查询mongoose文档中的数组

Question

我有1-用户和设备之间的关系(嵌入在用户架构中)

var UserSchema = new Schema({
    devices: [DeviceSchema] //list of devices for the user      
})

var DeviceSchema = new Schema({
    deviceRegistrationId: String,
    deviceOSType: String
});

我有快速POST/api /设备中的Rest调用(标头中提供了用户ID)以将设备添加到用户集合中,我想仅在设备尚未存在于用户模型中时才添加设备.电话会议的主体就像是

{ deviceRegistrationId : "xx2233", 
  deviceOSType: "Android"
}

我检查标头中的用户标识是否存在于用户集合中,如果存在,则仅在设备尚未存在于数据库中时才添加设备.

我目前的实现如下.

var userId = req.header('UserId');
        var deviceRegistrationId = req.body.deviceRegistrationId;
        User.findById({_id: userId}, function(err, user) {
             if (user && user!==undefined) {
                if (UserController.containsDevice(user.devices, deviceRegistrationId)) {
                    console.log('contains device - do nothing ');
                    res.send({errors: [{code: 666, message: 'Device Already Registered'}]})
                } else {
                    user.devices.addToSet(req.body);
                    user.save();
                    //todo check what to send back.. 
                    res.send(user);
                }
             } else {
                res.send({errors: [{code: 666, message: 'User not found in the database'}]});
             }

             if (err) 
                res.send({errors: [{code: 666, message: 'Unexpected issue in User Collection'}]});
        });


UserController.containsDevice = function(devices, deviceRegistrationId){
        console.log('UserController::containsDevice devices: ' + JSON.stringify(devices) + 
                    " deviceRegistrationId: " + deviceRegistrationId);
        var strDeviceRegistrationId = "" + deviceRegistrationId;
        for (var i = 0; i < devices.length; i++) {
            console.log(' device id :' + JSON.stringify(devices[i].deviceRegistrationId)); 
            if (devices[i].deviceRegistrationId == strDeviceRegistrationId) {
                console.log('id matched');
                return true;
            }
        }

            return false;          

    }

我想检查是否有一种方法不是设备阵列来确定设备是否已经存在.

Answer 1

您可以在查询中使用点分隔路径,如下所示:User.find({'devices.deviceRegistrationId': deviceRegistrationId}).如果该查询与任何文档都不匹配,则没有用户拥有该设备.请注意,devices当给出诸如此类的查询时,mongo足够智能地测试阵列的所有成员.如果要检查特定用户,还可以在查询条件中添加用户ID.