近日有朋友想了解一下CAS的协议的HTTP流程，我之前抓过包，现在贴出来，希望对那位朋友有所帮助。
CAS Server:caserver:7002
Tomcat APP应用:appserver01:8080
访问 appserver01:8080 的 SessionExample
GET /servlets-examples/servlet/SessionExample HTTP/1.1
Accept: */*
Accept-Language: zh-cn,en;q=0.8,zh;q=0.5,zh-tw;q=0.3
Accept-Encoding: gzip, deflate
User-Agent: Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.0; Maxthon; .NET CLR 2.0.50215)
Host: appserver01:8080
Connection: Keep-Alive
appserver01:8080 引导我到 casserver:7002 进行认证 , 注意 ,Service=SessionExmaple 的 URL
HTTP/1.1 302 Moved Temporarily
Set-Cookie: JSESSIONID=22311DC
Location: https://casserver:7002/cas/login?service=http%
Content-Length: 0
Date: Fri, 28 Oct 2005 06:33:54 GMT
Server: Apache-Coyote/1.1
紧接着，我的 IE 访问 casserver:7002 ，走 SSL 协议
__Q_M_Ca?R??d‰.!#U?-é?11úhx_??{?e???ò?_h|íA?6
?|__“w?o___
db____c_
casserver:7002 出示证书给我看，并且给予我 ServiecTicket, 下面的是乱码， SSL 协议是这样，将就一下 J
__:_6_Ca??bê| !ì_?^? ?AB__ü5;_s+_?2òG_a????“?dJEám:_ìo____y__u_r_á0?_?0?_??_______0
_*?H?÷
____0~1_0___U____BEA1_0__U____CN1_0__U____GZ1_0__U____GD1_0___U_
__BEA.CO.LTD1_0___U____BEA1_0__*?H?÷
051017081352Z_
061017073844Z0[1_0___U____CASSERVER1_0___U____BEA1_0
__U_
__DIANLI1_0__U____GZ1_0__U____GD1_0__U____CN0??0
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认证完毕，我得到ServiceTicket，我便用 casserver:7002 提供的 ServiceTicket 访问 appserver01:8080 的 SessionExample应用
GET /servlets-examples/servlet/SessionExample?ticket=ST-1-9xVu1SfonRNKcjdyKbG9 HTTP/1.1
Accept: */*
Accept-Language: zh-cn,en;q=0.8,zh;q=0.5,zh-tw;q=0.3
Accept-Encoding: gzip, deflate
User-Agent: Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.0; Maxthon; .NET CLR 2.0.50215)
Host: appserver01:8080
Connection: Keep-Alive
Cookie: JSESSIONID=22311DC
appserver01:8080 认为我的 Ticket 是正确的，因此正确返回网页给我。
HTTP/1.1 200 OK
Content-Type: text/html;charset=ISO-8859-1
Content-Length: 1188
Date: Fri, 28 Oct 2005 06:33:54 GMT
Server: Apache-Coyote/1.1
Sessions Example
Session ID: 22311DC
Created: Fri Oct 28 14:33:54 CST 2005
Last Accessed: Fri Oct 28 14:33:54 CST 2005
The following data is in your session:
edu.yale.its.tp.cas.client.filter.user = cas
Name of Session Attribute:
Value of Session Attribute:
GET based form:
Name of Session Attribute:
Value of Session Attribute:
URL encoded
IE会接着 获取网页上的图片，见 GET 后面那一串字符，什么 code.gif,return.gif..... ，获取的根据都是
靠那个 ticket=ST-1-9xVu1SfonRNKcjdyKbG9 ，如果这个 ST 不对，图片是获取不了的！
GET /servlets-examples/images/code.gif HTTP/1.1
Accept: */*
Referer: http://appserver01:8080/servlets-examples/servlet/SessionExample?ticket=ST-1-9xVu1SfonRNKcjdyKbG9
Accept-Language: zh-cn,en;q=0.8,zh;q=0.5,zh-tw;q=0.3
Accept-Encoding: gzip, deflate
If-Modified-Since: Sun, 29 Aug 2004 00:02:34 GMT
If-None-Match: W/"292-1093737754000"
User-Agent: Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.0; Maxthon; .NET CLR 2.0.50215)
Host: a