URI::Escape(3)						User Contributed Perl Documentation					    URI::Escape(3)

NAME

       URI::Escape - Escape and unescape unsafe characters

SYNOPSIS

	use URI::Escape;
	$safe = uri_escape("10% is enough
");
	$verysafe = uri_escape("foo", "-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 character 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-x1fx7f-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)