解析iOS SDK:如何设置用户“在线"地位? [英] Parse iOS SDK: How to set user "online" status?

问题描述

场景 = 我有一个应用程序，允许用户登录并查看在线"的其他用户.为了设置每个用户的在线状态我认为我应该设置代码...

Scenario = I have an app that allows users to log in and view other users who are also "online". In order to set each user's online status I believe that I should set the code...

[PFUser currentUser] setObject:[NSNumber numberWithBool:YES] forKey:@"isOnline"];
[[PFUser currentUser] saveInBackground];

在用户使用应用程序的特定时间.可能是 appDelegate，但我不确定.

at certain times in the application when the user uses the app. Probably the appDelegate but I'm not sure.

(如有不对之处请指正)

(if this is not correct then please correct me)

问题 = 应在应用程序内的何处设置此代码，以便它始终跟踪用户何时在线"和何时离线"?

Question = Where should this code be set inside the application so that it always keeps track of when a user is "online" and when they are "offline"?

(请包括方法名称)

推荐答案

最可靠的处理方法是创建一个名为 lastActive 的 Date 类型的列，然后创建一个 Cloud Code 函数来更新这与服务器时间有关(因此时钟差异不是问题).

The most reliable way to handle this is to create a column named lastActive of type Date, then create a Cloud Code function to update this with the server time (so clock differences isn't an issue).

然后为了让在线"用户拥有另一个 Cloud Functions 函数来执行查询，其中 lastActive 大于现在 - 一些时间窗口，比如 2 分钟.

Then to get "online" users just have another Cloud Function that does a query where lastActive is greater than now - some time window like 2 minutes.

var moment = require("moment");

Parse.Cloud.define("registerActivity", function(request, response) {
    var user = request.user;
    user.set("lastActive", new Date());
    user.save().then(function (user) {
        response.success();
    }, function (error) {
        console.log(error);
        response.error(error);
    });
});

Parse.Cloud.define("getOnlineUsers", function(request, response) {
    var userQuery = new Parse.Query(Parse.User);
    var activeSince = moment().subtract("minutes", 2).toDate();
    userQuery.greaterThan("lastActive", activeSince);
    userQuery.find().then(function (users) {
        response.success(users);
    }, function (error) {
        response.error(error);
    });
});

您的客户希望每 1.5 分钟调用一次 registerActivity 云函数，以允许一些重叠，这样如果用户的互联网速度有点慢，他们就不会看起来离线.

Your client will want to call the registerActivity Cloud Function every 1.5 minutes to allow some overlap so users don't appear to go offline if their internet is a bit slow.

当然，您可以调整时间窗口以满足您的需要.您还可以添加过滤哪​​些用户返回的功能(例如仅限在线朋友).

Of course you can adjust the time windows to suit your needs. You could also add the ability to filter which users are returned (e.g. online friends only).

这篇关于解析iOS SDK:如何设置用户“在线"地位?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！