Download a file from a provided url

download-file.js

const http = require('http');
const https = require('https');
const fs = require('fs');
const chalk = require('chalk');
const yargs = require('yargs');
const { hideBin } = require('yargs/helpers');

const downloadFailed = errorMsg => {
  fs.unlinkSync(tempFile);
  console.error(chalk.red(`\u2717 Download failed: ${errorMsg}`));
  process.exit(1);
};

const downloadSucceeded = fileName => {
  console.log(chalk.green(`\u2713 File downloaded successfully to ${fileName}`));
};

const args = yargs(hideBin(process.argv))
  .option('url', {
    alias: 'u',
    type: 'string',
    demandOption: true,
    description: 'URL of the file to download'
  })
  .option('output', {
    alias: 'o',
    type: 'string',
    demandOption: true,
    description: 'full file name to where the download should be output'
  })
  .option('secure', {
    alias: 's',
    type: 'boolean',
    default: false,
    description: 'when true use https instead of http'
  })
  .parse();

console.log(`> Downloading from ${args.url}`);

const tempFile = 'tmp_file';

const file = fs.createWriteStream(tempFile, { emitClose: false, autoClose: false });

const protocol = args.secure ? https : http;

const request = protocol
  .get(args.url, function (response) {
    if (response.statusCode !== 200) {
      downloadFailed(`request failed ${response.statusCode}:${response.statusMessage}`);
    }

    response.pipe(file);

    file.on('finish', () => {
      file.close();
      fs.rename(tempFile, args.output, function (error) {
        if (error) {
          downloadFailed(error.message);
        }
        downloadSucceeded(args.output);
      });
    });
  })
  .on('error', error => {
    downloadFailed(error.message);
  });