Python爬虫使用PyV8执行js代码

前言

这是一个奇葩的需求,爬虫去好好的爬数据不就行了,解析js干嘛?吃饱了撑的?

搜索一下互联网上关于这个问题还真不少,但是大多数童鞋是因为自己的js基础太烂,要么是HTML基础烂,要么ajax基础烂,反正各方面都很烂。基础这么渣不好好去学基础写什么爬虫?

那你肯定要问了“请问我的朋友,你TM怎么也有这个需求?莫非你是个技术渣?”

非也非也,博主作为一个拥有3年多前端经验的攻城尸,怎么会被这个问题给难倒呢,老夫今天遇到的问题很显然没有那么简单。

问题

那么博主到底是遇到什么问题了呢?

博主今天要去爬一个接口,但是调用那个接口需要带上令牌,也就是存储在Cookie中的一个类似token的东西,Cookie的值是一段js生成的,这段js又是通过另外一个接口获取回来的,而获取回来的js代码还是动态的,WTF!!!开发人员你这是 弄撒嘞?

路人甲:我擦嘞,声称经验老道的博主不会分析js的逻辑?

对,我就是不会,特么的js代码都是混淆加密的,眼睛都看瞎了都特么不知道写的都是写啥?

算了,我直接执行拿到结果就好了,管他写的是什么鬼。

思路

理一理思路,现在要做的事情其实很简单

  1. 请求接口A,拿到动态生成的混淆过的js代码
  2. 执行js代码,拿到生成的cookie值
  3. 请求接口B,带上js生成的令牌
  4. 拿到结果,愉快的玩耍...

思路相当的清晰,感觉秒秒钟就可以实现了呢。(

难题

Python里面执行js?有点意思,我干嘛不用nodejs呢?

因为Python是世界上最屌的语言啊!没有之一!

找到了PyV8这个神奇的模块,机器已经有了pip,执行安装一下不就OK了?

pip install pyv8
不要怀疑,博主机器装的是 Kali Linux ,Root 权限,不需要 sudo

接着报错

pip install -U PyV8
Collecting PyV8
  Using cached PyV8-0.5.zip
Building wheels for collected packages: PyV8
  Running setup.py bdist_wheel for PyV8 ... error
  Complete output from command /usr/bin/python -u -c "import setuptools, tokenize;__file__='/tmp/pip-build-QUm4bX/PyV8/setup.py';exec(compile(getattr(tokenize, 'open', open)(__file__).read().replace('\r\n', '\n'), __file__, 'exec'))" bdist_wheel -d /tmp/tmpb0udlepip-wheel- --python-tag cp27:
  running bdist_wheel
  running build
  running build_py
  creating build
  creating build/lib.linux-x86_64-2.7
  copying PyV8.py -> build/lib.linux-x86_64-2.7
  running build_ext
  building '_PyV8' extension
  creating build/temp.linux-x86_64-2.7
  creating build/temp.linux-x86_64-2.7/src
  x86_64-linux-gnu-gcc -pthread -DNDEBUG -g -fwrapv -O2 -Wall -Wstrict-prototypes -fno-strict-aliasing -Wdate-time -D_FORTIFY_SOURCE=2 -g -fdebug-prefix-map=/build/python2.7-cFt4xx/python2.7-2.7.12=. -fstack-protector-strong -Wformat -Werror=format-security -fPIC -DBOOST_PYTHON_STATIC_LIB -Ilib/python/inc -Ilib/boost/inc -Ilib/v8/inc -I/usr/include/python2.7 -c src/Exception.cpp -o build/temp.linux-x86_64-2.7/src/Exception.o
  cc1plus: warning: command line option ‘-Wstrict-prototypes’ is valid for C/ObjC but not for C++
  In file included from src/Exception.cpp:1:0:
  src/Exception.h:6:16: fatal error: v8.h: 没有那个文件或目录
   #include <v8.h>
                  ^
  compilation terminated.
  error: command 'x86_64-linux-gnu-gcc' failed with exit status 1
  
  ----------------------------------------
  Failed building wheel for PyV8
  Running setup.py clean for PyV8
Failed to build PyV8
Installing collected packages: PyV8
  Running setup.py install for PyV8 ... error
    Complete output from command /usr/bin/python -u -c "import setuptools, tokenize;__file__='/tmp/pip-build-QUm4bX/PyV8/setup.py';exec(compile(getattr(tokenize, 'open', open)(__file__).read().replace('\r\n', '\n'), __file__, 'exec'))" install --record /tmp/pip-7OAwUa-record/install-record.txt --single-version-externally-managed --compile:
    running install
    running build
    running build_py
    creating build
    creating build/lib.linux-x86_64-2.7
    copying PyV8.py -> build/lib.linux-x86_64-2.7
    running build_ext
    building '_PyV8' extension
    creating build/temp.linux-x86_64-2.7
    creating build/temp.linux-x86_64-2.7/src
    x86_64-linux-gnu-gcc -pthread -DNDEBUG -g -fwrapv -O2 -Wall -Wstrict-prototypes -fno-strict-aliasing -Wdate-time -D_FORTIFY_SOURCE=2 -g -fdebug-prefix-map=/build/python2.7-cFt4xx/python2.7-2.7.12=. -fstack-protector-strong -Wformat -Werror=format-security -fPIC -DBOOST_PYTHON_STATIC_LIB -Ilib/python/inc -Ilib/boost/inc -Ilib/v8/inc -I/usr/include/python2.7 -c src/Exception.cpp -o build/temp.linux-x86_64-2.7/src/Exception.o
    cc1plus: warning: command line option ‘-Wstrict-prototypes’ is valid for C/ObjC but not for C++
    In file included from src/Exception.cpp:1:0:
    src/Exception.h:6:16: fatal error: v8.h: 没有那个文件或目录
     #include <v8.h>
                    ^
    compilation terminated.
    error: command 'x86_64-linux-gnu-gcc' failed with exit status 1
    
    ----------------------------------------
Command "/usr/bin/python -u -c "import setuptools, tokenize;__file__='/tmp/pip-build-QUm4bX/PyV8/setup.py';exec(compile(getattr(tokenize, 'open', open)(__file__).read().replace('\r\n', '\n'), __file__, 'exec'))" install --record /tmp/pip-7OAwUa-record/install-record.txt --single-version-externally-managed --compile" failed with error code 1 in /tmp/pip-build-QUm4bX/PyV8/
似乎是因为缺少 v8.h 这个文件导致的,可是又看不懂啥意思。

解决

通过搜索引擎找到了解决方案,原来是因为 PyV8 依赖于Boost ,然而这个问题官方并没有说,所以得先安装下这个包

apt-get update && apt-get install libboost-all-dev
安装完成之后继续安装 PyV8 ,依然是上面同样的问题,看来只能手动来了。

下载 https://github.com/emmetio/pyv8-binaries

解压并选择合适自己系统环境的文件,再次解压 并把解压得到的文件复制到

/usr/lib/python2.7/dist-packages/
里面去,然后测试看是否成功,终端执行
python
import PyV8

如果没有报错,那就成功了,开始愉快的玩耍,下面是我需要解析的js代码

var l = [119, 98, 115, 33, 111, 109, 120, 105, 118, 62, 92, 50, 50, 54, 45, 50, 50, 51, 45, 50, 50, 55, 45, 50, 49, 58, 45, 50, 50, 49, 45, 50, 51, 51, 45, 50, 50, 52, 45, 50, 50, 51, 45, 50, 50, 54, 45, 50, 49, 55, 45, 50, 49, 58, 45, 50, 49, 50, 45, 50, 50, 54, 45, 50, 50, 58, 45, 50, 50, 49, 45, 50, 50, 51, 45, 50, 50, 58, 45, 50, 51, 51, 45, 50, 50, 58, 45, 50, 50, 55, 45, 50, 50, 54, 45, 50, 50, 54, 94, 60, 119, 98, 115, 33, 121, 119, 99, 100, 108, 62, 92, 49, 45, 51, 50, 45, 53, 45, 55, 45, 50, 50, 45, 57, 45, 56, 45, 50, 51, 45, 51, 45, 51, 49, 45, 50, 52, 45, 50, 54, 45, 50, 49, 45, 50, 57, 45, 52, 45, 58, 45, 50, 53, 45, 50, 56, 45, 54, 45, 50, 55, 45, 50, 58, 45, 50, 94, 60, 119, 98, 115, 33, 118, 62, 35, 35, 60, 103, 112, 115, 33, 41, 119, 62, 49, 60, 119, 61, 121, 119, 99, 100, 108, 47, 109, 102, 111, 104, 117, 105, 60, 119, 44, 44, 42, 124, 118, 44, 62, 84, 117, 115, 106, 111, 104, 47, 103, 115, 112, 110, 68, 105, 98, 115, 68, 112, 101, 102, 41, 111, 109, 120, 105, 118, 92, 121, 119, 99, 100, 108, 92, 119, 94, 94, 42, 126, 60, 37, 47, 100, 112, 112, 108, 106, 102, 41, 40, 114, 117, 112, 108, 102, 111, 40, 45, 118, 45, 124, 113, 98, 117, 105, 59, 40, 48, 40, 126, 42, 60];
eval(function(p, a, c, k, e, d) {
	e = function(c) {
		return (c < a ? "" : e(parseInt(c / a))) + ((c = c % a) > 35 ? String.fromCharCode(c + 29) : c.toString(36))
	};
	if (!''.replace(/^/, String)) {
		while (c--) d[e(c)] = k[c] || e(c);
		k = [function(e) {
			return d[e]
		}];
		e = function() {
			return '\\w+'
		};
		c = 1
	};
	while (c--) if (k[c]) p = p.replace(new RegExp('\\b' + e(c) + '\\b', 'g'), k[c]);
	return p
}('6 3=\'\';7(2=0;2<4.5;2++){3+=8.a(4[2]-1)};9(3)', 11, 11, '||i|t|l|length|var|for|String|eval|fromCharCode'.split('|'), 0, {}))

已经经过整理,其实刚开始就只有一行,比较尴尬

姿势

折腾的过程可谓是各种曲折,不过也学到了不少姿势,比如,如何把混淆的js还原成原始代码

使用Firebug插件就能轻松解决这个问题,打开firebug插件,找到脚本选项,选择带 eval 的项,一般解析到最后一行就是原始代码了,我上面的那段 js 还原之后就便成了这个样子

var balwi=[115,116,115,122,112,115,110,106,122,110,122,112,101,119,115,106,113,101,116,116,119,106];var ljpry=[15,21,4,9,12,14,11,0,18,20,8,16,7,2,1,10,17,13,19,6,5,3];var j="";for (k=0;k<ljpry.length;k++){j+=String.fromCharCode(balwi[ljpry[k]])};$.cookie('qtoken',j,{path:'/'});
稍微整理一下得到一个格式清晰的代码
var balwi = [115, 116, 115, 122, 112, 115, 110, 106, 122, 110, 122, 112, 101, 119, 115, 106, 113, 101, 116, 116, 119, 106];
var ljpry = [15, 21, 4, 9, 12, 14, 11, 0, 18, 20, 8, 16, 7, 2, 1, 10, 17, 13, 19, 6, 5, 3];
var j = "";
for (k = 0; k < ljpry.length; k++) {
	j += String.fromCharCode(balwi[ljpry[k]])
};
$.cookie('qtoken', j, {
	path: '/'
});

有了原始代码就很容易得到令牌的生成算法,使用Python生成,这回不用麻烦 PyV8 大神出马了。

参考

http://blog.tomsheep.net/2011/08/07/pyv8/

如果您觉得文章有帮助到您,请到 https://www.92ez.com/index.php?action=show&id=23403 进行打赏/捐赠,谢谢!
如果您觉得文章有帮助到您,请 使劲戳这里 进行打赏/捐赠,谢谢!
本文链接:https://www.92ez.com/?action=show&id=23406
提示:技术文章有一定的时效性,请先确认是否适用你当前的系统环境。

上一篇: 使用Python管理小米路由器
下一篇: CentOS 7 for ARM 上手测试

访客评论
目前还没有人评论,您发表点看法?
发表评论

评论内容 (必填):