爬虫新手学习2-爬虫进阶(urllib和urllib2 的区别、url转码、爬虫GET提交实例、批量爬取贴吧数据、fidder软件安装、有道翻译POST实例、豆瓣ajax数据获取)

爬虫新手学习1-爬虫基础

1、urllib和urllib2区别实例

urllib和urllib2都是接受URL请求相关模块，但是提供了不同的功能，两个最显著的不同如下：

urllib可以接受URL，不能创建设置headers的Request类实例，urlib2可以。

url转码

https://www.baidu.com/s?wd=%E5%AD%A6%E7%A5%9E

python字符集解码加码过程：

2.爬虫GET提交实例

#coding:utf-8

import urllib    #负责url编码处理
import urllib2

url = "https://www.baidu.com/s"
word = {"wd": "繁华"}
word = urllib.urlencode(word)   #转换成url编码格式(字符串)
newurl = url + "?" + word

headers = {"User-Agent": "Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/63.0.3239.84 Safari/537.36"}

request = urllib2.Request(newurl, headers=headers)

response = urllib2.urlopen(request)

print response.read()

#coding:utf-8

import urllib    #负责url编码处理
import urllib2

url = "https://www.baidu.com/s"
word = {"wd": "咖菲猫"}
word = urllib.urlencode(word)   #转换成url编码格式(字符串)
newurl = url + "?" + word

headers = {"User-Agent": "Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/63.0.3239.84 Safari/537.36"}

request = urllib2.Request(newurl, headers=headers)

response = urllib2.urlopen(request)

print response.read()

自定义爬虫GET提交实例

#coding:utf-8

import urllib    #负责url编码处理
import urllib2

url = "https://www.baidu.com/s"
keyword = raw_input("请输入要查询的关键字:")
word = {"wd": keyword}
word = urllib.urlencode(word)   #转换成url编码格式(字符串)
newurl = url + "?" + word

headers = {"User-Agent": "Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/63.0.3239.84 Safari/537.36"}

request = urllib2.Request(newurl, headers=headers)

response = urllib2.urlopen(request)

print response.read()

3.批量爬取贴吧页面数据

分析贴吧URL

http://tieba.baidu.com/f?kw=%E7%BB%9D%E5%9C%B0%E6%B1%82%E7%94%9F

pn递增50为一页

0为第一页

http://tieba.baidu.com/f?kw=%E7%BB%9D%E5%9C%B0%E6%B1%82%E7%94%9F&pn=0

50为第二页

http://tieba.baidu.com/f?kw=%E7%BB%9D%E5%9C%B0%E6%B1%82%E7%94%9F&pn=50

100为第三页

http://tieba.baidu.com/f?kw=%E7%BB%9D%E5%9C%B0%E6%B1%82%E7%94%9F&pn=100

批量爬贴吧实例

#coding:utf-8

import urllib
import urllib2

def loadPage(url, filename):
    ‘‘‘
        作用：根据url发送请求， 获取服务器响应文件
        url：需要爬取的url地址
        filename：文件名
    ‘‘‘

    print "正在下载" + filename

    headers = {
        "User-Agent": "Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/63.0.3239.84 Safari/537.36"}

    request = urllib2.Request(url, headers = headers)
    response = urllib2.urlopen(request)
    return response.read()

def writeFile(html, filename):
    ‘‘‘
        作用：保存服务器相应文件到本地硬盘文件里
        html：服务器相应文件
        filename：本地磁盘文件名
    ‘‘‘

    print "正在存储" + filename
    with open(unicode(filename, ‘utf-8‘), ‘w‘) as f:
        f.write(html)
    print "-" * 20

def tiebaSpider(url, beginPage, endPage, name):
    ‘‘‘
        作用：负责处理url，分配每个url去发送请求
        url：需要处理的第一个url
        beginPage：爬虫执行的起始页面
        endPage：爬虫执行的截止页面
    ‘‘‘
    for page in range(beginPage, endPage + 1):
        pn = (page - 1) * 50

        filename = "第" + name + "-" + str(page) + "页.html"
        #组合为完整的url，并且pn值每次增加50
        fullurl = url + "&pn=" + str(pn)
        #print fullurl

        #调用loadPage()发送请求获取HTML页面
        html = loadPage(fullurl, filename)
        #将获取到的HTML页面写入本地磁盘文件
        writeFile(html, filename)

#模拟main函数"
if __name__ == "__main__":
    kw = raw_input("请输入需要爬取的贴吧：")
    beginPage = int(raw_input("请输入起始页："))
    endPage = int(raw_input("请输入终止页："))

    url = "http://tieba.baidu.com/f?"
    key = urllib.urlencode({"kw": kw})

    #组合后的url示例：http://tieba.baidu.com/f?kw=绝地求生
    newurl = url + key
    tiebaSpider(newurl, beginPage, endPage, kw)

4.Fidder使用安装

下载fidder

安装后，照下图设置

5.有道翻译POST分析

调用有道翻译POST API实例

#coding:utf-8

import urllib
import urllib2

#通过抓包的方式获取的url，并不是浏览器上显示的url
url = "http://fanyi.youdao.com/translate?smartresult=dict&smartresult=rule&smartresult=ugc&sessionFrom=null"

#完整的headers
headers = {
    "Accept": "application/json, text/javascript, */*; q=0.01",
    "Origin": "http://fanyi.youdao.com",
    "X-Requested-With": "XMLHttpRequest",
    "User-Agent": "Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/63.0.3239.84 Safari/537.36",
    "Content-Type": "application/x-www-form-urlencoded; charset=UTF-8"
}

#用户接口输入
key = raw_input("请输入需要翻译的英文单词：")

#发送到web服务器的表单数据
formdata = {
    "i": key,
    "from": "AUTO",
    "to": "AUTO",
    "smartresult": "dict",
    "client": "fanyideskweb",
    "salt": "1513519318944",
    "sign": "29e3219b8c4e75f76f6e6aba0bb3c4b5",
    "doctype": "json",
    "version": "2.1",
    "keyfrom": "fanyi.web",
    "action": "FY_BY_REALTIME",
    "typoResult": "false"
}

#经过urlencode转码
data = urllib.urlencode(formdata)

#如果Request()方法里的data参数有值，那么这个请求就是POST
#如果没有，就是Get
request = urllib2.Request(url, data= data, headers= headers)

print urllib2.urlopen(request).read()

6.Ajax加载方式的数据获取

豆瓣分析Ajax

爬取豆瓣电影排行信息实例

#coding:utf-8

import urllib2
import urllib

url = "https://movie.douban.com/j/chart/top_list?type=11&interval_id=100%3A90&action="

headers = {"User-Agent": "Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/63.0.3239.84 Safari/537.36"}

formdata = {
    "start": "0",
    "limit": "20"
}

data = urllib.urlencode(formdata)

request = urllib2.Request(url, data = data, headers = headers)

print urllib2.urlopen(request).read()