Node-Casbin is a powerful and efficient open-source access control library for Node.js. It provides support for enforcing authorization based on various access control models, including ACL, RBAC, ABAC, and more. Node-Casbin offers a flexible policy language and can be easily integrated into existing Node.js applications.

Pros

• Supports multiple access control models out of the box
• Highly flexible and customizable policy language
• Efficient policy enforcement with minimal performance overhead
• Easy integration with various backends (e.g., file, database)

Cons

• Learning curve for understanding and implementing complex policies
• Limited built-in support for dynamic policy updates
• Documentation could be more comprehensive for advanced use cases

Code Examples

1. Basic usage with file-based policy:

const { newEnforcer } = require('casbin');

async function checkPermission() {
  const enforcer = await newEnforcer('model.conf', 'policy.csv');
  const result = await enforcer.enforce('alice', 'data1', 'read');
  console.log(result ? 'Allowed' : 'Denied');
}

checkPermission();

2. Adding a policy dynamically:

const { newEnforcer } = require('casbin');

async function addPolicy() {
  const enforcer = await newEnforcer('model.conf', 'policy.csv');
  const added = await enforcer.addPolicy('bob', 'data2', 'write');
  console.log(added ? 'Policy added' : 'Policy already exists');
}

addPolicy();

3. Checking permissions for a user with roles:

const { newEnforcer } = require('casbin');

async function checkRolePermission() {
  const enforcer = await newEnforcer('model.conf', 'policy.csv');
  const result = await enforcer.enforce('alice', 'data1', 'read');
  const roles = await enforcer.getRolesForUser('alice');
  console.log(`Allowed: ${result}, Roles: ${roles.join(', ')}`);
}

checkRolePermission();

Getting Started

To use Node-Casbin in your project:

1. Install the package:

   npm install casbin
   

2. Create a model file (e.g., model.conf) and a policy file (e.g., policy.csv).

3. Use the library in your code:

const { newEnforcer } = require('casbin');

async function main() {
  const enforcer = await newEnforcer('model.conf', 'policy.csv');
  const result = await enforcer.enforce('alice', 'data1', 'read');
  console.log(result ? 'Allowed' : 'Denied');
}

main();

For more advanced usage and configuration options, refer to the official Node-Casbin documentation.