Need Irule to replace http host based on pool member

when CLIENT_ACCEPTED {

if { [IP::addr [LB::server addr] equals $xyz] }{

set server xyz

} 

if { [IP::addr [LB::server addr] equals $def] }{

set server def

}

}

when HTTP_REQUEST {

STREAM::disable

HTTP::header remove "Accept-Encoding"

if {$server == xyz} {

HTTP::header replace "Host" "xyz.com"

}

if {$server == def} {

HTTP::header replace "Host" "def.com"

}

}

when HTTP_RESPONSE {

 if { [HTTP::header Location] contains "xyz.com" } { HTTP::header replace Location [string map {"xyz.com" "abc.com"} [HTTP::header Location]] }

 if { [HTTP::header Location] contains "def.com" } { HTTP::header replace Location [string map {"def.com" "abc.com"} [HTTP::header Location]] } 

 if {[HTTP::header value Content-Type] contains "text"}{

   STREAM::expression {@xyz.com@abc.com@@def.com@abc.com@}

   STREAM::enable

 }

}