL credentials:

   const config = {
     host: "localhost",
     port: 5432,
     password: "sanjay",
     userName: "postgres",
     db: "Hotel",
   };

3. Build and Run the client:

   npm run build
   npm run start

   You should see output for the connection, authentication, and query results (e.g., current date/time).

Example Output

RESULT  { now: '2025-05-30 13:10:54.039803+05:30' }
 Query Exectued SELECT 1