How to add a query string value to pass to servers in teh pool?

stjbrown, the value for HTTP::uri and most other HTTP:: commands is cached within the same iRule event. You can see the updated value by adding a second HTTP_REQUEST event with a priority that triggers after the defautl priority of 500:

 
 when HTTP_REQUEST { 
   set query_args "p1=v1" 
  
   log local0. "[IP::client_addr]:[TCP::client_port]: [HTTP::method] request to [HTTP::host][HTTP::uri]" 
   if { [HTTP::uri] ends_with "?" } { 
      http://www.foo.com/bar? -> http://www.foo.com/bar?p1=v1 
     HTTP::uri "[HTTP::uri]$query_args" 
   } elseif { [HTTP::uri] contains "?" } { 
      http://www.foo.com/bar?a=b -> http://www.foo.com/bar?a=b&p1=v1 
     HTTP::uri "[HTTP::uri]&$query_args" 
   } else { 
      http://www.foo.com/bar -> http://www.foo.com/bar?p1=v1 
     HTTP::uri "[HTTP::uri]?$query_args" 
   } 
 } 
 when HTTP_REQUEST priority 501 { 
   log local0. "[IP::client_addr]:[TCP::client_port]: (501) Updated URI: [HTTP::uri]" 
  
 } 
 

Aaron