[wechat applet] read the article, data request

Hello, old man , This is the front-end Xiaoliu not afraid of Niuniu channel , New articles have been updated in the applet series , Above, we explained the global and local configuration of wechat applet , So today, let's learn about the data request of wechat applet , This is for applet interaction and dynamic acquisition of binding data 、 Important operations of change ！！
are you ready? ？ Then we'll start , Quickly pick up a small notebook and make notes ！

Data request

My friends know , stay web Front end development has data requests , We have also learned and used Ajax request . And wechat applets also have data requests , however , The data request of wechat applet is different , First web The environment is browser , The environment of the applet is wechat client ,web Cross domain issues need to be considered , Small programs do not need to consider cross domain issues .

meanwhile , The data request of wechat is not called Ajax request , Why? ？ because web Terminal Ajax It's based on the object XMLHttpRequest, Wechat applets don't have this object , Therefore, the data request of wechat applet is not Ajax Request the , It is called Network data request , Don't make a mistake ~~

On the role of data requests , In fact, generally, there will be data requests for interactive effects , To transfer data , The user's behavior will be passed through a parameter , Then identify , The applet is making the corresponding presentation to complete the business . Dynamic presentation of data 、 Initialization of data 、 Data requests may be used in internal judgments of the logic layer .

One , Limiting conditions

For security reasons , Wechat official sets two conditions for the interface of data request , as follows .

• Only request HTTPS Interface of type

  First of all, here http The type and https Make a simple explanation of the differences between types ：
  HTTP It's the hypertext transfer protocol , It is the most widely used network protocol on the Internet , and HTTPS be relative to HTTP Come on , It's about security HTTP passageway , Simply put, it's the safe version （ Add one SSL Layer to encrypt ）,HTTPS need ca certificate , Information is not like http Plaintext transmission , It is ssl The encrypted .

• The interface domain name must be added to the trust list

  The simple understanding is , Wechat applet needs to set the communication domain name in advance , The applet can only communicate with the specified domain name , Safety guaranteed .

  The trust list can be found in the wechat developer tool The toolbar –> details –> Project settings –>request Legitimate domain name View in .

  
  request Legitimate domain name The default is empty. .

  So how to add , Look below .

Two , To configure request Legitimate domain name

It's simple , We only need to log in wechat applet to manage the background , And then you can go in Development –> Development and setup –> Server domain name Modified .

If this is the first configuration , Authentication is also required .

There are some things you should pay attention to about domain names tips

• Must be https type
• Out of commission ip and localhost Domain name of
• Domain name needs to be approved by ICP Keep on record
• You can only modify the server domain name five times a month

The domain name has been set , How should we send the request ？

3、 ... and , launch GET、POST request

In the wechat applet , Network data requests are made through top-level objects wx Of request() Method to send the request , such as GET request .

The structure is as follows ：

wx.request({
    
	url : " domain name ", // Need to be in the trust list 
	method : "GET",
	data : {
    
		// Put the requested data 
	},
	success : (res)=>{
    
		// Callback function called after successful request 
	}
})

POST The request structure is similar to GET No difference , Only need to method To change the value of POST that will do , Bloggers here don't do more demonstrations .

Four , The page has just loaded the request data

occasionally , We need to implement when the page is loaded , Make a data request , To help render the initial picture of the page ,“ Don't write dead ” A lot of data is requested once when the page is loaded .

And how should this be achieved , In fact, we can use the onload event , When the page is loaded, the event is triggered , Then we put the event handler in it , Our data request can be found in the event handler , In this way, you can request data when the page is loaded .

onLoad: function(options){
    
	// Data request operation 
}

5、 ... and , skip request Legal domain name verification

When developing a project , The front and rear progress cannot be determined , Sometimes there will be , The backend partners only provide http Interface of type , did not https Interface of type , The front end cannot be debugged , It will affect the progress of the project .

Now , We can use wechat developer tools , Temporarily enabled in local settings [ The development environment does not verify the requested domain name 、TLS Version and HTTPS certificate Button , As shown in the following square diagram , After opening , When opening an applet with wechat developer tools or mobile phones , The server domain name will not be verified 、TLS Version and HTTPS Certificate verification , That means we can use http Interface to protocol .

But here's the thing , The online version still needs to verify the server domain name , The above is only for developers .

That's the end of today's applet article , If it helps you , You can follow Niuniu's next article , Thank you for your support , Your support is the greatest motivation for my creation ！！！

Debt see ~~