arthas/tutorials/katacoda/case-http-401-en/case-http-401.md

In this case, the user will resolve the HTTP 401 issue.

Visit: https://HOST_SUBDOMAIN-80-KATACODA_HOST.environments.katacoda.com/admin

The result is:

Something went wrong: 401 Unauthorized

We know that 401 is usually intercepted by the permission-managed Filter, so which Filter returns 401?

Track all Filter methods

Start trace:

trace javax.servlet.Filter *{{execute T2}}

Visit: https://HOST_SUBDOMAIN-80-KATACODA_HOST.environments.katacoda.com/admin

At the deepest level of the call tree, you can find AdminFilterConfig$AdminFilter which returns 401:

+---[3.806273ms] javax.servlet.FilterChain:doFilter()
|   `---[3.447472ms] com.example.demo.arthas.AdminFilterConfig$AdminFilter:doFilter()
|       `---[0.17259ms] javax.servlet.http.HttpServletResponse:sendError()

Get the call stack through stack command

From the above result, we can find the method: HttpServletResponse:sendError(). So we can use stack command to resolved the HTTP 401 issue.

Run:

stack javax.servlet.http.HttpServletResponse sendError 'params[0]==401'{{execute T2}}

Visit: https://HOST_SUBDOMAIN-80-KATACODA_HOST.environments.katacoda.com/admin

The Result:

$ stack javax.servlet.http.HttpServletResponse sendError 'params[0]==401'
Press Q or Ctrl+C to abort.
Affect(class-cnt:2 , method-cnt:4) cost in 87 ms.
ts=2019-02-15 16:44:06;thread_name=http-nio-8080-exec-6;id=16;is_daemon=true;priority=5;TCCL=org.springframework.boot.context.embedded.tomcat.TomcatEmbeddedWebappClassLoader@8546cd5
    @org.apache.catalina.connector.ResponseFacade.sendError()
        at com.example.demo.arthas.AdminFilterConfig$AdminFilter.doFilter(AdminFilterConfig.java:38)
        at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
        at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
        at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:99)
        at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)