Role, Attribute and conditions based Access Control for Node.js

npm i role-acl --save

Many RBAC (Role-Based Access Control) implementations differ, but the basics is widely adopted since it simulates real life role (job) assignments. But while data is getting more and more complex; you need to define policies on resources, subjects or even environments. This is called ABAC (Attribute-Based Access Control).

With the idea of merging the best features of the two (see this NIST paper); this library implements RBAC basics and also focuses on resource, action attributes and conditions.

This library is an extension of AccessControl. But I removed support for possession and deny statements from orginal implementation.

Core Features

• Chainable, friendly API.
  e.g. ac.can(role).execute('create').on(resource)
• Role hierarchical inheritance.
• Define grants at once (e.g. from database result) or one by one.
• Grant permissions by resources and actions define by glob notation.
• Grant permissions by attributes defined by glob notation (with nested object support).
• Ability to filter data (model) instance by allowed attributes.
• Ability to control access using conditions.
• Supports AND, OR, NOT, EQUALS, NOT_EQUALS, STARTS_WITH, LIST_CONTAINS core conditions.
• You can specify dynamic context values in the core conditions using JSON Paths.
• Supports your own custom conditions e.g. custom:isArticleOwner.
• You can define your own function conditions too but please note if you use custom functions instead of standard conditions, you won't be able to save them as json in the DB.
• Policies are JSON compatible so can be stored and retrieved from database.
• Fast. (Grants are stored in memory, no database queries.)
• TypeScript support.
• Note:
  • For versions < 4.0: follow this ReadMe.

Guide

const AccessControl = require('role-acl');
// or:
// import { AccessControl } from 'role-acl';

Examples

Basic Examples

Define roles and grants one by one.

const ac = new AccessControl();
ac.grant('user')                    // define new or modify existing role. also takes an array.
    .execute('create').on('video')             // equivalent to .execute('create').on('video', ['*'])
    .execute('delete').on('video')
    .execute('read').on('video')
  .grant('admin')                   // switch to another role without breaking the chain
    .extend('user')                 // inherit role capabilities. also takes an array
    .execute('update').on('video', ['title'])  // explicitly defined attributes
    .execute('delete').on('video');

const permission = ac.can('user').execute('create').sync().on('video'); // <-- Sync Example
const permission = await ac.can('user').execute('create').on('video'); // <-- Async Example
console.log(permission.granted);    // —> true
console.log(permission.attributes); // —> ['*'] (all attributes)

permission = ac.can('admin').execute('update').sync().on('video'); // <-- Sync Example
permission = await ac.can('admin').execute('update').on('video'); // <-- Async Example
console.log(permission.granted);    // —> true
console.log(permission.attributes); // —> ['title']

Conditions Examples

const ac = new AccessControl();
ac.grant('user').condition(
    {
        Fn: 'EQUALS',
        args: {
            'category': 'sports'
        }
    }).execute('create').on('article');

let permission = ac.can('user').context({ category: 'sports' }).execute('create').sync().on('article'); // <-- Sync Example
let permission = await ac.can('user').context({ category: 'sports' }).execute('create').on('article'); // <-- Async Example
console.log(permission.granted);    // —> true
console.log(permission.attributes); // —> ['*'] (all attributes)

permission = ac.can('user').context({ category: 'tech' }).execute('create').sync().on('article'); // <-- Sync Example
permission = await ac.can('user').context({ category: 'tech' }).execute('create').on('article'); // <-- Async Example
console.log(permission.granted);    // —> false
console.log(permission.attributes); // —> []

// Condition with dynamic context values using JSONPath
// We can use this to allow only owner of the article to edit it
ac.grant('user').condition(
    {
        Fn: 'EQUALS',
        args: {
            'requester': '$.owner'
        }
    }).execute('edit').on('article');

permission =  ac.can('user').context({ requester: 'dilip', owner: 'dilip' }).execute('edit').sync().on('article'); // <-- Sync Example
permission =  await ac.can('user').context({ requester: 'dilip', owner: 'dilip' }).execute('edit').on('article'); // <-- Async Example
console.log(permission.granted);    // —> true

// We can use this to prevent someone to approve their own article so that it goes to review 
// by someone else before publishing
ac.grant('user').condition(
    {
        Fn: 'NOT_EQUALS',
        args: {
            'requester': '$.owner'
        }
    }).execute('approve').on('article');

permission = ac.can('user').context({ requester: 'dilip', owner: 'dilip' }).execute('approve').sync().on('article'); // <-- Sync Example
permission = await ac.can('user').context({ requester: 'dilip', owner: 'dilip' }).execute('approve').on('article'); // <-- Async Example
console.log(permission.granted);    // —> false

// Using custom/own condition functions
ac.grant('user').condition(
    (context) => {
        return context.category !== 'politics'
    }
).execute('create').on('article');
permission = ac.can('user').context({ category: 'sports' }).execute('create').sync().on('article'); // <-- Sync Example
permission = await ac.can('user').context({ category: 'sports' }).execute('create').on('article'); // <-- Async Example
console.log(permission.granted);    // —> true

Custom Conditions

You can declare your own conditions (requires version >= 4.5.2). Those declarations should be registerd with the library BEFORE your grants and permission checks. The custom condition declarations are allowing you to extend the library core conditions with your own business logic without sacrificing the abillity to serialize your grants.

Basic example:

// 1. Define the condition handler
const greaterOrEqual = (context, args) => {
    if (!args || typeof args.level !== 'number') {
        throw new Error('custom:gte requires "level" argument');
    }

    return +context.level >= args.level;
}

const ac = new AccessControl();

// 2. Register the condition with appropriate name
ac.registerConditionFunction('gte', greaterOrEqual);

// 3. Use it in grants, same as core conditions but with "custom:" prefix
ac.grant('user')
    .condition({
        Fn: 'custom:gte', 
        args: { level: 2 }
    })
    .execute('comment').on('article');

// 4. Evaluate permissions with appropraite context (sync) - same as core conditions
const permission1 = ac
    .can('user')
    .context({ level: 2 })
    .execute('comment')
    .sync()
    .on('article');

// prints "LEVEL 2 true"
console.log('LEVEL 2', permission1.granted);

const permission2 = ac
    .can('user')
    .context({ level: 1 })
    .execute('comment')
    .sync()
    .on('article');

// prints "LEVEL 1 false"
console.log('LEVEL 1', permission2.granted);

Argument is optional:

Custom condition argument is optional - same as core conditions.

const myConditions = {
    isArticleOwner: (context) => {
        return context.loginUserId && context.loginUserId === context.articleOwnerId
    }
}
const ac = new AccessControl();
ac.registerConditionFunction('isArticleOwner', myConditions.isArticleOwner);
ac.grant("user").condition('custom:isArticleOwner')
    .execute(['delete', 'update']).on('article');

ac.can('user').context({ loginUserId: 1, articleOwnerId: 1 })
    .execute('update').sync().on('article'); 
// { granted: true }

Custom condition can be async:

import { asyncCheckResourceForUser } from './somewhere'; 

const myConditions = {
    isResourceOwner: (context, args) => {
        const { resource } = args || {};
        const { loginUserId } = context;
        // your business logic to check resource owner e.g. vs DB
        // send resource name, currently logged in user ID, record.id 
        return asyncCheckResourceForUser(resource, loginUserId, context[resource]);
    }
}
const ac = new AccessControl();
ac.registerConditionFunction('isResourceOwner', myConditions.isResourceOwner);

ac.grant("user")
    .condition({ Fn: 'custom:isResourceOwner', args: { resource: 'article' } })
    .execute(['delete', 'update'])
    .on('article');

// Provide currently logged in user and article.id in the context
await ac.can('user').context({ loginUserId: 1, article: { id: 10 } })
    .execute('update').on('article'); 

Custom conditions allow security policy serializing and can be registered while initializing (in batch):

NOTE: function conditions are not serializeable, so custom conditions are the recommended way to implement your permission policy. You can easiely convert your current function conditions to custom conditions.

const myPolicy = {
    // Serialized policy, can be stored in file, DB, etc
    grants: [
        {
            role: 'user', 
            resource: 'profile', 
            action: ['delete', 'update'], 
            attributes: ['*'],
            condition: {
                Fn: 'custom:isResourceOwner',
                args: { resource: 'profile' }
            }
        },
        {
            role: 'user', 
            resource: 'article', 
            action: ['delete', 'update'], 
            attributes: ['*'],
            condition: {
                Fn: 'custom:isResourceOwner',
                args: { resource: 'article' }
            }
        },
    ],
    // Map your custom conditions to the serialized policy
    myConditions: {
        isResourceOwner: async ({ user, record }, { resource } = {}) => {
            // Your business logic here, e.g. query database...
            if (resource === 'profile' && user.id === 1 && record.id === 1) {
                return true;
            }
            if (resource === 'article' && user.id === 1 && record.id === 2) {
                return true;
            }
            return false;
        }
    }
};

// Register everything on initialization
const ac = new AccessControl(myPolicy.grants, myPolicy.myConditions);

// Use it
await ac.can('user').context({ user: { id: 1 }, record: { id: 1 } })
    .execute('update').on('profile'); // { granted: true }

await ac.can('user').context({ user: { id: 1 }, record: { id: 1 } })
    .execute('delete').on('article');  // { granted: false }

await ac.can('user').context({ user: { id: 1 }, record: { id: 2 } })
    .execute('delete').on('article');  // { granted: true }

Mix with core conditions, use JSON path helper:

NOTE: getValueByPath is available in versions >= 4.5.5

const myPolicy = {
    grants: [
        {
            role: 'editor/news',
            resource: 'article',
            action: 'approve',
            attributes: ['*'],
            // Mix core with custom conditions
            condition: {
                Fn: 'AND',
                args: [
                    {
                        Fn: 'custom:categoryMatcher',
                        args: { type: 'news' }
                    },
                    {
                        Fn: 'custom:isResourceOwner',
                        args: { resource: 'article' }
                    }
                ]
            }
        },
    ],
    myConditions: {
        categoryMatcher: (context, { type } = {}) => {
            // A naive use of the JSON path util
            // Keep in mind it comes with performance penalties
            return type && getValueByPath(context, '$.category.type') === type;
        },
        isResourceOwner: (context, { resource } = {}) => {
            if (!resource) {
                return false;
            }
            return getValueByPath(context, `$.${resource}.owner`) === getValueByPath(context, '$.user.id');
        },
    }
};
const ac = new AccessControl(myPolicy.grants, myPolicy.myConditions);

// Evaluate with article.owner equals to user.id, category.type equals to 'news'
await ac.can('editor/news').context({ user: { id: 1 }, article: { owner: 1 }, category: { type: 'news' } })
    .execute('approve').on('article'); // { granted: true }

// Evaluate with article.owner DOESN'T equal to user.id, category.type equals to 'news'
await ac.can('editor/news').context({ user: { id: 1 }, article: { owner: 2 }, category: { type: 'news' } })
    .execute('approve').on('article');  // { granted: false }

// Evaluate with article.owner equals to user.id, category.type DOESN'T equal to 'news'
await ac.can('editor/news').context({ user: { id: 1 }, article: { owner: 1 }, category: { type: 'tutorials' } })
    .execute('approve').on('article');  // { granted: false }

Wildcard (glob notation) Resource and Actions Examples

ac.grant({
    role: 'politics/editor',
    action: '*',
    resource: 'article',
    condition: {Fn: 'EQUALS', args: {category: 'politics'}},
    attributes: ['*']
});
ac.grant({
    role: 'politics/writer',
    action: ['*', '!publish'],
    resource: 'article',
    condition: {Fn: 'EQUALS', args: {category: 'politics'}},
    attributes: ['*']
});

ac.grant({
    role: 'admin',
    action: '*',
    resource: '*',
    condition: {Fn: 'EQUALS', args: {category: 'politics'}},
    attributes: ['*']
});
permission = ac.can('politics/editor').execute('publish').with({category: 'politics'}).sync().on('article'); // <-- Sync Example
permission = await ac.can('politics/editor').execute('publish').with({category: 'politics'}).on('article'); // <-- Async Example
console(permission.attributes); // -> ['*']
console(permission.granted); // -> true

permission = ac.can('admin').execute('publish').with({category: 'politics'}).sync().on('article'); // <-- Sync Example
permission = await ac.can('admin').execute('publish').with({category: 'politics'}).on('article'); // <-- Async Example
console(permission.attributes); // -> ['*']
console(permission.granted); // -> true

permission = ac.can('admin').execute('publish').with({category: 'politics'}).sync().on('blog'); // <-- Sync Example
permission = await ac.can('admin').execute('publish').with({category: 'politics'}).on('blog'); // <-- Async Example
console(permission.attributes); // -> ['*']
console(permission.granted); // -> true

permission = ac.can('politics/writer').execute('publish').with({category: 'politics'}).sync().on('arti`cle'); // <-- Sync Example
permission = await ac.can('politics/writer').execute('publish').with({category: 'politics'}).on('arti`cle'); // <-- Async Example
console(permission.granted); // -> false

Express.js Example

Check role permissions for the requested resource and action, if granted; respond with filtered attributes.

const ac = new AccessControl(grants);
// ...
router.get('/videos/:title', function (req, res, next) {
    const permission = ac.can(req.user.role).execute('read').on('video');
    if (permission.granted) {
        Video.find(req.params.title, function (err, data) {
            if (err || !data) return res.status(404).end();
            // filter data by permission attributes and send.
            res.json(permission.filter(data));
        });
    } else {
        // resource is forbidden for this user/role
        res.status(403).end();
    }
});

Roles

You can create/define roles simply by calling .grant(<role>) method on an AccessControl instance.

Roles can extend other roles.

// user role inherits viewer role permissions
ac.grant('user').extend('viewer');
// admin role inherits both user and editor role permissions
ac.grant('admin').extend(['user', 'editor']);
// both admin and superadmin roles inherit moderator permissions
ac.grant(['admin', 'superadmin']).extend('moderator');

Actions and Action-Attributes

ac.grant('editor').execute('publish').on('article');
let permission = ac.can('editor').execute('publish').sync().on('article'); // <-- Sync Example
let permission = await ac.can('editor').execute('publish').on('article'); // <-- Async Example
console(permission.attributes); // —> ['*'] (all attributes)
console(permission.granted); // -> true

ac.grant('sports/editor').execute('publish').when({Fn: 'EQUALS', args: {category: 'sports'}}).on('article');
permission = ac.can('sports/editor').execute('publish').with({category: 'sports'}).sync().on('article'); // <-- Sync Example
permission = await ac.can('sports/editor').execute('publish').with({category: 'sports'}).on('article'); // <-- Async Example
console(permission.attributes); // —> ['*'] (all attributes)
console(permission.granted); // -> true

permission = ac.can('sports/editor').execute('publish').with({category: 'politics'})).sync().on('article'); // <-- Sync Example
permission = await ac.can('sports/editor').execute('publish').with({category: 'politics'})).on('article'); // <-- Async Example
console(permission.attributes); // -> []
console(permission.granted); // -> false

Resources and Resource-Attributes

Multiple roles can have access to a specific resource. But depending on the context, you may need to limit the contents of the resource for specific roles.

This is possible by resource attributes. You can use Glob notation to define allowed or denied attributes.

For example, we have a video resource that has the following attributes: id, title and runtime. All attributes of any video resource can be read by an admin role:

ac.grant('admin').execute('read').on('video', ['*']);
// equivalent to:
// ac.grant('admin').execute('read').on('video');

But the id attribute should not be read by a user role.

ac.grant('user').execute('read').on('video', ['*', '!id']);
// equivalent to:
// ac.grant('user').execute('read').on('video', ['title', 'runtime']);

You can also use nested objects (attributes).

ac.grant('user').execute('read').on('account', ['*', '!record.id']);

Checking Permissions and Filtering Attributes

You can call .can(<role>).<action>(<resource>) on an AccessControl instance to check for granted permissions for a specific resource and action.

const permission = ac.can('user').execute('read').on('account');
permission.granted;       // true
permission.attributes;    // ['*', '!record.id']
permission.filter(data);  // filtered data (without record.id)

See express.js example.

Defining All Grants at Once

You can pass the grants directly to the AccessControl constructor. It accepts either an Object:

// This is actually how the grants are maintained internally.
let grantsObject = {
    admin: {
        grants: [
            {
                resource: 'video', action: '*', attributes: ['*']
            }
        ]
    },
    user: {
        grants: [
            {
                resource: 'video', action: 'create', attributes: ['*']
            },
            {
                resource: 'video', action: 'read', attributes: ['*']
            },
            {
                resource: 'video', action: 'update', attributes: ['*']
            },
            {
                resource: 'video', action: 'delete', attributes: ['*']
            },
        ]
    },
    "sports/editor": {
        grants: [
            {
                resource: 'article',
                action: '*',
                attributes: ["*"],
                condition: {
                    Fn: 'EQUALS',
                    args: {
                        'category': 'sports'
                    }
                }
            }   
        ] 
    },
    "sports/writer": {
        grants: [
            {
                resource: 'article',
                action: ['create', 'update'],
                attributes: ["*", "!status"],
                condition: {
                    Fn: 'EQUALS',
                    args: {
                        'category': 'sports'
                    }
                }
            }   
        ] 
    }
};

const ac = new AccessControl(grantsObject);

... or an Array (useful when fetched from a database):

// grant list fetched from Database (to be converted to a valid grants object, internally)
let grantList = [
    { role: 'admin', resource: 'video', action: 'create', attributes: ['*'] },
    { role: 'admin', resource: 'video', action: 'read', attributes: ['*'] },
    { role: 'admin', resource: 'video', action: 'update', attributes: ['*'] },
    { role: 'admin', resource: 'video', action: 'delete', attributes: ['*'] },

    { role: 'user', resource: 'video', action: 'create', attributes: ['*'] },
    { role: 'user', resource: 'video', action: 'read', attributes: ['*'] },
    { role: 'user', resource: 'video', action: 'update', attributes: ['*'] },
    { role: 'user', resource: 'video', action: 'delete', attributes: ['*'] },
    { role: 'user', resource: 'photo', action: '*', attributes: ['*'] },
    { role: 'user', resource: 'article', action: ['*', '!delete'], attributes: ['*'] },
    { role: 'sports/editor', resource: 'article', action: 'create', attributes: ['*'],
      condition: { "Fn": "EQUALS", "args": { "category": "sports" } }
    },
    {
        role: 'sports/editor', resource: 'article', action: 'update', attributes: ['*'],
        condition: { "Fn": "EQUALS", "args": { "category": "sports" } }
    }
];
const ac = new AccessControl(grantList);

You can set/get grants any time:

const ac = new AccessControl();
ac.setGrants(grantsObject);
console.log(ac.getGrants());
// You can save ac.getGrants() to Database
// Please note: User should be part of your code and wraps calls to User to table/collection.
await User.save({permissions: acl.toJSON()}); 
// Retrieve from DB
const perms = await User.getBydId(userId);
ac = AccessControl.fromJSON(user.permissions);

// if your DB supports storing JSON natively then you can use following code.
await User.save({permissions: acl.getGrants()}); 
// Retrieve from DB
const perms = await User.getBydId(userId);
ac.setGrants(user.permissions);

Extending Roles

const ac = new AccessControl();
const editorGrant = {
    role: 'editor',
    resource: 'post',
    action: 'create', // action
    attributes: ['*'] // grant only
};
ac.grant(editorGrant);
// first level of extension (extending with condition)
ac.extendRole('sports/editor', 'editor', {Fn: 'EQUALS', args: {category: 'sports'}});
ac.extendRole('politics/editor', 'editor', {Fn: 'EQUALS', args: {category: 'politics'}}); 


let permission = ac.can('sports/editor').context({category: 'sports'}).execute('create').sync().on('post'); // <-- Sync Example
let permission = await ac.can('sports/editor').context({category: 'sports'}).execute('create').on('post'); // <-- Async Example
console.log(permission.granted);    // —> true
console.log(permission.attributes); // —> ['*']

permission = ac.can('sports/editor').context({category: 'politics'}).execute('create').sync().on('post'); // <-- Sync Example
permission = await ac.can('sports/editor').context({category: 'politics'}).execute('create').on('post'); // <-- Async Example
console.log(permission.granted);    // —> false
console.log(permission.attributes); // —> []

// second level of extension (extending without condition)
ac.extendRole('sports-and-politics/editor', ['sports/editor', 'politics/editor']);
permission = ac.can('sports-and-politics/editor').context({category: 'politics'}).execute('create').sync().on('post'); // <-- Sync Example
permission = await ac.can('sports-and-politics/editor').context({category: 'politics'}).execute('create').on('post'); // <-- Async Example
console.log(permission.granted);    // —> true
console.log(permission.attributes); // —> ['*']

// third level of extension (extending with condition)
ac.extendRole('conditional/sports-and-politics/editor', 'sports-and-politics/editor', {
    Fn: 'EQUALS',
    args: { status: 'draft' }
}); // <-- Async Example

permission = ac.can('conditional/sports-and-politics/editor').context({category: 'politics', status: 'draft'}).execute('create').sync().on('post'); // <-- Sync Example
permission = await ac.can('conditional/sports-and-politics/editor').context({category: 'politics', status: 'draft'}).execute('create').on('post'); // <-- Async Example
console.log(permission.granted);    // —> true
console.log(permission.attributes); // —> ['*']

permission = ac.can('conditional/sports-and-politics/editor').context({category: 'politics', status: 'published'}).execute('create').sync().on('post'); // <-- Sync Example
permission = await ac.can('conditional/sports-and-politics/editor').context({category: 'politics', status: 'published'}).execute('create').on('post'); // <-- Async Example
console.log(permission.granted);    // —> false
console.log(permission.attributes); // —> []

Allowed Resources and actions

const ac = new AccessControl();
ac.grant('user').condition({Fn: 'EQUALS', args: {category: 'sports'}}).execute('create').on('article');
ac.grant('user').execute('*').on('image');
ac.extendRole('admin', 'user');

ac.grant('admin').execute('delete').on('article');        
ac.grant('admin').execute('*').on('category');
ac.extendRole('owner', 'admin'); // <-- Sync Example

ac.grant('owner').execute('*').on('video');

console.log(ac.allowedResourcesSync({role: 'user'}).sort()); // -> ['article', 'image'] 
console.log(await ac.allowedResources({role: 'user'}).sort()); // -> ['article', 'image'] 
console.log(ac.allowedResourcesSync({role: 'user', context: {category: 'politics'}}).sort()); // -> ['image']      
console.log(await ac.allowedResources({role: 'user', context: {category: 'politics'}}).sort()); // -> ['image']
console.log(ac.allowedResourcesSync({role: 'admin'}).sort()); // -> ['article', 'category', 'image']
console.log(await ac.allowedResources({role: 'admin'}).sort()); // -> ['article', 'category', 'image']
console.log(ac.allowedResourcesSync({role: 'owner'}).sort()); // -> ['article', 'category', 'image', 'video']
console.log(await ac.allowedResources({role: 'owner'}).sort()); // -> ['article', 'category', 'image', 'video']
console.log(ac.allowedResourcesSync({role: ['admin', 'owner']}).sort()); // -> ['article', 'category', 'image', 'video']
console.log(await ac.allowedResources({role: ['admin', 'owner']}).sort()); // -> ['article', 'category', 'image', 'video']

console.log(ac.allowedActionsSync({role: 'user', resource: 'article'}).sort()); // -> ['create']
console.log(await ac.allowedActions({role: 'user', resource: 'article'}).sort()); // -> ['create']
console.log(ac.allowedActionsSync({role: 'user', resource: 'article', context: {category: 'politics'}})); // -> []        
console.log(await ac.allowedActions({role: 'user', resource: 'article', context: {category: 'politics'}})); // -> []        
console.log(ac.allowedActionsSync({role: ['admin', 'user'], resource: 'article'}).sort()); // -> ['create', 'delete']
console.log(await ac.allowedActions({role: ['admin', 'user'], resource: 'article'}).sort()); // -> ['create', 'delete']
console.log(ac.allowedActionsSync({role: 'admin', resource: 'category'}).sort()); // -> ['*']
console.log(await ac.allowedActions({role: 'admin', resource: 'category'}).sort()); // -> ['*']
console.log(ac.allowedActionsSync({role: 'owner', resource: 'video'}).sort()); // -> ['*']
console.log(await ac.allowedActions({role: 'owner', resource: 'video'}).sort()); // -> ['*']

NOTE: allowedResources and allowedActions skip the conditions when context is not passed

Example for versions >= 4.0.0

Take a look at the test cases

Upgrading to >= 4.0.0

• There are many breaking changes so please update the code accordingly.
• All future updates and bug fixes will happen only to versions >= 4.
• New features only available in >= 4
  • Storing and retrieving of custom condition functions.
  • Promise based conditional functions.
  • For Sync use cases use function with Sync suffix.

Licenses

• role-acl: MIT.
• AccessControl: MIT.

Contact us

This product is supported and actively developed by Tensult. You can contact us at info@tensult.com.