Implement optimized allowedPermissions, fixing some bugs along the way.

Author: GabeIsman

lib/acl.js

@@ -65,6 +65,7 @@ var Acl = function (backend, logger, options){
   backend.getAsync = bluebird.promisify(backend.get);
   backend.cleanAsync = bluebird.promisify(backend.clean);
   backend.unionAsync = bluebird.promisify(backend.union);
+  backend.unionsAsync = bluebird.promisify(backend.unions);
 };
 
 /**
@@ -424,13 +425,17 @@ Acl.prototype.removePermissions = function(role, resources, permissions, cb){
 */
 Acl.prototype.allowedPermissions = function(userId, resources, cb){
   if (!userId)
-    return cb(null, []);
+    return cb(null, {});
 
   contract(arguments)
     .params('string|number', 'string|array', 'function')
     .params('string|number', 'string|array')
     .end();
 
+  if (this.backend.unions) {
+    return this.optimizedAllowedPermissions(userId, resources, cb);
+  }
+
   var _this = this;
   resources = makeArray(resources);
 
@@ -446,6 +451,55 @@ Acl.prototype.allowedPermissions = function(userId, resources, cb){
   }).nodeify(cb);
 };
 
+/**
+  optimizedAllowedPermissions( userId, resources, function(err, obj) )
+
+  Returns all the allowable permissions a given user have to
+  access the given resources.
+
+  It returns a map of resource name to a list of permissions for that resource.
+
+  This is the same as allowedPermissions, it just takes advantage of the unions
+  function if available to reduce the number of backend queries.
+
+  @param {String|Number} User id.
+  @param {String|Array} resource(s) to ask permissions for.
+  @param {Function} Callback called when finished.
+*/
+Acl.prototype.optimizedAllowedPermissions = function(userId, resources, cb){
+  if (!userId) {
+    return cb(null, {});
+  }
+
+  contract(arguments)
+    .params('string|number', 'string|array', 'function|undefined')
+    .params('string|number', 'string|array')
+    .end();
+
+  resources = makeArray(resources);
+  var self = this;
+
+  return this._allUserRoles(userId).then(function(roles) {
+    var buckets = resources.map(allowsBucket);
+    if (roles.length === 0) {
+      var emptyResult = {};
+      buckets.forEach(function(bucket) {
+        emptyResult[bucket] = [];
+      });
+      return bluebird.resolve(emptyResult);
+    }
+
+    return self.backend.unionsAsync(buckets, roles);
+  }).then(function(response) {
+    var result = {};
+    Object.keys(response).forEach(function(bucket) {
+      result[keyFromAllowsBucket(bucket)] = response[bucket];
+    });
+
+    return result;
+  }).nodeify(cb);
+};
+
 /**
   isAllowed( userId, resource, permissions, function(err, allowed) )
 
@@ -644,7 +698,7 @@ Acl.prototype.middleware = function(numPathComponents, userId, actions){
       }else if(allowed === false){
         if (acl.logger) {
           acl.logger.debug('Not allowed '+_actions+' on '+resource+' by user '+_userId);
-          acl.allowedPermissions(_userId, resource, function(err, obj){		
+          acl.allowedPermissions(_userId, resource, function(err, obj){
             acl.logger.debug('Allowed permissions: '+util.inspect(obj));
           });
         }
@@ -748,7 +802,7 @@ Acl.prototype._allRoles = function(roleNames, cb){
 // Return all roles in the hierarchy including the given roles.
 //
 Acl.prototype._allRoles = function(roleNames){
-  var _this = this, roles;
+  var _this = this;
 
   return this._rolesParents(roleNames).then(function(parents){
     if(parents.length > 0){
@@ -761,6 +815,21 @@ Acl.prototype._allRoles = function(roleNames){
   });
 };
 
+//
+// Return all roles in the hierarchy of the given user.
+//
+Acl.prototype._allUserRoles = function(userId) {
+  var _this = this;
+
+  return this.userRoles(userId).then(function(roles) {
+    if (roles && roles.length > 0) {
+      return _this._allRoles(roles);
+    } else {
+      return [];
+    }
+  });
+};
+
 //
 // Returns an array with resources for the given roles.
 //
@@ -848,10 +917,12 @@ function allowsBucket(role){
   return 'allows_'+role;
 }
 
+function keyFromAllowsBucket(str) {
+  return str.replace(/^allows_/, '');
+}
+
 
 // -----------------------------------------------------------------------------------
 
 
 exports = module.exports = Acl;
-
-

lib/redis-backend.js

@@ -71,13 +71,25 @@ RedisBackend.prototype = {
     var redisKeys = {};
     var batch = this.redis.batch();
     var self = this;
+
     buckets.forEach(function(bucket) {
       redisKeys[bucket] = self.bucketKey(bucket, keys);
       batch.sunion(redisKeys[bucket], noop);
     });
 
     batch.exec(function(err, replies) {
-      var result = Array.isArray(replies) ? _.zipObject(buckets, replies) : {};
+      if (!Array.isArray(replies)) {
+        return {};
+      }
+
+      var result = {};
+      replies.forEach(function(reply, index) {
+        if (reply instanceof Error) {
+          throw reply;
+        }
+
+        result[buckets[index]] = reply;
+      });
       cb(err, result);
     });
   },