What is authentication & authorization

Authentication and authorization are used in security, particularly when it comes to getting access to a system. Yet, there is a significant distinction between gaining entry into a house (authentication) and what you can do while inside (authorization).

In simple words, Authentication is the process of verifying who a user is (who you are), and 
Authorization is the process of verifying what they have access to (what you are allowed to do).

Authorization is the process of allowing authenticated users access to resources by determining whether they have system access permissions. By giving or denying specific licenses to an authenticated user, authorization enables you to control access privileges.
So, authorization occurs after the system authenticates your identity, granting you complete access to resources such as information, files, databases, funds, places, and anything else. That said, authorization affects your capacity to access the system and the extent to which you can do so

Authorization is a critical component of any web application, as it controls access to various resources based on user roles and permissions. Node.js is a popular platform for building web applications, and there are various approaches to implement authorization in Node.js applications. Here is all you need to know about authorization in Node.js.

Types of Authorization

There are generally two types of authorization:

1. Role-based Authorization: In this type of authorization, access is granted or denied based on the user's role or job function.

2. Permission-based Authorization: In this type of authorization, access is granted or denied based on the specific permissions granted to the user.

Implementing Authorization in Node.js

const authorize = (req, res, next) => {
  if (!req.user || !req.user.permissions.includes('view_data')) {
    return res.status(401).json({ error: 'Unauthorized' });
  }
  next();
};

const getData = (req, res) => {
  const data = { /* data */ };
  res.json(data);
};

// /data route that requires authorization
app.get('/data', authorize, getData);

This code defines a middleware function called authorize that checks if the user is authenticated and has the required permissions to access the resource. If not, the middleware returns a 401 Unauthorized error. It then defines a route handler function called getData that retrieves data from a data source and returns it to the client.

Finally, it uses the authorize middleware function to restrict access to the getData route handler function. This means that only authenticated users with the required permissions can access the /data route and retrieve data. In conclusion, this example demonstrates how to implement authorization using middleware functions in Node.js to ensure that users have the appropriate access to specific resources or functionalities based on their identity and permissions.