这是我的架构：
var userschema = new mongoose.Schema({
user: String,
follow: [String],
imagen: [{
title: String,
date: { type: Date, default: Date.now }
}]
});
这是代码：
usermodel.findOne({ user: req.session.user }, function (err, user){
usermodel.aggregate({$unwind: '$imagen'},
{$match: { _id: { $in: user.follow } }},
{imagen: true},
{$sort: {'imagen.date': 1}},
function (err, images){
console.log(images);
res.render('home.ejs', {
user: user,
following: images
});
});
});
follow包含用户的_id.
该代码有效，除非我包含$match. 我使用$match来过滤结果，只获取我正在关注的用户的图像，但是 console.log 显示aggregate搜索的结果是未定义的，但是当我不编写$match查询时，我得到了图像，但我获得了所有图像，而不仅仅是我关注的用户的图像。
有什么解决办法吗...？
谢谢提前！
编辑：
var express = require('express');
var MongoStore = require('connect-mongo')(express);
var fs = require('fs');
var mongoose = require('mongoose');
var app = express();
app.listen(9191);
var sessionStore = new MongoStore({db: 'session'});
app.configure(function(){
app.use(express.bodyParser());
app.set('views',__dirname + '/views');
app.set('view engine', 'ejs');
app.use(express.static(__dirname + '/public'));
app.use(express.cookieParser());
app.use(express.session({
store: sessionStore,
secret: 'secret'
}));
app.use(app.router);
});
var db = mongoose.createConnection('localhost', 'test');
var userschema = new mongoose.Schema({
user: String,
follow: [String],
imagen: [{
title: String,
date: { type: Date, default: Date.now }
}]
});
var usermodel = db.model('usermodel', userschema);
var ObjectId = require('mongoose').Types.ObjectId;
app.get('/', middleware.noses, function (req, res){
res.render('home0.ejs');
});
app.get('/home', middleware.yeses, function (req, res){
usermodel.findOne({ user: req.session.user }, function (err, user){
if (user.follow.length != 0){
usermodel.find({ _id: {$in: user.follow } }, { user: true }, function (err, users){
var usernames = users.map(function(u){ return u.user });
usermodel.aggregate({$match: { _id: { $in: user.follow.map(
function(id){ return new ObjectId(id); })}}},
{$unwind: '$imagen'},
{imagen: true},
{$sort: {'imagen.date': 1}},
function (err, images){
console.log(images);
res.render('home.ejs', {
user: user,
following: images
});
});
});
} else {
res.render('home.ejs', {
user: user,
following: undefined
});
}
});
});
编辑：
[ { __v: 4,
_id: 50fd9c7b8e6a9d087d000006,
follow: ['50fd9cbd1322de627d000006', '50fd9d3ce20da1dd7d000006'],
imagen:
[{ title: 'foo',
_id: 50fd9ca2bc9f163e7d000006,
date: Mon Jan 21 2013 20:53:06 GMT+0100 (CET) },
{ title: 'foot',
_id: 50fda83a3214babc88000005,
date: Mon Jan 21 2013 21:42:34 GMT+0100 (CET) }],
user: 'Mrmangado' }