Getting Started - Node.js

An example application of integrating Cerbos with an Express server.

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Dependencies

• Node.js v18+
• Docker for running the Cerbos Policy Decision Point (PDP)

Getting Started

1. Start up the Cerbos PDP instance docker container. This will be called by the Express app to check authorization.

cd cerbos
./start.sh

2. Install node dependencies

npm install

3. Start the Express server

npm run start

How it works

This example uses @cerbos/grpc to communicate with the Cerbos PDP over gRPC.

The Express server exposes three endpoints for managing articles:

• GET /article/:id - Read an article
• PATCH /article/:id - Update an article
• DELETE /article/:id - Delete an article

Each endpoint calls cerbos.checkResource() to determine if the current user is authorized to perform the requested action based on the policies defined in the cerbos/policies directory.

The Cerbos policy (cerbos/policies/article.yaml) defines the following rules:

• Admin and User roles can read and create articles
• Admin role can update and delete any article
• User role can only update and delete articles they own