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Chris_Lappi_164's avatar
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Jun 14, 2012

iRule routing to pool with URI trimming

I am trying to direct client requests to a specific pool based on URI information. When the URI contains "/pdf" we would like to send them to pool ABC. This works. What doesnt work is when sending them to this pool I would like to trim the /pdf off the URI. Here is an example:



Prior to trim


Post Trim



Below is our iRule. Maybe I am missing something or misunderstanding how it should work but any help would be greatly appreciated.



when HTTP_REQUEST { if {[string tolower [HTTP::host]] eq ""}{ switch -glob [HTTP::uri] { "/pdf/*" { HTTP::uri [string trimleft [HTTP::uri] /pdf] log local0. "Selected Pool:ABC" pool ABC } default { log local0. "Selected Pool:123" pool PL-123 } } } }


1 Reply

  • Hi Chris,

    string trimleft will trim character by character not by the trim string:

    string trimleft string ?chars?

    Returns a value equal to string except that any leading characters from the set given by chars are removed. If chars is not specified then white space is removed (spaces, tabs, newlines, and carriage returns).

    So /pdf/test123 would get rewritten to test123 (without a leading forward slash). This isn't a legal URI so the web app is probably sending back a 400 error for these requests. It would be more precise to use string range to get everything in the URI after the fourth character:

    when HTTP_REQUEST {
    log local0. "[IP::client_addr]:[TCP::client_port]: [HTTP::method] to [virtual name] [HTTP::host][HTTP::uri]"
    if {[string tolower [HTTP::host]] eq ""}{
    switch -glob [HTTP::uri] {
    "/pdf/*" {
    HTTP::uri [string range [HTTP::uri] 4 end /pdf]
    log local0. "[IP::client_addr]:[TCP::client_port]: Selected Pool ABC and trimmed /pdf"
    pool ABC
    default {
    log local0. "[IP::client_addr]:[TCP::client_port]: Selected Pool:123"
    pool PL-123