• 爬虫基础知识和流程梳理


    requests

    requests是一个python的第三方http库,它在python的内置模块基础上进行了封装,使我们用网络请求开发是变得轻松了很多,可以快速模拟浏览器的任何操作。

    1.get请求

    1.无参数

    1 import requests
    2 
    3 r1 = requests.get(url="http://www.sina.com")
    4 
    5 print(r1.text)

    2.有参数

    import requests
      
    p1 = {'id': 'value1', 'code': 'value2'}
    r2 = requests.get("http://www.sina.com/get", params=p1)
      
    print r2.url   # http://www.sina.com/get?id=xx&code=xx
    print r2.text

    2.POST请求

    1.基础

    import requests
    
    form_data = {'name':'ddd','pass','ddd'}
    
    cookie = {'sessionid': 'fdsafaa'}
    
    r3 = requests.post(url = "http://www.sina.com", data=form_data, cookies=cookie)
    
    print(r3.text)

    2.发送请求头和数据实例

    import requests
    
    import json
    
    url = 'https://api.github.com/some/endpoint'
    d2 = {'some': 'data'}
    headers = {'content-type': 'application/json','use-agent':'Mozilla, linux'}
    r4 = requests.post(url, data=json.dumps(d2), headers=headers)
    
    print r4.text
    print r4.cookies

    3.其他请求

    requests.get(url, params=None, **kwargs)
    requests.post(url, data=None, json=None, **kwargs)
    requests.put(url, data=None, **kwargs)
    requests.head(url, **kwargs)
    requests.delete(url, **kwargs)
    requests.patch(url, data=None, **kwargs)
    requests.options(url, **kwargs)
      
    # 以上方法均是在此方法的基础上构建
    requests.request(method, url, **kwargs)

    4.更多参数和示例

    def param_method_url():
        # requests.request(method='get', url='http://127.0.0.1:8000/test/')
        # requests.request(method='post', url='http://127.0.0.1:8000/test/')
        pass
    
    
    def param_param():
        # - 可以是字典
        # - 可以是字符串
        # - 可以是字节(ascii编码以内)
    
        # requests.request(method='get',
        # url='http://127.0.0.1:8000/test/',
        # params={'k1': 'v1', 'k2': '水电费'})
    
        # requests.request(method='get',
        # url='http://127.0.0.1:8000/test/',
        # params="k1=v1&k2=水电费&k3=v3&k3=vv3")
    
        # requests.request(method='get',
        # url='http://127.0.0.1:8000/test/',
        # params=bytes("k1=v1&k2=k2&k3=v3&k3=vv3", encoding='utf8'))
    
        # 错误
        # requests.request(method='get',
        # url='http://127.0.0.1:8000/test/',
        # params=bytes("k1=v1&k2=水电费&k3=v3&k3=vv3", encoding='utf8'))
        pass
    
    
    def param_data():
        # 可以是字典
        # 可以是字符串
        # 可以是字节
        # 可以是文件对象
    
        # requests.request(method='POST',
        # url='http://127.0.0.1:8000/test/',
        # data={'k1': 'v1', 'k2': '水电费'})
    
        # requests.request(method='POST',
        # url='http://127.0.0.1:8000/test/',
        # data="k1=v1; k2=v2; k3=v3; k3=v4"
        # )
    
        # requests.request(method='POST',
        # url='http://127.0.0.1:8000/test/',
        # data="k1=v1;k2=v2;k3=v3;k3=v4",
        # headers={'Content-Type': 'application/x-www-form-urlencoded'}
        # )
    
        # requests.request(method='POST',
        # url='http://127.0.0.1:8000/test/',
        # data=open('data_file.py', mode='r', encoding='utf-8'), # 文件内容是:k1=v1;k2=v2;k3=v3;k3=v4
        # headers={'Content-Type': 'application/x-www-form-urlencoded'}
        # )
        pass
    
    
    def param_json():
        # 将json中对应的数据进行序列化成一个字符串,json.dumps(...)
        # 然后发送到服务器端的body中,并且Content-Type是 {'Content-Type': 'application/json'}
        requests.request(method='POST',
                         url='http://127.0.0.1:8000/test/',
                         json={'k1': 'v1', 'k2': '水电费'})
    
    
    def param_headers():
        # 发送请求头到服务器端
        requests.request(method='POST',
                         url='http://127.0.0.1:8000/test/',
                         json={'k1': 'v1', 'k2': '水电费'},
                         headers={'Content-Type': 'application/x-www-form-urlencoded'}
                         )
    
    
    def param_cookies():
        # 发送Cookie到服务器端
        requests.request(method='POST',
                         url='http://127.0.0.1:8000/test/',
                         data={'k1': 'v1', 'k2': 'v2'},
                         cookies={'cook1': 'value1'},
                         )
        # 也可以使用CookieJar(字典形式就是在此基础上封装)
        from http.cookiejar import CookieJar
        from http.cookiejar import Cookie
    
        obj = CookieJar()
        obj.set_cookie(Cookie(version=0, name='c1', value='v1', port=None, domain='', path='/', secure=False, expires=None,
                              discard=True, comment=None, comment_url=None, rest={'HttpOnly': None}, rfc2109=False,
                              port_specified=False, domain_specified=False, domain_initial_dot=False, path_specified=False)
                       )
        requests.request(method='POST',
                         url='http://127.0.0.1:8000/test/',
                         data={'k1': 'v1', 'k2': 'v2'},
                         cookies=obj)
    
    
    def param_files():
        # 发送文件
        # file_dict = {
        # 'f1': open('readme', 'rb')
        # }
        # requests.request(method='POST',
        # url='http://127.0.0.1:8000/test/',
        # files=file_dict)
    
        # 发送文件,定制文件名
        # file_dict = {
        # 'f1': ('test.txt', open('readme', 'rb'))
        # }
        # requests.request(method='POST',
        # url='http://127.0.0.1:8000/test/',
        # files=file_dict)
    
        # 发送文件,定制文件名
        # file_dict = {
        # 'f1': ('test.txt', "hahsfaksfa9kasdjflaksdjf")
        # }
        # requests.request(method='POST',
        # url='http://127.0.0.1:8000/test/',
        # files=file_dict)
    
        # 发送文件,定制文件名
        # file_dict = {
        #     'f1': ('test.txt', "hahsfaksfa9kasdjflaksdjf", 'application/text', {'k1': '0'})
        # }
        # requests.request(method='POST',
        #                  url='http://127.0.0.1:8000/test/',
        #                  files=file_dict)
    
        pass
    
    
    def param_auth():
        from requests.auth import HTTPBasicAuth, HTTPDigestAuth
    
        ret = requests.get('https://api.github.com/user', auth=HTTPBasicAuth('wupeiqi', 'sdfasdfasdf'))
        print(ret.text)
    
        # ret = requests.get('http://192.168.1.1',
        # auth=HTTPBasicAuth('admin', 'admin'))
        # ret.encoding = 'gbk'
        # print(ret.text)
    
        # ret = requests.get('http://httpbin.org/digest-auth/auth/user/pass', auth=HTTPDigestAuth('user', 'pass'))
        # print(ret)
        #
    
    
    def param_timeout():
        # ret = requests.get('http://google.com/', timeout=1)
        # print(ret)
    
        # ret = requests.get('http://google.com/', timeout=(5, 1))
        # print(ret)
        pass
    
    
    def param_allow_redirects():
        ret = requests.get('http://127.0.0.1:8000/test/', allow_redirects=False)
        print(ret.text)
    
    
    def param_proxies():
        # proxies = {
        # "http": "61.172.249.96:80",
        # "https": "http://61.185.219.126:3128",
        # }
    
        # proxies = {'http://10.20.1.128': 'http://10.10.1.10:5323'}
    
        # ret = requests.get("http://www.proxy360.cn/Proxy", proxies=proxies)
        # print(ret.headers)
    
    
        # from requests.auth import HTTPProxyAuth
        #
        # proxyDict = {
        # 'http': '77.75.105.165',
        # 'https': '77.75.105.165'
        # }
        # auth = HTTPProxyAuth('username', 'mypassword')
        #
        # r = requests.get("http://www.google.com", proxies=proxyDict, auth=auth)
        # print(r.text)
    
        pass
    
    
    def param_stream():
        ret = requests.get('http://127.0.0.1:8000/test/', stream=True)
        print(ret.content)
        ret.close()
    
        # from contextlib import closing
        # with closing(requests.get('http://httpbin.org/get', stream=True)) as r:
        # # 在此处理响应。
        # for i in r.iter_content():
        # print(i)
    
    
    def requests_session():
        import requests
    
        session = requests.Session()
    
        ### 1、首先登陆任何页面,获取cookie
    
        i1 = session.get(url="http://dig.chouti.com/help/service")
    
        ### 2、用户登陆,携带上一次的cookie,后台对cookie中的 gpsd 进行授权
        i2 = session.post(
            url="http://dig.chouti.com/login",
            data={
                'phone': "8615131255089",
                'password': "xxxxxx",
                'oneMonth': ""
            }
        )
    
        i3 = session.post(
            url="http://dig.chouti.com/link/vote?linksId=8589623",
        )
        print(i3.text)
    
    参数示例

    参数示例

    BeautifulSoup4

     BeautifulSoup是一个python模块,该模块用于接收一个HTML或XML字符串,然后将其进行格式化,之后遍可以使用他提供的方法进行快速查找指定元素,从而使得在HTML或XML中查找指定元素变得简单。 像是Xpath。

    1.安装

    pip38 install beautifulsoup4
    
    需要依赖包soupsvise

    2.使用方法

    from bs4 import beautifulsoup4
    
    import requests
    
    r1 = requests.get("http://www.sina.com")
    
    s1 = BeautifulSoup(r1.text, 'html.parser / lxml')  # features="lxml  / html.parser"
    
    # 找到id=div1的div标签
    
    tag1 = s1.find(name='div', attrs={'id':'div1'})
    
    # 找到第一个a标签
    
    tag2 = s1.find(name= 'a')
    
    # 找到所有div标签
    
    tag3 = s1.find_all(name = 'div')
    
    # 找到id=link的标签
    
    tag4 = s1.select('#link')

    3.对转换格式后的标签节点进行操作

    1.name,标签名称

    name
    # tag = soup.find('a')
    # name = tag.name # 获取
    # print(name)
    # tag.name = 'span' # 设置
    # print(soup)

    2.attrs,标签属性

    # tag = soup.find('a',attrs={'id':'xxx'})
    # attrs = tag.attrs    # 获取
    # print(attrs)
    # tag.attrs = {'ik':123} # 设置
    # tag.attrs['id'] = 'iiiii' # 设置
    # print(soup)
    attrs

     3.children,所有子标签

    4.children,所有子子孙孙标签

    5.celear,讲标签的所有子孙标签全部清空,保留标签名

    6.decompose,递归删除所有标签

    7.extract,递归的删除所有标签,并获取删除的标签

    8.decode,转换为字符串,含当前标签;decode_contents不含当前标签

    9.encode,转换微字节,含当前标签。encode_contents不含当前标签

    10.find,获取匹配的第一个标签

    11.find_all,获取匹配的所有标签

    12.has_attr,检查标签是否具有该属性

    13.get_text,获取标签内部文本内容

    14.index,检查标签在某标签中的索引位置

    15.

    is_empty_element,是否是空标签(是否可以是空)或者自闭合标签,

    判断是否是如下标签:'br' , 'hr', 'input', 'img', 'meta','spacer', 'link', 'frame', 'base'

    16.当前的关联标签

    17.查找某标签的关联标签

    18.select,select_one,css选择器

    19.标签的内容

    20.append在当前标签内部追加一个标签

    21.insert在当前标签内部指定位置插入一个标签

    22.insert_after,insert_before在当前标签后或前插入

    23.replace_with在当前标签替换为指定标签

    24.创建标签之间的关系

    25.wrap,将指定标签把当前标签包裹

    26.unwrap,去掉当前标签,将保留其包裹的标签

     基本流程

    使用chrome,postman等工具获取request和response的请求头,返回头和请求体,返回体信息。

    模拟用户浏览器的操作,携带登录和验证信息,取得服务器返回的数据,用beautifulsoup等工具进行分析提取数据,把数据持久化保存到本地数据库,利用取得的数据做自己的应用。

    1.打开网站页面,不能直接去找爬取数据或登录的页面,会被认定为爬虫

    r1 = requests.get("http://sina.com")
    
      这里可能需要获取cookies或者在页面中取得隐藏数据,比如csrf token,认证码等
    
      my_cookie = r1.cookies.get_dict()
    
    r1.close

    2.post请求打开需要登录的页面

    #这一步需要多测试分析,比如携带的cookies,返回的response信息

    r2 = requests.post("http://sina.com/login",
    
      headers = {
    
        user_agren: Moliz, linux,
    
        .......
    
    },  
    
      data = {
    
       user : xxx,
    
               pass: xxx,
    
         Uid:xxx,
    
        keep : on, 
    
    }  
    
      cookies=my_cookies
    
    )  
    
    print(r2.text)

    3.格式化数据并获取需要的数据

    s1 = BeautifulSoup(r2.text, 'lxml')
    
    div = s1.find(name='div', attrs={'id':'xxx','':''})
    
    print(div.text)

    真实实例

    #!/usr/bin/env python
    # -*- coding:utf-8 -*-
    import requests
    
    
    # ############## 方式一 ##############
    """
    # ## 1、首先登陆任何页面,获取cookie
    i1 = requests.get(url="http://dig.chouti.com/help/service")
    i1_cookies = i1.cookies.get_dict()
    
    # ## 2、用户登陆,携带上一次的cookie,后台对cookie中的 gpsd 进行授权
    i2 = requests.post(
        url="http://dig.chouti.com/login",
        data={
            'phone': "8615131255089",
            'password': "xxooxxoo",
            'oneMonth': ""
        },
        cookies=i1_cookies
    )
    
    # ## 3、点赞(只需要携带已经被授权的gpsd即可)
    gpsd = i1_cookies['gpsd']
    i3 = requests.post(
        url="http://dig.chouti.com/link/vote?linksId=8589523",
        cookies={'gpsd': gpsd}
    )
    
    print(i3.text)
    """
    
    
    # ############## 方式二 ##############
    """
    import requests
    
    session = requests.Session()
    i1 = session.get(url="http://dig.chouti.com/help/service")
    i2 = session.post(
        url="http://dig.chouti.com/login",
        data={
            'phone': "8615131255089",
            'password': "xxooxxoo",
            'oneMonth': ""
        }
    )
    i3 = session.post(
        url="http://dig.chouti.com/link/vote?linksId=8589523"
    )
    print(i3.text)
    
    """
    抽屉新热榜
    抽屉
    #!/usr/bin/env python
    # -*- coding:utf-8 -*-
    
    import requests
    from bs4 import BeautifulSoup
    
    # ############## 方式一 ##############
    #
    # # 1. 访问登陆页面,获取 authenticity_token
    # i1 = requests.get('https://github.com/login')
    # soup1 = BeautifulSoup(i1.text, features='lxml')
    # tag = soup1.find(name='input', attrs={'name': 'authenticity_token'})
    # authenticity_token = tag.get('value')
    # c1 = i1.cookies.get_dict()
    # i1.close()
    #
    # # 1. 携带authenticity_token和用户名密码等信息,发送用户验证
    # form_data = {
    # "authenticity_token": authenticity_token,
    #     "utf8": "",
    #     "commit": "Sign in",
    #     "login": "wupeiqi@live.com",
    #     'password': 'xxoo'
    # }
    #
    # i2 = requests.post('https://github.com/session', data=form_data, cookies=c1)
    # c2 = i2.cookies.get_dict()
    # c1.update(c2)
    # i3 = requests.get('https://github.com/settings/repositories', cookies=c1)
    #
    # soup3 = BeautifulSoup(i3.text, features='lxml')
    # list_group = soup3.find(name='div', class_='listgroup')
    #
    # from bs4.element import Tag
    #
    # for child in list_group.children:
    #     if isinstance(child, Tag):
    #         project_tag = child.find(name='a', class_='mr-1')
    #         size_tag = child.find(name='small')
    #         temp = "项目:%s(%s); 项目路径:%s" % (project_tag.get('href'), size_tag.string, project_tag.string, )
    #         print(temp)
    
    
    
    # ############## 方式二 ##############
    # session = requests.Session()
    # # 1. 访问登陆页面,获取 authenticity_token
    # i1 = session.get('https://github.com/login')
    # soup1 = BeautifulSoup(i1.text, features='lxml')
    # tag = soup1.find(name='input', attrs={'name': 'authenticity_token'})
    # authenticity_token = tag.get('value')
    # c1 = i1.cookies.get_dict()
    # i1.close()
    #
    # # 1. 携带authenticity_token和用户名密码等信息,发送用户验证
    # form_data = {
    #     "authenticity_token": authenticity_token,
    #     "utf8": "",
    #     "commit": "Sign in",
    #     "login": "wupeiqi@live.com",
    #     'password': 'xxoo'
    # }
    #
    # i2 = session.post('https://github.com/session', data=form_data)
    # c2 = i2.cookies.get_dict()
    # c1.update(c2)
    # i3 = session.get('https://github.com/settings/repositories')
    #
    # soup3 = BeautifulSoup(i3.text, features='lxml')
    # list_group = soup3.find(name='div', class_='listgroup')
    #
    # from bs4.element import Tag
    #
    # for child in list_group.children:
    #     if isinstance(child, Tag):
    #         project_tag = child.find(name='a', class_='mr-1')
    #         size_tag = child.find(name='small')
    #         temp = "项目:%s(%s); 项目路径:%s" % (project_tag.get('href'), size_tag.string, project_tag.string, )
    #         print(temp)
    
    github
    Github
    #!/usr/bin/env python
    # -*- coding:utf-8 -*-
    import time
    
    import requests
    from bs4 import BeautifulSoup
    
    session = requests.Session()
    
    i1 = session.get(
        url='https://www.zhihu.com/#signin',
        headers={
            'User-Agent': 'Mozilla/5.0 (Macintosh; Intel Mac OS X 10_10_5) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/54.0.2840.98 Safari/537.36',
        }
    )
    
    soup1 = BeautifulSoup(i1.text, 'lxml')
    xsrf_tag = soup1.find(name='input', attrs={'name': '_xsrf'})
    xsrf = xsrf_tag.get('value')
    
    current_time = time.time()
    i2 = session.get(
        url='https://www.zhihu.com/captcha.gif',
        params={'r': current_time, 'type': 'login'},
        headers={
            'User-Agent': 'Mozilla/5.0 (Macintosh; Intel Mac OS X 10_10_5) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/54.0.2840.98 Safari/537.36',
        })
    
    with open('zhihu.gif', 'wb') as f:
        f.write(i2.content)
    
    captcha = input('请打开zhihu.gif文件,查看并输入验证码:')
    form_data = {
        "_xsrf": xsrf,
        'password': 'xxooxxoo',
        "captcha": 'captcha',
        'email': '424662508@qq.com'
    }
    i3 = session.post(
        url='https://www.zhihu.com/login/email',
        data=form_data,
        headers={
            'User-Agent': 'Mozilla/5.0 (Macintosh; Intel Mac OS X 10_10_5) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/54.0.2840.98 Safari/537.36',
        }
    )
    
    i4 = session.get(
        url='https://www.zhihu.com/settings/profile',
        headers={
            'User-Agent': 'Mozilla/5.0 (Macintosh; Intel Mac OS X 10_10_5) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/54.0.2840.98 Safari/537.36',
        }
    )
    
    soup4 = BeautifulSoup(i4.text, 'lxml')
    tag = soup4.find(id='rename-section')
    nick_name = tag.find('span',class_='name').string
    print(nick_name)
    
    知乎
    知乎
    #!/usr/bin/env python
    # -*- coding:utf-8 -*-
    import re
    import json
    import base64
    
    import rsa
    import requests
    
    
    def js_encrypt(text):
        b64der = 'MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQCp0wHYbg/NOPO3nzMD3dndwS0MccuMeXCHgVlGOoYyFwLdS24Im2e7YyhB0wrUsyYf0/nhzCzBK8ZC9eCWqd0aHbdgOQT6CuFQBMjbyGYvlVYU2ZP7kG9Ft6YV6oc9ambuO7nPZh+bvXH0zDKfi02prknrScAKC0XhadTHT3Al0QIDAQAB'
        der = base64.standard_b64decode(b64der)
    
        pk = rsa.PublicKey.load_pkcs1_openssl_der(der)
        v1 = rsa.encrypt(bytes(text, 'utf8'), pk)
        value = base64.encodebytes(v1).replace(b'
    ', b'')
        value = value.decode('utf8')
    
        return value
    
    
    session = requests.Session()
    
    i1 = session.get('https://passport.cnblogs.com/user/signin')
    rep = re.compile("'VerificationToken': '(.*)'")
    v = re.search(rep, i1.text)
    verification_token = v.group(1)
    
    form_data = {
        'input1': js_encrypt('wptawy'),
        'input2': js_encrypt('asdfasdf'),
        'remember': False
    }
    
    i2 = session.post(url='https://passport.cnblogs.com/user/signin',
                      data=json.dumps(form_data),
                      headers={
                          'Content-Type': 'application/json; charset=UTF-8',
                          'X-Requested-With': 'XMLHttpRequest',
                          'VerificationToken': verification_token}
                      )
    
    i3 = session.get(url='https://i.cnblogs.com/EditDiary.aspx')
    
    print(i3.text)
    
    博客园
    cnblogs
    #!/usr/bin/env python
    # -*- coding:utf-8 -*-
    
    import requests
    
    
    # 第一步:访问登陆页,拿到X_Anti_Forge_Token,X_Anti_Forge_Code
    # 1、请求url:https://passport.lagou.com/login/login.html
    # 2、请求方法:GET
    # 3、请求头:
    #    User-agent
    r1 = requests.get('https://passport.lagou.com/login/login.html',
                     headers={
                         'User-Agent': 'Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/63.0.3239.132 Safari/537.36',
                     },
                     )
    
    X_Anti_Forge_Token = re.findall("X_Anti_Forge_Token = '(.*?)'", r1.text, re.S)[0]
    X_Anti_Forge_Code = re.findall("X_Anti_Forge_Code = '(.*?)'", r1.text, re.S)[0]
    print(X_Anti_Forge_Token, X_Anti_Forge_Code)
    # print(r1.cookies.get_dict())
    # 第二步:登陆
    # 1、请求url:https://passport.lagou.com/login/login.json
    # 2、请求方法:POST
    # 3、请求头:
    #    cookie
    #    User-agent
    #    Referer:https://passport.lagou.com/login/login.html
    #    X-Anit-Forge-Code:53165984
    #    X-Anit-Forge-Token:3b6a2f62-80f0-428b-8efb-ef72fc100d78
    #    X-Requested-With:XMLHttpRequest
    # 4、请求体:
    # isValidate:true
    # username:15131252215
    # password:ab18d270d7126ea65915c50288c22c0d
    # request_form_verifyCode:''
    # submit:''
    r2 = requests.post(
        'https://passport.lagou.com/login/login.json',
        headers={
            'User-Agent': 'Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/63.0.3239.132 Safari/537.36',
            'Referer': 'https://passport.lagou.com/login/login.html',
            'X-Anit-Forge-Code': X_Anti_Forge_Code,
            'X-Anit-Forge-Token': X_Anti_Forge_Token,
            'X-Requested-With': 'XMLHttpRequest'
        },
        data={
            "isValidate": True,
            'username': '15131255089',
            'password': 'ab18d270d7126ea65915c50288c22c0d',
            'request_form_verifyCode': '',
            'submit': ''
        },
        cookies=r1.cookies.get_dict()
    )
    print(r2.text)
    拉勾网
    拉勾

     拉勾详细参考

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  • 原文地址:https://www.cnblogs.com/yanjidong/p/13296040.html
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