python通过链接抓取网站详解

class Website:  
def __init__(self, name, url, targetPattern, absoluteUrl,    
titleTag, bodyTag):    
self.name = name    
self.url = url    
self.targetPattern = targetPattern    
self.absoluteUrl=absoluteUrl    
self.titleTag = titleTag    
self.bodyTag = bodyTag
class Content:  
def __init__(self, url, title, body):    
self.url = url    
self.title = title    
self.body = body
def print(self):    
print("URL: {}".format(self.url))    
print("TITLE: {}".format(self.title))    
print("BODY:\n{}".format(self.body))

import re
class Crawler:  
def __init__(self, site):    
self.site = site    
self.visited = []
def getPage(self, url):    
try:
req = requests.get(url)    
except requests.exceptions.RequestException:      
return None
return BeautifulSoup(req.text, 'html.parser')
def safeGet(self, pageObj, selector):
selectedElems = pageObj.select(selector)
if selectedElems is not None and len(selectedElems) > 0:
return '\n'.join([elem.get_text() for
elem in selectedElems])
return ''
def parse(self, url):
bs = self.getPage(url)
if bs is not None:
title = self.safeGet(bs, self.site.titleTag)
body = self.safeGet(bs, self.site.bodyTag)
if title != '' and body != '':
content = Content(url, title, body)
content.print()
def crawl(self):
"""
获取网站主页的页面链接
"""
bs = self.getPage(self.site.url)
targetPages = bs.findAll('a',
href=re.compile(self.site.targetPattern))
for targetPage in targetPages:
targetPage = targetPage.attrs['href']
if targetPage not in self.visited:
self.visited.append(targetPage)
if not self.site.absoluteUrl:
targetPage = '{}{}'.format(self.site.url, targetPage)
self.parse(targetPage)
reuters = Website('Reuters', 'https://www.reuters.com', '^(/article/)', False,
'h1', 'div.StandardArticleBody_body_1gnLA') 
crawler = Crawler(reuters) 
crawler.crawl()