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alanning:roles

v3.2.1•Published 4 years ago

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meteor-roles v3

Authorization package for Meteor - compatible with built-in accounts package.

There are also older versions of this package:

Table of Contents

Contributors

Thanks to:

Authorization

This package lets you attach roles to a user which you can then check against later when deciding whether to grant access to Meteor methods or publish data. The core concept is very simple, essentially you are creating an assignment of roles to a user and then checking for the existence of those roles later. This package provides helper methods to make the process of adding, removing, and verifying those roles easier.

Permissions vs roles (or What's in a name...)

Although the name of this package is roles, you can define your roles, scopes or permissions however you like. They are essentially just tags that you assign to a user and which you can check upon later.

You can have traditional roles like, admin or webmaster, or you can assign more granular permissions such as, view-secrets, users.view, or users.manage. Often, more granular is actually better because you are able to handle all those pesky edge cases that come up in real-life usage without creating a ton of higher-level roles. With the roles package, it's all just a role object.

Roles can be put into a hierarchy. Roles can have multiple parents and can be children (subroles) of multiple roles. If a parent role is set to the user, all its descendants are also applying. You can use this to create "super roles" aggregating permissions all the way through the bottom of the tree. For example, you could name two top-level roles user and admin and then you could use your second-level roles as permissions and name them USERS_VIEW, POST_EDIT, and similar. Then you could set admin role as parent role for USERS_VIEW and POST_EDIT, while user would be parent only of the POST_EDIT role. You can then assign user and admin roles to your users. And if you need to change permissions later for the whole role, just add or remove children roles. You can create roles from this example with:

1Roles.createRole('user');
2Roles.createRole('admin');
3Roles.createRole('USERS_VIEW');
4Roles.createRole('POST_EDIT');
5Roles.addRolesToParent('USERS_VIEW', 'admin');
6Roles.addRolesToParent('POST_EDIT', 'admin');
7Roles.addRolesToParent('POST_EDIT', 'user');

What are "scopes"?

Sometimes it is useful to let a user have independent sets of roles. The roles package calls these independent sets "scopes" for lack of a better term. You can use them to represent various communities inside of your application. Or maybe your application supports multiple tenants. You can put each of those tenants into their own scope. Alternatively, you can use scopes to represent various resources you have.

Users can have both scope roles assigned, and global roles. Global roles are in effect for all scopes. But scopes are independent from each other. Users can have one set of roles in scope A and another set of roles in scope B. Let's go through an example of this using soccer/football teams as scopes.

1Roles.addUsersToRoles(joesUserId, ['manage-team','schedule-game'], 'manchester-united.com');
2Roles.addUsersToRoles(joesUserId, ['player','goalie'], 'real-madrid.com');
3
4Roles.userIsInRole(joesUserId, 'manage-team', 'manchester-united.com'); // true
5Roles.userIsInRole(joesUserId, 'manage-team', 'real-madrid.com'); // false

In this example we can see that Joe manages Manchester United and plays for Real Madrid. By using scopes, we can assign roles independently and make sure that they don't get mixed up between scopes.

Now, let's take a look at how to use the global roles. Say we want to give Joe permission to do something across all of our scopes. That is what the global roles are for:

1Roles.addUsersToRoles(joesUserId, 'super-admin', null); // Or you could just omit the last argument.
2
3if (Roles.userIsInRole(joesUserId, ['manage-team', 'super-admin'], 'real-madrid.com')) {
4  // True! Even though Joe doesn't manage Real Madrid, he has
5  // a 'super-admin' global role so this check succeeds.
6}

Changes to default Meteor behavior

  1. A new collection Meteor.roleAssignment contains the information which role has been assigned to which user.
  2. A new collection Meteor.roles contains a global list of defined role names.
  3. All existing roles are automatically published to the client.

Installing

  1. Add one of the built-in accounts packages so the Meteor.users collection exists. From a command prompt:

    meteor add accounts-password

  2. Add this package to your project. From a command prompt:

    meteor add alanning:roles

  3. Publish the role assignments you need to the client:

    1Meteor.publish(null, function () {
2  if (this.userId) {
3    return Meteor.roleAssignment.find({ 'user._id': this.userId });
4  } else {
5    this.ready()
6  }
7})

  4. Run your application:

    meteor

Migration to 3.0

If you are currently using this package in a version older than 2.x, please upgrade to 2.0 by running the migration script required there: https://github.com/Meteor-Community-Packages/meteor-roles/tree/v2#migration-to-20

In meteor-roles 3.0, functions are mostly backwards compatible with 2.x, but roles are stored differently in the database. Please take a backup of the users collection before migrating. To migrate the database to the new schema, run Meteor._forwardMigrate2() on the server:

meteor shell
> Package['alanning:roles'].Roles._forwardMigrate2()

In case something fails, there is also a script available for rolling back the changes. But be warned that a backward migration takes a magnitude longer than a foward migration. To migrate the database back to the old schema, run Meteor._backwardMigrate2() on the server:

meteor shell
> Package['alanning:roles'].Roles._backwardMigrate2()

Changes between 2.x and 3.0

Here is the list of important changes between meteor-roles 2.x and 3.0 to consider when migrating to 3.0:

  • Role assignments have been moved from the users documents to a separate collection called role-assignment, available at Meteor.roleAssignment.
  • Role assignments are not published automatically. If you want all your role-assignments to be published automatically please include the following code:
1Meteor.publish(null, function () {
2  if (this.userId) {
3    return Meteor.roleAssignment.find({ 'user._id': this.userId });
4  } else {
5    this.ready()
6  }
7})
  • [BC] The behavior of getRolesForUser() used with the option fullObjects changed. In case you need the old behavior ...
  • Added option anyScope to removeUsersFromRoles()
  • Add option onlyScoped to getRolesForUser() to allow limiting the result to only scoped permissions
  • All functions (excepted for those listed above) work with 2.x arguments, but in 3.x accept extra arguments and/or options.
  • Details and reasoning can be found in #276

Usage Examples

Here are some potential use cases:

-- Server --

Add users to roles:

1var users = [
2      {name:"Normal User",email:"normal@example.com",roles:[]},
3      {name:"View-Secrets User",email:"view@example.com",roles:['view-secrets']},
4      {name:"Manage-Users User",email:"manage@example.com",roles:['manage-users']},
5      {name:"Admin User",email:"admin@example.com",roles:['admin']}
6    ];
7
8users.forEach(function (user) {
9  var id;
10
11  id = Accounts.createUser({
12    email: user.email,
13    password: "apple1",
14    profile: { name: user.name }
15  });
16
17  if (Meteor.roleAssignment.find({ 'user._id': id }).count() === 0) {
18    user.roles.forEach(function (role) {
19      Roles.createRole(role, {unlessExists: true});
20    });
21    // Need _id of existing user record so this call must come after `Accounts.createUser`.
22    Roles.addUsersToRoles(id, user.roles);
23  }
24
25});

Check user roles before publishing sensitive data:

1// server/publish.js
2
3// Give authorized users access to sensitive data by scope
4Meteor.publish('secrets', function (scope) {
5  check(scope, String);
6
7  if (Roles.userIsInRole(this.userId, ['view-secrets','admin'], scope)) {
8    
9    return Meteor.secrets.find({scope: scope});
10    
11  } else {
12
13    // user not authorized. do not publish secrets
14    this.stop();
15    return;
16
17  }
18});

Prevent non-authorized users from creating new users:

1Accounts.validateNewUser(function (user) {
2  var loggedInUser = Meteor.user();
3
4  if (Roles.userIsInRole(loggedInUser, ['admin','manage-users'])) {
5    return true;
6  }
7
8  throw new Meteor.Error('unauthorized', "Not authorized to create new users");
9});

Prevent access to certain functionality, such as deleting a user:

1// server/userMethods.js
2
3Meteor.methods({
4  /**
5   * Revokes roles for a user in a specific scope.
6   * 
7   * @method revokeUser
8   * @param {String} targetUserId ID of user to revoke roles for.
9   * @param {String} scope Company to update roles for.
10   */
11  revokeUser: function (targetUserId, scope) {
12    check(targetUserId, String);
13    check(scope, String);
14  
15    var loggedInUser = Meteor.user();
16
17    if (!loggedInUser ||
18        !Roles.userIsInRole(loggedInUser, 
19                            ['manage-users', 'support-staff'], scope)) {
20      throw new Meteor.Error('access-denied', "Access denied")
21    }
22
23    // remove roles for target scope
24    Roles.setUserRoles(targetUserId, [], scope)
25  }
26})

Manage a user's roles:

1// server/userMethods.js
2
3Meteor.methods({
4  /**
5   * Update a user's roles.
6   *
7   * @param {Object} targetUserId Id of user to update.
8   * @param {Array} roles User's new roles.
9   * @param {String} scope Company to update roles for.
10   */
11  updateRoles: function (targetUserId, roles, scope) {
12    check(targetUserId, String);
13    check(roles, [String]);
14    check(scope, String);
15
16    var loggedInUser = Meteor.user();
17
18    if (!loggedInUser ||
19        !Roles.userIsInRole(loggedInUser, 
20                            ['manage-users', 'support-staff'], scope)) {
21      throw new Meteor.Error('access-denied', "Access denied");
22    }
23
24    Roles.setUserRoles(targetUserId, roles, scope);
25  }
26})

-- Client --

Client javascript doese not by default have access to all the same Roles functions as the server unless you publish these role-assignments. In addition, Blaze will have the addition of a isInRole handlebars helper which is automatically registered by the Roles package.

As with all Meteor applications, client-side checks are a convenience, rather than a true security implementation since Meteor bundles the same client-side code to all users. Providing the Roles functions client-side also allows for latency compensation during Meteor method calls. Roles functions which modify the database should not be called directly, but inside the Meteor methods.

NOTE: Any sensitive data needs to be controlled server-side to prevent unwanted disclosure. To be clear, Meteor sends all templates, client-side javascript, and published data to the client's browser. This is by design and is a good thing. The following example is just sugar to help improve the user experience for normal users. Those interested in seeing the 'admin_nav' template in the example below will still be able to do so by manually reading the bundled client.js file. It won't be pretty but it is possible. But this is not a problem as long as the actual data is restricted server-side.

To check for global roles or when not using scopes:

<!-- client/myApp.html -->

<template name="header">
  ... regular header stuff
  {{#if isInRole 'admin'}}
    {{> admin_nav}}  
  {{/if}}
  {{#if isInRole 'admin,editor'}}
    {{> editor_stuff}}
  {{/if}}
</template>

To check for roles when using scopes:

<!-- client/myApp.html -->

<template name="header">
  ... regular header stuff
  {{#if isInRole 'admin,editor' 'group1'}}
    {{> editor_stuff}}  
  {{/if}}
</template>

API Docs

Online API docs found here: https://meteor-community-packages.github.io/meteor-roles/

API docs generated using YUIDoc

To re-generate documentation:

  1. install YUIDoc
  2. cd meteor-roles
  3. yuidoc

To serve documentation locally:

  1. install YUIDoc
  2. cd meteor-roles
  3. yuidoc --server 5000
  4. point browser at http://localhost:5000/

Example Apps

The examples directory contains Meteor apps which show off the following features:

  • Server-side publishing with authorization to secure sensitive data
  • Client-side navigation with link visibility based on user roles
  • 'Sign-in required' app with up-front login page using accounts-ui
  • Client-side routing

View the flow-router example app online @ http://roles.meteor.com/

  1. git clone https://github.com/Meteor-Community-Packages/meteor-roles.git
  2. choose an example, eg.
* `cd meteor-roles/examples/iron-router` or
* `cd meteor-roles/examples/flow-router`
  1. meteor
  2. point browser to http://localhost:3000

Tests

To run tests:

  1. cd meteor-roles
  2. npm run test