本文实例讲述了Python实现抓取HTML网页并以PDF文件形式保存的方法。分享给大家供大家参考,具体如下:

一、前言

今天介绍将HTML网页抓取下来,然后以PDF保存,废话不多说直接进入教程。

今天的例子以廖雪峰老师的Python教程网站为例:http://www.liaoxuefeng.com/wiki/0014316089557264a6b348958f449949df42a6d3a2e542c000

二、准备工作

1. PyPDF2的安装使用(用来合并PDF):

PyPDF2版本:1.25.1

https://pypi.python.org/pypi/PyPDF2/1.25.1

https://github.com/mstamy2/PyPDF2

安装:

pip install PyPDF2

使用示例:

from PyPDF2 import PdfFileMerger
merger = PdfFileMerger()
input1 = open("hql_1_20.pdf", "rb")
input2 = open("hql_21_40.pdf", "rb")
merger.append(input1)
merger.append(input2)
# Write to an output PDF document
output = open("hql_all.pdf", "wb")
merger.write(output)

2. requests、beautifulsoup 是爬虫两大神器,reuqests 用于网络请求,beautifusoup 用于操作 html 数据。有了这两把梭子,干起活来利索。scrapy 这样的爬虫框架我们就不用了,这样的小程序派上它有点杀鸡用牛刀的意思。此外,既然是把 html 文件转为 pdf,那么也要有相应的库支持, wkhtmltopdf 就是一个非常的工具,它可以用适用于多平台的 html 到 pdf 的转换,pdfkit 是 wkhtmltopdf 的Python封装包。首先安装好下面的依赖包

pip install requests
pip install beautifulsoup4
pip install pdfkit

3. 安装 wkhtmltopdf

Windows平台直接在 http://wkhtmltopdf.org/downloads.html 下载稳定版的 wkhtmltopdf 进行安装,安装完成之后把该程序的执行路径加入到系统环境 $PATH 变量中,否则 pdfkit 找不到 wkhtmltopdf 就出现错误 “No wkhtmltopdf executable found”。Ubuntu 和 CentOS 可以直接用命令行进行安装

$ sudo apt-get install wkhtmltopdf # ubuntu
$ sudo yum intsall wkhtmltopdf   # centos

三、数据准备

1. 获取每篇文章的url

def get_url_list():
  """
  获取所有URL目录列表
  :return:
  """
  response = requests.get("http://www.liaoxuefeng.com/wiki/0014316089557264a6b348958f449949df42a6d3a2e542c000")
  soup = BeautifulSoup(response.content, "html.parser")
  menu_tag = soup.find_all(class_="uk-nav uk-nav-side")[1]
  urls = []
  for li in menu_tag.find_all("li"):
    url = "http://www.liaoxuefeng.com" + li.a.get('href')
    urls.append(url)
  return urls

2. 通过文章url用模板保存每篇文章的HTML文件

html模板:

html_template = """
<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
</head>
<body>
{content}
</body>
</html>
"""

进行保存:

def parse_url_to_html(url, name):
  """
  解析URL,返回HTML内容
  :param url:解析的url
  :param name: 保存的html文件名
  :return: html
  """
  try:
    response = requests.get(url)
    soup = BeautifulSoup(response.content, 'html.parser')
    # 正文
    body = soup.find_all(class_="x-wiki-content")[0]
    # 标题
    title = soup.find('h4').get_text()
    # 标题加入到正文的最前面,居中显示
    center_tag = soup.new_tag("center")
    title_tag = soup.new_tag('h1')
    title_tag.string = title
    center_tag.insert(1, title_tag)
    body.insert(1, center_tag)
    html = str(body)
    # body中的img标签的src相对路径的改成绝对路径
    pattern = "(<img .*")(.*")"
    def func(m):
      if not m.group(3).startswith("http"):
        rtn = m.group(1) + "http://www.liaoxuefeng.com" + m.group(2) + m.group(3)
        return rtn
      else:
        return m.group(1)+m.group(2)+m.group(3)
    html = re.compile(pattern).sub(func, html)
    html = html_template.format(content=html)
    html = html.encode("utf-8")
    with open(name, 'wb') as f:
      f.write(html)
    return name
  except Exception as e:
    logging.error("解析错误", exc_info=True)

3. 把html转换成pdf

def save_pdf(htmls, file_name):
  """
  把所有html文件保存到pdf文件
  :param htmls: html文件列表
  :param file_name: pdf文件名
  :return:
  """
  options = {
    'page-size': 'Letter',
    'margin-top': '0.75in',
    'margin-right': '0.75in',
    'margin-bottom': '0.75in',
    'margin-left': '0.75in',
    'encoding': "UTF-8",
    'custom-header': [
      ('Accept-Encoding', 'gzip')
    ],
    'cookie': [
      ('cookie-name1', 'cookie-value1'),
      ('cookie-name2', 'cookie-value2'),
    ],
    'outline-depth': 10,
  }
  pdfkit.from_file(htmls, file_name, options=options)

4. 把转换好的单个PDF合并为一个PDF

merger = PdfFileMerger()
for pdf in pdfs:
  merger.append(open(pdf,'rb'))
  print u"合并完成第"+str(i)+'个pdf'+pdf

完整源码:

# coding=utf-8
import os
import re
import time
import logging
import pdfkit
import requests
from bs4 import BeautifulSoup
from PyPDF2 import PdfFileMerger
html_template = """
<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
</head>
<body>
{content}
</body>
</html>
"""
def parse_url_to_html(url, name):
  """
  解析URL,返回HTML内容
  :param url:解析的url
  :param name: 保存的html文件名
  :return: html
  """
  try:
    response = requests.get(url)
    soup = BeautifulSoup(response.content, 'html.parser')
    # 正文
    body = soup.find_all(class_="x-wiki-content")[0]
    # 标题
    title = soup.find('h4').get_text()
    # 标题加入到正文的最前面,居中显示
    center_tag = soup.new_tag("center")
    title_tag = soup.new_tag('h1')
    title_tag.string = title
    center_tag.insert(1, title_tag)
    body.insert(1, center_tag)
    html = str(body)
    # body中的img标签的src相对路径的改成绝对路径
    pattern = "(<img .*")(.*")"
    def func(m):
      if not m.group(3).startswith("http"):
        rtn = m.group(1) + "http://www.liaoxuefeng.com" + m.group(2) + m.group(3)
        return rtn
      else:
        return m.group(1)+m.group(2)+m.group(3)
    html = re.compile(pattern).sub(func, html)
    html = html_template.format(content=html)
    html = html.encode("utf-8")
    with open(name, 'wb') as f:
      f.write(html)
    return name
  except Exception as e:
    logging.error("解析错误", exc_info=True)
def get_url_list():
  """
  获取所有URL目录列表
  :return:
  """
  response = requests.get("http://www.liaoxuefeng.com/wiki/0014316089557264a6b348958f449949df42a6d3a2e542c000")
  soup = BeautifulSoup(response.content, "html.parser")
  menu_tag = soup.find_all(class_="uk-nav uk-nav-side")[1]
  urls = []
  for li in menu_tag.find_all("li"):
    url = "http://www.liaoxuefeng.com" + li.a.get('href')
    urls.append(url)
  return urls
def save_pdf(htmls, file_name):
  """
  把所有html文件保存到pdf文件
  :param htmls: html文件列表
  :param file_name: pdf文件名
  :return:
  """
  options = {
    'page-size': 'Letter',
    'margin-top': '0.75in',
    'margin-right': '0.75in',
    'margin-bottom': '0.75in',
    'margin-left': '0.75in',
    'encoding': "UTF-8",
    'custom-header': [
      ('Accept-Encoding', 'gzip')
    ],
    'cookie': [
      ('cookie-name1', 'cookie-value1'),
      ('cookie-name2', 'cookie-value2'),
    ],
    'outline-depth': 10,
  }
  pdfkit.from_file(htmls, file_name, options=options)
def main():
  start = time.time()
  file_name = u"liaoxuefeng_Python3_tutorial"
  urls = get_url_list()
  for index, url in enumerate(urls):
   parse_url_to_html(url, str(index) + ".html")
  htmls =[]
  pdfs =[]
  for i in range(0,124):
    htmls.append(str(i)+'.html')
    pdfs.append(file_name+str(i)+'.pdf')
    save_pdf(str(i)+'.html', file_name+str(i)+'.pdf')
    print u"转换完成第"+str(i)+'个html'
  merger = PdfFileMerger()
  for pdf in pdfs:
    merger.append(open(pdf,'rb'))
    print u"合并完成第"+str(i)+'个pdf'+pdf
  output = open(u"廖雪峰Python_all.pdf", "wb")
  merger.write(output)
  print u"输出PDF成功!"
  for html in htmls:
    os.remove(html)
    print u"删除临时文件"+html
  for pdf in pdfs:
    os.remove(pdf)
    print u"删除临时文件"+pdf
  total_time = time.time() - start
  print(u"总共耗时:%f 秒" % total_time)
if __name__ == '__main__':
  main()

更多Python相关内容感兴趣的读者可查看本站专题:《Python文件与目录操作技巧汇总》、《Python编码操作技巧总结》、《Python数据结构与算法教程》、《Python函数使用技巧总结》、《Python字符串操作技巧汇总》及《Python入门与进阶经典教程》

希望本文所述对大家Python程序设计有所帮助。

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