152 lines
6.0 KiB
Python
152 lines
6.0 KiB
Python
from operator import truediv
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import re
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from urllib import robotparser
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from urllib.parse import urlparse
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from urllib.parse import urljoin
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from urllib.robotparser import RobotFileParser
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from bs4 import BeautifulSoup
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def scraper(url, resp):
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links = extract_next_links(url, resp)
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links_valid = list()
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valid_links = open("valid_links.txt",'a')
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invalid_links = open("invalid_links.txt",'a')
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for link in links:
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if is_valid(link):
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links_valid.append(link)
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valid_links.write(link + "\n")
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else:
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invalid_links.write("From: " + url + "\n")
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invalid_links.write(link + "\n")
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return links_valid
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# hopefuly fixes some loop traps and repeating (looping) directories
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# the amount of repeated subdirectories allowed can be changed
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# https://subscription.packtpub.com/book/big-data-and-business-intelligence/9781782164364/1/ch01lvl1sec11/crawling-your-first-website
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# https://www.searchenginejournal.com/crawler-traps-causes-solutions-prevention/305781/
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def is_a_loop_trap(url):
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word_dict = {}
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parsed = urlparse(url)
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url_path = str(parsed.path)
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word_list = url_path.split('/')
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for word in word_list:
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if word in word_dict:
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word_dict[word] += 1
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if word_dict[word] == 3:
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return True
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else:
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word_dict[word] = 1
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return False
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# Tests to see if the url is ok to be crawled by checking against the robots.txt
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# file. It does so by checking the URL or URL prefixes and will return true if page is allowed to be crawled
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# https://docs.python.org/3/library/urllib.robotparser.html#urllib.robotparser.RobotFileParser
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# http://pymotw.com/2/robotparser/
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def robots_ok(baseurl):
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eva = robotparser.RobotFileParser()
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rooturl = str(urljoin(baseurl, '/')[:-1]) # get each subdomain by itself
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eva.set_url(rooturl + "/robots.txt") # set location of robots.txt
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eva.read() # read and fead to parser
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return eva.can_fetch('*', baseurl) # returns true if useragent is allowed to crawl
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def extract_next_links(url, resp):
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# Implementation required.
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# url: the URL that was used to get the page
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# resp.url: the actual url of the page
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# resp.status: the status code returned by the server. 200 is OK, you got the page. Other numbers mean that there was some kind of problem.
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# resp.error: when status is not 200, you can check the error here, if needed.
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# resp.raw_response: this is where the page actually is. More specifically, the raw_response has two parts:
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# resp.raw_response.url: the url, again
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# resp.raw_response.content: the content of the page!
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# Return a list with the hyperlinks (as strings) scrapped from resp.raw_response.content
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pages = list()
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if resp.status == 200:
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#do stuff
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soup = BeautifulSoup(resp.raw_response.content)
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tempFile = open("test6.txt", 'a')
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#Getting all the links, href = true means at least theres a href value, dont know what it is yet
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for link in soup.find_all('a', href=True):
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#There is a lot of relative paths stuff here gotta add them
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href_link = link.get('href')
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#Relative path
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##Suprisingly index fail safe
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#some <a href> give //thenlink.com...
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if href_link.startswith("//"):
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href_link = href_link[2:]
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#Relative path fixing
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if(href_link.startswith("/")):
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href_link = urljoin(url,href_link)
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#skipping query with specific actions which mutate the websites and cause a trap
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if "do=" in href_link:
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continue
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'''
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# this is currently in the is_vaild but implimended in a different way, don't know which one would make more sense
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# skip as not allowed
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if not robots_ok(href_link):
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continue
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'''
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tempFile.write(href_link + "\n")
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#Adding to the boi wonder pages
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pages.append(href_link)
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else:
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print("Page error !")
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return pages
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#*.ics.uci.edu/*
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#*.cs.uci.edu/*
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#*.informatics.uci.edu/*
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#*.stat.uci.edu/*
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#today.uci.edu/department/information_computer_sciences/*
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def is_valid(url):
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# Decide whether to crawl this url or not.
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# If you decide to crawl it, return True; otherwise return False.
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# There are already some conditions that return False.
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try:
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#Gotta check if they are in the domain
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parsed = urlparse(url)
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if parsed.scheme not in set(["http", "https"]):
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return False
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elif re.match(
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r".*\.(css|js|bmp|gif|jpe?g|ico"
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+ r"|png|tiff?|mid|mp2|mp3|mp4"
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+ r"|wav|avi|mov|mpeg|ram|m4v|mkv|ogg|ogv|pdf"
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+ r"|ps|eps|tex|ppt|pptx|doc|docx|xls|xlsx|names"
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+ r"|data|dat|exe|bz2|tar|msi|bin|7z|psd|dmg|iso"
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+ r"|epub|dll|cnf|tgz|sha1"
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+ r"|thmx|mso|arff|rtf|jar|csv"
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+ r"|rm|smil|wmv|swf|wma|zip|rar|gz)$",parsed.path.lower()):
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return False
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elif not re.match(
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r".*ics.uci.edu/.*"
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+ r"|.*cs.uci.edu/.*"
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+ r"|.*informatics.uci.edu/.*"
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+ r"|.*stat.uci.edu/.*"
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+ r"|today.uci.edu/department/information_computer_sciences/.*",url):
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return False
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elif parsed.fragment:
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return False
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elif is_a_loop_trap(url):
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return False
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# maybe this should go in the next link?
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elif not robots_ok(url):
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return False
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# https://support.archive-it.org/hc/en-us/articles/208332963-Modify-crawl-scope-with-a-Regular-Expression
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# add lem check
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# add another dir check
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# add extra dir check
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# add cal check
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else:
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return True
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except TypeError:
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print ("TypeError for ", parsed)
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raise
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