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Ian_Amos_37833's avatar
Ian_Amos_37833
Icon for Nimbostratus rankNimbostratus
Aug 31, 2007

URL rewrite..

Hello all,

 

 

here's what i'm trying to do:

 

 

There is a site with both internal and external URL's (INT dev.site.sub, EXT dev.site.net) where the external URL is fronted by an LTM.

 

 

Sections of this site (/rweb) are protected via Siteminder.

 

 

When you hit the internal URL dev.site.sub/rweb, Siteminder kicks in and presents dev.site.sub/siteminder.. and requests authentication - which all works perfectly, as everything is within our CN.

 

 

When you hit the external URL dev.site.net/rweb, Siteminder kicks in but still presents dev.site.sub/siteminder.. which is fine if you happen to be in the CN, but obviously not over the web.

 

 

What I would like to do is have the LTM rewrite the URL, such that when Siteminder presents dev.site.sub/siteminder, the iRule rewrites that to dev.site.net/siteminder etc..

 

 

I have read Kirk's ProxyPass iRule and given it a go, but still cannot get it to work (unfortunately I am not given any errors in the log).

 

 

I have working rules which rewrite the URL, but ideally only want this rule to rewrite everything behind /siteminder..

 

 

Can anyone suggest anything else to try?
application delivery
dev
devops
iRules
  • Kirk_Bauer_1018's avatar
    Kirk_Bauer_1018
    Icon for Nimbostratus rankNimbostratus
    Aug 31, 2007
    ProxyPass as it is written today assumes the client will ask for a URL which we will then translate, not that a server will redirect to a name that needs to be translated (although that is something I may need to consider). Try this rule out:

     

     

    when HTTP_RESPONSE {

     

    if { [HTTP::header exists "Location"] } {

     

    if { [HTTP::header] starts_with "http://dev.site.sub" } {

     

    set remainder [substr [HTTP::header "Location"] 20]

     

    HTTP::header replace "Location" "http://dev.site.net/$remainder"

     

    }

     

    }

     

    }

     

     

    Untested, but it should give you a place to start.

     

  • Ian_Amos_37833's avatar
    Ian_Amos_37833
    Icon for Nimbostratus rankNimbostratus
    Aug 31, 2007
    Hmmm.. thanks for this.

    Using: 

    when HTTP_RESPONSE {
if { [HTTP::header exists "Location"] } {
if { [HTTP::header starts_with "http://dev.site.sub/siteminder"] } {
set remainder [substr [HTTP::header "Location"] 20]
HTTP::header replace "Location" "http://dev.site.net/siteminder/$remainder"
}
}
}

    I get the following error in the logs:

    http_process_state_prepend - Invalid action EV_EGRESS_DATA during ST_HTTP_PREPEND_HEADERS

    Also, what can I use as an 'ignore' statement? i.e., I need something as a catch-all for the traffic that is not behind /siteminder..
  • Kirk_Bauer_1018's avatar
    Kirk_Bauer_1018
    Icon for Nimbostratus rankNimbostratus
    Aug 31, 2007
    All I can find on that error is here:

     

     

    http://devcentral.f5.com/Default.aspx?tabid=53&view=topic&forumid=5&postid=4343
  • Joe_Pruitt's avatar
    Joe_Pruitt
    Aug 31, 2007

    Posted By IanAmos on 08/31/2007 7:00 AM

     

     

    ...

     

     

    when HTTP_RESPONSE {
if { [HTTP::header exists "Location"] } {
if { [HTTP::header starts_with "http://dev.site.sub/siteminder"] } {
set remainder [substr [HTTP::header "Location"] 20]
HTTP::header replace "Location" "http://dev.site.net/siteminder/$remainder"
}
}
}

     

     

    I get the following error in the logs:

     

     

    http_process_state_prepend - Invalid action EV_EGRESS_DATA during ST_HTTP_PREPEND_HEADERS

     

     

    ...

     

     

     

     

    I see a couple of issues with your code.

     

     

    1. It seems that you have your second if statement incorrect. There is no "HTTP::header starts_with" command. I think you might have meant to compare the "Location" header with "http://dev.site.sub/siteminder".

     

     

    2. Your substr command is pulling off everything past http://dev.site.sub/ so for a uri of "http://dev.site.sub/siteminder/foo/bar", remainder will be "siteminder/foo/bar" and your replacement header will be "http://dev.site.net/siteminder/siteminder/foo/bar" (notice the extra siteminder). If this is what you were intending, then ignore 2 but it kind of stuck out to me.

     

     

    when HTTP_RESPONSE {
  if { [HTTP::header exists "Location"] } {
     1: compare Location header with uri
    if { [HTTP::header "Location"] starts_with "http://dev.site.sub/siteminder" } {
      set remainder [substr [HTTP::header "Location"] 20]
       2: removed "siteminder/" from replacement string
      HTTP::header replace "Location" "http://dev.site.net/$remainder"
    }
  }
}

     

     

    Or, a more optimized version:

     

     

    when HTTP_RESPONSE {
  if { [HTTP::header exists "Location"] } {
    if { [HTTP::header "Location"] starts_with "http://dev.site.sub/siteminder" } {
      HTTP::header replace "Location" "http://dev.site.net/[substr [HTTP::header "Location"] 20]"
    }
  }
}

     

     

    See if that fixes things up...

     

     

    -Joe
  • Ian_Amos_37833's avatar
    Ian_Amos_37833
    Icon for Nimbostratus rankNimbostratus
    Sep 03, 2007

    Posted By Joe on 08/31/2007 10:42 AM

    Or, a more optimized version:

    when HTTP_RESPONSE {
  if { [HTTP::header exists "Location"] } {
    if { [HTTP::header "Location"] starts_with "http://dev.site.sub/siteminder" } {
      HTTP::header replace "Location" "http://dev.site.net/[substr [HTTP::header "Location"] 20]"
    }
  }
}

    See if that fixes things up...

    -Joe

    Thanks, I understand this rule a bit better.

    I'm still getting the below error:

    7 http_process_state_prepend - Invalid action EV_EGRESS_DATA during ST_HTTP_PREPEND_HEADERS

    I'm going to read up on TCPDump and see what's happening.