How to determine whether the network request is successful in uniapp

In the development process of mobile applications, we often need to request data through the network, and the uniapp framework provides a series of APIs to help us complete this task. In network requests, we usually need to determine whether our data request is successful. This article will introduce how to determine whether the network request is successful in uniapp.

1. Basic principles of network requests

Before understanding how to determine whether a network request is successful, we first need to understand the basic principles of network requests. When we make a network request from the client to the server, we need to go through the following steps:

1. The client sends a request message to the server
2. The server receives the request Message and process data
3. The server encapsulates the requested data in the response message
4. The server sends a response message to the client
5. The client receives the response message and parses it Data

If there is an error in the data transfer between the client and the server during this process, we can consider the request unsuccessful. Therefore, we need to judge and process the request results in the client.

2. Methods to determine whether a network request is successful

In the uniapp framework, there are many ways to determine whether a network request is successful. Three common methods will be introduced below. .

2.1 Using wx.request

wx.request is a common network request API in the uniapp framework. When using it to send network requests, we can judge by the res parameter in the callback function. Whether the request was successful. res contains the status code of the request. Usually, status code 200 represents success, and other status codes represent failure. Therefore, when judging whether the network request is successful, we can judge by the obtained statusCode.

//发送网络请求
wx.request({
  url: 'https://www.example.com',
  success: function(res) {
    //成功处理逻辑
    if (res.statusCode == 200) {
      console.log('请求成功');
    }
  },
  fail: function() {
    //失败处理逻辑
    console.log('请求失败');
  }
})

2.2 Using uni.request

In the uniapp framework, in addition to wx.request, there is also a commonly used network request API, namely uni.request. Similar to wx.request, when using uni.request to send a network request, we can also use then and catch to determine whether the request is successful. If the request is successful, the code in the then part will be executed, otherwise the code in the catch part will be executed.

//发送网络请求
uni.request({
  url: 'https://www.example.com',
  method: 'GET'
})
.then(res => {
  //请求成功处理逻辑
  console.log('请求成功');
})
.catch(err => {
  //请求失败处理逻辑
  console.log('请求失败');
})

2.3 Using async/await

In the uniapp framework, you can also use async/await to determine whether the network request is successful. async/await is a way of handling asynchronous functions in JavaScript. It allows us to handle asynchronous functions in a synchronous manner. When using async/await to determine whether the network request is successful, we can use the try/catch code block to determine whether the request is successful by catching exceptions.

async function fetchData() {
  try {
    const res = await uni.request({
      url: 'https://www.example.com',
      method: 'GET'
    });
    //请求成功处理逻辑
    console.log('请求成功');
  } catch(err) {
    //请求失败处理逻辑
    console.log('请求失败');
  }
}

3. Summary

The above three methods can be used to determine whether the network request is successful. In actual development, we can choose a method that suits us according to our actual situation. No matter which method is used, what we need to pay attention to is that we can't just judge whether the request is successful, we also need to handle the error. For example, if a request fails, we need to let the user know. Only when users know what error has occurred can we fix the problem promptly and satisfy the user.

Therefore, judging whether the network request is successful is only the first step in completing the network request, and being thoughtful, comprehensive, and friendly in the interaction is the ultimate goal of completing the network request.

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