Edit File: URI::Escape.3pm
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Always turn off hyphenation; it makes .\" way too many mistakes in technical documents. .if n .ad l .nh .SH "NAME" URI::Escape \- Percent\-encode and percent\-decode unsafe characters .SH "SYNOPSIS" .IX Header "SYNOPSIS" .Vb 4 \& use URI::Escape; \& $safe = uri_escape("10% is enough\en"); \& $verysafe = uri_escape("foo", "\e0\-\e377"); \& $str = uri_unescape($safe); .Ve .SH "DESCRIPTION" .IX Header "DESCRIPTION" This module provides functions to percent-encode and percent-decode \s-1URI\s0 strings as defined by \s-1RFC\s0 3986. Percent-encoding \s-1URI\s0's is informally called \*(L"\s-1URI\s0 escaping\*(R". This is the terminology used by this module, which predates the formalization of the terms by the \s-1RFC\s0 by several years. .PP A \s-1URI\s0 consists of a restricted set of characters. 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. They are made up of the \&\*(L"unreserved\*(R" and \*(L"reserved\*(R" character sets as defined in \s-1RFC\s0 3986. .PP .Vb 4 \& unreserved = ALPHA / DIGIT / "\-" / "." / "_" / "~" \& reserved = ":" / "/" / "?" / "#" / "[" / "]" / "@" \& "!" / "$" / "&" / "\*(Aq" / "(" / ")" \& / "*" / "+" / "," / ";" / "=" .Ve .PP In addition, any byte (octet) can be represented in a \s-1URI\s0 by an escape sequence: a triplet consisting of the character \*(L"%\*(R" followed by two hexadecimal digits. A byte can also be represented directly by a character, using the US-ASCII character for that octet. .PP Some of the characters are \fIreserved\fR for use as delimiters or as part of certain \s-1URI\s0 components. These must be escaped if they are to be treated as ordinary data. Read \s-1RFC\s0 3986 for further details. .PP The functions provided (and exported by default) from this module are: .ie n .IP "uri_escape( $string )" 4 .el .IP "uri_escape( \f(CW$string\fR )" 4 .IX Item "uri_escape( $string )" .PD 0 .ie n .IP "uri_escape( $string, $unsafe )" 4 .el .IP "uri_escape( \f(CW$string\fR, \f(CW$unsafe\fR )" 4 .IX Item "uri_escape( $string, $unsafe )" .PD Replaces each unsafe character in the \f(CW$string\fR with the corresponding escape sequence and returns the result. The \f(CW$string\fR argument should be a string of bytes. The \fIuri_escape()\fR function will croak if given a characters with code above 255. Use \fIuri_escape_utf8()\fR if you know you have such chars or/and want chars in the 128 .. 255 range treated as \&\s-1UTF\-8\s0. .Sp The \fIuri_escape()\fR 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.: .Sp .Vb 3 \& "\ex00\-\ex1f\ex7f\-\exff" # all control and hi\-bit characters \& "a\-z" # all lower case characters \& "^A\-Za\-z" # everything not a letter .Ve .Sp The default set of characters to be escaped is all those which are \&\fInot\fR part of the \f(CW\*(C`unreserved\*(C'\fR character class shown above as well as the reserved characters. I.e. the default is: .Sp .Vb 1 \& "^A\-Za\-z0\-9\e\-\e._~" .Ve .ie n .IP "uri_escape_utf8( $string )" 4 .el .IP "uri_escape_utf8( \f(CW$string\fR )" 4 .IX Item "uri_escape_utf8( $string )" .PD 0 .ie n .IP "uri_escape_utf8( $string, $unsafe )" 4 .el .IP "uri_escape_utf8( \f(CW$string\fR, \f(CW$unsafe\fR )" 4 .IX Item "uri_escape_utf8( $string, $unsafe )" .PD Works like \fIuri_escape()\fR, but will encode chars as \s-1UTF\-8\s0 before escaping them. This makes this function able to deal with characters with code above 255 in \f(CW$string\fR. Note that chars in the 128 .. 255 range will be escaped differently by this function compared to what \&\fIuri_escape()\fR would. For chars in the 0 .. 127 range there is no difference. .Sp Equivalent to: .Sp .Vb 2 \& utf8::encode($string); \& my $uri = uri_escape($string); .Ve .Sp Note: JavaScript has a function called \fIescape()\fR that produces the sequence \*(L"%uXXXX\*(R" for chars in the 256 .. 65535 range. This function has really nothing to do with \s-1URI\s0 escaping but some folks got confused since it \*(L"does the right thing\*(R" in the 0 .. 255 range. Because of this you sometimes see \*(L"URIs\*(R" with these kind of escapes. The JavaScript \fIencodeURIComponent()\fR function is similar to \fIuri_escape_utf8()\fR. .IP "uri_unescape($string,...)" 4 .IX Item "uri_unescape($string,...)" Returns a string with each \f(CW%XX\fR sequence replaced with the actual byte (octet). .Sp This does the same as: .Sp .Vb 1 \& $string =~ s/%([0\-9A\-Fa\-f]{2})/chr(hex($1))/eg; .Ve .Sp but does not modify the string in-place as this \s-1RE\s0 would. Using the \&\fIuri_unescape()\fR function instead of the \s-1RE\s0 might make the code look cleaner and is a few characters less to type. .Sp In a simple benchmark test I did, calling the function (instead of the inline \s-1RE\s0 above) if a few chars were unescaped was something like 40% slower, and something like 700% slower if none were. If you are going to unescape a lot of times it might be a good idea to inline the \s-1RE\s0. .Sp If the \fIuri_unescape()\fR function is passed multiple strings, then each one is returned unescaped. .PP The module can also export the \f(CW%escapes\fR hash, which contains the mapping from all 256 bytes to the corresponding escape codes. Lookup in this hash is faster than evaluating \f(CW\*(C`sprintf("%%%02X", ord($byte))\*(C'\fR each time. .SH "SEE ALSO" .IX Header "SEE ALSO" \&\s-1URI\s0 .SH "COPYRIGHT" .IX Header "COPYRIGHT" Copyright 1995\-2004 Gisle Aas. .PP This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.
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