Escape(3)

NAME

       URI::Escape - Escape and unescape unsafe characters

SYNOPSIS

        use URI::Escape;
        $safe = uri_escape("10% is enough\n");
        $verysafe = uri_escape("foo", "\0-\377");
        $str  = uri_unescape($safe);

DESCRIPTION

       This module provides functions to escape and unescape URI strings as
       defined by RFC 2396 (and updated by RFC 2732).  URIs consist of a
       restricted set of characters, denoted as "uric" in RFC 2396.  The
       restricted set of characters consists of digits, letters, and a few
       graphic symbols chosen from those common to most of the character
       encodings and input facilities available to Internet users:

         "A" .. "Z", "a" .. "z", "0" .. "9",
         ";", "/", "?", ":", "@", "&", "=", "+", "$", ",", "[", "]",   # reserved
         "-", "_", ".", "!", "~", "*", "'", "(", ")"

       In addition any byte (octet) can be represented in a URI by an escape
       sequence; a triplet consisting of the character "%" followed by two
       hexadecimal digits.  Bytes can also be represented directly by a char-
       acter using the US-ASCII character for that octet (iff the character is
       part of "uric").

       Some of the "uric" characters are reserved for use as delimiters or as
       part of certain URI components.  These must be escaped if they are to
       be treated as ordinary data.  Read RFC 2396 for further details.

       The functions provided (and exported by default) from this module are:

       uri_escape($string, [$unsafe])
           This function replaces all unsafe characters in the $string with
           their escape sequences and returns the result.

           The uri_escape() function takes an optional second argument that
           overrides the set of characters that are to be escaped.  The set is
           specified as a string that can be used in a regular expression
           character class (between [ ]).  E.g.:

             "\x00-\x1f\x7f-\xff"          # all control and hi-bit characters
             "a-z"                         # all lower case characters
             "^A-Za-z"                     # everything not a letter

           The default set of characters to be escaped is all those which are
           not part of the "uric" character class shown above as well as the
           reserved characters.  I.e. the default is:

             "^A-Za-z0-9\-_.!~*'()"

       uri_unescape($string,...)
           Returns a string with all %XX sequences replaced with the actual
           byte (octet).

           This does the same as:

              $string =~ s/%([0-9A-Fa-f]{2})/chr(hex($1))/eg;

           but does not modify the string in-place as this RE would.  Using
           the uri_unescape() function instead of the RE might make the code
           look cleaner and is a few characters less to type.

           In a simple benchmark test I made I got something like 40% slowdown
           by calling the function (instead of the inline RE above) if a few
           chars where unescaped and something like 700% slowdown if none
           where.  If you are going to unescape a lot of times it might be a
           good idea to inline the RE.

           If the uri_unescape() function is passed multiple strings, then
           each one is unescaped returned.

       The module can also export the %escapes hash which contains the mapping
       from all 256 bytes to the corresponding escape code.  Lookup in this
       hash is faster than evaluating "sprintf("%%%02X", ord($byte))" each
       time.

SEE ALSO

       URI

COPYRIGHT

       Copyright 1995-2001 Gisle Aas.

       This program is free software; you can redistribute it and/or modify it
       under the same terms as Perl itself.

perl v5.8.0                       2002-07-18                    URI::Escape(3)