In-depth understanding of Vue request method and its application

Vue is a popular front-end framework that provides many powerful features, one of which is making HTTP requests. Vue's request method is a Promise-based API that can easily use AJAX to call back-end services. In this article, we will take an in-depth look at the Vue request method and its applications.

1. Basics of Vue request method

The Vue request method is an API in Vue that allows developers' Vue applications to initiate HTTP requests. It is packaged based on the Axios library, which is a Promise-based HTTP client for browsers and Node.js.

In Vue, we can use Vue.prototype.$http to call the request method:

this.$http.get('/api/users').then(response => {
  console.log(response)
})

In the above example, we send GET to /api/users request, and use the then method to handle the response. When the response is successfully obtained, the then method is executed and the response is passed as its parameter.

Different from GET requests, you can also use HTTP methods such as POST, PUT, PATCH, and DELETE:

this.$http.post('/api/users', { username: 'John', password: '123' }).then(response => {
  console.log(response)
})

this.$http.put('/api/users/1', { username: 'John', password: '123' }).then(response => {
  console.log(response)
})

this.$http.patch('/api/users/1', { password: '456' }).then(response => {
  console.log(response)
})

this.$http.delete('/api/users/1').then(response => {
  console.log(response)
})

In these examples, we use the POST, PUT, PATCH, and DELETE methods to send requests to the server. Send a request and pass the data in the request body. Similarly, when the response is successfully obtained, the then method will be executed and the response will be passed as a parameter.

2. Vue request method sets request headers and interceptors

In addition to the basic HTTP request method, Vue request also allows developers to set request headers and interceptors. Request headers can contain useful information such as authorization headers, other application-specific headers, etc. Use interceptors to modify or intercept requests before the request is sent or after the response is returned.

Setting request headers is very simple. We can set request headers by passing an options object:

this.$http.get('/api/users', {
  headers: {
    'Authorization': 'Bearer ' + token
  }
}).then(response => {
  console.log(response)
})

In this example, we add an Authorization header and add a Bearer-based token within it.

Similarly, we can also add interceptors to modify requests and responses. These interceptors can be called before the request is sent and after the response is returned:

// 添加请求拦截器
this.$http.interceptors.request.use(config => {
  // 在请求发送之前执行
  config.headers.Authorization = 'Bearer ' + token
  // 如果需要修改请求的数据，可以在此处修改并返回config
  return config
}, error => {
  // 对请求错误做些什么
  console.log(error)
})

// 添加响应拦截器
this.$http.interceptors.response.use(response => {
  // 对响应数据做些什么
  return response
}, error => {
  // 对响应错误做些什么
  console.log(error)
})

In this example, we add a request interceptor that modifies the request's header information before sending the request. We also added a response interceptor to modify the response after it has been returned. The return value of the interceptor will overwrite the original request and response.

3. Encapsulation and use of Vue request method

For large projects, we usually encapsulate the Vue request method. The encapsulated request method will simplify the code and make it easier to maintain and upgrade. The following is a simple encapsulation example:

import axios from 'axios'

export function get(url, params = {}) {
  return new Promise((resolve, reject) => {
    axios.get(url, {
      params
    }).then(response => {
      resolve(response.data)
    }).catch(error => {
      reject(error)
    })
  })
}

export function post(url, data = {}) {
  return new Promise((resolve, reject) => {
    axios.post(url, data).then(response => {
      resolve(response.data)
    }).catch(error => {
      reject(error)
    })
  })
}

In this example, we use the axios library to initiate an HTTP request and return a Promise. We encapsulate GET requests and POST requests into two independent functions. When the request is successful, the resolve method will return the processed data; when the request fails, the reject method will return error information. Request headers and interceptors can be added as needed.

When using the encapsulated request method, you can use the get and post methods by importing files:

import { get, post } from '@/api/http'

get('/api/users').then(data => {
  console.log(data)
})

post('/api/login', { username: 'john', password: '123' }).then(data => {
  console.log(data)
})

In this example, we import the get and post functions and use them to initiate GET and POST ask. Query parameters and request body data can be passed if required.

4. Conclusion

The Vue request method is one of the necessary functions when using the Vue framework. It uses Promise API to simplify request processing for the server API interface, and also provides the function of custom request headers and interceptors. Developers can encapsulate the request method according to their needs to simplify the code and improve maintainability. For example, we might choose to encapsulate common requests into a global plugin for use throughout the Vue application.

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