Forum Discussion

kai_wang_48807's avatar
kai_wang_48807
Icon for Nimbostratus rankNimbostratus
Feb 04, 2007

if syntax help!

1. Whether the if could be nested in iRule?

 

E.g if {} {

 

if {} {

 

}

 

elseif {} {

 

}

 

}

 

 

2. Whether the when could be nested in iRule?

 

E.g when xx {

 

when xx {

 

}

 

}

 

 

Thanks!

 

 

Kai
application delivery
devops
irule editor
iRules
  • Joe_Pruitt's avatar
    Joe_Pruitt
    Feb 05, 2007
    Nested conditional statements are absolutely legal.

    So, this IS legal:

    when HTTP_REQUEST {
  if { condition_1 } {
    if { condition_2 } {
      if { condition_3 } {
      } elseif { condition_4 } {
         and on and on an on...
      } else {
      }
    } elseif { condition_5 } {
    } else {
    }
  } elseif { condition_6 } {
  } else {
  }
}

    But the when statement is a special F5 extension to TCL that allows for event triggering. Think of it like a function in C. These are only allowed at the outermost scope within an iRule.

    This is NOT legal:

    when HTTP_REQUEST {
  when HTTP_RESPONSE {
  }
}

    But, this IS legal:

    when HTTP_REQUEST {
  ...
}
when HTTP_RESPONSE {
  ...
}

    -Joe