Python网络爬虫项目：内容提取器的定义

#!/usr/bin/python
# -*- coding: utf-8 -*-
# 模块名: gooseeker
# 类名: gsExtractor
# Version: 2.0
# 说明: html内容提取器
# 功能: 使用xslt作为模板，快速提取HTML DOM中的内容。
# released by 集搜客(http://www.gooseeker.com) on May 18, 2016
# github: https://github.com/FullerHua/jisou/core/gooseeker.py

from urllib import request
from urllib.parse import quote
from lxml import etree
import time

class gsExtractor(object):
  def _init_(self):
    self.xslt = ""
  # 从文件读取xslt
  def setXsltFromFile(self , xsltFilePath):
    file = open(xsltFilePath , 'r' , encoding='UTF-8')
    try:
      self.xslt = file.read()
    finally:
      file.close()
  # 从字符串获得xslt
  def setXsltFromMem(self , xsltStr):
    self.xslt = xsltStr
  # 通过GooSeeker API接口获得xslt
  def setXsltFromAPI(self , APIKey , theme, middle=None, bname=None):
    apiurl = "http://www.gooseeker.com/api/getextractor?key="+ APIKey +"&theme="+quote(theme)
    if (middle):
      apiurl = apiurl + "&middle="+quote(middle)
    if (bname):
      apiurl = apiurl + "&bname="+quote(bname)
    apiconn = request.urlopen(apiurl)
    self.xslt = apiconn.read()
  # 返回当前xslt
  def getXslt(self):
    return self.xslt
  # 提取方法，入参是一个HTML DOM对象，返回是提取结果
  def extract(self , html):
    xslt_root = etree.XML(self.xslt)
    transform = etree.XSLT(xslt_root)
    result_tree = transform(html)
    return result_tree

#-*_coding:utf8-*-
# 使用gsExtractor类的示例程序
# 访问集搜客论坛，以xslt为模板提取论坛内容
# xslt保存在xslt_bbs.xml中
from urllib import request
from lxml import etree
from gooseeker import gsExtractor

# 访问并读取网页内容
url = "http://www.gooseeker.com/cn/forum/7"
conn = request.urlopen(url)
doc = etree.HTML(conn.read())

# 生成xsltExtractor对象
bbsExtra = gsExtractor()
# 调用set方法设置xslt内容
bbsExtra.setXsltFromFile("xslt_bbs.xml")
# 调用extract方法提取所需内容
result = bbsExtra.extract(doc)
# 显示提取结果
print(str(result))