服务器是怎么要求客户端强行弹出身份验证窗口的

我们访问tomcat服务器的时候如果试图访问Tomcat Manager就会发现浏览器弹出一个登陆对话框，和我们平常的网页对话框不同，而且查看页面的时候查不到生成这个对话框的代码，禁止脚本也毫无作用。手头的资料对这个东西没有任何介绍，它到底是怎么弹出来的呢？

用jmeter创建一个http request的sampler，再建一个view result tree的lisenter来看看服务器返回了些什么污七八糟的：

HTTP response headers:
HTTP/1.1 401 Unauthorized
Pragma: No-cache
Cache-Control: no-cache
Expires: Thu, 01 Jan 1970 08:00:00 CST
WWW-Authenticate: Basic realm="Tomcat Manager Application"
Content-Type: text/html;charset=utf-8
Content-Length: 954
Date: Thu, 30 Jun 2005 09:27:26 GMT
Server: Apache-Coyote/1.1

嘿嘿，原来是一个带WWW-Authenticate的401错误啊。自己写个jsp模拟一下看看怎么样：

<%
response.addHeader("WWW-Authenticate","Basic realm=/"Tomcat Manager Application/"");
response.sendError(401,"Unauthorized");
%>

果然，一个一模一样的登陆窗口跳出来了。不过身份验证的具体过程要怎么做呢？google了一下，果然看到好东西了： http://www.chinadata.cn/showContent.asp?projectID=2083

按照说明构造了一个jsp文件：


<%


sun.misc.BASE64Decoder decoder = new sun.misc.BASE64Decoder();


boolean authenticated = false;


String authorization = request.getHeader("authorization");


System.out.println("authorization:"+authorization);




if (authorization != null)

{




if (authorization.startsWith("Basic"))

{


authorization = authorization.substring(authorization.indexOf(' ')+1);


byte[] bytes = decoder.decodeBuffer(authorization);


authorization = new String(bytes);


String userName = authorization.substring(0,authorization.indexOf(':'));


String password = authorization.substring(authorization.indexOf(':')+1);


System.out.println("userName:"+userName);


System.out.println("password:"+password);


authenticated =userName.equals("abc") && password.equals("abc");




}else if (authorization.startsWith("Digest"))

{


String userName = authorization.substring(authorization.indexOf("username="));


userName = userName.substring("username=/"".length());


userName = userName.substring(0,userName.indexOf('"'));


String password = authorization.substring(authorization.indexOf("response="));


password = password.substring("response=/"".length());


password = password.substring(0,password.indexOf('"'));


authenticated =userName.equals("abc") && password.equals("3cf1135d3b8e20dd9272d06288569a56");


}


}




if (!authenticated)

{


// response.addHeader("WWW-Authenticate","Digest realm=/"Tomcat Manager Application/"");


response.addHeader("WWW-Authenticate","Basic realm=/"Tomcat Manager Application/"");


response.sendError(401,"Unauthorized");




}else

{


out.println("hello abc");


}


%>



cool，和tomcat一模一样的登陆页面做出来了。

用户名密码均为abc，hard code在代码里面了。不过还没查到Digest方式的情况下是对哪些信息进行MD5的