Backend Permissions: A Simple Guide

TL;DR

This guide shows you how to control who can do what in your backend system (your server-side code). We’ll cover roles, permissions, and a basic way to check if someone has the right access before letting them perform an action.

1. Understand Roles and Permissions

Think of it like this:

• Roles are job titles (e.g., ‘admin’, ‘editor’, ‘viewer’).
• Permissions are specific actions someone can do (e.g., ‘create_posts’, ‘edit_users’, ‘view_reports’).

A role usually has multiple permissions. For example, an ‘admin’ might have all permissions, while an ‘editor’ only has permission to create and edit posts.

2. Define Your Roles

First, decide what roles you need in your system. List them out clearly. Example:

• Admin
• Editor
• Author
• Viewer

3. Define Permissions

Next, list the actions users will need to perform and assign them as permissions. Example:

• create_posts
• edit_posts
• delete_posts
• publish_posts
• view_users
• edit_users

4. Assign Permissions to Roles

Now, link the permissions to the roles. You can do this in a database table or configuration file. Here’s an example using a simple Python dictionary:

permissions = {
    'admin': ['create_posts', 'edit_posts', 'delete_posts', 'publish_posts', 'view_users', 'edit_users'],
    'editor': ['create_posts', 'edit_posts', 'publish_posts'],
    'author': ['create_posts', 'edit_posts'],
    'viewer': ['view_posts']
}

5. Check Permissions in Your Code

Before allowing a user to do something, check if their role has the necessary permission. Here’s an example using Python:

def check_permission(user_role, required_permission):
    if user_role in permissions and required_permission in permissions[user_role]:
        return True
    else:
        return False

6. Implement the Check in Your Routes/Controllers

Use the check_permission function (or similar) in your backend code before processing sensitive requests.

# Example using a Flask route
from flask import Flask, request

app = Flask(__name__)

@app.route('/posts/delete/')
def delete_post(post_id):
    user_role = get_current_user_role() # Function to retrieve the user's role
    if check_permission(user_role, 'delete_posts'):
        # Delete the post logic here
        return "Post deleted successfully!"
    else:
        return "Permission denied.", 403

7. Store User Roles

You need a way to store which role each user has. This is usually done in your database, linked to the user’s account.

8. Consider More Advanced Solutions

• Access Control Lists (ACLs): Allow permissions on individual resources (e.g., a specific post).
• Role-Based Access Control (RBAC) Libraries: Use existing libraries to simplify permission management.
• JSON Web Tokens (JWT): Include role information in the JWT for easy access by your backend.