How to use the Node.js axios library for making HTTP requests with interceptors for automatic retries in Koa

To use the Node.js Axios library for making HTTP requests with interceptors for automatic retries in a Koa application, you can follow these steps:

1. Install Axios: First, you need to install the Axios library if you haven't already.

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   npm install axios
   

2. Set up Axios with interceptors: Axios allows you to set up interceptors for handling requests and responses. You can use interceptors to implement automatic retries.

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   const axios = require('axios');
   
   // Create an Axios instance with default configuration
   const axiosInstance = axios.create({
       baseURL: 'http://api.example.com', // Replace with your API base URL
       timeout: 5000, // Request timeout in milliseconds
   });
   
   // Define a function to intercept and retry failed requests
   const interceptors = axiosInstance.interceptors.response.use(
       (response) => {
           // If the request succeeds, return the response directly
           return response;
       },
       async (error) => {
           const { config, response } = error;
           // If request fails due to a specific reason (e.g., network error), retry
           if (error.code === 'ECONNABORTED' || !response) {
               // Retry logic can be customized here
               config.retryCount = config.retryCount || 0;
               if (config.retryCount < 3) {
                   config.retryCount += 1;
                   return new Promise((resolve) => {
                       setTimeout(() => resolve(axiosInstance(config)), 1000);
                   });
               }
           }
           // If retries fail or the error is not retryable, throw the error
           return Promise.reject(error);
       }
   );
   

3. Use Axios in your Koa application: You can now use the axiosInstance to make HTTP requests within your Koa application.

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   const Koa = require('koa');
   const app = new Koa();
   
   // Example route handler using Axios for making HTTP requests
   app.use(async (ctx) => {
       try {
           const response = await axiosInstance.get('/endpoint');
           ctx.body = response.data;
       } catch (error) {
           ctx.status = error.response ? error.response.status : 500;
           ctx.body = error.response ? error.response.data : 'Internal Server Error';
       }
   });
   
   // Start the Koa application
   const server = app.listen(3000, () => {
       console.log('Koa server listening on port 3000');
   });
   

With this setup, Axios interceptors will automatically retry failed requests (based on your retry logic) in your Koa application. Adjust the retry logic according to your specific requirements and error conditions.