[Python]豆瓣用户读书短评下载工具

简介

朋友问我能不能做一个下载他在豆瓣读书上的短评的工具，于是就做了这个“豆瓣用户读书短评下载工具”。
GitHub链接：https://github.com/xiaff/dbc-downloader。

这个小工具使用Python3.4编写，其工作流程为：

用户输入其豆瓣ID；
抓取用户评论列表网页
对网页进行解析；
存储评论相关信息；
将Markdown格式文件转换为Html。

用到的库主要有：

urllib.request
BeautifulSoup4
markdown

抓取网页

所需要抓取的信息在这样的网页中：http://book.douban.com/people/ahbei/collect?sort=time&start=0&filter=all&mode=grid&tags_sort=count，URL中包含了用户ID（people/之后）、评论序号（start=）等信息。

url_1=\'http://book.douban.com/people/\'
url_2=\'/collect?sort=time&start=\'
url_3=\'&filter=all&mode=grid&tags_sort=count\'

url=url_1+uId+url_2+index+url_3,其中 UID 为豆瓣用户ID，index 为评论序号。评论序号从0开始编号，每页显示15条，因为每个url中的序号依次为0、15、30……15*i。 i的最大值即为 网页页数-1，在解析第一张网页的时候可以获取页数。

在抓取网页的时候可以选择使用代理服务器，因此使用urllib.request设置代理：

proxyInfo=input(\'Please type in your HTTP Proxy: \')
proxySupport=urllib.request.ProxyHandler({\'http\':proxyInfo})
opener=urllib.request.build_opener(proxySupport)
urllib.request.install_opener(opener)

不过，如果只设置了代理就访问豆瓣的用户读书评论列表，豆瓣会返回403 Forbidden。
解决办法就是添加请求标头（Request Headers）来模拟浏览器访问。标头信息可以在浏览器中打开网页时按F12进入控制台，在Network选项卡中找到 请求标头（Request Headers） 。
比如，这是我在Edge浏览器中访问豆瓣的请求标头。

head= {
   \'Accept\':\'text/html, application/xhtml+xml, image/jxr, */*\',
   \'Accept-Language\': \'zh-Hans-CN, zh-Hans; q=0.5\',
   \'Connection\':\'Keep-Alive\',
   \'Cookie\':\'bid=lkpO8Id/Kbs; __utma=30149280.1824146216.1438612767.1440248573.1440319237.13; __utmz=30149280.1438612767.1.1.utmcsr=(direct)|utmccn=(direct)|utmcmd=(none); as=http://book.douban.com/people/133476248/; ll=108288; viewed=26274009_1051580; ap=1; ps=y; ct=y; __utmb=30149280.23.10.1440319237; __utmc=30149280; __utmt_douban=1; _pk_id.100001.3ac3=b288f385b4d73e38.1438657126.3.1440319394.1440248628.; __utma=81379588.142106303.1438657126.1440248573.1440319240.3; __utmz=81379588.1440319240.3.2.utmcsr=movie.douban.com|utmccn=(referral)|utmcmd=referral|utmcct=/; _pk_ses.100001.3ac3=*; __utmb=81379588.23.10.1440319240; __utmt=1; __utmc=81379588; _pk_ref.100001.3ac3=%5B%22%22%2C%22%22%2C1440319240%2C%22http%3A%2F%2Fmovie.douban.com%2F%22%5D\',
   \'Host\':\'book.douban.com\',
   \'User-Agent\':\'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/42.0.2311.135 Safari/537.36 Edge/12.10240\'}

然后在访问网页的时候加上header信息：

full_url=urllib.request.Request(url,headers=head)
response=urllib.request.urlopen(full_url)
html=response.read()

这样就可以正确抓取到网页内容了。

解析网页

在我之前一片文章[Python]从豆瓣电影批量获取看过某部电影的用户列表讲过了使用 BeautifulSoup 解析网页了，其实只要看看官方文档就很容易上手了。这里就不再赘述了。

Markdown转Html

最后一步是将以Markdown格式保存的文件转换成Html文件，这样可以让不熟悉Markdown的人在浏览器中直接查看或者另存为PDF文件。
markdown包可以做到这一点：

md = markdown.markdown(contents)
html = \'<html><meta charset="UTF-8">\'
html+=\'<title>\'+title+\'</title>\'
html += "<body>" + md + "</body></html>"

md = markdown.markdown(contents)转换出来的md是不包含<html>标签的，因此需要自己加上这些标签后再保存。

源代码

#coding=utf-8
#Python 3.4
##从豆瓣网页中得到用户的所有读书短评

##网页地址类型：http://book.douban.com/people/1000001/collect?sort=time&start=0&filter=all&mode=grid&tags_sort=count
##            http://book.douban.com/people/1000001/collect?sort=time&start=15&filter=all&mode=grid&tags_sort=count

from bs4 import BeautifulSoup
import time
import urllib.request,urllib.parse
from urllib.error import URLError,HTTPError
import os
import markdown

#换行符
lineSep=\'\n\'

#设置HTTP代理
ans=input(\'Do you want to use a HTTP Proxy (N/y)? \')
ans=ans.lower()
if ans==\'y\' or ans==\'yes\':
    print(\'HTTP Proxy formart: IP:PORT \nExample: 127.0.0.1:80\')
    print(\'Do NOT contain any unnecessary characters.\')
    proxyInfo=input(\'Please type in your HTTP Proxy: \')
    proxySupport=urllib.request.ProxyHandler({\'http\':proxyInfo})
    opener=urllib.request.build_opener(proxySupport)
    urllib.request.install_opener(opener)
else:
    pass

#头信息
head= {
   \'Accept\':\'text/html, application/xhtml+xml, image/jxr, */*\',
   \'Accept-Language\': \'zh-Hans-CN, zh-Hans; q=0.5\',
   \'Connection\':\'Keep-Alive\',
   \'Cookie\':\'bid=lkpO8Id/Kbs; __utma=30149280.1824146216.1438612767.1440248573.1440319237.13; __utmz=30149280.1438612767.1.1.utmcsr=(direct)|utmccn=(direct)|utmcmd=(none); as=http://book.douban.com/people/133476248/; ll=108288; viewed=26274009_1051580; ap=1; ps=y; ct=y; __utmb=30149280.23.10.1440319237; __utmc=30149280; __utmt_douban=1; _pk_id.100001.3ac3=b288f385b4d73e38.1438657126.3.1440319394.1440248628.; __utma=81379588.142106303.1438657126.1440248573.1440319240.3; __utmz=81379588.1440319240.3.2.utmcsr=movie.douban.com|utmccn=(referral)|utmcmd=referral|utmcct=/; _pk_ses.100001.3ac3=*; __utmb=81379588.23.10.1440319240; __utmt=1; __utmc=81379588; _pk_ref.100001.3ac3=%5B%22%22%2C%22%22%2C1440319240%2C%22http%3A%2F%2Fmovie.douban.com%2F%22%5D\',
   \'Host\':\'book.douban.com\',
   \'User-Agent\':\'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/42.0.2311.135 Safari/537.36 Edge/12.10240\'}

#url=url_1+uId+url_2+Index+url_3
url_1=\'http://book.douban.com/people/\'
url_2=\'/collect?sort=time&start=\'
url_3=\'&filter=all&mode=grid&tags_sort=count\'

def is_chinese(uchar):
    """判断一个unicode是否是汉字
    """
    if uchar >= u\'\u4e00\' and uchar<=u\'\u9fa5\':
        return True
    else:
        return False

def isChineseBook(title):
    """判断书名是否为中文书名
    """
    for c in title:
        if(is_chinese(c)):
            return True
    return False

def getHtml(url):
    """返回指定的网页内容
    """
    print(\'Loading: \'+url+\'......\')
    full_url=urllib.request.Request(url,headers=head)
    TRY_TIMES=3
    response=None
    while TRY_TIMES>0 and response==None :
        TRY_TIMES-=1
        try:
            response=urllib.request.urlopen(full_url)   #open=urlopen  
        except HTTPError as e:
            print(\'HTTP Error:\',e.code)
        except URLError as e:  
            print(\'URL Error: \',e.reason)
    if response==None:
        print(\'Error!\')
        os.system("pause")
        exit()
    html=response.read()
    return html

def getBookComment(html):
    """解析网页并返回5个列表：
    书名，出版信息，标记日期，标签，评论
    """
    titleList=[]    #书名
    pubList=[]      #出版信息
    dateList=[]     #标记日期
    tagsList=[]     #标签
    commentList=[]  #评论

    soup=BeautifulSoup(html,\'html.parser\')
    lis=soup.findAll(\'li\',\'subject-item\')
    for li in lis:
        infoDiv=li.find(\'div\',\'info\')
        commentP=infoDiv.find(\'p\',\'comment\')
        if commentP!=None:
            a=infoDiv.a
            #书名
            title1=a.get(\'title\').strip()
            title2Span=a.span
            if title2Span!=None:
                title2=a.span.text.strip()
            else:
                title2=\'\'
            title=title1+title2
            c1=title[0]
            c2=title[-1]
            #如果是中文书名，则加上书名号
            if isChineseBook(title):
                title=u\'《\'+title+u\'》\'
            else:   #英文书加斜体
                title=\'*\'+title+\'*\'
            titleList.append(title)
            #出版信息
            pubDiv=infoDiv.find(\'div\',\'pub\')
            pub=pubDiv.text.strip()
            pubList.append(pub)
            #标记日期
            dataSpan=infoDiv.find(\'span\',\'date\')
            words=dataSpan.text.split(\'\n\')
            date=words[0]+words[1]
            dateList.append(date)
            #标签
            tagsSpan=infoDiv.find(\'span\',\'tags\')
            if tagsSpan!=None:
                tags=tagsSpan.text.strip()
            else:
                tags=\'\'
            tagsList.append(tags)
            #评论
            comment=commentP.text.strip()
            commentList.append(comment)
    return (titleList,pubList,dateList,tagsList,commentList)

def getHtmlTitle(html):
    """
    获取网页标题
    """
    soup=BeautifulSoup(html,\'html.parser\')
    title=soup.head.title.text
    return title

def clearOldFile(uId):
    """
    清除之前已保存的文件
    """
    fileName=\'booksComments_\'+uId+\'.md\'
    temp=open(fileName,\'w\',encoding=\'utf-8\')
    temp.close()

def saveBookComment(titleList,pubList,dateList,tagsList,commentList,uId):
    """保存书评至文件
    """
    fileName=\'booksComments_\'+uId+\'.md\'
    wf=open(fileName,mode=\'a\',encoding=\'utf-8\')
    size=len(titleList)
    for i in range(size):
        title=titleList[i]
        pub=pubList[i]
        date=dateList[i]
        tags=tagsList[i]
        comment=commentList[i]
        wf.write(\'## \'+title+lineSep)
        wf.write(pub+\'  \'+lineSep)
        wf.write(date+\'  \'+lineSep)
        wf.write(tags+lineSep+lineSep)
        wf.write(comment+lineSep+lineSep)
    wf.close()
    return fileName

def getPageNum(html):
    """解析第一页网页，返回该用户的书评页数
    """
    soup=BeautifulSoup(html,\'html.parser\')
    paginator=soup.find(\'div\',\'paginator\')
    pas=paginator.findAll(\'a\')
    num=int(pas[-2].text)
    return num

def convertMd2Html(mdName,title):
    """
    将Markdown文件转换为Html格式文件
    """
    htmlName=mdName.replace(\'.md\',\'.html\')
    mdFile=open(mdName,\'r\',encoding=\'utf-8\')
    contents=mdFile.read()
    mdFile.close()
    md = markdown.markdown(contents)
    html = \'<html><meta charset="UTF-8">\'
    html+=\'<title>\'+title+\'</title>\'
    html += "<body>" + md + "</body></html>"
    htmlFile=open(htmlName,\'w\',encoding=\'utf-8\')
    htmlFile.write(html)
    htmlFile.close()
    return htmlName


#输入User-Id
print(\'\nYou can find User-Id in the url.\')
print(\'E.g. Someone\\'s homepage\\'url is http://book.douban.com/people/1000001/ , the User-Id should be 1000001 .\')
uId=input(\'User-Id: \')
while(uId==\'\'):
    uId=input(\'User-Id: \')
#计数器
count=0

#读取第一页
index=0
url=url=url_1+uId+url_2+str(index)+url_3
html=getHtml(url)
(titleList,pubList,dateList,tagsList,commentList)=getBookComment(html)
htmlTitle=getHtmlTitle(html)
clearOldFile(uId);
fileName=saveBookComment(titleList,pubList,dateList,tagsList,commentList,uId)

count+=len(titleList)
try:
    pageNum=getPageNum(html)    #用户读过的书的网页页数
except:
    pageNum=1
index+=1
#读取后续页
for i in range(index*15,15*pageNum,15):
    print(\'Sleep for 5 seconds.\')
    time.sleep(5)
    print(\'%d/%d\' %(i/15+1,pageNum))
    url=url=url_1+uId+url_2+str(i)+url_3
    html=getHtml(url)
    (titleList,pubList,dateList,tagsList,commentList)=getBookComment(html)
    count+=len(titleList)
    saveBookComment(titleList,pubList,dateList,tagsList,commentList,uId)
print(\'\nMission accomplished!\')
print(\'%d comments have been saved to %s.\' %(count,fileName))
ans=input(\'\nDo you want to convert Markdown file to html file(Y/n)?\')
ans=ans.lower()
if ans!=\'n\':
    htmlName=convertMd2Html(fileName,htmlTitle)
    print(\'Convert success: %s\' %htmlName)
os.system("pause")