Unlocking Secure Access Control in GraphQL: A Comprehensive Guide

The Importance of Authorization in Web Applications

When building a web application, it’s crucial to ensure that users have access to only the resources they’re entitled to. This is where authorization comes in – the process of granting users access to specific parts and capabilities of an application.

Access Control Policies: RBAC vs ABAC

There are two popular access control policies: Role-Based Access Control (RBAC) and Attribute-Based Access Control (ABAC).

• RBAC: grants permissions based on roles
• ABAC: grants permissions based on metadata assigned to entities, including users, assets, and environment conditions

ABAC is generally preferred due to its fine-grained control and unequivocal permission objectives.

Implementing Access Control in GraphQL

When accessing a GraphQL application, it’s essential to validate whether a user has access to the requested elements from the schema.

query {
  protectedField
}

The authorization logic belongs to the business logic layer, not the GraphQL layer. This allows for a single source of truth for authorization, which can be used for other access points, such as REST endpoints.

Defining Permissions for the GraphQL Schema

In the business layer, we decide which policy to implement for the application. Based on the employed policy, the GraphQL layer validates whether the user has access to the requested fields from the schema, asking questions like:

• Is the user logged in?
• Is the user an admin?
• Does the user have a certain required role or capability?
• Is the user accessing the site from a specific IP range or country?

Decoupling Access Control Logic from GraphQL

To avoid tightly coupling the GraphQL layer and the authorization strategy, it’s best to keep access control in a specific place, such as using GraphQL modules or directives.

directive @validateIsUserLoggedIn on FIELD_DEFINITION
directive @validateDoesLoggedInUserHaveAnyCapability on FIELD_DEFINITION

This allows for easy updates when the policy changes.

Completely Decoupling Access Control Logic from GraphQL

By treating access control as configuration instead of code, the GraphQL layer can immediately reflect changes to the access control policy without requiring code updates or recompilation.

const accessControlConfig = {
  rules: [
    {
      field: 'protectedField',
      validate: 'isUserLoggedIn'
    }
  ]
};

This approach is used by some GraphQL APIs, which satisfies access control through directives like @validateIsUserLoggedIn and @validateDoesLoggedInUserHaveAnyCapability.

Dynamic Access Control Configuration

Using access control lists (ACLs), the site admin can configure the fields to validate, rules to apply, and visibility settings. This configuration is stored in the database and applied to the GraphQL schema on runtime, allowing for immediate changes to the access control policy.

The Future of Access Control in GraphQL

When working with GraphQL, it’s essential to implement both authentication and authorization to ensure secure access to resources. By structuring the application to use authentication functionality from the business layer and decoupling the GraphQL layer from the business layer, we can minimize the impact of updating access control policies.

Secure access control is crucial for ensuring the integrity of your GraphQL application. By following these best practices, you can ensure that your application remains secure and scalable.