Forum Discussion

Brandon's avatar
Brandon
Icon for Cirrostratus rankCirrostratus
Feb 03, 2021

irule to look to see if the value is in the Body

I was trying to figure out how to write an iRule to look for a parameter in the Body. I thought the token would be in the header. However the developer put it in the body. How do I look in the body of a http req.

 

Thanks for your help.

 

when HTTP_REQUEST {

  if { [HTTP::uri] equals "login.aspx" } {

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

      log local0. "Request from [IP::client_addr] for login.aspx includes HTTP header token with value: [HTTP::header "token"]"

    } else {

      log local0. "Request from [IP::client_addr] for login.aspx does not include HTTP header token"

    }

  }

}

 

application delivery
BIG-IP
iRules
  • Amine_Kadimi's avatar
    Amine_Kadimi
    Icon for MVP rankMVP
    Feb 03, 2021
    when HTTP_REQUEST {
  if {[HTTP::method] eq "POST"}{
    if {[HTTP::header "Content-Length"] ne "" && [HTTP::header "Content-Length"] <= 1048576}{
      set content_length [HTTP::header "Content-Length"]
    } else {
        set content_length 1048576
    }
    if { $content_length > 0} {
      HTTP::collect $content_length
    }
  }
}
when HTTP_REQUEST_DATA {
  log local0. "Token = [findstr [HTTP::payload] "token=" 6 &]"
}

    source: https://support.f5.com/csp/article/K07535385

    • Daniel_Wolf's avatar
      Daniel_Wolf
      Icon for MVP rankMVP
      Feb 04, 2021

      This is the way, however I would be careful to implement it. I'd recommend to do performance testing before deploying it in a production environment.

      Just recently I had a similar requirement and it works good with small requests. However the customer had POST requests up to 400kb. Then this suddenly becomes heavy on the CPU.