I am creating a fairly simple site with Node, Express and Mongoose. The site needs to have have user roles and permissions. My thoughts are that i'll validate permissions based on user interaction with the data base.
In mongoose is there a way to determine the type of CRUD operation currently being carried out possibly by a user?
I've found a solution. It would be great to hear peoples opinions on this.
I have a permissions config object which defines each role and their permissions.
Permissions config object
roles.admin = {
id: "admin",
name: "Admin",
description: "",
resource : [
{
id : 'blog',
permissions: ['create', 'read', 'update', 'delete']
},
{
id : 'user',
permissions: ['create', 'read', 'update', 'delete']
},
{
id : 'journal',
permissions: ['create', 'read', 'update', 'delete']
},
]
};
roles.editor = {
id: "editor",
name: "Editor",
description: "",
resource : [
{
id : 'blog',
permissions: ['create', 'read', 'update', 'delete']
},
{
id : 'user',
permissions: ['read']
},
{
id : 'journal',
permissions: ['create', 'read', 'update']
},
]
};
Middleware function
var roles = require('./config');
var permissions = (function () {
var getRoles = function (role) {
var rolesArr = [];
if (typeof role === 'object' && Array.isArray(role)) {
// Returns selected roles
for (var i = 0, len = role.length; i < len; i++) {
rolesArr.push(roles[role[i]]);
};
return rolesArr;
} else if (typeof role === 'string' || !role) {
// Returns all roles
if (!role) {
for (var role in roles) {
rolesArr.push(roles[role]);
};
}
// Returns single role
rolesArr.push(roles[role]);
return rolesArr;
}
},
check = function (action, resource, loginRequired) {
return function(req, res, next) {
var isAuth = req.isAuthenticated();
// If user is required to be logged in & isn't
if (loginRequired && !isAuth) {
return next(new Error("You must be logged in to view this area"));
}
if (isAuth || !loginRequired) {
var authRole = isAuth ? req.user.role : 'user',
role = get(authRole),
hasPermission = false;
(function () {
for (var i = 0, len = role[0].resource.length; i < len; i++){
if (role[0].resource[i].id === resource && role[0].resource[i].permissions.indexOf(action) !== -1) {
hasPermission = true;
return;
}
};
})();
if (hasPermission) {
next();
} else {
return next(new Error("You are trying to " + action + " a " + resource + " and do not have the correct permissions."));
}
}
}
}
return {
get : function (role) {
var roles = getRoles(role);
return roles;
},
check : function (action, resource, loginRequired) {
return check(action, resource, loginRequired);
}
}
})();
module.exports = permissions;
Then i created a middleware function, when the check method gets called it gets the users role from the req object (req.user.role). It then looks at the params passed to the middleware and cross references them with those in the permissions config object.
Route with middlware
app.get('/journal', `**permissions.check('read', 'journal')**`, function (req, res) {
// do stuff
};
This is my implementation. The code is reusable for client and server. I use it for my express/angular website
in app/both/both.js
var accessList = {
//note: same name as controller's function name
assignEditor: 'assignEditor'
,adminPage: 'adminPage'
,editorPage: 'editorPage'
,profilePage: 'profilePage'
,createArticle: 'createArticle'
,updateArticle: 'updateArticle'
,deleteArticle: 'deleteArticle'
,undeleteArticle: 'undeleteArticle'
,banArticle: 'banArticle'
,unbanArticle: 'unbanArticle'
,createComment: 'createComment'
,updateComment: 'updateComment'
,deleteComment: 'deleteComment'
,undeleteComment: 'undeleteComment'
,banComment: 'banComment'
,unbanComment: 'unbanComment'
,updateProfile: 'updateProfile'
}
exports.accessList = accessList
var resourceList = {
//Note: same name as req.resource name
profile: 'profile'
,article: 'article'
,comment: 'comment'
}
exports.resourceList = resourceList
var roleList = {
admin: 'admin'
,editor: 'editor'
,entityCreator: 'entityCreator'
,profileOwner: 'profileOwner' //creator or profile owner
,normal: 'normal' //normal user, signed in
,visitor: 'visitor' //not signed in, not used, open pages are uncontrolled
}
var permissionList = {}
permissionList[accessList.assignEditor] = [roleList.admin]
permissionList[accessList.adminPage] = [roleList.admin]
permissionList[accessList.editorPage] = [roleList.admin, roleList.editor]
permissionList[accessList.profilePage] = [roleList.admin, roleList.editor, roleList.normal]
permissionList[accessList.createArticle] = [roleList.admin, roleList.editor, roleList.normal]
permissionList[accessList.updateArticle] = [roleList.admin, roleList.editor, roleList.entityCreator]
permissionList[accessList.deleteArticle] = [roleList.admin, roleList.editor, roleList.entityCreator]
permissionList[accessList.undeleteArticle] = [roleList.admin, roleList.editor, roleList.entityCreator]
permissionList[accessList.banArticle] = [roleList.admin, roleList.editor]
permissionList[accessList.unbanArticle] = [roleList.admin, roleList.editor]
permissionList[accessList.createComment] = [roleList.admin, roleList.editor, roleList.normal]
permissionList[accessList.updateComment] = [roleList.admin, roleList.editor, roleList.entityCreator]
permissionList[accessList.deleteComment] = [roleList.admin, roleList.editor, roleList.entityCreator]
permissionList[accessList.undeleteComment] = [roleList.admin, roleList.editor, roleList.entityCreator]
permissionList[accessList.banComment] = [roleList.admin, roleList.editor]
permissionList[accessList.unbanComment] = [roleList.admin, roleList.editor]
permissionList[accessList.updateProfile] = [roleList.admin, roleList.profileOwner]
var getRoles = function(access, resource, isAuthenticated, entity, user) {
var roles = [roleList.visitor]
if (isAuthenticated) {
roles = [roleList.normal]
if (user.username === 'admin')
roles = [roleList.admin]
else if (user.type === 'editor')
roles = [roleList.editor]
if (resource) {
if (resource === resourceList.profile) {
//Note: on server _id is a object, client _id is string, which does not have equals method
if (entity && entity._id.toString() === user._id.toString())
roles.push(roleList.profileOwner)
}
else if (resource === resourceList.article) {
if (entity && entity.statusMeta.createdBy._id.toString() === user._id.toString())
roles.push(roleList.entityCreator)
}
else if (resource === resourceList.comment) {
if (entity && entity.statusMeta.createdBy._id.toString() === user._id.toString())
roles.push(roleList.entityCreator)
}
}
}
return roles
}
exports.havePermission = function(access, resource, isAuthenticated, entity, user) {
var roles = getRoles(access, resource, isAuthenticated, entity, user)
//Note: we can implement black list here as well, like IP Ban
if (!permissionList[access])
return true
for (var i = 0; i < roles.length; i++) {
var role = roles[i]
if (permissionList[access].indexOf(role) !== -1)
return true
}
return false
}
Then on app/server/helper.js (act as adapter)
var both = require(dir.both + '/both.js')
exports.accessList = both.accessList
exports.resourceList = both.resourceList
exports.havePermission = function(access, resource, req) {
return both.havePermission(access, resource, req.isAuthenticated(), req[resource], req.user)
}
//todo: use this function in other places
exports.getPermissionError = function(message) {
var err = new Error(message || 'you do not have the permission')
err.status = 403
return err
}
exports.getAuthenticationError = function(message) {
var err = new Error(message || 'please sign in')
err.status = 401
return err
}
exports.requiresPermission = function(access, resource) {
return function(req, res, next) {
if (exports.havePermission(access, resource, req))
return next()
else {
if (!req.isAuthenticated())
return next(exports.getAuthenticationError())
else
return next(exports.getPermissionError())
}
}
}
on app/client/helper.js, also act as adapter.
exports.accessList = both.accessList
exports.resourceList = both.resourceList
exports.havePermission = function(access, resource, userService, entity) {
//Note: In debugging, we can grant client helper all access, and test robustness of server
return both.havePermission(access, resource, userService.isAuthenticated(), entity, userService.user)
}
I personnally took inspiration from ghost. In my config there is the perms, and permissions.jsexport a canThisfunction that take the current logged user. Here is the whole project
Part of my config file
"user_groups": {
"admin": {
"full_name": "Administrators",
"description": "Adminsitators.",
"allowedActions": "all"
},
"modo": {
"full_name": "Moderators",
"description": "Moderators.",
"allowedActions": ["mod:*", "comment:*", "user:delete browse add banish edit"]
},
"user": {
"full_name": "User",
"description": "User.",
"allowedActions": ["mod:browse add star", "comment:browse add", "user:browse"]
},
"guest": {
"full_name": "Guest",
"description": "Guest.",
"allowedActions": ["mod:browse", "comment:browse", "user:browse add"]
}
},
mongoose = require("mongoose")
###
This utility function determine whether an user can do this or this
using the permissions. e. g. "mod" "delete"
@param userId the id of the user
@param object the current object name ("mod", "user"...)
@param action to be executed on the object (delete, edit, browse...)
@param owner the optional owner id of the object to be "actionned"
###
# **Important this is a promise but to make a lighter code I removed it**
exports.canThis = (userId, object, action, ownerId, callback) ->
User = mongoose.model("User")
if typeof ownerId is "function"
callback = ownerId
ownerId = undefined
if userId is ""
return process(undefined, object, action, ownerId, callback)
User.findById(userId, (err, user) ->
if err then return callback err
process(user, object, action, ownerId, callback)
)
process = (user, object, action, ownerId, callback) ->
if user then role = user.role or "user"
group = config.user_groups[role or "guest"]
if not group then return callback(new Error "No suitable group")
# Parses the perms
actions = group.allowedActions
for objAction in actions when objAction.indexOf object is 0
# We get all the allowed actions for the object and group
act = objAction.split(":")[1]
obj = objAction.split(":")[0]
if act.split(" ").indexOf(action) isnt -1 and obj is object
return callback true
callback false
config = require "../config"
Usage example:
exports.edit = (userid, name) ->
# Q promise
deferred = Q.defer()
# default value
can = false
# We check wheteher it can or not
canThis(userid, "user", "edit").then((can)->
if not userid
return deferred.reject(error.throwError "", "UNAUTHORIZED")
User = mongoose.model "User"
User.findOne({username: name}).select("username location website public_email company bio").exec()
).then((user) ->
# Can the current user do that?
if not user._id.equals(userid) and can is false
return deferred.reject(error.throwError "", "UNAUTHORIZED")
# Done!
deferred.resolve user
).fail((err) ->
deferred.reject err
)
deferred.promise
Perhaps what I've done isn't good, but it works well as far as I can see.
Check the Node module permission for that matter. It's pretty simple concept, I hope they'll allow all CRUD methods too.
Yes, you can access that through the request argument.
app.use(function(req,res,next){
console.log(req.method);
});
http://nodejs.org/api/http.html#http_message_method
Edit:
Misread your question. It would probably just be better to assign user permissions and allow access to the database based upon the permissions. I don't understand what you mean by validate by means of interaction with the database. If you are already allowing them to interact with the database and they don't have the proper permissions to do so, isn't that a security issue?
