Skip to main content
Version: 1.3

Cheerio crawler

This example demonstrates how to use CheerioCrawler to crawl a list of URLs from an external file, load each URL using a plain HTTP request, parse the HTML using the Cheerio library and extract some data from it: the page title and all h1 tags.

const Apify = require('apify');

// Apify.utils contains various utilities, e.g. for logging.
// Here we use debug level of logging to improve the debugging experience.
// This functionality is optional!
const { log } = Apify.utils;
log.setLevel(log.LEVELS.DEBUG);

// Apify.main() function wraps the crawler logic (it is optional).
Apify.main(async () => {
// Create an instance of the RequestList class that contains a list of URLs to crawl.
// Add URLs to a RequestList
const requestList = await Apify.openRequestList('start-urls', [
{ url: 'http://www.example.com/page-1' },
{ url: 'http://www.example.com/page-2' },
{ url: 'http://www.example.com/page-3' },
]);
// Create an instance of the CheerioCrawler class - a crawler
// that automatically loads the URLs and parses their HTML using the cheerio library.
const crawler = new Apify.CheerioCrawler({
// Let the crawler fetch URLs from our list.
requestList,

// The crawler downloads and processes the web pages in parallel, with a concurrency
// automatically managed based on the available system memory and CPU (see AutoscaledPool class).
// Here we define some hard limits for the concurrency.
minConcurrency: 10,
maxConcurrency: 50,

// On error, retry each page at most once.
maxRequestRetries: 1,

// Increase the timeout for processing of each page.
handlePageTimeoutSecs: 30,

// Limit to 10 requests per one crawl
maxRequestsPerCrawl: 10,

// This function will be called for each URL to crawl.
// It accepts a single parameter, which is an object with options as:
// https://sdk.apify.com/docs/typedefs/cheerio-crawler-options#handlepagefunction
// We use for demonstration only 2 of them:
// - request: an instance of the Request class with information such as URL and HTTP method
// - $: the cheerio object containing parsed HTML
handlePageFunction: async ({ request, $ }) => {
log.debug(`Processing ${request.url}...`);

// Extract data from the page using cheerio.
const title = $('title').text();
const h1texts = [];
$('h1').each((index, el) => {
h1texts.push({
text: $(el).text(),
});
});

// Store the results to the default dataset. In local configuration,
// the data will be stored as JSON files in ./apify_storage/datasets/default
await Apify.pushData({
url: request.url,
title,
h1texts,
});
},

// This function is called if the page processing failed more than maxRequestRetries+1 times.
handleFailedRequestFunction: async ({ request }) => {
log.debug(`Request ${request.url} failed twice.`);
},
});

// Run the crawler and wait for it to finish.
await crawler.run();

log.debug('Crawler finished.');
});