Locked urlgetopt.txt

[koepp]

#! /bin/sh

##########################################################################

# Title : urlgetopt - decode "urlencoded" forms data (RFC 1866)

# Author :

# Date : 1999-06-27

# Category : CGI, File Conversion

# Requires : -

# SCCS-Id. : @(#) urlgetopt 1.6 05/04/20

##########################################################################

# usage

# urlgetopt [-l] [-p prefix] [urlencoded-data]

# -l: print fields on a separate line

#

# Description

# Data entered within a HTML-FORM is transfered to the HTTP-Server

# using the "application/x-www-form-urlencoded" encoding type

# This script decodes "form-urlencoded" data in a form

# suitable to be used within shell scripts

#

# Example:

# The form-urlencoded string

# name=Heiner+Steven&org=Heiner%27s+SHELLdorado

#

# will be decoded to

# name='Heiner Steven'

# org='Heiner'"'"'s SHELLdorado'

#

# usage example (i.e. from within a CGI script):

#

# eval `urlgetopt -p FORM_ -l "$QUERY_STRING"`

#

# Without "eval":

#

# OIFS=$IFS

# IFS="\n"

# set -- `urlgetopt -l "$QUERY_STRING"`

# IFS=$OIFS

# echo $# arguments:

# for arg

# do

# echo "<$arg>"

# done

#

# Notes

# o Assumes form-data in the format "name=value", but should

# handle other values as well

# o An apostrophe ' within apostrophes cannot be written as '\'' (in sh,

# bash, ksh88), so we use the work around ' "'" '. Using ksh93,

# we could just use $'\''.

# o If the last character of a value in an assignment is an

# apostrophe ('), the printed assignment will contain two

# superfluous apostrophes ('').

#

# Portability

# Solaris 9 "nawk"

# Linux 2.4 "awk" (= GNU awk) 3.1.0

#

# Changes:

# 2005-04-20 claudio allow values with leading whitespace (thanks to

# Claudio Jolowicz ) (1.6)

# 2002-03-26 heiner Handle a "-n" argument correctly (1.4)

# Thanks to Brian Hiles for

# pointing this out.

##########################################################################

 

PN=`basename "$0"` # Program name

VER="1.6"

 

# Set the following variable to shorten startup time. Otherwise the

# directories from the PATH variable will be searched for a suitable AWK

# implementation

#: ${NAWK=nawk} # Set this variable to speed up startup

 

usage () {

echo >&2 "$PN - decode "urlencoded" CGI form data, $VER

usage: $PN [-lF] [-p prefix] [urlencoded-string]

-l: print fields on a separate line

-p: prefix for generated environment variable names

-F: force output of invalid assignments

 

Example:

eval \`urlgetopt -l "\$QUERY_STRING"\`"

exit 1

}

 

# We use "getopts" instead of "getopt" to preserve whitespace within

# arguments.

 

VarPrefix=

LongFormat=no

EvalCheck=true

while getopts :hFlp: opt

do

case "$opt" in

F) EvalCheck=false;;

h) usage;;

l) LongFormat=yes;;

p) VarPrefix=$OPTARG;;

?) usage;;

esac

done

shift `expr $OPTIND - 1`

 

# We need a new AWK program supporting the "gsub()" function.

# Most AWKs (i.e. "gawk") do support it, but some older NAWKs do not.

# Search for a "gsub" capable NAWK using the current PATH.

if [ X"$NAWK" = X ]

then

for path in `echo "$PATH" | sed 's|^:|./ |;s|:$| ./|;s|:| |g'`

do

for awk in $path/*awk

do

[ -f "$awk" -a -x "$awk" ] || continue

case "$awk" in

*.*) continue; # ignore "script.awk"

esac

# Now check for the "gsub()" function

result=`echo "UU" | $awk '{ gsub (/U/, "X"); print }' 2>/dev/null`

[ X"$result" = X"XX" ] || continue

NAWK=$awk; break 2 # Found!

done

done

: ${NAWK:=awk}

fi

 

if [ $# -gt 0 ]

then # Process arguments, if specified...

# Special handling: BSD derived "echo" implementations

# will not echo "-n", but omit the trailing newline. "echo --"

# doesn't work as expected, too, so we add a non-dash character

# as the first character to the "echo", and remove it later on.

 

echo X"$@" |

sed "s/^X//"

else # ...otherwise read standard input

cat

fi |

$NAWK -F'[&]' '

BEGIN {

FieldSep = ("'"$LongFormat"'" == "yes") ? "\n" : " "

VarPrefix = "'"$VarPrefix"'"

evalcheck = ("'"$EvalCheck"'" == "true")

 

Hex ["0"] = 0; Hex ["1"] = 1; Hex ["2"] = 2; Hex ["3"] = 3;

Hex ["4"] = 4; Hex ["5"] = 5; Hex ["6"] = 6; Hex ["7"] = 7;

Hex ["8"] = 8; Hex ["9"] = 9; Hex ["A"] = 10; Hex ["B"] = 11;

Hex ["C"] = 12; Hex ["D"] = 13; Hex ["E"] = 14; Hex ["F"] = 15;

squote = sprintf ("%c", 39)

exitcode = 0

}

{

gsub (/\+/, " ");

 

# Parse assignment separated by "&", e.g. "a=b&c=d&..."

 

for ( field=1; field<=NF; ++field ) {

# Substitute %HH with the "real" character

if ( $field ~ /%[0-9A-F][0-9A-F]/ ) {

newfield = ""

for ( i=1; i<=length ($field); i++ ) {

if ( substr ($field, i, 1) == "%" ) {

dec = Hex [substr ($field, i+1, 1)] * 16 + \

Hex [substr ($field, i+2, 1)]

newfield = sprintf ("%s%c", newfield, dec)

i += 2;

} else {

newfield = newfield substr ($field, i, 1);

}

}

$field = newfield

}

#print "after % processing " $0

 

# Decode "var=value" pairs.

#

# If "evalcheck" is true, we ensure that the result is a

# valid variable assignment:

# 1. it has the form varname=value

# 2. the variable name must be a valid shell

# identifier: start with letter or underscore, followed

# only be letters, underscores or digits

 

if (evalcheck && !match ($field, /^[a-zA-Z_][a-zA-Z_0-9]*=/)) {

print "invalid assignment: " $field | "cat >&2"

exit (exitcode=1);

}

 

# Now parse assignments of the form "a=b".

 

if ( $field ~ /\=/ ) {

newfield = ""

equalseen = 0

fieldlength = length ($field)

for ( i=1; i<=fieldlength; i++ ) {

s = substr ($field, i, 1)

if ( s == "=" ) {

if ( !equalseen ) s = s squote

equalseen = 1

} else if ( equalseen ) { # value

if ( s == squote ) {

# Special handling: since an apostrophe

# (in this example represented by a dot

# .) cannot be quoted using a backslash,

# we use the following work around: we

# replace it with "."

 

if ( i

s = squote """ squote """ squote

} else {

# Special handling: if the last character

# is a single quote, we do not want to add

# "squote" to the end, because this would

# result in two trailing superfluous

# apostrophes.

}

}

}

newfield = newfield s

}

if ( s != squote ) {

$field = newfield squote

} else {

# Special handling: last character was an apostrophe:

$field = newfield """ squote """

}

} else if ( evalcheck ) {

# We cannot get here...

print "invalid assignment: " $field | "cat >&2"

exit (exitcode=1)

}

#print "after = processing " $0

}

 

for ( i=1; i<=NF; ++i ) {

printf ("%s%s", VarPrefix, $i)

if ( i

}

}

END {

exit (exitcode)

}

'