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Yaoxie_117356's avatar
Yaoxie_117356
Icon for Nimbostratus rankNimbostratus
Jul 05, 2016

basic question about variable assign

Hi folk,

 

very new to APM, have a lot questions on assign variable

 

why sometimes it's

 

variables { { expression "mcget {session.logon.last.username}" varname session.sso.token.last.username } { expression "mcget {session.logon.last.password}" varname session.sso.token.last.password } }

 

but sometimes it has another "expr" in front, what's the difference?

 

variables { { expression "expr {[mcget {session.logon.last.password}]}" varname session.logon.last.password2 } }

 

APM
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  • Josiah_39459's avatar
    Josiah_39459
    Historic F5 Account
    Jul 05, 2016

    expr just tells it to evaluate the string, so "1+1" without expr would be "1+1" and with expr would be 2. People tend to use it a lot when it's not necessarily needed. Personally, I prefer using "return" and returning explicitly what I want.

     

  • Saravanan_M_K's avatar
    Saravanan_M_K
    Icon for Employee rankEmployee
    Jul 05, 2016
    variables { 
  { 
    expression "expr {[mcget {session.logon.last.password}]}" 
    varname session.logon.last.password2 
  }
}

    In your example, the expr is actually not needed. The above will produce the same result as in the config:

    variables { 
  { 
    expression "mcget {session.logon.last.password}" 
    varname session.logon.last.password2 
  }
}

    However, you can evaluate any tcl expression using "expr". For example:

    variables {
  {
    expression "expr {[string tolower [mcget {session.logon.last.username}]]}"
    varname session.custom.user
  }
}