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1
| /**
ACL System inspired on Zend_ACL.
All functions accept strings, objects or arrays unless specified otherwise.
'*' is used to express 'all'
Database structure in Redis (using default prefix 'acl')
Users:
acl_roles_{userid} = set(roles)
Roles:
acl_roles = {roleNames} // Used to remove all the permissions associated to ONE resource.
acl_parents_{roleName} = set(parents)
acl_resources_{roleName} = set(resourceNames)
Permissions:
acl_allows_{resourceName}_{roleName} = set(permissions)
Note: user ids, role names and resource names are all case sensitive.
Roadmap:
- Add support for locking resources. If a user has roles that gives him permissions to lock
a resource, then he can get exclusive write operation on the locked resource.
This lock should expire if the resource has not been accessed in some time.
*/
"use strict";
var _ = require('lodash'),
util = require('util'),
bluebird = require('bluebird'),
contract = require('./contract');
bluebird.longStackTraces();
contract.debug = true;
var Acl = function (backend, logger){
contract(arguments)
.params('object')
.params('object','object')
.end();
this.logger = logger;
this.backend = backend;
// Promisify async methods
backend.endAsync = bluebird.promisify(backend.end);
backend.getAsync = bluebird.promisify(backend.get);
backend.cleanAsync = bluebird.promisify(backend.clean);
backend.unionAsync = bluebird.promisify(backend.union);
};
/**
addUserRoles( userId, roles, function(err) )
Adds roles to a given user id.
@param {String|Number} User id.
@param {String|Array} Role(s) to add to the user id.
@param {Function} Callback called when finished.
@return {Promise} Promise resolved when finished
*/
Acl.prototype.addUserRoles = function(userId, roles, cb){
var promise = bluebird.defer();
contract(arguments)
.params('string|number','string|array','function')
.params('string|number','string|array')
.end();
var transaction = this.backend.begin();
this.backend.add(transaction, 'meta', 'users', userId);
this.backend.add(transaction, 'users', userId, roles);
return this.backend.endAsync(transaction).nodeify(cb);
};
/**
removeUserRoles( userId, roles, function(err) )
Remove roles from a given user.
@param {String|Number} User id.
@param {String|Array} Role(s) to remove to the user id.
@param {Function} Callback called when finished.
@return {Promise} Promise resolved when finished
*/
Acl.prototype.removeUserRoles = function(userId, roles, cb){
contract(arguments)
.params('string|number','string|array','function')
.params('string|number','string|array')
.end();
var transaction = this.backend.begin();
this.backend.remove(transaction, 'users', userId, roles);
return this.backend.endAsync(transaction).nodeify(cb);
};
/**
userRoles( userId, function(err, roles) )
Return all the roles from a given user.
@param {String|Number} User id.
@param {Function} Callback called when finished.
@return {Promise} Promise resolved with an array of user roles
*/
Acl.prototype.userRoles = function(userId, cb){
return this.backend.getAsync('users', userId).nodeify(cb);
};
/**
addRoleParents( role, parents, function(err) )
Adds a parent or parent list to role.
@param {String|Number} User id.
@param {String|Array} Role(s) to remove to the user id.
@param {Function} Callback called when finished.
@return {Promise} Promise resolved when finished
*/
Acl.prototype.addRoleParents = function(role, parents, cb){
contract(arguments)
.params('string|number','string|array','function')
.params('string|number','string|array')
.end();
var transaction = this.backend.begin();
this.backend.add(transaction, 'meta', 'roles', role);
this.backend.add(transaction, 'parents', role, parents);
return this.backend.endAsync(transaction).nodeify(cb);
};
/**
removeRole( role, function(err) )
Removes a role from the system.
@param {String} Role to be removed
@param {Function} Callback called when finished.
*/
Acl.prototype.removeRole = function(role, cb){
contract(arguments)
.params('string','function')
.params('string').end();
var _this = this;
// Note that this is not fully transactional.
return this.backend.getAsync('resources', role).then(function(resources){
var transaction = _this.backend.begin();
resources.forEach(function(resource){
var bucket = allowsBucket(resource);
_this.backend.del(transaction, bucket, role);
});
_this.backend.del(transaction, 'resources', role);
_this.backend.del(transaction, 'parents', role);
_this.backend.remove(transaction, 'meta', 'roles', role);
// `users` collection keeps the removed role
// because we don't know what users have `role` assigned.
return _this.backend.endAsync(transaction);
}).nodeify(cb);
};
/**
removeResource( resource, function(err) )
Removes a resource from the system
@param {String} Resource to be removed
@param {Function} Callback called when finished.
@return {Promise} Promise resolved when finished
*/
Acl.prototype.removeResource = function(resource, cb){
contract(arguments)
.params('string', 'function')
.params('string')
.end();
var _this = this;
return this.backend.getAsync('meta', 'roles').then(function(roles){
var transaction = _this.backend.begin();
_this.backend.del(transaction, allowsBucket(resource), roles);
roles.forEach(function(role){
_this.backend.remove(transaction, 'resources', role, resource);
})
return _this.backend.endAsync(transaction);
}).nodeify(cb)
};
/**
allow( roles, resources, permissions, function(err) )
Adds the given permissions to the given roles over the given resources.
@param {String|Array} role(s) to add permissions to.
@param {String|Array} resource(s) to add permisisons to.
@param {String|Array} permission(s) to add to the roles over the resources.
@param {Function} Callback called when finished.
allow( permissionsArray, function(err) )
@param {Array} Array with objects expressing what permissions to give.
[{roles:{String|Array}, allows:[{resources:{String|Array}, permissions:{String|Array}]]
@param {Function} Callback called when finished.
@return {Promise} Promise resolved when finished
*/
Acl.prototype.allow = function(roles, resources, permissions, cb){
contract(arguments)
.params('string|array','string|array','string|array','function')
.params('string|array','string|array','string|array')
.params('array','function')
.params('array')
.end();
if((arguments.length == 1) || ((arguments.length===2)&&_.isObject(roles)&&_.isFunction(resources))){
return this._allowEx(roles).nodeify(resources);
}else{
var _this = this;
roles = makeArray(roles);
resources = makeArray(resources);
var transaction = _this.backend.begin();
_this.backend.add(transaction, 'meta', 'roles', roles);
resources.forEach(function(resource){
roles.forEach(function(role){
_this.backend.add(transaction, allowsBucket(resource), role, permissions);
});
});
roles.forEach(function(role){
_this.backend.add(transaction, 'resources', role, resources);
});
return _this.backend.endAsync(transaction).nodeify(cb);
}
};
Acl.prototype.removeAllow = function(role, resources, permissions, cb){
contract(arguments)
.params('string','string|array','string|array','function')
.params('string','string|array','string|array')
.params('string','string|array','function')
.params('string','string|array')
.end();
resources = makeArray(resources);
Eif(cb){
permissions = makeArray(permissions);
}else{
cb = permissions;
permissions = null;
}
return this.removePermissions(role, resources, permissions, cb);
}
/**
removePermissions( role, resources, permissions)
Remove permissions from the given roles owned by the given role.
Note: we loose atomicity when removing empty role_resources.
@param {String}
@param {String|Array}
@param {String|Array}
*/
Acl.prototype.removePermissions = function(role, resources, permissions, cb){
var _this = this;
var transaction = _this.backend.begin();
resources.forEach(function(resource){
var bucket = allowsBucket(resource);
Eif(permissions){
_this.backend.remove(transaction, bucket, role, permissions);
}else{
_this.backend.del(transaction, bucket, role);
_this.backend.remove(transaction, 'resources', role, resource);
}
});
// Remove resource from role if no rights for that role exists.
// Not fully atomic...
return _this.backend.endAsync(transaction).then(function(){
var transaction = _this.backend.begin();
return bluebird.all(resources.map(function(resource){
var bucket = allowsBucket(resource);
return _this.backend.getAsync(bucket, role).then(function(permissions){
if(permissions.length==0){
_this.backend.remove(transaction, 'resources', role, resource);
}
});
})).then(function(){
return _this.backend.endAsync(transaction);
});
}).nodeify(cb);
};
/**
allowedPermissions( userId, resources, function(err, obj) )
Returns all the allowable permissions a given user have to
access the given resources.
It returns an array of objects where every object maps a
resource name to a list of permissions for that resource.
@param {String|Number} User id.
@param {String|Array} resource(s) to ask permissions for.
@param {Function} Callback called when finished.
*/
Acl.prototype.allowedPermissions = function(userId, resources, cb){
contract(arguments)
.params('string|number', 'string|array', 'function')
.params('string|number', 'string|array')
.end();
var _this = this;
resources = makeArray(resources);
return _this.userRoles(userId).then(function(roles){
var result = {};
return bluebird.all(resources.map(function(resource){
return _this._resourcePermissions(roles, resource).then(function(permissions){
result[resource] = permissions;
});
})).then(function(){
return result;
});
}).nodeify(cb);
};
/**
isAllowed( userId, resource, permissions, function(err, allowed) )
Checks if the given user is allowed to access the resource for the given
permissions (note: it must fulfill all the permissions).
@param {String|Number} User id.
@param {String|Array} resource(s) to ask permissions for.
@param {String|Array} asked permissions.
@param {Function} Callback called wish the result.
*/
Acl.prototype.isAllowed = function(userId, resource, permissions, cb){
contract(arguments)
.params('string|number', 'string', 'string|array', 'function')
.params('string|number', 'string', 'string|array')
.end();
var _this = this;
return this.backend.getAsync('users', userId).then(function(roles){
if(roles.length){
return _this.areAnyRolesAllowed(roles, resource, permissions);
}else{
return false;
}
}).nodeify(cb);
};
/**
areAnyRolesAllowed( roles, resource, permissions, function(err, allowed) )
Returns true if any of the given roles have the right permissions.
@param {String|Array} Role(s) to check the permissions for.
@param {String} resource(s) to ask permissions for.
@param {String|Array} asked permissions.
@param {Function} Callback called with the result.
*/
Acl.prototype.areAnyRolesAllowed = function(roles, resource, permissions, cb){
contract(arguments)
.params('string|array', 'string', 'string|array', 'function')
.params('string|array', 'string', 'string|array')
.end();
roles = makeArray(roles);
permissions = makeArray(permissions);
Iif(roles.length===0){
return bluebird.resolve(false).nodeify(cb);
}else{
return this._checkPermissions(roles, resource, permissions).nodeify(cb);
}
};
/**
whatResources(role, function(err, {resourceName: [permissions]})
Returns what resources a given role or roles have permissions over.
whatResources(role, permissions, function(err, resources) )
Returns what resources a role has the given permissions over.
@param {String|Array} Roles
@param {String[Array} Permissions
@param {Function} Callback called wish the result.
*/
Acl.prototype.whatResources = function(roles, permissions, cb){
contract(arguments)
.params('string|array','function')
.params('string|array','string|array','function')
.end();
roles = makeArray(roles);
if (_.isFunction(permissions)){
cb = permissions;
permissions = undefined;
}else{
permissions = makeArray(permissions);
}
return this.permittedResources(roles, permissions, cb);
};
Acl.prototype.permittedResources = function(roles, permissions, cb){
var _this = this;
var result = _.isUndefined(permissions) ? {} : [];
return this._rolesResources(roles).then(function(resources){
return bluebird.all(resources.map(function(resource){
return _this._resourcePermissions(roles, resource).then(function(p){
if(permissions){
var commonPermissions = _.intersection(permissions, p);
Eif(commonPermissions.length>0){
result.push(resource);
}
}else{
result[resource] = p;
}
});
})).then(function(){
return result;
});
}).nodeify(cb);
}
/**
clean ()
Cleans all the keys with the given prefix from redis.
Note: this operation is not reversible!.
*/
/*
Acl.prototype.clean = function(callback){
var acl = this;
this.redis.keys(this.prefix+'*', function(err, keys){
if(keys.length){
acl.redis.del(keys, function(err){
callback(err);
});
}else{
callback();
}
});
};
*/
/**
Express Middleware
*/
Acl.prototype.middleware = function(numPathComponents, userId, actions){
contract(arguments)
.params()
.params('number')
.params('number','string|number|function')
.params('number','string|number|function', 'string|array')
.end();
var acl = this;
var HttpError = function(errorCode, msg){
this.errorCode = errorCode;
this.msg = msg;
Error.captureStackTrace(this, arguments);
Error.call(this, msg);
};
return function(req, res, next){
var _userId = userId,
resource,
url;
// call function to fetch userId
if(typeof userId === 'function'){
_userId = userId(req, res);
}
if (!userId) {
if((req.session) && (req.session.userId)){
_userId = req.session.userId;
}else{
next(new HttpError(401, 'User not authenticated'));
return;
}
}
url = req.url.split('?')[0];
if(!numPathComponents){
resource = url;
}else{
resource = url.split('/').slice(0,numPathComponents+1).join('/');
}
if(!actions){
actions = req.method.toLowerCase();
}
acl.logger?acl.logger.debug('Requesting '+actions+' on '+resource+' by user '+_userId):null;
acl.isAllowed(_userId, resource, actions, function(err, allowed){
if (err){
next(new Error('Error checking permissions to access resource'));
}else if(allowed === false){
acl.logger?acl.logger.debug('Not allowed '+actions+' on '+resource+' by user '+_userId):null;
acl.allowedPermissions(_userId, resource, function(err, obj){
acl.logger?acl.logger.debug('Allowed permissions: '+util.inspect(obj)):null;
});
next(new HttpError(401,'Insufficient permissions to access resource'));
}else{
acl.logger?acl.logger.debug('Allowed '+actions+' on '+resource+' by user '+_userId):null;
next();
}
});
};
};
//-----------------------------------------------------------------------------
//
// Private methods
//
//-----------------------------------------------------------------------------
//
// Same as allow but accepts a more compact input.
//
Acl.prototype._allowEx = function(objs){
var _this = this;
objs = makeArray(objs);
var demuxed = [];
objs.forEach(function(obj){
var roles = obj.roles;
obj.allows.forEach(function(allow){
demuxed.push({
roles:roles,
resources:allow.resources,
permissions:allow.permissions});
});
});
return bluebird.all(demuxed.map(function(obj){
return _this.allow(obj.roles, obj.resources, obj.permissions);
}));
};
//
// Returns the parents of the given roles
//
Acl.prototype._rolesParents = function(roles){
return this.backend.unionAsync('parents', roles);
};
//
// Return all roles in the hierarchy including the given roles.
//
/*
Acl.prototype._allRoles = function(roleNames, cb){
var _this = this, roles;
_this._rolesParents(roleNames, function(err, parents){
roles = _.union(roleNames, parents);
async.whilst(
function (){
return parents.length >0;
},
function (cb) {
_this._rolesParents(parents, function(err, result){
if(!err){
roles = _.union(roles, parents);
parents = result;
}
cb(err);
});
},
function(err){
cb(err, roles);
}
);
});
};
*/
//
// Return all roles in the hierarchy including the given roles.
//
Acl.prototype._allRoles = function(roleNames){
var _this = this, roles;
return this._rolesParents(roleNames).then(function(parents){
if(parents.length > 0){
return _this._allRoles(parents).then(function(parentRoles){
return _.union(roleNames, parentRoles);
});
}else{
return roleNames;
}
});
};
//
// Returns an array with resources for the given roles.
//
Acl.prototype._rolesResources = function(roles){
var _this = this;
roles = makeArray(roles);
return this._allRoles(roles).then(function(allRoles){
var result = [];
// check if bluebird.map simplifies this code
return bluebird.all(allRoles.map(function(role){
return _this.backend.getAsync('resources', role).then(function(resources){
result = result.concat(resources);
});
})).then(function(){
return result;
});
});
};
//
// Returns the permissions for the given resource and set of roles
//
Acl.prototype._resourcePermissions = function(roles, resource){
var _this = this;
if(roles.length===0){
return bluebird.resolve([]);
}else{
return this.backend.unionAsync(allowsBucket(resource), roles).then(function(resourcePermissions){
return _this._rolesParents(roles).then(function(parents){
if(parents && parents.length){
return _this._resourcePermissions(parents, resource).then(function(morePermissions){
return _.union(resourcePermissions, morePermissions);
});
}else{
return resourcePermissions;
}
});
});
}
};
//
// NOTE: This function will not handle circular dependencies and result in a crash.
//
Acl.prototype._checkPermissions = function(roles, resource, permissions){
var _this = this;
return this.backend.unionAsync(allowsBucket(resource), roles).then(function(resourcePermissions){
Iif (resourcePermissions.indexOf('*') !== -1){
return true;
}else{
permissions = permissions.filter(function(p){
return resourcePermissions.indexOf(p) === -1;
});
if(permissions.length === 0){
return true;
}else{
return _this.backend.unionAsync('parents', roles).then(function(parents){
if(parents && parents.length){
return _this._checkPermissions(parents, resource, permissions);
}else{
return false;
}
});
}
}
});
};
//-----------------------------------------------------------------------------
//
// Helpers
//
//-----------------------------------------------------------------------------
function makeArray(arr){
return Array.isArray(arr) ? arr : [arr];
}
function allowsBucket(role){
return 'allows_'+role;
}
// -----------------------------------------------------------------------------------
exports = module.exports = Acl;
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