爬虫前奏,带你感受爬虫

Posted 琪齐

tags:

篇首语:本文由小常识网(cha138.com)小编为大家整理,主要介绍了爬虫前奏,带你感受爬虫相关的知识,希望对你有一定的参考价值。

爬虫

网络爬虫(又被称为网页蜘蛛,网络机器人,在FOAF社区中间,更经常的称为网页追逐者),是一种按照一定的规则,自动地抓取万维网信息的程序或者脚本。

另外一些不常使用的名字还有蚂蚁、自动索引、模拟程序或者蠕虫。大概知道什么是爬虫了吧,那就带你看看它的好玩之处。

Requests

在带进爬虫的世界中之前那肯定是要一一系列的准备工作了,首先就是requests这个模块喽。言归正传......

Python标准库中提供了:urllib、urllib2、httplib等模块以供Http请求,但是,它的 API 太渣了。它是为另一个时代、另一个互联网所创建的。

它需要巨量的工作,甚至包括各种方法覆盖,来完成最简单的任务。

import urllib2
import json
import cookielib


def urllib2_request(url, method="GET", cookie="", headers={}, data=None):
    """
    :param url: 要请求的url
    :param cookie: 请求方式,GET、POST、DELETE、PUT..
    :param cookie: 要传入的cookie,cookie= \'k1=v1;k1=v2\'
    :param headers: 发送数据时携带的请求头,headers = {\'ContentType\':\'application/json; charset=UTF-8\'}
    :param data: 要发送的数据GET方式需要传入参数,data={\'d1\': \'v1\'}
    :return: 返回元祖,响应的字符串内容 和 cookiejar对象
    对于cookiejar对象,可以使用for循环访问:
        for item in cookiejar:
            print item.name,item.value
    """
    if data:
        data = json.dumps(data)

    cookie_jar = cookielib.CookieJar()
    handler = urllib2.HTTPCookieProcessor(cookie_jar)
    opener = urllib2.build_opener(handler)
    opener.addheaders.append([\'Cookie\', \'k1=v1;k1=v2\'])
    request = urllib2.Request(url=url, data=data, headers=headers)
    request.get_method = lambda: method

    response = opener.open(request)
    origin = response.read()

    return origin, cookie_jar


# GET
result = urllib2_request(\'http://127.0.0.1:8001/index/\', method="GET")

# POST
result = urllib2_request(\'http://127.0.0.1:8001/index/\',  method="POST", data= {\'k1\': \'v1\'})

# PUT
result = urllib2_request(\'http://127.0.0.1:8001/index/\',  method="PUT", data= {\'k1\': \'v1\'})
封装urllib请求

 

Requests 是使用 Apache2 Licensed 许可证的 基于Python开发的HTTP 库,其在Python内置模块的基础上进行了高度的封装,从而使得Pythoner进行网络请求时,

变得美好了许多,使用Requests可以轻而易举的完成浏览器可有的任何操作。

  1、GET请求

# 1、无参数实例
 
import requests
 
ret = requests.get(\'https://github.com/timeline.json\')
 
print ret.url
print ret.text
 
 
# 2、有参数实例
 
import requests
 
payload = {\'key1\': \'value1\', \'key2\': \'value2\'}
ret = requests.get("http://httpbin.org/get", params=payload)
 
print ret.url
print ret.text

向 https://github.com/timeline.json 发送一个GET请求,将请求和响应相关均封装在 ret 对象中。

  2、POST请求

# 1、基本POST实例
 
import requests
 
payload = {\'key1\': \'value1\', \'key2\': \'value2\'}
ret = requests.post("http://httpbin.org/post", data=payload)
 
print ret.text
 
 
# 2、发送请求头和数据实例
 
import requests
import json
 
url = \'https://api.github.com/some/endpoint\'
payload = {\'some\': \'data\'}
headers = {\'content-type\': \'application/json\'}
 
ret = requests.post(url, data=json.dumps(payload), headers=headers)
 
print ret.text
print ret.cookies

向https://api.github.com/some/endpoint发送一个POST请求,将请求和相应相关的内容封装在 ret 对象中。

  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)

requests模块已经将常用的Http请求方法为用户封装完成,用户直接调用其提供的相应方法即可。

def request(method, url, **kwargs):
    """Constructs and sends a :class:`Request <Request>`.

    :param method: method for the new :class:`Request` object.
    :param url: URL for the new :class:`Request` object.
    :param params: (optional) Dictionary or bytes to be sent in the query string for the :class:`Request`.
    :param data: (optional) Dictionary, bytes, or file-like object to send in the body of the :class:`Request`.
    :param json: (optional) json data to send in the body of the :class:`Request`.
    :param headers: (optional) Dictionary of HTTP Headers to send with the :class:`Request`.
    :param cookies: (optional) Dict or CookieJar object to send with the :class:`Request`.
    :param files: (optional) Dictionary of ``\'name\': file-like-objects`` (or ``{\'name\': (\'filename\', fileobj)}``) for multipart encoding upload.
    :param auth: (optional) Auth tuple to enable Basic/Digest/Custom HTTP Auth.
    :param timeout: (optional) How long to wait for the server to send data
        before giving up, as a float, or a :ref:`(connect timeout, read
        timeout) <timeouts>` tuple.
    :type timeout: float or tuple
    :param allow_redirects: (optional) Boolean. Set to True if POST/PUT/DELETE redirect following is allowed.
    :type allow_redirects: bool
    :param proxies: (optional) Dictionary mapping protocol to the URL of the proxy.
    :param verify: (optional) whether the SSL cert will be verified. A CA_BUNDLE path can also be provided. Defaults to ``True``.
    :param stream: (optional) if ``False``, the response content will be immediately downloaded.
    :param cert: (optional) if String, path to ssl client cert file (.pem). If Tuple, (\'cert\', \'key\') pair.
    :return: :class:`Response <Response>` object
    :rtype: requests.Response

    Usage::

      >>> import requests
      >>> req = requests.request(\'GET\', \'http://httpbin.org/get\')
      <Response [200]>
    """

    # By using the \'with\' statement we are sure the session is closed, thus we
    # avoid leaving sockets open which can trigger a ResourceWarning in some
    # cases, and look like a memory leak in others.
    with sessions.Session() as session:
        return session.request(method=method, url=url, **kwargs)
更多参数

如果这些还不能满足你,更多requests模块相关的文档见:http://cn.python-requests.org/zh_CN/latest/

 

自动登陆抽屉并点赞

 感受下不在抽屉登录页面登录,自己写脚本来实现登录效果,并且可以点赞的那种小过瘾。

### 1、首先登陆任何页面,获取cookie
 
i1 = requests.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 = requests.post(
    url= "http://dig.chouti.com/login",
    data= {
        \'phone\': "86手机号",
        \'password\': "密码",
        \'oneMonth\': ""
    },
    cookies = i1.cookies.get_dict()
)
 
### 3、点赞(只需要携带已经被授权的gpsd即可)
gpsd = i1.cookies.get_dict()[\'gpsd\']
i3 = requests.post(
    url="http://dig.chouti.com/link/vote?linksId=8589523",
    cookies={\'gpsd\': gpsd}
)
print(i3.text)

 

“破解”微信公众号

 上面的是不是有点意思,那就在来点刺激的。我们来“破解”微信公众号。是不是期待...

“破解”微信公众号其实就是使用Python代码自动实现【登陆公众号】->【获取观众用户】-> 【向关注用户发送消息】。

注:只能向48小时内有互动的粉丝主动推送消息

   1、自动登陆

分析对于web登录页面,用户验证时做的操作:

①登陆的URL:https://mp.weixin.qq.com/cgi-bin/login?lang=zh_CN

②POST的数据为:

    {
         \'username\': 用户名,
         \'pwd\': 密码的MD5值,
         \'imgcode\': "", 
         \'f\': \'json\'
    }

③POST的请求头的Referer值,微信后台用次来检查是谁发送来的请求

④请求发送并登陆成功后,获取用户响应的cookie,以后操作其他页面时需要携带此cookie 

⑤请求发送并登陆成功后,获取用户相应的内容中的token

# -*- coding:utf-8 -*- 
import requests
import time
import hashlib


def _password(pwd):
    ha = hashlib.md5()
    ha.update(pwd)
    return ha.hexdigest()

def login():
    
    login_dict = {
        \'username\': "用户名",
        \'pwd\': _password("密码"),
        \'imgcode\': "",
        \'f\': \'json\'
    }

    login_res = requests.post(
        url= "https://mp.weixin.qq.com/cgi-bin/login?lang=zh_CN",
        data=login_dict,
        headers={\'Referer\': \'https://mp.weixin.qq.com/cgi-bin/login?lang=zh_CN\'})

    # 登陆成功之后获取服务器响应的cookie
    resp_cookies_dict = login_res.cookies.get_dict()
    # 登陆成功后,获取服务器响应的内容
    resp_text = login_res.text
    # 登陆成功后,获取token
    token = re.findall(".*token=(\\d+)", resp_text)[0]

    print resp_text
    print token
    print resp_cookies_dict

login()
登录代码

 

 登陆成功获取的相应内容如下:

响应内容:
{"base_resp":{"ret":0,"err_msg":"ok"},"redirect_url":"\\/cgi-bin\\/home?t=home\\/index&lang=zh_CN&token=537908795"}
 
响应cookie:
{\'data_bizuin\': \'3016804678\', \'bizuin\': \'3016804678\', \'data_ticket\': \'CaoX+QA0ZA9LRZ4YM3zZkvedyCY8mZi0XlLonPwvBGkX0/jY/FZgmGTq6xGuQk4H\', \'slave_user\': \'gh_5abeaed48d10\', \'slave_sid\': \'elNLbU1TZHRPWDNXSWdNc2FjckUxalM0Y000amtTamlJOUliSnRnWGRCdjFseV9uQkl5cUpHYkxqaGJNcERtYnM2WjdFT1pQckNwMFNfUW5fUzVZZnFlWGpSRFlVRF9obThtZlBwYnRIVGt6cnNGbUJsNTNIdTlIc2JJU29QM2FPaHZjcTcya0F6UWRhQkhO\'}

  2、获取信息

访问其他页面获取用户信息

分析用户管理页面,通过Pyhton代码以Get方式访问此页面,分析响应到的 html 代码,

从中获取用户信息:

①获取用户的URL:https://mp.weixin.qq.com/cgi-bin/user_tag?action=get_all_data&lang=zh_CN&token=登陆时获取的token

②发送GET请求时,需要携带登陆成功后获取的cookie

{\'data_bizuin\': \'3016804678\', \'bizuin\': \'3016804678\', \'data_ticket\': \'C4YM3zZ...

③获取当前请求的响应的html代码

④通过正则表达式获取html中的指定内容(Python的模块Beautiful Soup)

⑤获取html中每个用户的 data-fakeid属性,该值是用户的唯一标识,通过它可向用户推送消息

 

# -*- coding:utf-8 -*- 
import requests
import time
import hashlib
import json
import re

LOGIN_COOKIES_DICT = {}

def _password(pwd):
    ha = hashlib.md5()
    ha.update(pwd)
    return ha.hexdigest()

def login():
    
    login_dict = {
        \'username\': "用户名",
        \'pwd\': _password("密码"),
        \'imgcode\': "",
        \'f\': \'json\'
    }

    login_res = requests.post(
        url= "https://mp.weixin.qq.com/cgi-bin/login?lang=zh_CN",
        data=login_dict,
        headers={\'Referer\': \'https://mp.weixin.qq.com/cgi-bin/login?lang=zh_CN\'})

    # 登陆成功之后获取服务器响应的cookie
    resp_cookies_dict = login_res.cookies.get_dict()
    # 登陆成功后,获取服务器响应的内容
    resp_text = login_res.text
    # 登陆成功后,获取token
    token = re.findall(".*token=(\\d+)", resp_text)[0]

    return {\'token\': token, \'cookies\': resp_cookies_dict}


def standard_user_list(content):
    content = re.sub(\'\\s*\', \'\', content)
    content = re.sub(\'\\n*\', \'\', content)
    data = re.findall("""cgiData=(.*);seajs""", content)[0]
    data = data.strip()
    while True:
        temp = re.split(\'({)(\\w+)(:)\', data, 1)
        if len(temp) == 5:
            temp[2] = \'"\' + temp[2] + \'"\'
            data = \'\'.join(temp)
        else:
            break

    while True:
        temp = re.split(\'(,)(\\w+)(:)\', data, 1)
        if len(temp) == 5:
            temp[2] = \'"\' + temp[2] + \'"\'
            data = \'\'.join(temp)
        else:
            break

    data = re.sub(\'\\*\\d+\', "", data)
    ret = json.loads(data)
    return ret


def get_user_list():

    login_dict = login()
    LOGIN_COOKIES_DICT.update(login_dict)

    login_cookie_dict = login_dict[\'cookies\']
    res_user_list = requests.get(
        url= "https://mp.weixin.qq.com/cgi-bin/user_tag",
        params = {"action": "get_all_data", "lang": "zh_CN", "token": login_dict[\'token\']},
        cookies = login_cookie_dict,
        headers={\'Referer\': \'https://mp.weixin.qq.com/cgi-bin/login?lang=zh_CN\'}
    )
    user_info = standard_user_list(res_user_list.text)
    for item in user_info[\'user_list\']:
        print "%s %s " % (item[\'nick_name\'],item[\'id\'],)
    
get_user_list()

  3、发送消息

分析给用户发送消息的页面,从网络请求中剖析得到发送消息的URL,从而使用Python代码发送消息:

①发送消息的URL:https://mp.weixin.qq.com/cgi-bin/singlesend?t=ajax-response&f=json&token=登陆时获取的token放在此处&lang=zh_CN

②从登陆时相应的内容中获取:token和cookie

③从用户列表中获取某个用户唯一标识: fake_id

④封装消息,并发送POST请求

send_dict = {
    \'token\': 登陆时获取的token,
    \'lang\': "zh_CN",
    \'f\': \'json\',
    \'ajax\': 1,
    \'random\': "0.5322618900912392",
    \'type\': 1,
    \'content\': 要发送的内容,
    \'tofakeid\': 用户列表中获取的用户的ID,
    \'imgcode\': \'\'
}
# -*- coding:utf-8 -*- 
import requests
import time
import hashlib
import json
import re

LOGIN_COOKIES_DICT = {}

def _password(pwd):
    ha = hashlib.md5()
    ha.update(pwd)
    return ha.hexdigest()

def login():
    
    login_dict = {
        \'username\': "用户名",
        \'pwd\': _password("密码"),
        \'imgcode\': "",
        \'f\': \'json\'
    }

    login_res = requests.post(
        url= "https://mp.weixin.qq.com/cgi-bin/login?lang=zh_CN",
        data=login_dict,
        headers={\'Referer\': \'https://mp.weixin.qq.com/cgi-bin/login?lang=zh_CN\'})

    # 登陆成功之后获取服务器响应的cookie
    resp_cookies_dict = login_res.cookies.get_dict()
    # 登陆成功后,获取服务器响应的内容
    resp_text = login_res.text
    # 登陆成功后,获取token
    token = re.findall(".*token=(\\d+)", resp_text)[0]

    return {\'token\': token, \'cookies\': resp_cookies_dict}


def standard_user_list(content):
    content = re.sub(\'\\s*\', \'\', content)
    content = re.sub(\'\\n*\', \'\', content)
    data = re.findall("""cgiData=(.*);seajs""", content)[0]
    data = data.strip()
    while True:
        temp = re.split(\'({)(\\w+)(:)\', data, 1)
        if len(temp) == 5:
            temp[2] = \'"\' + temp[2] + \'"\'
            data = \'\'.join(temp)
        else:
            break

    while True:
        temp = re.split(\'(,)(\\w+)(:)\', data, 1)
        if len(temp) == 5:
            temp[2] = \'"\' + temp[2] + \'"\'
            data = \'\'.join(temp)
        else:
            break

    data = re.sub(\'\\*\\d+\', "", data)
    ret = json.loads(data)
    return ret


def get_user_list():

    login_dict = login()
    LOGIN_COOKIES_DICT.update(login_dict)

    login_cookie_dict = login_dict[\'cookies\']
    res_user_list = requests.get(
        url= "https://mp.weixin.qq.com/cgi-bin/user_tag",
        params = {"action": "get_all_data", "lang": "zh_CN", "token": login_dict[\'token\']},
        cookies = login_cookie_dict,
        headers={\'Referer\': \'https://mp.weixin.qq.com/cgi-bin/login?lang=zh_CN\'}
    )
    user_info = standard_user_list(res_user_list.text)
    for item in user_info[\'user_list\']:
        print "%s %s " % (item[\'nick_name\'],item[\'id\'],)
    

def send_msg(user_fake_id, content=\'啥也没发\'):

    login_dict = LOGIN_COOKIES_DICT
    
    token = login_dict[\'token\']
    login_cookie_dict = login_dict[\'cookies\']

    send_dict = {
        \'token\': token,
        \'lang\': "zh_CN",
        \'f\': \'json\',
        \'ajax\': 1,
        \'random\': "0.5322618900912392",
        \'type\': 1,
        \'content\': content,
        \'tofakeid\': user_fake_id,
        \'imgcode\': \'\'
    }
   
    send_url = "https://mp.weixin.qq.com/cgi-bin/singlesend?t=ajax-response&f=json&token=%s&lang=zh_CN" % (token,)
    message_list = requests.post(
        url=send_url, 
        data=send_dict, 
        cookies=login_cookie_dict, 
        headers={\'Referer\': \'https://mp.weixin.qq.com/cgi-bin/login?lang=zh_CN\'}
    )


get_user_list()
fake_id = raw_input(\'请输入用户ID:\')
content = raw_input(\'请输入消息内容:\')
send_msg(fake_id, content)
放送消息代码

 

以上就是“破解”微信公众号的整个过程,通过Python代码实现了自动【登陆微信公众号平台】【获取用户列表】【指定用户发送消息】。

有没有一点点“黑客”的赶脚,是不是迫不及待的想去尝试了...

 上面的代码可能比较分散,直接上源码把:猛击

想要学习更多的爬虫后续的更新在:http://www.cnblogs.com/kongqi816-boke/p/5827243.html

有意想不到的呦。

 

 如果还不能满足你的求知欲望,还有更多详见:http://www.cnblogs.com/wupeiqi/articles/5354900.html

以上是关于爬虫前奏,带你感受爬虫的主要内容,如果未能解决你的问题,请参考以下文章

爬虫前奏

21天搞定Python分布式爬虫-知了课堂

爬虫开发前奏

网络爬虫前奏:HTTP的请求与响应

带你玩转模型法线,实验一下大胆的想法(法线贴图 | shader | Unity | python | 爬虫)

带你玩转模型法线,实验一下大胆的想法(法线贴图 | shader | Unity | python | 爬虫)