keep-alive | 易学教程

vue的keep-alive

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<keep-alive>是Vue的内置组件，能在组件切换过程中将状态保留在内存中，防止重复渲染DOM <keep-alive> 包裹动态组件时，会缓存不活动的组件实例，而不是销毁它们。和 <transition> 相似，<keep-alive>是一个抽象组件：它自身不会渲染一个 DOM 元素，也不会出现在父组件链中。方法1 include: 字符串或正则表达式。只有匹配的组件会被缓存。 exclude: 字符串或正则表达式。任何匹配的组件都不会被缓存。 exclude优先级大于include <keep-alive include="a,b">  <component :is="view"></component> </keep-alive> 方法2 （结合berforeRouteEnter，缓存部分页面）缓存的页面 created 会执行只有一次，activated每次都会执行， created 里面做第一次 isFirstEnter = true(由于页面被缓存，所以一直生效)，之后再activated 里面做判断只有 “不是返回回来的” 和 “第一次进来的” 就刷新数据，并且要在下面都设为false, 以免缓存各标识不对，在进入 “列表页” 时，通过router钩子函数

javascript code to prevent screensaver from starting

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问题 I am completely new to javascript programming and I have a question that I didn't manage to find an answer for anywhere. I have recently put together a simple slideshow to view the photos remotely that I host on my home computer. This by itself works fine. The problem I run into is that when I'm viewing photos I don't interact with the hardware, which after some time causes the monitor to switch off. This is particularly annoying when watching photos on my mobile phone. My question is: is

Simple comet example using php and jquery

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Can anyone give me a good and simple example of the comet technique using PHP? I just need an example that uses a persistent HTTP connection or something similar. I don't want to use a polling technique, because I have something like that set up and not only is it difficult to work with and manage its a big hog of resources. Also I am using IIS7 not Apache. A good example would be really helpful so I can move on from this ugly polling technique. You should use polling, or use a web server which is specially conceived for long requests and COMET, with a good JS backend: function listen() { $

Keep-alive header clarification

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I was asked to build a site , and one of the co-developer told me That I would need to include the keep-alive header. Well I read alot about it and still I have questions. msdn -> The open connection improves performance when a client makes multiple requests for Web page content, because the server can return the content for each request more quickly. Otherwise, the server has to open a new connection for every request Looking at When The IIS (F) sends keep alive header ( or user sends keep-alive ) , does it mean that ( E , C , B ) save a connection which is only for my session ? Where does

JSch: How to keep the session alive and up

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问题 I'm writing Java GUI program for static route management using SSH. My code is as follows: import com.jcraft.jsch.*; import java.io.*; public class Konsep { String status; static String username; static String hostname; String inputcommand; String output; static Session session; JSch jsch = new JSch(); public String status(String stringstatus) { stringstatus = status; return stringstatus; } public String InputCommand(String inputcommandstatus) { inputcommandstatus = inputcommand; return

http keep-alive in the modern age

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问题 So according to the haproxy author, who knows a thing or two about http: Keep-alive was invented to reduce CPU usage on servers when CPUs were 100 times slower. But what is not said is that persistent connections consume a lot of memory while not being usable by anybody except the client who openned them. Today in 2009, CPUs are very cheap and memory is still limited to a few gigabytes by the architecture or the price. If a site needs keep-alive, there is a real problem. Highly loaded sites

Getting disconnection notification using TCP Keep-Alive on write blocked socket

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问题 I use TCP Keep-Alive option to detect dead connection. It works well with connection that use reading sockets: setsockopt(mysock,...) // set various keep alive options epoll_ctl(ep,mysock,{EPOLLIN|EPOLERR|EPOLLHUP},) epoll_wait -> (exits after several seconds when remove host disconnects cable) Epoll wait exits with EPOLLIN|EPOLLHUP on socket without a problem. However if I try to write a lot to socket till I get EAGAIN and then poll for both reading and writing I don't get a error when I

How to use SO_KEEPALIVE option properly to detect that the client at the other end is down?

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问题 so I was trying to learn the usage of option SO_KEEPALIVE in socket programming in C language under Linux environment. I created a server socket and used my browser to connect to it. It was successful and I was able to read the GET request, but I got stuck on the usage of SO_KEEPALIVE. I checked this link keepalive_description@tldg.org but I could not find any example which shows how to use it. As soon as I detect the client's request on accept() function I set the SO_KEEPALIVE option value 1

WebSockets ping/pong, why not TCP keepalive?

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WebSockets have the option of sending pings to the other end, where the other end is supposed to respond with a pong. Upon receipt of a Ping frame, an endpoint MUST send a Pong frame in response, unless it already received a Close frame. It SHOULD respond with Pong frame as soon as is practical. TCP offers something similar in the form of keepalive: [Y]ou send your peer a keepalive probe packet with no data in it and the ACK flag turned on. You can do this because of the TCP/IP specifications, as a sort of duplicate ACK, and the remote endpoint will have no arguments, as TCP is a stream

VUE vue面试题

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看看面试题，只是为了查漏补缺，看看自己那些方面还不懂。切记不要以为背了面试题，就万事大吉了，最好是理解背后的原理，这样面试的时候才能侃侃而谈。不然，稍微有水平的面试官一看就能看出，是否有真才实学还是刚好背中了这道面试题。（都是一些基础的vue面试题，大神不用浪费时间往下看）一、对于MVVM的理解？ MVVM 是 Model-View-ViewModel 的缩写。 Model 代表数据模型，也可以在Model中定义数据修改和操作的业务逻辑。 View 代表UI 组件，它负责将数据模型转化成UI 展现出来。 ViewModel 监听模型数据的改变和控制视图行为、处理用户交互，简单理解就是一个同步View 和 Model的对象，连接Model和View。在MVVM架构下，View 和 Model 之间并没有直接的联系，而是通过ViewModel进行交互，Model 和 ViewModel 之间的交互是双向的，因此View 数据的变化会同步到Model中，而Model 数据的变化也会立即反应到View 上。 ViewModel 通过双向数据绑定把 View 层和 Model 层连接了起来，而View 和 Model 之间的同步工作完全是自动的，无需人为干涉，因此开发者只需关注业务逻辑，不需要手动操作DOM, 不需要关注数据状态的同步问题，复杂的数据状态维护完全由 MVVM