proc init {} {
variable formMap
variable alphanumeric a-zA-Z0-9
for {set i 0} {$i <= 256} {incr i} {
set c [format %c $i]
if {![string match \[$alphanumeric\] $c]} {
set formMap($c) %[format %.2x $i]
}
}
# These are handled specially
array set formMap { " " + \n %0d%0a }
}
init
proc url-encode {string} {
variable map
variable alphanumeric
# The spec says: "non-alphanumeric characters are replaced by '%HH'"
# 1 leave alphanumerics characters alone
# 2 Convert every other character to an array lookup
# 3 Escape constructs that are "special" to the tcl parser
# 4 "subst" the result, doing all the array substitutions
regsub -all \[^$alphanumeric\] $string {$map(&)} string
# This quotes cases like $map([) or $map($) => $map(\[) ...
regsub -all {[][{})\\]\)} $string {\\&} string
return [subst -nocommand $string]
}
proc url-decode str {
# rewrite "+" back to space
# protect \ from quoting another '\'
set str [string map [list + { } "\\" "\\\\"] $str]
# prepare to process all %-escapes
regsub -all -- {%([A-Fa-f0-9][A-Fa-f0-9])} $str {\\u00\1} str
# process \u unicode mapped chars
return [subst -novar -nocommand $str]
}
This is almost exactly source taken from the implementations of http and ncgi.