Scraping Multiple Pages in Javascript with Cheerio

Web scraping is useful to programmatically extract data from websites. Often you need to scrape multiple pages from a site to gather complete information. In this article, we'll see how to scrape multiple pages in Javascript using the cheerio library.

Prerequisites

To follow along, you'll need:

npm install cheerio

Import Modules

We'll need the request module to fetch pages and cheerio to parse HTML:

const request = require('request');
const cheerio = require('cheerio');

Define Base URL

—

We'll scrape a blog - https://copyblogger.com/blog/. The page URLs follow a pattern:

<https://copyblogger.com/blog/>
<https://copyblogger.com/blog/page/2/>
<https://copyblogger.com/blog/page/3/>

Let's define the base URL pattern:

const baseUrl = '<https://copyblogger.com/blog/page/{}/>';

The {} allows us to insert the page number.

Specify Number of Pages

Next, we'll specify how many pages to scrape. Let's scrape the first 5 pages:

const numPages = 5;

Loop Through Pages

We can now loop from 1 to numPages and construct the URL for each page:

for(let pageNum = 1; pageNum <= numPages; pageNum++) {

  // Construct page URL
  const url = baseUrl.replace('{}', pageNum);

  // Code to scrape each page

}

Send Request and Check Response

Inside the loop, we'll use request() to fetch the page URL:

request(url, (error, response, html) => {

  if(!error){
    // Page retrieved, can parse HTML
  } else {
    console.log('Error retrieving page ' + pageNum);
  }

});

We check for any error to ensure the request succeeded.

Parse HTML with Cheerio

If no error, we can parse the HTML using cheerio:

const $ = cheerio.load(html);

The $ gives a jQuery-style selector to extract data.

Extract Data

Now within the loop we can use $ to find and extract data from each page.

For example, to get article elements:

const articles = $('article');

We can loop through articles and extract information like title, URL, author etc.

Full Code

Our full code to scrape 5 pages is:

const request = require('request');
const cheerio = require('cheerio');

const baseUrl = '<https://copyblogger.com/blog/page/{}/>';
const numPages = 5;

for(let pageNum = 1; pageNum <= numPages; pageNum++) {

  const url = baseUrl.replace('{}', pageNum);

  request(url, (error, response, html) => {

    if(!error){

      const $ = cheerio.load(html);

      const articles = $('article');

      articles.each((index, element) => {

        // Extract data from article

        const title = $(element).find('h2.entry-title').text().trim();
        const url = $(element).find('a.entry-title-link').attr('href');
        const author = $(element).find('div.post-author a').text().trim();

        const categories = [];
        $(element).find('div.entry-categories a').each((i, el) => {
          categories.push($(el).text().trim());
        });

        // Print data
        console.log('Title: ' + title);
        console.log('URL: ' + url);
        console.log('Author: ' + author);
        console.log('Categories: ' + categories.join(', '));
        console.log();

      });

    } else {
      console.log('Error retrieving page ' + pageNum);
    }

  });

}

This allows us to scrape and extract data from multiple pages sequentially. The code can be extended to scrape any number of pages.

Summary

Web scraping enables collecting large datasets programmatically. With the techniques here, you can scrape and extract information from multiple pages of a website in Javascript.

While these examples are great for learning, scraping production-level sites can pose challenges like CAPTCHAs, IP blocks, and bot detection. Rotating proxies and automated CAPTCHA solving can help.

Proxies API offers a simple API for rendering pages with built-in proxy rotation, CAPTCHA solving, and evasion of IP blocks. You can fetch rendered pages in any language without configuring browsers or proxies yourself.

This allows scraping at scale without headaches of IP blocks. Proxies API has a free tier to get started. Check out the API and sign up for an API key to supercharge your web scraping.

With the power of Proxies API combined with Python libraries like Beautiful Soup, you can scrape data at scale without getting blocked.