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Tom_K_185554's avatar
Tom_K_185554
Icon for Nimbostratus rankNimbostratus
Dec 28, 2017

Need to parse the [HTTP::uri] and modify it for a redirect

Hello - I found a really useful irule from Joe Pruitt for parsing the uri `when HTTP_REQUEST { log local0. "‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐" log local0. "URI Information" log l...
devops
iRules
LTM
  • nitass_89166's avatar
    nitass_89166
    Dec 29, 2017

    could you please explain what exactly the code is doing especially the regular expression part and the string map ?

     

    /~ is literal chars (i.e. it matches /~)

     

    %[^/] matches every chars but not / and the matching string will be stored in variable specified later (e.g. it matches geverest and geverest will be stored in first variable)

     

    [scan [HTTP::uri] {/~%[^/]} first] returns number of matching string. so, we can use it to determine whether it is uri we are interested (i.e. 1).

     

    [string map "/~$first/ /" [HTTP::uri]] replace /~$first/ with / in uri (e.g. it replaces /~geverest/ with /).

     

    [root@bip1a:Active:In Sync] config  tclsh
% set uri "/~geverest/home/data-modeling-course/course-flyer"
/~geverest/home/data-modeling-course/course-flyer

% scan $uri {/~%[^/]} first
1

% put $first
geverest

% string map "/~$first/ /" $uri
/home/data-modeling-course/course-flyer
nitass's avatar
nitass
Icon for Employee rankEmployee

may this be usable?

e.g.

// config

[root@ve13a:Active:In Sync] config  tmsh list ltm virtual bar
ltm virtual bar {
    destination 172.28.24.10:80
    ip-protocol tcp
    mask 255.255.255.255
    profiles {
        http { }
        tcp { }
    }
    rules {
        qux
    }
    source 0.0.0.0/0
    translate-address enabled
    translate-port enabled
    vs-index 4
}
[root@ve13a:Active:In Sync] config  tmsh list ltm rule qux
ltm rule qux {
when HTTP_REQUEST {
  if { [scan [HTTP::uri] {/~%[^/]} first] } {
    HTTP::respond 301 noserver Location "http://[HTTP::host][string map "/~$first/ /" [HTTP::uri]]"
  }
}
}

// test

[root@ve13a:Active:In Sync] config  curl -I http://172.28.24.10/~geverest/home/data-modeling-course/course-flyer
HTTP/1.0 301 Moved Permanently
Location: http://172.28.24.10/home/data-modeling-course/course-flyer
Connection: Keep-Alive
Content-Length: 0

[root@ve13a:Active:In Sync] config  curl -I http://172.28.24.10/~helloworld/home/data-modeling-course/course-flyer
HTTP/1.0 301 Moved Permanently
Location: http://172.28.24.10/home/data-modeling-course/course-flyer
Connection: Keep-Alive
Content-Length: 0
Tom_K_185554's avatar
Tom_K_185554
Icon for Nimbostratus rankNimbostratus
Dec 28, 2017

Thank you, This is awesome - does exactly what I need. I am not that great with irules at this level - could you please explain what exactly the code is doing especially the regular expression part and the string map ?

 

 `when HTTP_REQUEST {
     if { [scan [HTTP::uri] {/~%[^/]} first] } {
     HTTP::respond 301 noserver Location "http://[HTTP::host][string map "/~$first/ /" 
       [HTTP::uri]]"
      }
     }`