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This article mainly introduces "how Mini Program realizes Wechat check-in and message on-screen comment function". In daily operation, it is believed that many people have doubts about how Mini Program can achieve Wechat check-in and message on-screen comment function. The editor has consulted all kinds of materials and sorted out simple and easy-to-use operation methods. I hope it will be helpful for everyone to answer the doubts about "how Mini Program can achieve Wechat check-in and message on-screen comment function". Next, please follow the editor to study!

The most closely watched Web technology in the HTML5 specification is WebSocket API, which is rapidly becoming popular. WebSocket provides a popular technology to replace the Ajax technology that we have been using for the past few years. This new API provides a way to effectively push messages to the server from the client using a simple syntax. Let's take a look at Html5's WebSocket API: it can be used on both the client and the server side. And there is an excellent third-party API named Socket.IO. Real-time message processing can be easily realized by using WebSocket, and WebSocket can be used to complete Wechat check-in and message on-screen comments in an interactive system.

What is WebSocket API?

WebSocket API is the next generation client-server asynchronous communication method. This communication replaces a single TCP socket, uses ws or wss protocols, and can be used for any client and server program. WebSocket is currently standardized by the W3C. WebSocket is already supported by browsers such as Firefox 4, Chrome 4, Opera 10.70, and Safari 5.

The greatest thing about WebSocket API is that the server and client can push information to each other at any time within a given time frame. WebSocket is not limited to Ajax (or XHR) communication, because Ajax technology requires clients to initiate requests, and WebSocket servers and clients can push information to each other; XHR is limited by domains, while WebSocket allows cross-domain communication.

The clever thing about Ajax technology is that there is no way to design it to use. WebSocket is created for the specified destination and is used to push messages in both directions.

II. The usage of WebSocket API

Focus only on client-side API, because each server-side language has its own API. The following code snippet opens a connection, creates an event listener for the connection, disconnects, sends a message back to the server, and closes the connection.

[

/ / Open Socket socket.onopen = function (event) {

/ / send an initialization message socket.send ('I am the client and I\'m listeningrequests')

/ / listen for message socket.onmessage = function (event) {console.log ('Client received a message',event);}

/ / turn off monitoring Socket socket.onclose = function (event) {console.log ('Client notified socket has closed',event);}

/ / close Socket.... / / socket.close ()}

Let's look at the initialization snippet above. The parameter URL,ws indicates the WebSocket protocol. The onopen, onclose, and onmessage methods connect events to the Socket instance. Each method provides an event to represent the state of the Socket.

The onmessage event provides a data property that can contain the Body portion of the message. The Body part of the message must be a string that can be serialized / deserialized to pass more data.

The syntax of WebSocket is very simple, and using WebSockets is incredibly easy. Unless the client does not support WebSocket. IE browsers currently do not support WebSocket communication. If your client does not support WebSocket communication, here are some backup solutions for you to use:

Flash technology-Flash can provide a simple replacement. The most obvious disadvantage of using Flash is that not all clients have Flash installed, and some clients, such as iPhone/iPad, do not support Flash.

AJAX Long-Polling technology-using AJAX's long-polling to simulate WebSocket has been in the industry for some time. It is a feasible technology, but it cannot optimize the information sent. In other words, it is a solution, but not the best technical solution.

Since current browsers such as IE do not support WebSocket, what should we do to provide WebSocket event handling, return transmission, and use a unified API on the server side? Fortunately, Guillermo Rauch created a Socket.IO technology.

At this point, the study on "how Mini Program can achieve Wechat check-in and message on-screen comment" is over. I hope to be able to solve your doubts. The collocation of theory and practice can better help you learn, go and try it! If you want to continue to learn more related knowledge, please continue to follow the website, the editor will continue to work hard to bring you more practical articles!

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