豆丁网文档免登陆免积分下载工具原理分析

类似于：百度文库下载工具的原理与实现

我们分析“豆丁文档免登陆免积分下载工具原理”，这里的实验文档网址是：http://www.docin.com/p-239490008.html，和上回说的是一个文档，不过一个是在百度一个是在豆丁。

首先下载http://www.docin.com/p-239490008.html，找到网页内容：

    <script language="javascript" type="text/javascript">
        
        var playcontent = {"converSuccess":[30],"downloadPrice":[9.38],"autherId":[29814826],"pdtType":["pdf"],"onlinePrice":[0],"bookMarkId":[0],"initLoadCtrl":[true],"pdtState":[0],"pageNum":[1],"autherNickName":["yy_js92"],"sharetime":["2011-08-03 14:27:15"],"pdtTitle":["侧方位停车图解教你侧方停车技巧"],"pdtSize":[""],"pdtFreeDown":[false],"bookMark":[0],"errorCode":[0],"pdtDescription":["侧方位停车图解教你侧方停车技巧"],"onlinePage":[0],"auditLevel":[1],"pcatid":["5"]};
        function returnJson(){
            return playcontent;
        }
         
        var fo = new SWFObject("http://pics.wanlibo.com/players/DocinViewer.swf?rand=20110819", "player", "100%", "100%", "9.0.16.0");
        fo.addVariable("productId",239490008);
        fo.addVariable("channel",0);
        fo.addVariable("loadurl" , "file1.yimk.com");
        fo.addVariable("aid" , 499);
        fo.addParam("align","middle");
        fo.addParam("wmode","transparent");
        fo.addParam("quality","high");
        fo.addParam("allowScriptAccess","always");
        fo.addParam("allowFullScreen","true");
        fo.addParam("wmode","transparent");
        
        fo.useExpressInstall('http://pics.wanlibo.com/players/expressinstall.swf');
        fo.write("DocinViewer");
    </script>

其中playcontent中是文档的具体信息，找到file1.yimk.com，那么构造网址：

http://file1.yimk.com/docin_239490008.docin然后下载得到一个swf文件，这个文件是加密过的。

解析……