静态html提取正文的API和开源算法

2019 年 10 月 5 日
笔记

本文链接：https://blog.csdn.net/xc_zhou/article/details/100994876

1.arex https://github.com/ahkimkoo/arex 2.Html2Article http://www.cnblogs.com/jasondan/p/3497757.html

主要python包：requests+lxml+jparser+url2io。

其中jparser、url2io都用于网页文本正文提取，url2io准确率高，但不稳定，解析错误时则调用jparser。通过两者结合使用来提高正文提取的效果。

jparser

安装

pip install jparser

使用

可参考官网：https://pypi.org/project/jparser/0.0.10/

url2io

下载安装，即下载url2io.py文件。可以到这个github项目上下载：https://github.com/Neo-Luo/scrapy_baidu github主页下载最新版：https://github.com/url2io/url2io-python-sdk/
官网注册获取token：http://url2io.applinzi.com/
使用：https://github.com/url2io/url2io-python-sdk/
url2io python3

#coding: utf-8  #  # This program is free software. It comes without any warranty, to  # the extent permitted by applicable law. You can redistribute it  # and/or modify it under the terms of the Do What The Fuck You Want  # To Public License, Version 2, as published by Sam Hocevar. See  # http://sam.zoy.org/wtfpl/COPYING (copied as below) for more details.  #  #                DO WHAT THE FUCK YOU WANT TO PUBLIC LICENSE  #                        Version 2, December 2004  #  #     Copyright (C) 2004 Sam Hocevar <[email protected]>  #  #     Everyone is permitted to copy and distribute verbatim or modified  #     copies of this license document, and changing it is allowed as long  #     as the name is changed.  #  #                DO WHAT THE FUCK YOU WANT TO PUBLIC LICENSE  #       TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION  #  #      0. You just DO WHAT THE FUCK YOU WANT TO.    """a simple url2io sdk  example:  api = API(token)  api.article(url='http://www.url2io.com/products', fields=['next', 'text'])  """    __all__ = ['APIError', 'API']      DEBUG_LEVEL = 1    import sys  import socket  import json  import urllib,urllib.request,urllib.error,urllib.parse  from urllib.request import urlopen  import time  from collections import Iterable    class APIError(Exception):      code = None      """HTTP status code"""        url = None      """request URL"""        body = None      """server response body; or detailed error information"""        def __init__(self, code, url, body):          self.code = code          self.url = url          self.body = body        def __str__(self):          return 'code={s.code}nurl={s.url}n{s.body}'.format(s = self)        __repr__ = __str__      class API(object):      token = None      server = 'http://api.url2io.com/'        decode_result = True      timeout = None      max_retries = None      retry_delay = None        def __init__(self, token, srv = None,                   decode_result = True, timeout = 30, max_retries = 5,                   retry_delay = 3):          """:param srv: The API server address          :param decode_result: whether to json_decode the result          :param timeout: HTTP request timeout in seconds          :param max_retries: maximal number of retries after catching URL error              or socket error          :param retry_delay: time to sleep before retrying"""          self.token = token          if srv:              self.server = srv          self.decode_result = decode_result          assert timeout >= 0 or timeout is None          assert max_retries >= 0          self.timeout = timeout          self.max_retries = max_retries          self.retry_delay = retry_delay            _setup_apiobj(self, self, [])        def update_request(self, request):          """overwrite this function to update the request before sending it to          server"""          pass      def _setup_apiobj(self, apiobj, path):      if self is not apiobj:          self._api = apiobj          self._urlbase = apiobj.server + '/'.join(path)        lvl = len(path)      done = set()      for i in _APIS:          if len(i) <= lvl:              continue          cur = i[lvl]          if i[:lvl] == path and cur not in done:              done.add(cur)              setattr(self, cur, _APIProxy(apiobj, i[:lvl + 1]))      class _APIProxy(object):      _api = None        _urlbase = None        def __init__(self, apiobj, path):          _setup_apiobj(self, apiobj, path)        def __call__(self, post = False, *args, **kwargs):          # /article          # url = 'http://xxxx.xxx',          # fields = ['next',],          #          if len(args):              raise TypeError('only keyword arguments are allowed')          if type(post) is not bool:              raise TypeError('post argument can only be True or False')            url = self.geturl(**kwargs)            request = urllib.request.Request(url)            self._api.update_request(request)            retry = self._api.max_retries          while True:              retry -= 1              try:                  ret = urlopen(request, timeout = self._api.timeout).read()                  break              except urllib.error.HTTPError as e:                  raise APIError(e.code, url, e.read())              except (socket.error, urllib.error.URLError) as e:                  if retry < 0:                      raise e                  _print_debug('caught error: {}; retrying'.format(e))                  time.sleep(self._api.retry_delay)            if self._api.decode_result:              try:                  ret = json.loads(ret)              except:                  raise APIError(-1, url, 'json decode error, value={0!r}'.format(ret))          return ret        def _mkarg(self, kargs):          """change the argument list (encode value, add api key/secret)          :return: the new argument list"""          def enc(x):              #if isinstance(x, unicode):              #    return x.encode('utf-8')              #return str(x)              return x.encode('utf-8') if isinstance(x, str) else str(x)            kargs = kargs.copy()          kargs['token'] = self._api.token          for (k, v) in kargs.items():              if isinstance(v, Iterable) and not isinstance(v, str):                  # kargs[k] = ','.join([enc(i) for i in v])                  kargs[k] = ','.join([str(i) for i in v])              else:                  kargs[k] = enc(v)            return kargs        def geturl(self, **kargs):          """return the request url"""          return self._urlbase + '?' + urllib.parse.urlencode(self._mkarg(kargs))      def _print_debug(msg):      if DEBUG_LEVEL:          sys.stderr.write(str(msg) + 'n')    _APIS = [      '/article',      #'/images',  ]    _APIS = [i.split('/')[1:] for i in _APIS]

主要代码

# -*- coding:utf-8 -*-  import url2io,requests,time  from jparser import PageModel  from newspaper import Article      headers = {      'Accept': 'text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,image/apng,*/*;q=0.8',      'Accept-Encoding': 'gzip, deflate',      'Accept-Language': 'zh-CN,zh;q=0.9',      'Connection': 'keep-alive',      'User-Agent': 'Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/63.0.3239.132 Safari/537.36',  }    def get_url2io(url):      try:          ret = api.article(url=url, fields=['text', 'next'])          content=ret['text'].replace('r', '').replace('n', '')          return content      except Exception as e:          # import traceback          # ex_msg = '{exception}'.format(exception=traceback.format_exc())          # print(ex_msg, e)          return ''    def get_jparser(url):      try:          response = requests.get(url, headers=headers)          en_code = response.encoding          de_code = response.apparent_encoding          # print(en_code,de_code,'-----------------')          if de_code == None:              if en_code in ['utf-8', 'UTF-8']:  # en_code=utf-8时，de_code=utf-8,可以获取到内容                  de_code = 'utf-8'          elif de_code in ['ISO-8859-1', 'ISO-8859-2', 'Windows-1254', 'UTF-8-SIG']:              de_code = 'utf-8'          html = response.text.encode(en_code, errors='ignore').decode(de_code, errors='ignore')          pm = PageModel(html)          result = pm.extract()          ans = [x['data'] for x in result['content'] if x['type'] == 'text']          content=''.join(ans)          return content      except Exception as e:          # import traceback          # ex_msg = '{exception}'.format(exception=traceback.format_exc())          # print(ex_msg, e)          return ''      if __name__=='__main__':      token = '111111111'  # 请到url2io官网注册获取token      api = url2io.API(token)      url = 'https://36kr.com/p/5245238'      url = 'http://sc.stock.cnfol.com/ggzixun/20190909/27678429.shtml'      url='https://news.pedaily.cn/201908/445881.shtml'      # content=get_url2io(url)      content = get_jparser(url)      print(content)

Python Goose的使用：

代码比较方便，但是有些网址没有解析出来。示例代码如下所示：

from goose import Goose  from goose.text import StopWordsChinese  url = 'http://www.chinanews.com/gj/2014/11-19/6791729.shtml'  g = Goose({'stipwords_class':StopWordsChinese})  article = g.extract(url = url)  print article.cleaned_text[:150]

结果：效果不好，有些网址解析不出来。

基于行块分布函数的通用网页正文抽取 http://wenku.baidu.com/link?url=TOBoIHWT_k68h5z8k_Pmqr-wJMPfCy2q64yzS8hxsgTg4lMNH84YVfOCWUfvfORTlccMWe5Bd1BNVf9dqIgh75t4VQ728fY2Rte3x3CQhaS

网页正文及内容图片提取算法 http://www.jianshu.com/p/d43422081e4b

这一算法的主要原理基于两点：

正文区密度：在去除HTML中所有tag之后，正文区字符密度更高，较少出现多行空白；行块长度：非正文区域的内容一般单独标签（行块）中较短。

测试源码： https://github.com/rainyear/cix-extractor-py/blob/master/extractor.py#L9

#! /usr/bin/env python3  # -*- coding: utf-8 -*-  import requests as req  import re    DBUG   = 0    reBODY = r'<body.*?>([sS]*?)</body>'  reCOMM = r'<!--.*?-->'  reTRIM = r'<{0}.*?>([sS]*?)</{0}>'  reTAG  = r'<[sS]*?>|[ trfv]'    reIMG  = re.compile(r'<img[sS]*?src=['|"]([sS]*?)['|"][sS]*?>')    class Extractor():      def __init__(self, url = "", blockSize=3, timeout=5, image=False):          self.url       = url          self.blockSize = blockSize          self.timeout   = timeout          self.saveImage = image          self.rawPage   = ""          self.ctexts    = []          self.cblocks   = []        def getRawPage(self):          try:              resp = req.get(self.url, timeout=self.timeout)          except Exception as e:              raise e          if DBUG: print(resp.encoding)          resp.encoding = "UTF-8"          return resp.status_code, resp.text    #去除所有tag，包括样式、Js脚本内容等，但保留原有的换行符n：      def processTags(self):          self.body = re.sub(reCOMM, "", self.body)          self.body = re.sub(reTRIM.format("script"), "" ,re.sub(reTRIM.format("style"), "", self.body))          # self.body = re.sub(r"[n]+","n", re.sub(reTAG, "", self.body))          self.body = re.sub(reTAG, "", self.body)    #将网页内容按行分割，定义行块 blocki 为第 [i,i+blockSize] 行文本之和并给出行块长度基于行号的分布函数：      def processBlocks(self):          self.ctexts   = self.body.split("n")          self.textLens = [len(text) for text in self.ctexts]          self.cblocks  = [0]*(len(self.ctexts) - self.blockSize - 1)          lines = len(self.ctexts)          for i in range(self.blockSize):              self.cblocks = list(map(lambda x,y: x+y, self.textLens[i : lines-1-self.blockSize+i], self.cblocks))          maxTextLen = max(self.cblocks)          if DBUG: print(maxTextLen)          self.start = self.end = self.cblocks.index(maxTextLen)          while self.start > 0 and self.cblocks[self.start] > min(self.textLens):              self.start -= 1          while self.end < lines - self.blockSize and self.cblocks[self.end] > min(self.textLens):              self.end += 1          return "".join(self.ctexts[self.start:self.end])    #如果需要提取正文区域出现的图片，只需要在第一步去除tag时保留<img>标签的内容：      def processImages(self):          self.body = reIMG.sub(r'{{1}}', self.body)    #正文出现在最长的行块，截取两边至行块长度为 0 的范围：      def getContext(self):          code, self.rawPage = self.getRawPage()          self.body = re.findall(reBODY, self.rawPage)[0]          if DBUG: print(code, self.rawPage)          if self.saveImage:              self.processImages()          self.processTags()          return self.processBlocks()          # print(len(self.body.strip("n")))    if __name__ == '__main__':      ext = Extractor(url="http://blog.rainy.im/2015/09/02/web-content-and-main-image-extractor/",blockSize=5, image=False)      print(ext.getContext())

以上算法基本可以应对大部分（中文）网页正文的提取，针对有些网站正文图片多于文字的情况，可以采用保留

标签中图片链接的方法，增加正文密度。目前少量测试发现的问题有： 1）文章分页或动态加载的网页； 2）评论长度过长喧宾夺主的网页。

参考： https://blog.csdn.net/weixin_43098787/article/details/88633973 https://www.cnblogs.com/zhaobang/p/7472091.html https://blog.csdn.net/levy_cui/article/details/51481306 https://www.v2ex.com/t/309948