Apache HttpClient模拟登陆网站（待续）

网上有一些相册的下载工具，设置好帐号密码就可以下图片到本地。现在用java代码模拟一下。
HTTPClient的包有类似的例子。




public static void test() throws HttpException, IOException ...{


final String HOST = "photo.server.net";


final int PORT = 80;


final String getMethodStr= "/userAccount/1524712";


HttpClient client = new HttpClient();


client.getHostConfiguration().setHost(HOST, PORT, "http");


client.getParams().setCookiePolicy(CookiePolicy.BROWSER_COMPATIBILITY);




//Get first


GetMethod getMethod = new GetMethod(getMethodStr);


client.executeMethod(getMethod);


System.err.println("------ Get content /userAccount/1524712: ");


printOutStream(getMethod.getResponseBodyAsStream(), getMethod.getRequestCharSet());


Header[] headers = getMethod.getResponseHeaders();




for (Header header : headers) ...{


System.err.println(header.toString());


}


getMethod.releaseConnection();




//Get the useful session


//CookieSpec cookieSpec = CookiePolicy.getDefaultSpec();


Cookie[] getCookies = client.getState().getCookies();


System.err.println("----- -Useful cookies: ");




for (Cookie cookie : getCookies) ...{


System.err.println(cookie.toString());


}




//POST password
//其实无论客户端的页面怎么复杂，但是发过去的也只是包，可以使用一些抓包工具获取。


final String url = "http://" + HOST + getMethodStr;


final String encodedUrl = url.replaceAll(":", "%3A");


final String postUrl = "/@restrict?furl=" + encodedUrl;


PostMethod postMethod = new PostMethod(postUrl);


NameValuePair text = new NameValuePair("text", "");


NameValuePair pwd = new NameValuePair("pwd", "hello");


NameValuePair abId = new NameValuePair("ab_id", "");




postMethod.setRequestBody(new NameValuePair[]...{text, pwd, abId});


client.executeMethod(postMethod);


System.err.println("----------------");


System.err.println("get post feedback:");


printOutStream(postMethod.getResponseBodyAsStream(), postMethod.getResponseCharSet());


postMethod.releaseConnection();




//Redirect to other page.


int statusCode = postMethod.getStatusCode();


System.err.println(statusCode);




if (statusCode == HttpStatus.SC_MOVED_TEMPORARILY || statusCode == HttpStatus.SC_MOVED_PERMANENTLY)...{


Header locationHeader = postMethod.getResponseHeader("location");




if (locationHeader != null) ...{


String redirectUri = locationHeader.getValue();




if (redirectUri == null || "".equals(redirectUri)) ...{


redirectUri = "/";


}


getMethod = new GetMethod(redirectUri);


client.executeMethod(getMethod);


System.err.println("get redirect:");


headers = getMethod.getResponseHeaders();




for (Header header : headers) ...{


System.err.println(header.toString());


}


printOutStream(getMethod.getResponseBodyAsStream(), getMethod.getResponseCharSet());


getMethod.releaseConnection();


}


}






}

可以看到在一般的网站里面session-id是一直传递的。这里面的很都步骤都是可以使用java的URLConnection的，但有一种情况它不能很好处理. 例如, 登陆成功后, 服务器response.sendRedirect到一个新的URL, 这个时候返回的HTTP相应包应该只有HTTP头的, 里面包含一些返回状态码和要导向的URL地址.


HTTP/1.0 302 Moved Temporarily


Date: Sat, 03 Mar 2007 00:00:27 GMT


Server: Microsoft-IIS/6.3


Vary: Accept-Encoding


Expires: Thu, 19 Nov 1981 08:52:00 GMT


Cache-Control: no-store, no-cache, must-revalidate, post-check=0, pre-check=0


Pragma: no-cache


Location: http://photo.xxxxxx.com/newurl

Content-Type: text/html; charset=UTF-8


Via: 1.0 photo.xxxx.com:8000 (Microsoft-IIS/7.1)


Connection: close

碰到(statusCode == HttpStatus.SC_MOVED_TEMPORARILY || statusCode == HttpStatus.SC_MOVED_PERMANENTLY)...这些返回码的时候, URLConnection会主动跳转到这个location, 但是却没传递任何的cookies, 服务器肯定不认帐了. URLConnection虽然有设置requestProperty设置请求的属性, 但上面这种情况好像是无法设置cookies头的, 而且他提供的设置setDefaultProperty好像也不管用. 甚至你连location也无法获取到.
顺便在这里提一下, 一些防盗链接其实可以用cookies头, 如果是经过当前网站来的请求, 藏点东西在cookies头里面; 还有一种可能是用Referer, 请求一个页面的时候, 不敢确定是不是因为返回了Cache-Control这些头,之后再去该网站拿其他东西的时候都要发送个Referer过去.
//第一次请求的返回包


HTTP/1.0 200 OK


Date: Fri, 02 Mar 2007 23:54:04 GMT


Server: Microsoft-IIS/6.3


Vary: Accept-Encoding


Pragma: no-cache


Cache-Control: no-store, no-cache, must-revalidate, post-check=0, pre-check=0


Set-Cookie: FOTOSSID=a2d1a5c9f34308c3b49ad88813f11491; path=/; domain=.photo.xxxxx.net


Expires: Thu, 19 Nov 1981 08:52:00 GMT


Content-Type: text/html; charset=UTF-8


Content-Encoding: gzip


Content-Length: 2762


Via: 1.0 photo.xxxx.net:8000 (Microsoft-IIS/7.1)


Connection: keep-alive

//再次请求包


Host: s.photo.xxxxx.net


User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; zh-CN; rv:1.8.1.2) Gecko/20070219 Firefox/2.0.0.2


Accept: image/png,*/*;q=0.5


Accept-Language: zh-cn,zh;q=0.5


Accept-Encoding: gzip,deflate


Accept-Charset: gb2312,utf-8;q=0.7,*;q=0.7


Keep-Alive: 300


Connection: keep-alive


Referer: http://photo.xxx.net/userName/1524712

Cookie: FOTOSSID=a2d1a5c9f34308c3b49ad88813f11491

可以看到HttpClient还是很好用的, 用它甚至可以做一些简单的程序做点自动化的web页面的测试d.
用这个破解别人的相册? 估计效率是不怎么行的, 服务器狠些,再加个随机图片验证,或者几次失败之后封杀你的连接:)