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David_Jones_227's avatar
David_Jones_227
Icon for Nimbostratus rankNimbostratus
Feb 20, 2017

Enable or disable chunking based on URI

We have a website with two different applications on it. For example, and .

 

Due to some older code that the app-a application is running, they are forced to used Compatibility Mode within IE to make it work. When we migrated the application from our old Cisco ACE load balancers to our F5's (11.6.1 HF1), the application broke. What we eventually figured out is that we had to set Request Chunking in the http profile to 'Rechunk' for it to work.

 

Unfortunately, this broke app-b. So with Rechunk on, it fixes app-a but breaks app-b. With it off, it breaks app-a but fixes app-b.

 

What I'm trying to find out is, is there a way, with an irule, to say "if the uri includes app-a, enable rechunk for response chunking but if it includes app-b (or maybe anything else), don't enable it"?

 

I tried using an irule to tell the web server to only use http 1.0, so chunking wouldn't be an issue and although the rule worked, if I didn't have rechunk turned on, the app-a application didn't work.

 

application delivery
BIG-IP
iRules

3 Replies

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  • Vijay_E's avatar
    Vijay_E
    Icon for Cirrus rankCirrus
    Feb 20, 2017

    I am not aware of iRule that can chunk based on URI. May be someone else can help you out. Simplest option available to you is to separate the app into 2 sites (mysite.a.com & mysite.b.com) and use 2 different VS.

     

  • Max_Q_factor's avatar
    Max_Q_factor
    Icon for Cirrocumulus rankCirrocumulus
    Mar 01, 2017

    I think the answer may be to set the Virtual Server to use HTTP 1.0 (in the HTTP profile) and trigger re-chunking on the application URL that requires re-chunking, using a modified iRule like:

     

    when HTTP_REQUEST {
   if { [string tolower [HTTP::uri]] starts_with "/app-a" } {
      set app a
      HTTP::version "1.1"
   }
}
when HTTP_RESPONSE {
   if {$app == a} {
      HTTP::version "1.0"
      if {[HTTP::header exists "Transfer-Encoding"]} {
         HTTP::payload unchunk
         HTTP::header remove "Transfer-Encoding"
      }
   }
}