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Gortguy_105156's avatar
Gortguy_105156
Icon for Nimbostratus rankNimbostratus
Aug 31, 2011

Strange issue with "matches_regex" and case sensitivity

I'm a relative newbie to iRules, so please don't laugh if this is too simplistic.

 

 

I also have two environments, call them primary and test. I use essentially the same rule (copy/paste) for the two; they differ only by the pools they direct traffic to which is determined by the URI.

 

 

Here's the rule for the primary site:

 

when HTTP_REQUEST {

 

if {[HTTP::uri] matches_regex "/MyURIString" } {

 

pool alt_pool

 

} else {

 

pool main_pool}

 

}

 

 

The rule for the test site:

 

when HTTP_REQUEST {

 

if {[HTTP::uri] matches_regex "/MyURIString" } {

 

pool alttest_pool

 

} else {

 

pool maintest_pool}

 

}

 

 

 

The rule for the primary site works fine, regardless of the case of the URI.

 

ex: https://mysite.com/MyURIString/page.html = OK

 

https://mysite.com/MYURISTRING/page.html = OK

 

https://mysite.com/myuristring/page.html = OK

 

 

In the test site, however, the URL is case-sensitive:

 

ex: https://mytestsite.com/MyURIString/page.html = OK

 

https://mytestsite.com/myuristring/page.html = broken

 

 

Why would one rule require case-sensitivity while the other does not?

 

application delivery
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  • Michael_Yates's avatar
    Michael_Yates
    Icon for Nimbostratus rankNimbostratus
    Aug 31, 2011
    There is a good write-up that covers case-sensitivity in the URL here: http://www.w3.org/TR/WD-html40-970708/htmlweb.html

     

     

    As a general rule of thumb you should always do your compare with your data in a "known" state, so doing a string tolower will always help and make sure that the compare works.

     

     

    If you change this line to this, it should resolve your problem:

     

    if {[string tolower [HTTP::uri]] matches_regex "/myuristring" } {

     

     

    What operating systems do each over your environments run on? I ask because for the most part IIS hosted Websites are case insensitive, but UNIX hosted applications are case sensitive.
  • Gortguy_105156's avatar
    Gortguy_105156
    Icon for Nimbostratus rankNimbostratus
    Aug 31, 2011
    They're all IIS on the back end, so I know that isn't the case.

     

     

    Thanks for the other information, though. I'll give that a try.
  • hooleylist's avatar
    hooleylist
    Icon for Cirrostratus rankCirrostratus
    Aug 31, 2011
    You should also consider using string functions instead of regexes if you can:

     

     

    if {[string tolower [HTTP::uri]] starts_with "/myuristring" } {

     

     

    Aaron
  • naladar_65658's avatar
    naladar_65658
    Icon for Altostratus rankAltostratus
    Sep 01, 2011
    Hey Gort,

     

     

    Are the BIG-IP's that you are using running two different version of TMOS or are they at different patch levels?
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