133 lines
3.6 KiB
Python
133 lines
3.6 KiB
Python
from enum import Enum, unique
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from queue import Queue
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from random import random
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from threading import Thread, current_thread
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from time import sleep
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from urllib.parse import urlparse
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import requests
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from bs4 import BeautifulSoup
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@unique
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class SpiderStatus(Enum):
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IDLE = 0
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WORKING = 1
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def decode_page(page_bytes, charsets=('utf-8',)):
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page_html = None
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for charset in charsets:
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try:
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page_html = page_bytes.decode(charset)
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break
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except UnicodeDecodeError:
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pass
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return page_html
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class Retry(object):
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def __init__(self, *, retry_times=3,
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wait_secs=5, errors=(Exception, )):
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self.retry_times = retry_times
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self.wait_secs = wait_secs
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self.errors = errors
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def __call__(self, fn):
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def wrapper(*args, **kwargs):
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for _ in range(self.retry_times):
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try:
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return fn(*args, **kwargs)
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except self.errors as e:
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print(e)
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sleep((random() + 1) * self.wait_secs)
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return None
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return wrapper
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class Spider(object):
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def __init__(self):
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self.status = SpiderStatus.IDLE
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@Retry()
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def fetch(self, current_url, *, charsets=('utf-8', ),
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user_agent=None, proxies=None):
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thread_name = current_thread().name
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print(f'[{thread_name}]: {current_url}')
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headers = {'user-agent': user_agent} if user_agent else {}
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resp = requests.get(current_url,
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headers=headers, proxies=proxies)
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return decode_page(resp.content, charsets) \
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if resp.status_code == 200 else None
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def parse(self, html_page, *, domain='m.sohu.com'):
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soup = BeautifulSoup(html_page, 'lxml')
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url_links = []
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for a_tag in soup.body.select('a[href]'):
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parser = urlparse(a_tag.attrs['href'])
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scheme = parser.scheme or 'http'
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netloc = parser.netloc or domain
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if scheme != 'javascript' and netloc == domain:
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path = parser.path
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query = '?' + parser.query if parser.query else ''
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full_url = f'{scheme}://{netloc}{path}{query}'
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if full_url not in visited_urls:
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url_links.append(full_url)
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return url_links
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def extract(self, html_page):
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pass
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def store(self, data_dict):
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pass
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class SpiderThread(Thread):
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def __init__(self, name, spider, tasks_queue):
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super().__init__(name=name, daemon=True)
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self.spider = spider
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self.tasks_queue = tasks_queue
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def run(self):
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while True:
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current_url = self.tasks_queue.get()
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visited_urls.add(current_url)
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self.spider.status = SpiderStatus.WORKING
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html_page = self.spider.fetch(current_url)
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if html_page not in [None, '']:
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url_links = self.spider.parse(html_page)
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for url_link in url_links:
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self.tasks_queue.put(url_link)
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self.spider.status = SpiderStatus.IDLE
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def is_any_alive(spider_threads):
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return any([spider_thread.spider.status == SpiderStatus.WORKING
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for spider_thread in spider_threads])
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visited_urls = set()
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def main():
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task_queue = Queue()
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task_queue.put('http://m.sohu.com/')
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spider_threads = [SpiderThread('thread-%d' % i, Spider(), task_queue)
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for i in range(10)]
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for spider_thread in spider_threads:
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spider_thread.start()
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while not task_queue.empty() or is_any_alive(spider_threads):
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sleep(5)
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print('Over!')
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if __name__ == '__main__':
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main()
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