Refactor getNameById to use mongo db's $in instead of parallel and use a new generic method in Handler.coffee

app/lib/NameLoader.coffee

@@ -12,6 +12,6 @@ class NameLoader extends CocoClass
   loadedNames: (newNames) =>
     _.extend namesCache, newNames
     
-  getName: (id) -> namesCache[id]
+  getName: (id) -> namesCache[id].name
 
 module.exports = new NameLoader()

app/views/play/ladder/my_matches_tab.coffee

@@ -35,7 +35,7 @@ module.exports = class MyMatchesTabView extends CocoView
       for session in @sessions.models
         for match in session.get('matches') or []
           opponent = match.opponents[0]
-          @nameMap[opponent.userID] ?= nameMap[opponent.userID]
+          @nameMap[opponent.userID] ?= nameMap[opponent.userID].name
       @finishRendering()
 
     $.ajax('/db/user/-/names', {

server/commons/Handler.coffee

@@ -375,3 +375,17 @@ module.exports = class Handler
     return done(validation) unless validation.valid
 
     document.save (err) -> done(err)
+
+  getPropertiesFromMultipleDocuments: (res, model, properties, ids) ->
+    query = model.find()
+    ids = ids.split(',') if _.isString ids
+    ids = _.uniq ids
+    for id in ids
+      return errors.badInput(res, "Given an invalid id: #{id}") unless Handler.isID(id)
+    query.where({'_id': { $in: ids} })
+    query.select(properties).exec (err, documents) ->
+      dict = {}
+      _.each documents, (document) ->
+        dict[document.id] = document
+      res.send dict
+      res.end()

server/users/user_handler.coffee

@@ -120,34 +120,11 @@ UserHandler = class UserHandler extends Handler
       return @sendSuccess(res, @formatEntity(req, req.user, 256))
     super(req, res, id)
 
-  getNamesByIds: (req, res) ->
+  getNamesByIDs: (req, res) ->
     ids = req.query.ids or req.body.ids
-    ids = ids.split(',') if _.isString ids
-    ids = _.uniq ids
-
-    # TODO: Extend and repurpose this handler to return other public info about a user more flexibly,
-    #   say by a query parameter that lists public properties to return.
     returnWizard = req.query.wizard or req.body.wizard
-    query = if returnWizard then {name:1, wizard:1} else {name:1}
-
-    makeFunc = (id) ->
-      (callback) ->
-        User.findById(id, query).exec (err, document) ->
-          return done(err) if err
-          if document and returnWizard
-            callback(null, {name:document.get('name'), wizard:document.get('wizard') or {}})
-          else
-            callback(null, document?.get('name') or '')
-
-    funcs = {}
-    for id in ids
-      return errors.badInput(res, "Given an invalid id: #{id}") unless Handler.isID(id)
-      funcs[id] = makeFunc(id)
-
-    async.parallel funcs, (err, results) ->
-      return errors.serverError err if err
-      res.send results
-      res.end()
+    properties = if returnWizard then "name wizard" else "name"
+    @getPropertiesFromMultipleDocuments res, User, properties, ids
 
   nameToID: (req, res, name) ->
     User.findOne({nameLower:name.toLowerCase()}).exec (err, otherUser) ->
@@ -206,7 +183,7 @@ UserHandler = class UserHandler extends Handler
   getByRelationship: (req, res, args...) ->
     return @agreeToCLA(req, res) if args[1] is 'agreeToCLA'
     return @avatar(req, res, args[0]) if args[1] is 'avatar'
-    return @getNamesByIds(req, res) if args[1] is 'names'
+    return @getNamesByIDs(req, res) if args[1] is 'names'
     return @nameToID(req, res, args[0]) if args[1] is 'nameToID'
     return @getLevelSessions(req, res, args[0]) if args[1] is 'level.sessions'
     return @getCandidates(req, res) if args[1] is 'candidates'