/ 技术

爬取今日头条新闻列表

今天闲着没事干,想抓点新闻内容玩玩,就盯上了今日头条。本以为很容易就能抓到的,没想到过程却如此的艰辛。

API

今日头条的首页是通过ajax的形式获取文章列表的。API地址如下:

https://www.toutiao.com/api/pc/feed/?min_behot_time=0&category=__all__&utm_source=toutiao&widen=1&tadrequire=true&as=A1C57B62EFC6465&cp=5B2F660476957E1&_signature=GsVHahAaQe6ls7aMnisgwhrFR3
  1. 参数

乍一看参数还挺多,打开Postman贴入地址,尝试精简一下未知请求参数,发现ascp两个参数是可以去掉不要的,那么未知参数就只剩下_signature,一开始以为这个参数是csrf_token,于是找遍了网页源码也没发现这个参数的值,说明并不是csrf_token,猜不到的时候,就全局搜索一下吧,也没有搜到这个参数的值。那就搜搜参数名吧,结果找到了,在index.js里面发现了这个参数名,看了一下它的值生成的代码如下:

var e = (0, p.default)() , i = 0;
this.url = this._url, "refresh" === t ? (i = this.list.length > 0 ? this.list[0].behot_time : 0, this.url += "min_behot_time=" + i) : (i = this.list.length > 0 ? this.list[this.list.length - 1].behot_time : 0, this.url += "max_behot_time=" + i);
var n = (0,
    v.sign)(i + "");
(0,
    a.default)(this.params, {
    as: e.as,
    cp: e.cp,
    _signature: n
})

原来_signature是用js生成的一段加密字符串,调用了v.sign方法,参数就一个,就是min_behot_time的值。再看看v.sign方法代码吧,结果费劲找了半天就是找不着,js混淆真的是很蛋疼,偏偏就欺负我这种不玩前端的人。咱们看看别的分类吧,也许能找到点有用的。于是我选了科技分类,确实发现了不一样的东西。加密代码写在home.js里面
API请求是

https://www.toutiao.com/api/pc/feed/?category=news_tech&utm_source=toutiao&widen=1&max_behot_time=0&max_behot_time_tmp=0&tadrequire=true&as=A1A5AB324FB69A3&cp=5B2F16B93AA36E1&_signature=mozFvQAAwa8l-jRbqxd7QZqMxa
function e(t) {
        var e = ascp.getHoney()
          , i = "";
        window.TAC && (i = TAC.sign("refresh" === t ? 0 : r.params.max_behot_time_tmp)),
        r.params = _.extend({}, r.params, {
            as: e.as,
            cp: e.cp,
            max_behot_time: "refresh" === t ? 0 : r.params.max_behot_time_tmp,
            _signature: i
        })
    }

就是说调用了这个TAC.sign方法,参数是max_behot_time_tmp或者0,再看看TAC的源码,有点长:

Function(function(t) {
        return 'e(e,a,r){(b[e]||(b[e]=t("x,y","x "+e+" y")(r,a)}a(e,a,r){(k[r]||(k[r]=t("x,y","new x[y]("+Array(r+1).join(",x[y]")(1)+")")(e,a)}r(e,a,r){n,t,s={},b=s.d=r?r.d+1:0;for(s["$"+b]=s,t=0;t<b;t)s[n="$"+t]=r[n];for(t=0,b=s=a;t<b;t)s[t]=a[t];c(e,0,s)}c(t,b,k){u(e){v[x]=e}f{g=,ting(bg)}l{try{y=c(t,b,k)}catch(e){h=e,y=l}}for(h,y,d,g,v=[],x=0;;)switch(g=){case 1:u(!)4:f5:u((e){a=0,r=e;{c=a<r;c&&u(e[a]),c}}(6:y=,u((y8:if(g=,lg,g=,y===c)b+=g;else if(y!==l)y9:c10:u(s(11:y=,u(+y)12:for(y=f,d=[],g=0;g<y;g)d[g]=y.charCodeAt(g)^g+y;u(String.fromCharCode.apply(null,d13:y=,h=delete [y]14:59:u((g=)?(y=x,v.slice(x-=g,y:[])61:u([])62:g=,k[0]=65599*k[0]+k[1].charCodeAt(g)>>>065:h=,y=,[y]=h66:u(e(t[b],,67:y=,d=,u((g=).x===c?r(g.y,y,k):g.apply(d,y68:u(e((g=t[b])<"<"?(b--,f):g+g,,70:u(!1)71:n72:+f73:u(parseInt(f,3675:if(){bcase 74:g=<<16>>16g76:u(k[])77:y=,u([y])78:g=,u(a(v,x-=g+1,g79:g=,u(k["$"+g])81:h=,[f]=h82:u([f])83:h=,k[]=h84:!085:void 086:u(v[x-1])88:h=,y=,h,y89:u({e{r(e.y,arguments,k)}e.y=f,e.x=c,e})90:null91:h93:h=0:;default:u((g<<16>>16)-16)}}n=this,t=n.Function,s=Object.keys||(e){a={},r=0;for(c in e)a[r]=c;a=r,a},b={},k={};r'.replace(/[-]/g, function(e) {
            return t[15 & e.charCodeAt(0)]
        })
    }("v[x++]=v[--x]t.charCodeAt(b++)-32function return ))++.substrvar .length(),b+=;break;case ;break}".split("")))()('gr$Daten Иb/s!l y͒yĹg,(lfi~ah`{mv,-n|jqewVxp{rvmmx,&effkx[!cs"l".Pq%widthl"@q&heightl"vr*getContextx$"2d[!cs#l#,*;?|u.|uc{uq$fontl#vr(fillTextx$$龘ฑภ경2<[#c}l#2q*shadowBlurl#1q-shadowOffsetXl#$$limeq+shadowColorl#vr#arcx88802[%c}l#vr&strokex[ c}l"v,)}eOmyoZB]mx[ cs!0s$l$Pb<k7l l!r&lengthb%^l$1+s$jl  s#i$1ek1s$gr#tack4)zgr#tac$! +0o![#cj?o ]!l$b%s"o ]!l"l$b*b^0d#>>>s!0s%yA0s"l"l!r&lengthb<k+l"^l"1+s"jl  s&l&z0l!$ +["cs\'(0l#i\'1ps9wxb&s() &{s)/s(gr&Stringr,fromCharCodes)0s*yWl ._b&s o!])l l Jb<k$.aj;l .Tb<k$.gj/l .^b<k&i"-4j!+& s+yPo!]+s!l!l Hd>&l!l Bd>&+l!l <d>&+l!l 6d>&+l!l &+ s,y=o!o!]/q"13o!l q"10o!],l 2d>& s.{s-yMo!o!]0q"13o!]*Ld<l 4d#>>>b|s!o!l q"10o!],l!& s/yIo!o!].q"13o!],o!]*Jd<l 6d#>>>b|&o!]+l &+ s0l-l!&l-l!i\'1z141z4b/@d<l"b|&+l-l(l!b^&+l-l&zl\'g,)gk}ejo{cm,)|yn~Lij~em["cl$b%@d<l&zl\'l $ +["cl$b%b|&+l-l%8d<@b|l!b^&+ q$sign ', [TAC = {}]),

WTF...这他妈的是啥玩意

我表示这他不是欺负人嘛,完全看不懂这是个啥啊。有大神看的懂的可以告诉我,反正我是完全懵逼的。

  1. 曲线救国

既然咱们看不懂这段代码的意思,那就直接调用它吧,反正咱们知道它的参数,调用它生成_signature就好了。那么大家就会问了,我要在后端爬文章啊,怎么调用js代码啊?回答是:Node.js啊!是不是有种恍然大悟的感觉...

于是乎我们写了这样一段代码:

Function(function (t) {
    return 'e(e,a,r){(b[e]||(b[e]=t("x,y","x "+e+" y")(r,a)}a(e,a,r){(k[r]||(k[r]=t("x,y","new x[y]("+Array(r+1).join(",x[y]")(1)+")")(e,a)}r(e,a,r){n,t,s={},b=s.d=r?r.d+1:0;for(s["$"+b]=s,t=0;t<b;t)s[n="$"+t]=r[n];for(t=0,b=s=a;t<b;t)s[t]=a[t];c(e,0,s)}c(t,b,k){u(e){v[x]=e}f{g=,ting(bg)}l{try{y=c(t,b,k)}catch(e){h=e,y=l}}for(h,y,d,g,v=[],x=0;;)switch(g=){case 1:u(!)4:f5:u((e){a=0,r=e;{c=a<r;c&&u(e[a]),c}}(6:y=,u((y8:if(g=,lg,g=,y===c)b+=g;else if(y!==l)y9:c10:u(s(11:y=,u(+y)12:for(y=f,d=[],g=0;g<y;g)d[g]=y.charCodeAt(g)^g+y;u(String.fromCharCode.apply(null,d13:y=,h=delete [y]14:59:u((g=)?(y=x,v.slice(x-=g,y:[])61:u([])62:g=,k[0]=65599*k[0]+k[1].charCodeAt(g)>>>065:h=,y=,[y]=h66:u(e(t[b],,67:y=,d=,u((g=).x===c?r(g.y,y,k):g.apply(d,y68:u(e((g=t[b])<"<"?(b--,f):g+g,,70:u(!1)71:n72:+f73:u(parseInt(f,3675:if(){bcase 74:g=<<16>>16g76:u(k[])77:y=,u([y])78:g=,u(a(v,x-=g+1,g79:g=,u(k["$"+g])81:h=,[f]=h82:u([f])83:h=,k[]=h84:!085:void 086:u(v[x-1])88:h=,y=,h,y89:u({e{r(e.y,arguments,k)}e.y=f,e.x=c,e})90:null91:h93:h=0:;default:u((g<<16>>16)-16)}}n=this,t=n.Function,s=Object.keys||(e){a={},r=0;for(c in e)a[r]=c;a=r,a},b={},k={};r'.replace(/[-]/g, function (i) {
        return t[15 & i.charCodeAt(0)]
    })
}("v[x++]=v[--x]t.charCodeAt(b++)-32function return ))++.substrvar .length(),b+=;break;case ;break}".split("")))()('gr$Daten Иb/s!l y͒yĹg,(lfi~ah`{mv,-n|jqewVxp{rvmmx,&effkx[!cs"l".Pq%widthl"@q&heightl"vr*getContextx$"2d[!cs#l#,*;?|u.|uc{uq$fontl#vr(fillTextx$$龘ฑภ경2<[#c}l#2q*shadowBlurl#1q-shadowOffsetXl#$$limeq+shadowColorl#vr#arcx88802[%c}l#vr&strokex[ c}l"v,)}eOmyoZB]mx[ cs!0s$l$Pb<k7l l!r&lengthb%^l$1+s$jl  s#i$1ek1s$gr#tack4)zgr#tac$! +0o![#cj?o ]!l$b%s"o ]!l"l$b*b^0d#>>>s!0s%yA0s"l"l!r&lengthb<k+l"^l"1+s"jl  s&l&z0l!$ +["cs\'(0l#i\'1ps9wxb&s() &{s)/s(gr&Stringr,fromCharCodes)0s*yWl ._b&s o!])l l Jb<k$.aj;l .Tb<k$.gj/l .^b<k&i"-4j!+& s+yPo!]+s!l!l Hd>&l!l Bd>&+l!l <d>&+l!l 6d>&+l!l &+ s,y=o!o!]/q"13o!l q"10o!],l 2d>& s.{s-yMo!o!]0q"13o!]*Ld<l 4d#>>>b|s!o!l q"10o!],l!& s/yIo!o!].q"13o!],o!]*Jd<l 6d#>>>b|&o!]+l &+ s0l-l!&l-l!i\'1z141z4b/@d<l"b|&+l-l(l!b^&+l-l&zl\'g,)gk}ejo{cm,)|yn~Lij~em["cl$b%@d<l&zl\'l $ +["cl$b%b|&+l-l%8d<@b|l!b^&+ q$sign ', [TAC = {}]);

var data = TAC.sign(0);//生成加密字符串
console.log(data);//输出加密字符串
$ node test.js
TypeError: Cannot read property 'userAgent' of undefined

结果出来这么个玩意,意思是读不到某个对象的userAgent变量。这乍一看userAgent是浏览器UA的意思啊,莫非是一定要在浏览器环境下执行么?那就尴尬了啊。

Google一下这个错误吧,你别说,还真找到了有用的东西。在Github一个项目里有人回复了这样一个答案:

That's an interesting problem. We probably wouldn't want to change anything in videojs, though, maybe have a way to set an external useragent instead of relying on navigator.userAgent.
Also, we use the global module from npm to get window which returns global if window is undefined`, so, doing something like:

global.navigator.userAgent = '...'
should fix that issue.

搜打死内,那咱么试试吧,于是有了下面这段代码:

global.navigator = {};
global.navigator.userAgent = "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_13_5) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/67.0.3396.87 Safari/537.36";
Function(function (t) {
    return 'e(e,a,r){(b[e]||(b[e]=t("x,y","x "+e+" y")(r,a)}a(e,a,r){(k[r]||(k[r]=t("x,y","new x[y]("+Array(r+1).join(",x[y]")(1)+")")(e,a)}r(e,a,r){n,t,s={},b=s.d=r?r.d+1:0;for(s["$"+b]=s,t=0;t<b;t)s[n="$"+t]=r[n];for(t=0,b=s=a;t<b;t)s[t]=a[t];c(e,0,s)}c(t,b,k){u(e){v[x]=e}f{g=,ting(bg)}l{try{y=c(t,b,k)}catch(e){h=e,y=l}}for(h,y,d,g,v=[],x=0;;)switch(g=){case 1:u(!)4:f5:u((e){a=0,r=e;{c=a<r;c&&u(e[a]),c}}(6:y=,u((y8:if(g=,lg,g=,y===c)b+=g;else if(y!==l)y9:c10:u(s(11:y=,u(+y)12:for(y=f,d=[],g=0;g<y;g)d[g]=y.charCodeAt(g)^g+y;u(String.fromCharCode.apply(null,d13:y=,h=delete [y]14:59:u((g=)?(y=x,v.slice(x-=g,y:[])61:u([])62:g=,k[0]=65599*k[0]+k[1].charCodeAt(g)>>>065:h=,y=,[y]=h66:u(e(t[b],,67:y=,d=,u((g=).x===c?r(g.y,y,k):g.apply(d,y68:u(e((g=t[b])<"<"?(b--,f):g+g,,70:u(!1)71:n72:+f73:u(parseInt(f,3675:if(){bcase 74:g=<<16>>16g76:u(k[])77:y=,u([y])78:g=,u(a(v,x-=g+1,g79:g=,u(k["$"+g])81:h=,[f]=h82:u([f])83:h=,k[]=h84:!085:void 086:u(v[x-1])88:h=,y=,h,y89:u({e{r(e.y,arguments,k)}e.y=f,e.x=c,e})90:null91:h93:h=0:;default:u((g<<16>>16)-16)}}n=this,t=n.Function,s=Object.keys||(e){a={},r=0;for(c in e)a[r]=c;a=r,a},b={},k={};r'.replace(/[-]/g, function (i) {
        return t[15 & i.charCodeAt(0)]
    })
}("v[x++]=v[--x]t.charCodeAt(b++)-32function return ))++.substrvar .length(),b+=;break;case ;break}".split("")))()('gr$Daten Иb/s!l y͒yĹg,(lfi~ah`{mv,-n|jqewVxp{rvmmx,&effkx[!cs"l".Pq%widthl"@q&heightl"vr*getContextx$"2d[!cs#l#,*;?|u.|uc{uq$fontl#vr(fillTextx$$龘ฑภ경2<[#c}l#2q*shadowBlurl#1q-shadowOffsetXl#$$limeq+shadowColorl#vr#arcx88802[%c}l#vr&strokex[ c}l"v,)}eOmyoZB]mx[ cs!0s$l$Pb<k7l l!r&lengthb%^l$1+s$jl  s#i$1ek1s$gr#tack4)zgr#tac$! +0o![#cj?o ]!l$b%s"o ]!l"l$b*b^0d#>>>s!0s%yA0s"l"l!r&lengthb<k+l"^l"1+s"jl  s&l&z0l!$ +["cs\'(0l#i\'1ps9wxb&s() &{s)/s(gr&Stringr,fromCharCodes)0s*yWl ._b&s o!])l l Jb<k$.aj;l .Tb<k$.gj/l .^b<k&i"-4j!+& s+yPo!]+s!l!l Hd>&l!l Bd>&+l!l <d>&+l!l 6d>&+l!l &+ s,y=o!o!]/q"13o!l q"10o!],l 2d>& s.{s-yMo!o!]0q"13o!]*Ld<l 4d#>>>b|s!o!l q"10o!],l!& s/yIo!o!].q"13o!],o!]*Jd<l 6d#>>>b|&o!]+l &+ s0l-l!&l-l!i\'1z141z4b/@d<l"b|&+l-l(l!b^&+l-l&zl\'g,)gk}ejo{cm,)|yn~Lij~em["cl$b%@d<l&zl\'l $ +["cl$b%b|&+l-l%8d<@b|l!b^&+ q$sign ', [TAC = {}]);

var data = TAC.sign(0);
console.log(data);

执行结果:

$ node test.js
ntWDLwAAxgZhKnzQ0m7GL57Vgz

咱们拿这个算出来的字符串,填入API,去掉ascp两个参数请求试试:

https://www.toutiao.com/api/pc/feed/?category=news_tech&utm_source=toutiao&widen=1&max_behot_time=0&max_behot_time_tmp=0&tadrequire=true&_signature=ntWDLwAAxgZhKnzQ0m7GL57Vgz

WX20180624-181222@2x

Yeah!搜易贼,妈妈再也拦不住我扒今日头条了(^__^)