Skip to main content

A multi-threaded, open source web crawler

Project description

A multi-threaded, open source web crawler

Features

  • Use multiple threads to visit web pages

  • Extract web page data using XPath expressions or CSS selectors

  • Extract urls from a web page and visit extracted urls

  • Write extracted data to an output file

  • Set HTTP session parameters such as: cookies, SSL certificates, proxies

  • Set HTTP request parameters such as: header, body, authentication

  • Download files from the urls

  • Supports Python 2 and Python 3

Installation

pip install xcrawler

When installing lxml library on Windows you may encounter Microsoft Visual C++ is required errors.
To install lxml library on Windows:
  1. Download and install Microsoft Windows SDK:

  2. Click the Start Menu, search for and open the command prompt:

    • For Python 2.6, 2.7, 3.0, 3.1, 3.2: CMD Shell

    • For Python 3.3, 3.4: Windows SDK 7.1 Command Prompt

  3. Install lxml

setenv /x86 /release && SET DISTUTILS_USE_SDK=1 && set STATICBUILD=true && pip install lxml

Usage

Data and urls are extracted from a web page by a page scraper.
To extract data and urls from a web page use the following methods:
extract returns data extracted from a web page
visit returns next Pages to be visited

A crawler can be configured before crawling web pages. A user can configure such settings of the crawler as:
* the number of threads used to visit web pages
* the name of an output file
* the request timeout
To run the crawler call:
crawler.run()

Examples how to use xcrawler can be found at: https://github.com/cardsurf/xcrawler/tree/master/examples

XPath Example

from xcrawler import XCrawler, Page, PageScraper


class Scraper(PageScraper):
    def extract(self, page):
        topics = page.xpath("//a[@class='question-hyperlink']/text()")
        return topics


start_pages = [ Page("http://stackoverflow.com/questions/16622802/center-image-within-div", Scraper()) ]
crawler = XCrawler(start_pages)
crawler.config.output_file_name = "stackoverflow_example_crawler_output.csv"
crawler.run()

CSS Example

from xcrawler import XCrawler, Page, PageScraper


class StackOverflowItem:
    def __init__(self):
        self.title = None
        self.votes = None
        self.tags = None
        self.url = None


class UrlsScraper(PageScraper):
    def visit(self, page):
        hrefs = page.css_attr(".question-summary h3 a", "href")
        urls = page.to_urls(hrefs)
        return [Page(url, QuestionScraper()) for url in urls]


class QuestionScraper(PageScraper):
    def extract(self, page):
        item = StackOverflowItem()
        item.title = page.css_text("h1 a")[0]
        item.votes = page.css_text(".question .vote-count-post")[0].strip()
        item.tags = page.css_text(".question .post-tag")[0]
        item.url = page.url
        return item


start_pages = [ Page("http://stackoverflow.com/questions?sort=votes", UrlsScraper()) ]
crawler = XCrawler(start_pages)
crawler.config.output_file_name = "stackoverflow_css_crawler_output.csv"
crawler.config.number_of_threads = 3
crawler.run()

File Example

from xcrawler import XCrawler, Page, PageScraper


class WikimediaItem:
    def __init__(self):
        self.name = None
        self.base64 = None


class EncodedScraper(PageScraper):
    def extract(self, page):
        url = page.xpath("//div[@class='fullImageLink']/a/@href")[0]
        item = WikimediaItem()
        item.name = url.split("/")[-1]
        item.base64 = page.file(url)
        return item


start_pages = [ Page("https://commons.wikimedia.org/wiki/File:Records.svg", EncodedScraper()) ]
crawler = XCrawler(start_pages)
crawler.config.output_file_name = "wikimedia_file_example_output.csv"
crawler.run()

Session Example

from xcrawler import XCrawler, Page, PageScraper
from requests.auth import HTTPBasicAuth


class Scraper(PageScraper):
    def extract(self, page):
        return page.__str__()


start_pages = [ Page("http://192.168.1.1/", Scraper()) ]
crawler = XCrawler(start_pages)
crawler.config.output_file_name = "router_session_example_output.csv"
crawler.config.session.headers = {"User-Agent": "Custom User Agent",
                                  "Accept-Language": "fr"}
crawler.config.session.auth = HTTPBasicAuth('admin', 'admin')
crawler.run()

Request Example

from xcrawler import XCrawler, Page, PageScraper


class Scraper(PageScraper):
    def extract(self, page):
        return page.__str__()


start_page = Page("http://192.168.5.5", Scraper())
start_page.request.cookies = {"theme": "classic"}
crawler = XCrawler([start_page])
crawler.config.request_timeout = (5, 5)
crawler.config.output_file_name = "router_request_example_output.csv"
crawler.run()

Documentation

For more information about xcrawler see the source code and Python Docstrings: source code
The documentation can also be accessed at runtime with Python’s built-in help function:
>>> import xcrawler
>>> help(xcrawler.Config)
    # Information about the Config class
>>> help(xcrawler.PageScraper.extract)
    # Information about the extract method of the PageScraper class

Licence

GNU GPL v2.0

Project details


Download files

Download the file for your platform. If you're not sure which to choose, learn more about installing packages.

Source Distribution

xcrawler-1.3.0.tar.gz (30.0 kB view hashes)

Uploaded Source

Supported by

AWS AWS Cloud computing and Security Sponsor Datadog Datadog Monitoring Fastly Fastly CDN Google Google Download Analytics Microsoft Microsoft PSF Sponsor Pingdom Pingdom Monitoring Sentry Sentry Error logging StatusPage StatusPage Status page