Python之爬虫-- js加密（破解有道词典加密的算法）

js加密

• 有的反爬虫策略采用js对需要传输的数据进行加密处理（通常是取md5值)
• 经过加密，传输的就是密文，但是
• 加密函数或者过程一定是在浏览器完成，也就是一定会把代码（js代码）暴露给使用者
• 通过阅读加密算法，就可以模拟出加密过程，从而达到破解
• 过程参看案例1, 案例2
• 过程比较啰嗦，笔记比较少，仔细观察

案例1： 

'''
破解有道词典
V1
'''

from urllib import request, parse


def youdao(key):

    url = "http://fanyi.youdao.com/translate_o?smartresult=dict&smartresult=rule"

    data = {
        "i": "boy",
        "from":"AUTO",
        "to": "AUTO",
        "smartresult": "dict",
        "client": "fanyideskweb",
        "salt": "1523100789519",
        "sign": "b8a55a436686cd89873fa46514ccedbe",
        "doctype": "json",
        "version": "2.1",
        "keyfrom": "fanyi.web",
        "action":"FY_BY_REALTIME",
        "typoResult": "false"
    }

    # 参数data需要是bytes格式
    data = parse.urlencode(data).encode()

    headers = {
                  "Accept": "application/json,text/javascript,*/*;q=0.01",
                  #"Accept-Encoding": "gzip,deflate",
                  "Accept-Language": "zh-CN,zh;q=0.9",
                  "Connection": "keep-alive",
                  "Content-Length": "200",
                  "Content-Type": "application/x-www-form-urlencoded;charset=UTF-8",
                  "Cookie": "[email protected];JSESSIONID=aaaTLWzfvp5Hfg9mAhFkw;OUTFOX_SEARCH_USER_ID_NCOO=1999296830.4784973;___rl__test__cookies=1523100789517",
                  "Host": "fanyi.youdao.com",
                  "Origin": "http://fanyi.youdao.com",
                  "Referer": "http://fanyi.youdao.com/",
                  "User-Agent": "Mozilla/5.0( X11; Linux x86_64) AppleWebKit/537.36(KHTML, like Gecko) Chrome/64.0.3282.119 Safari/537.36 X-Requested-With: XMLHttpRequest"
    }

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

    rsp = request.urlopen(req)

    html = rsp.read().decode()
    print(html)

if __name__ == '__main__':
    youdao("boy")

案例2： 

'''
V2
处理js加密代码
'''

'''
通过查找，能找到js代码中操作代码
1. 这个是计算salt的公式 r = "" + ((new Date).getTime() + parseInt(10 * Math.random(), 10));
2. sign: n.md5("fanyideskweb" + t + r + "ebSeFb%=XZ%T[KZ)c(sy!");
md5一共需要四个参数，第一个和第四个都是固定值的字符串，第三个是所谓的salt，第二个是。。。。。
第二个参数就是输入的要查找的单词

'''

#得到盐
def getSalt():
    '''
    salt公式是：  "" + ((new Date).getTime() + parseInt(10 * Math.random(), 10));
    把他翻译成python代码
    :return:
    '''
    import time, random
	#通过对js代码查找，然后把盐的公式中的两项在浏览器的F12状态下console中运行查找结果，然后用Python代码替换(他们的结果相同)
    salt = int(time.time()*1000) + random.randint(0,10)

    return salt
#得到md5值
def getMD5(v):
    import hashlib
	#生成md5实例
    md5 = hashlib.md5()

    # update需要一共bytes格式的参数
    md5.update(v.encode("utf-8"))

    sign = md5.hexdigest()

    return sign


def getSign(key, salt):

    sign = 'fanyideskweb'+ key + str(salt) + "ebSeFb%=XZ%T[KZ)c(sy!"
    sign = getMD5(sign)

    return sign

from urllib import request, parse


def youdao(key):

    url = "http://fanyi.youdao.com/translate_o?smartresult=dict&smartresult=rule"
	#要确定多个地方是同一个盐
    salt = getSalt()

    data = {
        "i": key,
        "from":"AUTO",
        "to": "AUTO",
        "smartresult": "dict",
        "client": "fanyideskweb",
        "salt": str(salt) ,
        "sign": getSign(key, salt),
        "doctype": "json",
        "version": "2.1",
        "keyfrom": "fanyi.web",
        "action":"FY_BY_REALTIME",
        "typoResult": "false"
    }

    print(data)

    # 参数data需要是bytes格式
    data = parse.urlencode(data).encode()

    headers = {
        "Accept": "application/json,text/javascript,*/*;q=0.01",
        #"Accept-Encoding": "gzip,deflate",
        "Accept-Language": "zh-CN,zh;q=0.9",
        "Connection": "keep-alive",
        "Content-Length": len(data),
        "Content-Type": "application/x-www-form-urlencoded;charset=UTF-8",
        "Cookie": "[email protected];JSESSIONID=aaaTLWzfvp5Hfg9mAhFkw;OUTFOX_SEARCH_USER_ID_NCOO=1999296830.4784973;___rl__test__cookies=1523100789517",
        "Host": "fanyi.youdao.com",
        "Origin": "http://fanyi.youdao.com",
        "Referer": "http://fanyi.youdao.com/",
        "User-Agent": "Mozilla/5.0( X11; Linux x86_64) AppleWebKit/537.36(KHTML, like Gecko) Chrome/64.0.3282.119 Safari/537.36 X-Requested-With: XMLHttpRequest"
    }

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

    rsp = request.urlopen(req)

    html = rsp.read().decode()
    print(html)

if __name__ == '__main__':
    youdao("boy")