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NetSnoopy's avatar
NetSnoopy
Icon for Cirrus rankCirrus
Apr 13, 2017

Base64 ( b64encode) vs Base64Url Encode and Base64UrlDecode

Hello all,

The last days i had a lot of problems to build a iRule that contains strings with Base64UrlEncode. URLencode means replace "+" to "-" and "/" to "_" and cut trailing "=".

  1. URI::encode is not URL encode
  2. first do a b64encode
  3. replace string with "[string map [list + - \/ _ = "" ] $var]"

In a Irule shows like:

set var_b64_url "[string map [list + - \/ _ = "" ] [b64encode "$var"]"

But i do not have a solution to do this revers for Base64UrlDecode

my idea is 

set var_b64 "[string map [list - + _ \/ ] $var_b64_url"]"
set var_decode "[b64decode $var_b64]"

But i don't have a solution for the trailing "=" ?

Cheers, NetSnoopy

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  • cjunior's avatar
    cjunior
    Icon for Nacreous rankNacreous
    Apr 13, 2017

    Hi, it is an interesting your request, so I'll not ask what you are intending and just try a statement.

    set var_b64 "[string map [list - + _ \/ ] $var_b64_url]"
if { [string length $var_b64] % 4 != 0 } {
    append var_b64 [string repeat = [expr {4 - [string length $var_b64] % 4}]]
}

    I hope it helps you.