Fetch Crawler

API | Examples | Changelog

Distributed crawler powered by Fetch Crawler

Features

Fetch Crawler is designed to provide a basic, flexible and robust API for crawling websites.

The crawler provides simple APIs to crawl these static websites with the following features:

• Distributed crawling
• Configure parallel, retry, max requests, time between request (to avoid spam) ...
• Support both depth-first search and breadth-first search algorithm
• Stop at the max request
• Insert Cheerio automatically for scraping
• [Promise] support

Getting Started

Installation

# npm i @viclafouch/fetch-crawler

Note: Fetch Crawler does not contain Puppeteer. It using the fetch-node module.

Usage

import FetchCrawler from '@viclafouch/fetch-crawler'

// I use Cheerio to get the content of the page
// See https://cheerio.js.org
const collectContent = $ =>
  $('body')
    .find('h1')
    .text()
    .trim()

// After getting content of the page, do what you want :)
// Accept async function
const doSomethingWith = (content, url) => console.log(`Here the title '${content}' from ${url}`)

// Here I start my crawler
// You can await for it if you want
FetchCrawler.launch({
  url: 'https://github.com',
  evaluatePage: $ => collectContent($),
  onSuccess: ({ result, url }) => doSomethingWith(result, url),
  onError: ({ error, url }) => console.log('Whouaa something wrong happened :('),
  maxRequest: 20
})

FAQ

How is this different from Puppeteer?

This crawler is built on top of node-fetch.

Puppeteer is a project from the Google Chrome team which enables us to control a Chrome (or any other Chrome DevTools Protocol based browser) and execute common actions, much like in a real browser. Fetch Crawler is a static crawler based on simple requests to HTML files. So it will be difficult to scrap the contents when the HTML dynamically changes on browsers.

Node Support Policy

Fetch Crawler is currently supported by the Node Foundation.

Currently supported versions:

• 8.x
• 10.x
• 12.x

Contributing

Any contributions and/or pull requests would be welcome.

License

Copyright (c) 2019, Victor de la Fouchardiere.

All rights reserved.

Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:

• Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.
• Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.