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TMaCEvans_92750's avatar
TMaCEvans_92750
Icon for Nimbostratus rankNimbostratus
Aug 16, 2011

converting regex to irule

i'm wondering if its possible to carry out the below rules below in an irule?

 

 

article page: match url="^([A-Za-z\-]+)/([A-Za-z\-0-9.]+)/([0-9]+)(/)" url="Full_Article.aspx?art_id={R:3}"

 

 

category archive page: match url="^Archive/([A-Za-z\-0-9.]+)/([0-9]+)/([0-9]+)(/)" url="archive.aspx?cat_id={R:2}&pg={R:3}

 

 

date archive page: match url="^Archive/([0-9]+)\-([0-9]+)/([0-9]+)(/)" url="archive.aspx?mon={R:1}&yr={R:2}&pg={R:3}

 

 

news homepage: match url="^/" url="Home.aspx"

 

 

rss page: match url="^Rss" url="RSS.aspx"
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  • hooleylist's avatar
    hooleylist
    Icon for Cirrostratus rankCirrostratus
    Aug 16, 2011
    Can you give a few sample strings for each case? We should be able to adapt this to iRule code using scan or string commands instead of regexes for better performance.

     

     

    http://devcentral.f5.com/Tutorials/TechTips/tabid/63/articleType/ArticleView/articleId/1086476/iRules-10118Revisiting-the-TCL-Scan-Command.aspx

     

    http://www.tcl.tk/man/tcl8.4/TclCmd/scan.htm

     

     

    Aaron
  • Colin_Walker_12's avatar
    Colin_Walker_12
    Historic F5 Account
    Aug 16, 2011
    The answer is definitely yes. As Aaron indicated, using something other than regular expressions will likely be vastly superior performance wise. Regular expressions are powerful and when necessary iRules can certainly allow you to use them, but we tend to recommend them as a last option.

     

     

    Colin
  • TMaCEvans_92750's avatar
    TMaCEvans_92750
    Icon for Nimbostratus rankNimbostratus
    Aug 25, 2011
    I've managed to get all the rules working accept for this one

     

    category archive page: match url="^Archive/([A-Za-z\-0-9.]+)/([0-9]+)/([0-9]+)(/)" url="archive.aspx?cat_id={R:2}&pg={R:3}

     

     

    } elseif { [scan [HTTP::uri] {/Archive/%[A-Za-z\-0-9.]/%[0-9]/%[0-9]} s1 s2 s3] == 3 } {

     

    scan [HTTP::uri] {/Archive/%[A-Za-z\-0-9.]/%[0-9]/%[0-9]} s1 s2 s3

     

    log -noname local0. "$s1 $s2 $s3"

     

    HTTP::respond 301 Location "http://[HTTP::host]/archive.aspx?cat_id=$s2&pg=$s3"

     

     

    I'm not sure how to simulate the (+) as when i try add it in i get the following error on the f5

     

     

    Aug 25 11:15:12 local/tmm err tmm[5040]: 01220001:3: TCL error: NewsRegex - bad scan conversion character "(" while executing "scan [HTTP::uri] {/Archive/%([A-Za-z\-0-9]+)/%([0-9]+)/%[0-9]} s1 s2 s3"