更新

Python-100-Days/Day66-75/code/main.py

@@ -0,0 +1,132 @@
+from enum import Enum, unique
+from queue import Queue
+from random import random
+from threading import Thread, current_thread
+from time import sleep
+from urllib.parse import urlparse
+
+import requests
+from bs4 import BeautifulSoup
+
+
+@unique
+class SpiderStatus(Enum):
+    IDLE = 0
+    WORKING = 1
+
+
+def decode_page(page_bytes, charsets=('utf-8',)):
+    page_html = None
+    for charset in charsets:
+        try:
+            page_html = page_bytes.decode(charset)
+            break
+        except UnicodeDecodeError:
+            pass
+    return page_html
+
+
+class Retry(object):
+
+    def __init__(self, *, retry_times=3,
+                 wait_secs=5, errors=(Exception, )):
+        self.retry_times = retry_times
+        self.wait_secs = wait_secs
+        self.errors = errors
+
+    def __call__(self, fn):
+
+        def wrapper(*args, **kwargs):
+            for _ in range(self.retry_times):
+                try:
+                    return fn(*args, **kwargs)
+                except self.errors as e:
+                    print(e)
+                    sleep((random() + 1) * self.wait_secs)
+            return None
+
+        return wrapper
+
+
+class Spider(object):
+
+    def __init__(self):
+        self.status = SpiderStatus.IDLE
+
+    @Retry()
+    def fetch(self, current_url, *, charsets=('utf-8', ),
+              user_agent=None, proxies=None):
+        thread_name = current_thread().name
+        print(f'[{thread_name}]: {current_url}')
+        headers = {'user-agent': user_agent} if user_agent else {}
+        resp = requests.get(current_url,
+                            headers=headers, proxies=proxies)
+        return decode_page(resp.content, charsets) \
+            if resp.status_code == 200 else None
+
+    def parse(self, html_page, *, domain='m.sohu.com'):
+        soup = BeautifulSoup(html_page, 'lxml')
+        url_links = []
+        for a_tag in soup.body.select('a[href]'):
+            parser = urlparse(a_tag.attrs['href'])
+            scheme = parser.scheme or 'http'
+            netloc = parser.netloc or domain
+            if scheme != 'javascript' and netloc == domain:
+                path = parser.path
+                query = '?' + parser.query if parser.query else ''
+                full_url = f'{scheme}://{netloc}{path}{query}'
+                if full_url not in visited_urls:
+                    url_links.append(full_url)
+        return url_links
+
+    def extract(self, html_page):
+        pass
+
+    def store(self, data_dict):
+        pass
+
+
+class SpiderThread(Thread):
+
+    def __init__(self, name, spider, tasks_queue):
+        super().__init__(name=name, daemon=True)
+        self.spider = spider
+        self.tasks_queue = tasks_queue
+
+    def run(self):
+        while True:
+            current_url = self.tasks_queue.get()
+            visited_urls.add(current_url)
+            self.spider.status = SpiderStatus.WORKING
+            html_page = self.spider.fetch(current_url)
+            if html_page not in [None, '']:
+                url_links = self.spider.parse(html_page)
+                for url_link in url_links:
+                    self.tasks_queue.put(url_link)
+            self.spider.status = SpiderStatus.IDLE
+
+
+def is_any_alive(spider_threads):
+    return any([spider_thread.spider.status == SpiderStatus.WORKING
+                for spider_thread in spider_threads])
+
+
+visited_urls = set()
+
+
+def main():
+    task_queue = Queue()
+    task_queue.put('http://m.sohu.com/')
+    spider_threads = [SpiderThread('thread-%d' % i, Spider(), task_queue)
+                      for i in range(10)]
+    for spider_thread in spider_threads:
+        spider_thread.start()
+
+    while not task_queue.empty() or is_any_alive(spider_threads):
+    	sleep(5)
+
+    print('Over!')
+
+
+if __name__ == '__main__':
+    main()