"Module not found: Can't resolve 'net'" in Next.js with PostgreSQL: A Common Error and Its Solution
You're building a Next.js application that uses PostgreSQL for its database, and you encounter a frustrating error: "Module not found: Can't resolve 'net'". This error often arises when you attempt to use modules like pg or pg-promise to connect to your PostgreSQL database, but it seems like Next.js can't find the necessary 'net' module.
Let's break down this common error and explore a simple solution.
Scenario:
Imagine you have a Next.js project where you're using the pg library to connect to a PostgreSQL database. You might have a file like this:
// lib/db.js
const { Pool } = require('pg');
const pool = new Pool({
user: 'your_user',
host: 'your_host',
database: 'your_database',
password: 'your_password',
port: 5432,
});
module.exports = pool;
When you try to run your application, you're greeted with the dreaded "Module not found: Can't resolve 'net'" error.
Explanation:
The core issue lies in the way Next.js handles server-side rendering (SSR). When running your application, Next.js creates a serverless environment, meaning each request triggers a new, isolated process. In this process, the 'net' module, which is essential for network communication (including database connections), might not be available by default.
Solution:
The simplest fix is to install the 'net' module as a dependency in your project:
npm install net
After installing, you might need to restart your Next.js development server for the change to take effect.
Why this works:
By explicitly installing 'net', you ensure that the module is present in your Next.js environment. This allows your database connection code to function correctly.
Additional Insights:
- Other Libraries: If you're using a different PostgreSQL library (e.g.,
pg-promise), the solution remains the same: install the 'net' module. - Serverless Functions: This error might also occur when working with serverless functions (e.g., AWS Lambda) that require network access. The 'net' module is often a necessary dependency in such scenarios.
Conclusion:
The "Module not found: Can't resolve 'net'" error in Next.js with PostgreSQL is a common issue that arises due to the serverless environment. By installing the 'net' module, you can easily resolve this issue and connect to your database seamlessly. Remember to restart your Next.js development server to apply the changes.
Remember: Always consult the documentation for the specific database library you're using for any potential configuration or troubleshooting tips.
