Rewrite URL based on selected node for load-balancing

Hi,

 

 

it's me again 🙂 but this time only for giving you feedback.

 

 

@Kevin

 

 

I don't know why below code caught all the host name between https:// and the next / except the first letter!

 

 

 if { [scan $uri_old {%*[http://|https://]%[^/]} host_old] } { 

 

 

So I changed it like this:

 

 if { [scan $uri_old {%[^//]//%[^/]]} host_tmp host_old] } { 

 

Certainly not the best, but at least it is working 😄

 

 

Finally the iRule became:

 

when RULE_INIT {

     Log debug messages to /var/log/ltm? 1=yes, 0=no
    set static::rewrite_debug 1
    
     External hostname for the web application
    set static::external "mypublicsite.com"
}

when HTTP_REQUEST_SEND {

     Need to force the host header replacement and HTTP:: commands into the clientside context
     as the HTTP_REQUEST_SEND event is in the serverside context
    clientside {

         Different action depending on the node selected for load-balancing
        switch [LB::server addr] {

            "1.1.1.1" {

                HTTP::header replace Host "internalhost01.com"
                if {$static::rewrite_debug}{log local0. "[IP::client_addr]:[TCP::client_port]: HTTP Host header rewritten with internalhost01.com"}
            }
            "1.1.1.2" {
       
                HTTP::header replace Host "internalhost02.com"
                if {$static::rewrite_debug}{log local0. "[IP::client_addr]:[TCP::client_port]: HTTP Host header rewritten with internalhost02.com"}
            }
        }
    }
}

when HTTP_RESPONSE {

     Replace all internal Host headers with $static::external value defined in RULE_INIT section
    HTTP::header replace Host $static::external
    if {$static::rewrite_debug}{log local0. "[IP::client_addr]:[TCP::client_port]: HTTP Host header rewritten with -> $static::external"}

    if { [HTTP::is_redirect] } {

         Log if we detect an HTTP redirection
        if {$static::rewrite_debug}{log local0. "[IP::client_addr]:[TCP::client_port]: HTTP redirection detected"}

         Store Location HTTP header coming from backend server
        set uri_old [string tolower [HTTP::header Location]]
        
         Store backend server host name
        if { [scan $uri_old {%[^//]//%[^/]]} host_tmp host_old] } {

             Replace backend server host name with external host name into HTTP Location header
            set map_exp "set uri_new \[string map {$host_old $static::external} $uri_old\]"
            eval $map_exp
            
             Finally rewrite HTTP Location header
            HTTP::header replace Location $uri_new
            if {$static::rewrite_debug}{log local0. "[IP::client_addr]:[TCP::client_port]: HTTP Location header rewritten with -> $uri_new"}
        }
    }
}
 

 

 

I sincerely thank you all for your very valuable help! Without you this story would have taken me too much time, really thank you.