express-reaccess

express-reaccess

Express middleware to check user access based on the ressources URIs and HTTP methods.

Usage

var reaccess = require('express-reaccess');

app.use(reaccess({
  rightsProp: 'user.rights',
  tplValueProp: 'user'
}));

Assumming a middleware placed before the above example and adding a property like this on the request object for a given authenticated user:

req.user = {
  id: 1,
  login: 'nfroidure',
  organization: {
    id: 1,
    name: 'simplifield'
  },
  rights: [{
    path: '/users/:login',
    methods: reaccess.METHODS ^ reaccess.DELETE
  },{
    path: '/organisations/:organization.name',
    methods: reaccess.OPTIONS | reaccess.HEAD | reaccess.GET
  },{
    path: 'public/(.*)',
    methods: reaccess.OPTIONS | reaccess.HEAD | reaccess.GET
  }]
};

Then, the user will be able to access the following URI/method couples:

• OPTIONS/HEAD/GET/PUT/POST - /users/nfroidure
• OPTIONS/HEAD/GET - /organizations/simplifield
• OPTIONS/GET/HEAD - /public/*

Warning: Since this middleware is based on RegExp, you have to be aware of RegExp special chars. By example, the following rules:

req.user.rights = [{
  path: '/blog/posts/([0-9]+)/?page=([0-9]+)',
  methods: reaccess.OPTIONS | reaccess.HEAD | reaccess.GET
}]

Will allow access to 'blog/posts/1page=1' wich is probably not what you want. So, do not forget to escape special chars:

req.user.rights = [{
  path: '/blog/posts/([0-9]+)/\\?page=([0-9]+)',
  methods: reaccess.OPTIONS | reaccess.HEAD | reaccess.GET
}]

The best is to unit test your access rules.

API

reaccess(options)

options

Type: Object

The options of the reaccess middleware.

options.rightsProp

Type: String Default: 'user.rights'

The property in wich the user rights will be read. This property must be filled on the request object by any other middleware.

This property must contain an Array of object of this kind :

req.user.rights = [{
 path: '/organizations/:orgId/users.json'
 methods: reaccess.GET | reaccess.POST
}];

options.userProp

Type: String

The property in wich any templated value found in the path must be searched for.

By example, if the user rights are the following :

req.user.rights = [{
 path: '/organizations/:org.id/users.json'
 methods: reaccess.GET | reaccess.POST
}];

He will be able to access this URI /organizations/1/users.json if a previously set middleware have set the req.user.org.id to 1 and options.userProp to 'user'.

options.errorConstructor

Type: Error constructor Default: Error

Allows to use your own Error contructor for reaccess access errors.

options.accessErrorMessage

Type: String Default: Unauthorized access!

Allows to define your own error message. Note this middleware will not throw 401 responses for you. This is your responsibility to do so in your own error handler middleware. Defining a custom access error message could help detect when to answer with a 401 status code.

Static properties

Reaccess use bitwise operators to match methods. The reaccess function provides static constants to help you make cleaner code.

reaccess.OPTIONS

Type: Number Value: 1

reaccess.GET

Type: Number Value: 2

reaccess.POST

Type: Number Value: 4

reaccess.PUT

Type: Number Value: 8

reaccess.PATCH

Type: Number Value: 16

reaccess.DELETE

Type: Number Value: 32

reaccess.METHODS

Type: Number Value: 63

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