Download images, given that a `data.json` file is present

reddit-image-downloader.js

const fs = require('fs');
const https = require('https');

function downloadImage(url, destinationPath) {
  if (!url) {
    console.error('Error: URL is empty.');
    return;
  }

  https.get(url, (response) => {
    const statusCode = response.statusCode;
    if (statusCode !== 200) {
      console.error('Error downloading image:', statusCode);
      return;
    }

    const fileStream = fs.createWriteStream(destinationPath);
    response.pipe(fileStream);

    fileStream.on('finish', () => {
      fileStream.close();
      console.log('Image downloaded successfully:', destinationPath);
    });
  }).on('error', (err) => {
    console.error('Error while downloading image:', err.message);
  });
}

function getRandomFilename(extension) {
  const randomString = Math.random().toString(36).substr(2, 10);
  return `data/${randomString}.${extension}`;
}

function extractImageUrls(post) {
  const urls = [];
  if (post.data?.is_gallery) {
    const galleryImages = post.data?.gallery_data?.items || [];
    galleryImages.forEach((image, idx) => {
      const imageUrl =
        image?.media_id ||
        image?.media?.gif?.source?.url ||
        image?.media?.reddit_video?.fallback_url;
      if (imageUrl) {
        urls.push(imageUrl);
      }
    });
  } else {
    const url = post.data?.url || post.data?.url_overridden_by_dest;
    urls.push(url);
  }
  return urls;
}

function downloadImages(data) {
  data.data.children.forEach((post, index) => {
    const imageUrls = extractImageUrls(post);
    imageUrls.forEach((url) => {
      const extension = url.substring(url.lastIndexOf('.') + 1).toLowerCase();
      if (!['jpg', 'jpeg', 'png'].includes(extension)) {
        console.log('Skipping non-image URL:', url);
        return;
      }

      const destinationPath = getRandomFilename(extension);
      downloadImage(url, destinationPath);
    });
  });
}

fs.readFile('data.json', 'utf8', (err, data) => {
  if (err) {
    console.error('Error reading the JSON file:', err);
    return;
  }

  try {
    const jsonData = JSON.parse(data);
    downloadImages(jsonData);
  } catch (parseError) {
    console.error('Error parsing JSON data:', parseError);
  }
});