graphql-shield

What is graphql-shield?

graphql-shield is a library for creating permission layers for your GraphQL server. It allows you to define rules and apply them to your schema to protect your data from unauthorized access.

What are graphql-shield's main functionalities?

Defining Permissions

This feature allows you to define rules for your GraphQL schema. In this example, the `isAuthenticated` rule checks if the user is authenticated before allowing access to the `user` query.

const { rule, shield, and, or, not } = require('graphql-shield');

const isAuthenticated = rule()((parent, args, ctx, info) => {
  return ctx.user !== null;
});

const permissions = shield({
  Query: {
    user: isAuthenticated,
  },
});

Combining Rules

This feature allows you to combine multiple rules using logical operators like `and`, `or`, and `not`. In this example, the `adminData` query is protected by both `isAuthenticated` and `isAdmin` rules.

const { rule, shield, and, or, not } = require('graphql-shield');

const isAuthenticated = rule()((parent, args, ctx, info) => {
  return ctx.user !== null;
});

const isAdmin = rule()((parent, args, ctx, info) => {
  return ctx.user.role === 'admin';
});

const permissions = shield({
  Query: {
    adminData: and(isAuthenticated, isAdmin),
  },
});

Error Handling

This feature allows you to handle errors gracefully. You can specify custom error messages for individual rules or provide a fallback error message for the entire permission layer.

const { rule, shield } = require('graphql-shield');

const isAuthenticated = rule({
  cache: 'contextual',
  error: 'Not Authenticated',
})((parent, args, ctx, info) => {
  return ctx.user !== null;
});

const permissions = shield({
  Query: {
    user: isAuthenticated,
  },
}, {
  fallbackError: 'You are not authorized to access this resource',
});

Other packages similar to graphql-shield

graphql-auth

graphql-auth is another library for adding authentication and authorization to your GraphQL server. It provides a simpler API compared to graphql-shield but lacks some of the advanced features like combining rules with logical operators.

graphql-permissions

graphql-permissions is a lightweight library for defining permissions in your GraphQL schema. It is similar to graphql-shield but focuses more on simplicity and ease of use, making it a good choice for smaller projects.

graphql-authorization

graphql-authorization is a library that provides a flexible way to add authorization to your GraphQL server. It offers a more customizable approach compared to graphql-shield, allowing you to define complex authorization logic.

README

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