aiocrawler's Introduction

AIOCrawler

Asynchronous web crawler built on asyncio

Installation

pip install pyaiocrawler

Usage

Generating sitemap

import asyncio
from aiocrawler import SitemapCrawler

crawler = SitemapCrawler('https://www.google.com', depth=3)
sitemap = asyncio.run(crawler.get_results())

Configuring the crawler

from aiocrawler import SitemapCrawler

crawler = SitemapCrawler(
    init_url='https://www.google.com', # The base URL to start crawling from
    depth=3,                           # The maximum depth to crawl till
    concurrency=300,                   # Maximum concurrent requests to make
    max_retries=3,                     # Maximum times the crawler will retry to get a response from a URL
    user_agent='My Crawler',           # Use a custom user agent for requests
)

Extending the crawler

To create your own crawler, simply subclass AIOCrawler and implement the parse method. For every page crawled, the parse method is executed with the url of the page, the links in that page and the html of the page. The return of the parse method is appended to an array which is then available when the get_results method is called. We have implemented an example crawler here that extracts the title from the page.

import asyncio
from aiocrawler import AIOCrawler
from bs4 import BeautifulSoup          # We will use beautifulsoup to extract the title from the html
from typing import Set, Tuple


class TitleScraper(AIOCrawler):
    '''
    Subclasses AIOCrawler to extract titles for the pages on the given domain
    '''
    timeout = 10
    max_redirects = 2

    def parse(self, url: str, links: Set[str], html: bytes) -> Tuple[str, str]:
        '''
        Returns the url and the title of the url
        '''
        soup = BeautifulSoup(html, 'html.parser')
        title = soup.find('title').string
        return url, title


crawler = TitleScraper('https://www.google.com', 3)
titles = asyncio.run(crawler.get_results())