HTTP redirect maintaining original URL

If you want to redirect to the host or URI that the client made a request to, you'd need to save the host or URI in HTTP_REQUEST for every request and then reference it in LB_FAILED:

 
 when HTTP_REQUEST { 
  
     Save the host header value 
    set host [HTTP::host] 
  
     Save the URI (not sure you want to do anything with the URI though) 
    set uri [HTTP::uri] 
 } 
 when LB_FAILED { 
  
     Send 302 redirect with the host header value from the request 
    HTTP::respond 302 Location "http://$host/sorry/"  
 } 
 

Aaron

Hi,

 

thanks for this..

 

I'm not sure if it's going to do what i need though.

 

currently the redirect i have (the first part when LB_FAILED) redirects the user to the sorry page just fine.

 

 

What i was looking to do was redirect the user but without changing the address location in the client browser

 

 

so user comes in looking for www.mypage.com

 

but because there are no servers available (LB_FAILED) i redirect them to another url : www.sorry.com.

 

 

However, I want to retain their original url in the browser so if they just click refresh it comes back www.mypage.com and if there are any servers available they get the content they expected, if not back through the above cycle.

 

 

sorry about the convoluted description, but as you can guess irules and not my expertise! :-)

 

thanks

 

dan

 

 

 

 

Hi Dan,

If you don't want the client to see the updated URI, you could create a sorry pool and use that pool in LB_FAILED.

Here is an untested example based on this post:

http://devcentral.f5.com/Default.aspx?tabid=53&forumid=5&tpage=1&view=topic&postid=2922629646

 
 when CLIENT_ACCEPTED { 
  
     Initialise a variable to track whether the load balancing attempt has failed 
    set retries 0 
 } 
  
 when HTTP_REQUEST { 
  
     Check if there has been a load balancing failure 
    if { $retries > 0 } { 
  
        Rewrite the URI if it hasn't already been rewritten 
       if {not ([HTTP::path] contains "sorry")}{ 
  
   Rewrite the URI for the sorry page 
          HTTP::uri "/sorry/sorry.html" 
       } 
  
    } else { 
  
        This isn't a retry, so save the request headers and data 
       set request [HTTP::request] 
    } 
 } 
  
 when LB_SELECTED { 
  
     Check if there has been a load balancing failure 
    if { $retries >= 1 } { 
  
        Select a new pool member from the sorry pool 
       LB::reselect pool sorry_pool 
    } 
 } 
  
 when LB_FAILED { 
  
     Track that the load balancing attempt failed 
    incr retries 
  
     Retry the HTTP request 
    HTTP::retry $request 
 } 
 when HTTP_RESPONSE { 
  
     There was a successful response, so we could reset retries to 0? 
    set retries 0 
 } 
 

If the sorry.html page references images or other content, you might need to add logic to HTTP_REQUEST to specify the sorry pool for any request which has "sorry" in the path.

If this doesn't work for you, can you add logging to the iRule and post the log output from /var/log/ltm?

Thanks,

Aaron