Downloading Images from a Website with Javascript and cheerio

Oct 15, 2023 · 4 min read

In this article, we will learn how to use Javascript and the cheerio library to download all the images from a Wikipedia page.

—-

Overview

The goal is to extract the names, breed groups, local names, and image URLs for all dog breeds listed on this Wikipedia page. We will store the image URLs, download the images and save them to a local folder.

Here are the key steps we will cover:

  1. Import required modules
  2. Send HTTP request to fetch the Wikipedia page
  3. Parse the page HTML using cheerio
  4. Find the table with dog breed data using a CSS selector
  5. Iterate through the table rows
  6. Extract data from each column
  7. Download images and save locally
  8. Print/process extracted data

Let's go through each of these steps in detail.

Imports

We need these modules:

const request = require('request');
const cheerio = require('cheerio');
const fs = require('fs');
  • request - Sends HTTP requests
  • cheerio - Scrapes HTML/XML
  • fs - Filesystem handling
  • Send HTTP Request

    To download the web page:

    const url = '<https://commons.wikimedia.org/wiki/List_of_dog_breeds>';
    
    request({
      url: url,
      headers: {
        'User-Agent': 'Mozilla/5.0'
      }
    }, (error, response, html) => {
    
      // Parse HTML
    
    });
    

    We make a GET request and provide a user-agent header.

    Parse HTML

    To parse the HTML:

    const $ = cheerio.load(html);
    

    The cheerio object allows querying the document.

    Find Breed Table

    We use a CSS selector to find the table element:

    const table = $('table.wikitable.sortable');
    

    This selects the

    tag with classes wikitable and sortable.

    Iterate Through Rows

    We loop through the rows:

    table.find('tr').slice(1).each((i, elem) => {
    
      // Extract data
    
    });
    

    We slice to skip the header row.

    Extract Column Data

    Inside the loop, we extract the column data:

    const cells = $(elem).find('td, th');
    
    const name = $(cells[0]).find('a').text().trim();
    const group = $(cells[1]).text().trim();
    
    const localName = $(cells[2]).find('span').text().trim() || '';
    
    const img = $(cells[3]).find('img');
    const photograph = img.attr('src') || '';
    

    We use text() for text and attr() for attributes.

    Download Images

    To download and save images:

    if (photograph) {
    
      request(photograph).pipe(fs.createWriteStream(`dog_images/${name}.jpg`));
    
    }
    

    We pipe the image stream directly to a file.

    Store Extracted Data

    We store the extracted data:

    names.push(name);
    groups.push(group);
    localNames.push(localName);
    photographs.push(photograph);
    

    The arrays can then be processed as needed.

    And that's it! Here is the full code:

    // Imports
    const request = require('request');
    const cheerio = require('cheerio');
    const fs = require('fs');
    
    // Arrays to store data
    let names = [];
    let groups = [];
    let localNames = [];
    let photographs = [];
    
    // Fetch HTML
    const url = '<https://commons.wikimedia.org/wiki/List_of_dog_breeds>';
    
    request({
      url: url,
      headers: {
        'User-Agent': 'Mozilla/5.0'
      }
    }, (error, response, html) => {
    
      // Load HTML
      const $ = cheerio.load(html);
    
      // Find table
      const table = $('table.wikitable.sortable');
    
      // Iterate rows
      table.find('tr').slice(1).each((i, elem) => {
    
        // Get cells
        const cells = $(elem).find('td, th');
    
        // Extract data
        const name = $(cells[0]).find('a').text().trim();
        const group = $(cells[1]).text().trim();
    
        const localName = $(cells[2]).find('span').text().trim() || '';
    
        const img = $(cells[3]).find('img');
        const photograph = img.attr('src') || '';
    
        // Download image
        if (photograph) {
    
          request(photograph).pipe(fs.createWriteStream(`dog_images/${name}.jpg`));
    
        }
    
        // Store data
        names.push(name);
        groups.push(group);
        localNames.push(localName);
        photographs.push(photograph);
    
      });
    
    });
    

    This provides a complete Javascript solution using cheerio to scrape data and images from HTML tables. The same approach can apply to many websites.

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