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Nick_T_68319's avatar
Nick_T_68319
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Feb 26, 2014

APM not rewriting properly

I am trying to setup an APM portal for a call recording product. Everything is working perfectly except we found that one page has some kind of hard coded URL in the HTML. APM is not rewriting it, so on the outside it breaks.

 

for example, in the HTML javascript portion, there is something like this

 

document.VXReplay.WaveFileName = "http://internalservername:8080" + strURL;

 

So obviously this breaks since the user is connecting through the portal externally. What is the best solution to rewrite this? Is there an option in APM? Or do I need to setup an iRule to catch the stream and rewrite the servername to the external DNS name?

 

application delivery
BIG-IP Access Policy Manager (APM)
deployment
design
devops
iRules
security

3 Replies

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  • Rene_C_'s avatar
    Rene_C_
    Icon for Nimbostratus rankNimbostratus
    Feb 27, 2014

    As far as i know, nothing is rewritten per default from the backend.

    The cleanest solution would now be that the backend code is changed to something like

    document.VXReplay.WaveFileName = "http://" + window.location.hostname + strURL;

    If for some reason its not possible to change the backend code or the configuration accordingly, your only chance is to modify the response-stream directly through an iRule.

    • Nick_T_68319's avatar
      Nick_T_68319
      Icon for Nimbostratus rankNimbostratus
      Feb 27, 2014
      Ugh yeah, I hate when people code stuff like that. We are trying to get the vendor to update the code, but I don't know if it will be possible. So I was looking into modifying the response-stream, but how do you append that long URL that APM adds f5w.....? Is that some kind of session id?
  • Rene_C_'s avatar
    Rene_C_
    Icon for Nimbostratus rankNimbostratus
    Feb 27, 2014

    Wouldnt it be sufficient to just rewrite the http://internalservername:8080 with the current hostname?

    So some iRule like this:

     

     when HTTP_REQUEST {
   Don't allow data to be chunked so we can correctly
   replace payload below
  if { [HTTP::version] eq "1.1" } {
      if { [HTTP::header is_keepalive] } {
         HTTP::header replace "Connection" "Keep-Alive"
      }
      HTTP::version "1.0"
  }

   save host
  set hostname [HTTP::host]
}

when HTTP_RESPONSE {
     collect response data
    if { [HTTP::header exists "Content-Length"] } {
       set content_length [HTTP::header "Content-Length"]
    } else {
       set content_length 4294967295
    }
    if { $content_length > 0 } {
       HTTP::collect $content_length
    }
}

when HTTP_RESPONSE_DATA {
  if { $::patch_apple_and_banana } {
    set find "http://internalservername:8080"
    set replace "https://$hostname"
    set offset 0
    set diff [expr [string length $replace] - [string length $find]]

     Get indices of all instances of find string in the payload
    set indices [regexp -all -inline -indices $find [HTTP::payload]]  
    foreach idx $indices {
      set start [expr [lindex $idx 0] + $offset]
      set end [expr [lindex $idx 1] + $offset]
      set len [expr {$end - $start + 1}]

       replace the instance of find with the contents of replace
      HTTP::payload replace $start $len $replace

       modify offset if the replace string is larger or smaller
       than find.
      incr offset $diff
    }
  }
}

     

    (based on this site)

    Though i'm not sure if you really should inspect any response that's coming through; But i guess you get the point.