How to use the Node.js axios library for making HTTP requests with interceptors for FormData and file uploads in Koa

  Arif Babu

         

  NodeJS



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To use the Node.js Axios library for making HTTP requests with interceptors for FormData and file uploads in a Koa application, you can create a custom interceptor to handle FormData and file uploads. Here's a guide on how to achieve this:

  1. Install Axios:

    First, make sure you have Axios installed in your project:

    bash
    npm install axios

  2. Set up Axios with interceptors:

    Import Axios and set up interceptors to handle FormData and file uploads:

    javascript
    const axios = require('axios');
const FormData = require('form-data');
const fs = require('fs');

// 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
});

// Add an interceptor for FormData and file uploads
axiosInstance.interceptors.request.use(
    (config) => {
        // Check if request data is FormData
        if (config.data instanceof FormData) {
            // Set content type to multipart/form-data
            config.headers['Content-Type'] = 'multipart/form-data';
        }

        // Check if request data contains file uploads
        if (config.data && config.data.files) {
            const formData = new FormData();

            // Append file data to FormData
            for (const file of config.data.files) {
                formData.append(file.fieldname, fs.createReadStream(file.path), {
                    filename: file.originalname,
                    contentType: file.mimetype
                });
            }

            // Append other form fields to FormData
            delete config.data.files;
            for (const key in config.data) {
                formData.append(key, config.data[key]);
            }

            // Override request data with FormData
            config.data = formData;
        }

        return config;
    },
    (error) => {
        return Promise.reject(error);
    }
);

    This interceptor checks if the request data is FormData or contains file uploads. If it is, it converts the data into FormData and appends file uploads to it.

  3. Use Axios in your Koa application:

    Now, you can use the axiosInstance to make HTTP requests within your Koa application:

    javascript
    const Koa = require('koa');
const app = new Koa();

// Example route handler using Axios for making HTTP requests
app.use(async (ctx) => {
    try {
        // Example: Uploading files
        const response = await axiosInstance.post('/upload', {
            // Other form fields
            field1: 'value1',
            field2: 'value2',
            // Files
            files: [
                {
                    fieldname: 'file1',
                    originalname: 'file1.txt',
                    mimetype: 'text/plain',
                    path: '/path/to/file1.txt'
                },
                {
                    fieldname: 'file2',
                    originalname: 'file2.txt',
                    mimetype: 'text/plain',
                    path: '/path/to/file2.txt'
                }
            ]
        });
        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 handle FormData and file uploads in your Koa application. Adjust the interceptor logic according to your specific requirements.

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