def _init(self):
# 线程池,指定线程数
self.thread_pool = ThreadPool(self.thread_num)
self.depth = 2
# 标注初始爬虫深度，从1开始
self.current_depth = 1
# 已访问的链接
self.visited_hrefs = set()
# 待访问的链接
self.unvisited_hrefs = deque()
# 标记爬虫是否开始执行任务
self.is_crawling = False
self.resource_details = ResourceDetailCollection()
class Crawler(object):
def __init__(self, args):
self.thread_num = args.thread_num
self.output = args.output
if not os.path.exists(self.output):
os.mkdir(self.output)
self.domain_pattern = re.compile(
r"^([0-9a-zA-Z][0-9a-zA-Z-]{0,62}\.)+([0-9a-zA-Z][0-9a-zA-Z-]{0,62})\.?$")
def _init(self):
# 线程池,指定线程数
self.thread_pool = ThreadPool(self.thread_num)
self.depth = 2
# 标注初始爬虫深度，从1开始
self.current_depth = 1
# 已访问的链接
self.visited_hrefs = set()
# 待访问的链接
self.unvisited_hrefs = deque()
# 标记爬虫是否开始执行任务
self.is_crawling = False
self.resource_details = ResourceDetailCollection()
def _format_url(self, raw_value):
raw_value_str = raw_value.strip().strip('\n')
if len(raw_value_str) <= 0:
return ''
if not self.domain_pattern.match(raw_value_str):
return ''
if not raw_value_str.startswith('http'):
value = 'http://' + raw_value_str
else:
value = raw_value_str
return value
def crawl(self, url):
self._init()
formatted_url = self._format_url(url)
self.resource_details.set_main_frame_url(formatted_url)
self.unvisited_hrefs.append(formatted_url)
print '\nStart Crawling url %s\n' % formatted_url
self.is_crawling = True
self.thread_pool.start_threads()
while self.current_depth < self.depth + 1:
# 分配任务,线程池并发下载当前深度的所有页面（该操作不阻塞）
self._assigin_current_depth_tasks()
# 等待当前线程池完成所有任务,当池内的所有任务完成时，即代表爬完了一个网页深度
# self.thread_pool.task_join()可代替以下操作，可无法Ctrl-C Interupt
while self.thread_pool.get_task_left():
time.sleep(8)
print 'Depth %d Finish. Totally visited %d links. \n' % (
self.current_depth, len(self.visited_hrefs))
log.info('Depth %d Finish. Total visited Links: %d\n' % (
self.current_depth, len(self.visited_hrefs)))
self.current_depth += 1
# After finishing all the tasks, stop this crawling.
print "all Tasks has finished"
self._on_all_tasks_finished()
self.stop()
def stop(self):
self.is_crawling = False
self.thread_pool.stop_threads()
def get_already_visited_num(self):
# visitedHrefs保存已经分配给taskQueue的链接，有可能链接还在处理中。
# 因此真实的已访问链接数为visitedHrefs数减去待访问的链接数
return len(self.visited_hrefs) - self.thread_pool.get_task_left()
def _on_all_tasks_finished(self):
resource_detail_data = unicode(json.dumps(
self.resource_details.to_json_data(), indent=4))
hashed_file_name = hashlib.new("md5",
self.resource_details.main_frame_url).hexdigest() + ".json"
resource_detail_dataPath = os.path.join(self.output, hashed_file_name)
with io.open(resource_detail_dataPath, 'w') as file:
file.write(unicode(resource_detail_data))
def _assigin_current_depth_tasks(self):
mylock.acquire()
copied_unvisited_hrefs = deque()
while self.unvisited_hrefs:
copied_unvisited_hrefs.append(self.unvisited_hrefs.popleft())
mylock.release()
while copied_unvisited_hrefs:
url = copied_unvisited_hrefs.popleft()
# 标注该链接已被访问,或即将被访问,防止重复访问相同链接
self.visited_hrefs.add(url)
# 向任务队列分配任务
self.thread_pool.put_task(self._task_handler, url)
def _task_handler(self, url):
# 先拿网页源码，再保存,两个都是高阻塞的操作，交给线程处理
url_fetcher = URLFetcher(url)
retry = 1
if url_fetcher.fetch(retry):
self._save_task_results(url, url_fetcher)
self._add_unvisited_hrefs(url_fetcher)
def _save_task_results(self, url, url_fetcher):
print 'Visited URL : %s \n' % url
response_headers = url_fetcher.get_response_headers()
response_detail = ResourceDetail(url,
url_fetcher.request_time,
url_fetcher.response_time,
response_headers)
mylock.acquire()
self.resource_details.add_detail(response_detail)
mylock.release()
def _add_unvisited_hrefs(self, url_fetcher):
'''添加未访问的链接。将有效的url放进UnvisitedHrefs列表'''
# 对链接进行过滤:1.只获取http或https网页;2.保证每个链接只访问一次
url, page_source = url_fetcher.get_data()
hrefs = self.get_all_resource_hrefs(url, page_source)
mylock.acquire()
for href in hrefs:
if self._is_http_or_https_protocol(href):
if not self._is_href_repeated(href):
self.unvisited_hrefs.append(href)
mylock.release()
def get_all_resource_hrefs(self, url, page_source):
'''解析html源码，获取页面所有链接。返回链接列表'''
hrefs = []
soup = BeautifulSoup(page_source)
results = soup.find_all(True)
for tag in results:
href = None
if tag.name == 'a':
continue
# 必须将链接encode为utf8, 因为中文文件链接如 http://aa.com/文件.pdf
# 在bs4中不会被自动url编码，从而导致encodeException
if tag.has_attr('href'):
href = tag.get('href').encode('utf8')
elif tag.has_attr('src'):
href = tag.get('src').encode('utf8')
if href is not None:
if not href.startswith('http'):
href = urljoin(url, href) # 处理相对链接的问题
hrefs.append(href)
return hrefs
def _is_http_or_https_protocol(self, href):
protocal = urlparse(href).scheme
if protocal == 'http' or protocal == 'https':
return True
return False
def _is_href_repeated(self, href):
if href in self.visited_hrefs or href in self.unvisited_hrefs:
return True
return False
