urlToS3ImageUploader.js

const AWS = require('aws-sdk');
const request = require('request');

// define configs
const config = {
  accessKeyId: '<S3_accessKeyId>',
  secretAccessKey: '<S3_secretAccessKey>',
  region: '<S3_region>',
  signatureVersion: 'v4',
  S3ImagesPathPrefix: 'profileImages',
  bucketName: '<bucket_name>',
};

// Init S3
const S3 = new AWS.S3({
  accessKeyId: config.accessKeyId,
  secretAccessKey: config.secretAccessKey,
  region: config.region,
  signatureVersion: config.signatureVersion,
});

const loadImageFromUrlToBuffer = (imageUrl) => new Promise((res, rej) => {
  try {
    const reqOptions = { url: imageUrl, method: 'get', encoding: null };

    request(reqOptions, (error, response, body) => {
      if (error) {
        throw error;
      }
      // log success download or some additional actions here
      return res(body);
    });
  } catch (err) {
    // log download fail here or some additional actions here
    rej(err);
  }
});

const storeBufferedImageToS3 = (buffer, fileName) => new Promise((resolve, rej) => {
  try {
    const params = {
      Bucket: config.bucketName,
      Key: `${config.S3ImagesPathPrefix}/${fileName}.jpeg`,
      Body: buffer,
      ACL:'public-read',
      ContentType: 'image/jpeg',
    };

    S3.upload(params, (err, res) => {
      if (err) {
        throw err;
      }
      // log success upload or some additional actions here
      resolve(res.Location);
    });
  } catch (err) {
    // log upload fail here or some additional actions here    
    rej(err);
  }
});

// userId will be used as unique file name
const storeSocialNetworkImageToS3 = async (imageUrl, userId) => {
  try {
    const imageFileBuffer = await loadImageFromUrlToBuffer(imageUrl);
    const s3ImageLink = await storeBufferedImageToS3(imageFileBuffer, userId);
    // log sucess action or some additional code here

    return s3ImageLink;
  } catch (err) {
    // error handling functionnality can be here
    throw err;
  }
};

// fn call sample
const userImageLink = '<valid image link>';
const userId = '<some id string>';
const S3UserImageLink = await storeSocialNetworkImageToS3(userImageLink, userId);