mirror of
https://github.com/ezyang/htmlpurifier.git
synced 2024-11-10 07:38:41 +00:00
24cde9c891
git-svn-id: http://htmlpurifier.org/svnroot/htmlpurifier/trunk@327 48356398-32a2-884e-a903-53898d9a118a
475 lines
18 KiB
PHP
475 lines
18 KiB
PHP
<?php
|
|
|
|
require_once 'HTMLPurifier/Token.php';
|
|
|
|
HTMLPurifier_ConfigDef::define(
|
|
'Core', 'AcceptFullDocuments', true, 'bool',
|
|
'This parameter determines whether or not the filter should accept full '.
|
|
'HTML documents, not just HTML fragments. When on, it will '.
|
|
'drop all sections except the content between body. Depending on '.
|
|
'the implementation in use, this may speed up document parse times.'
|
|
);
|
|
|
|
/**
|
|
* Forgivingly lexes HTML (SGML-style) markup into tokens.
|
|
*
|
|
* A lexer parses a string of SGML-style markup and converts them into
|
|
* corresponding tokens. It doesn't check for well-formedness, although its
|
|
* internal mechanism may make this automatic (such as the case of
|
|
* HTMLPurifier_Lexer_DOMLex). There are several implementations to choose
|
|
* from.
|
|
*
|
|
* A lexer is HTML-oriented: it might work with XML, but it's not
|
|
* recommended, as we adhere to a subset of the specification for optimization
|
|
* reasons.
|
|
*
|
|
* This class should not be directly instantiated, but you may use create() to
|
|
* retrieve a default copy of the lexer. Being a supertype, this class
|
|
* does not actually define any implementation, but offers commonly used
|
|
* convenience functions for subclasses.
|
|
*
|
|
* @note The unit tests will instantiate this class for testing purposes, as
|
|
* many of the utility functions require a class to be instantiated.
|
|
* Be careful when porting this class to PHP 5.
|
|
*
|
|
* @par
|
|
*
|
|
* @note
|
|
* We use tokens rather than create a DOM representation because DOM would:
|
|
*
|
|
* @par
|
|
* -# Require more processing power to create,
|
|
* -# Require recursion to iterate,
|
|
* -# Must be compatible with PHP 5's DOM (otherwise duplication),
|
|
* -# Has the entire document structure (html and body not needed), and
|
|
* -# Has unknown readability improvement.
|
|
*
|
|
* @par
|
|
* What the last item means is that the functions for manipulating tokens are
|
|
* already fairly compact, and when well-commented, more abstraction may not
|
|
* be needed.
|
|
*
|
|
* @see HTMLPurifier_Token
|
|
*/
|
|
class HTMLPurifier_Lexer
|
|
{
|
|
|
|
/**
|
|
* Lexes an HTML string into tokens.
|
|
*
|
|
* @param $string String HTML.
|
|
* @return HTMLPurifier_Token array representation of HTML.
|
|
*/
|
|
function tokenizeHTML($string, $config = null) {
|
|
trigger_error('Call to abstract class', E_USER_ERROR);
|
|
}
|
|
|
|
/**
|
|
* Retrieves or sets the default Lexer as a Prototype Factory.
|
|
*
|
|
* Depending on what PHP version you are running, the abstract base
|
|
* Lexer class will determine which concrete Lexer is best for you:
|
|
* HTMLPurifier_Lexer_DirectLex for PHP 4, and HTMLPurifier_Lexer_DOMLex
|
|
* for PHP 5 and beyond.
|
|
*
|
|
* Passing the optional prototype lexer parameter will override the
|
|
* default with your own implementation. A copy/reference of the prototype
|
|
* lexer will now be returned when you request a new lexer.
|
|
*
|
|
* @note
|
|
* Though it is possible to call this factory method from subclasses,
|
|
* such usage is not recommended.
|
|
*
|
|
* @param $prototype Optional prototype lexer.
|
|
* @return Concrete lexer.
|
|
*/
|
|
function create($prototype = null) {
|
|
// we don't really care if it's a reference or a copy
|
|
static $lexer = null;
|
|
if ($prototype) {
|
|
$lexer = $prototype;
|
|
}
|
|
if (empty($lexer)) {
|
|
if (version_compare(PHP_VERSION, '5', '>=')) {
|
|
require_once 'HTMLPurifier/Lexer/DOMLex.php';
|
|
$lexer = new HTMLPurifier_Lexer_DOMLex();
|
|
} else {
|
|
require_once 'HTMLPurifier/Lexer/DirectLex.php';
|
|
$lexer = new HTMLPurifier_Lexer_DirectLex();
|
|
}
|
|
}
|
|
return $lexer;
|
|
}
|
|
|
|
/**
|
|
* Decimal to parsed string conversion table for special entities.
|
|
* @protected
|
|
*/
|
|
var $_special_dec2str =
|
|
array(
|
|
34 => '"',
|
|
38 => '&',
|
|
39 => "'",
|
|
60 => '<',
|
|
62 => '>'
|
|
);
|
|
|
|
/**
|
|
* Stripped entity names to decimal conversion table for special entities.
|
|
* @protected
|
|
*/
|
|
var $_special_ent2dec =
|
|
array(
|
|
'quot' => 34,
|
|
'amp' => 38,
|
|
'lt' => 60,
|
|
'gt' => 62
|
|
);
|
|
|
|
/**
|
|
* Most common entity to raw value conversion table for special entities.
|
|
* @protected
|
|
*/
|
|
var $_special_entity2str =
|
|
array(
|
|
'"' => '"',
|
|
'&' => '&',
|
|
'<' => '<',
|
|
'>' => '>',
|
|
''' => "'",
|
|
''' => "'",
|
|
''' => "'"
|
|
);
|
|
|
|
/**
|
|
* Callback regex string for parsing entities.
|
|
* @protected
|
|
*/
|
|
var $_substituteEntitiesRegex =
|
|
'/&(?:[#]x([a-fA-F0-9]+)|[#]0*(\d+)|([A-Za-z]+));?/';
|
|
// 1. hex 2. dec 3. string
|
|
|
|
/**
|
|
* Substitutes non-special entities with their parsed equivalents. Since
|
|
* running this whenever you have parsed character is t3h 5uck, we run
|
|
* it before everything else.
|
|
*
|
|
* @protected
|
|
* @param $string String to have non-special entities parsed.
|
|
* @returns Parsed string.
|
|
*/
|
|
function substituteNonSpecialEntities($string) {
|
|
// it will try to detect missing semicolons, but don't rely on it
|
|
return preg_replace_callback(
|
|
$this->_substituteEntitiesRegex,
|
|
array($this, 'nonSpecialEntityCallback'),
|
|
$string
|
|
);
|
|
}
|
|
|
|
/**
|
|
* Callback function for substituteNonSpecialEntities() that does the work.
|
|
*
|
|
* @warning Though this is public in order to let the callback happen,
|
|
* calling it directly is not recommended.
|
|
* @note Based on Feyd's function at
|
|
* <http://forums.devnetwork.net/viewtopic.php?p=191404#191404>,
|
|
* which is in public domain.
|
|
* @note While we're going to do code point parsing anyway, a good
|
|
* optimization would be to refuse to translate code points that
|
|
* are non-SGML characters. However, this could lead to duplication.
|
|
* @param $matches PCRE matches array, with 0 the entire match, and
|
|
* either index 1, 2 or 3 set with a hex value, dec value,
|
|
* or string (respectively).
|
|
* @returns Replacement string.
|
|
* @todo Implement string translations
|
|
*/
|
|
|
|
// +----------+----------+----------+----------+
|
|
// | 33222222 | 22221111 | 111111 | |
|
|
// | 10987654 | 32109876 | 54321098 | 76543210 | bit
|
|
// +----------+----------+----------+----------+
|
|
// | | | | 0xxxxxxx | 1 byte 0x00000000..0x0000007F
|
|
// | | | 110yyyyy | 10xxxxxx | 2 byte 0x00000080..0x000007FF
|
|
// | | 1110zzzz | 10yyyyyy | 10xxxxxx | 3 byte 0x00000800..0x0000FFFF
|
|
// | 11110www | 10wwzzzz | 10yyyyyy | 10xxxxxx | 4 byte 0x00010000..0x0010FFFF
|
|
// +----------+----------+----------+----------+
|
|
// | 00000000 | 00011111 | 11111111 | 11111111 | Theoretical upper limit of legal scalars: 2097151 (0x001FFFFF)
|
|
// | 00000000 | 00010000 | 11111111 | 11111111 | Defined upper limit of legal scalar codes
|
|
// +----------+----------+----------+----------+
|
|
|
|
function nonSpecialEntityCallback($matches) {
|
|
// replaces all but big five
|
|
$entity = $matches[0];
|
|
$is_num = (@$matches[0][1] === '#');
|
|
if ($is_num) {
|
|
$is_hex = (@$entity[2] === 'x');
|
|
$code = $is_hex ? hexdec($matches[1]) : (int) $matches[2];
|
|
|
|
// abort for special characters
|
|
if (isset($this->_special_dec2str[$code])) return $entity;
|
|
|
|
if($code > 1114111 or $code < 0 or
|
|
($code >= 55296 and $code <= 57343) ) {
|
|
// bits are set outside the "valid" range as defined
|
|
// by UNICODE 4.1.0
|
|
return '';
|
|
}
|
|
|
|
$x = $y = $z = $w = 0;
|
|
if ($code < 128) {
|
|
// regular ASCII character
|
|
$x = $code;
|
|
} else {
|
|
// set up bits for UTF-8
|
|
$x = ($code & 63) | 128;
|
|
if ($code < 2048) {
|
|
$y = (($code & 2047) >> 6) | 192;
|
|
} else {
|
|
$y = (($code & 4032) >> 6) | 128;
|
|
if($code < 65536) {
|
|
$z = (($code >> 12) & 15) | 224;
|
|
} else {
|
|
$z = (($code >> 12) & 63) | 128;
|
|
$w = (($code >> 18) & 7) | 240;
|
|
}
|
|
}
|
|
}
|
|
// set up the actual character
|
|
$ret = '';
|
|
if($w) $ret .= chr($w);
|
|
if($z) $ret .= chr($z);
|
|
if($y) $ret .= chr($y);
|
|
$ret .= chr($x);
|
|
|
|
return $ret;
|
|
} else {
|
|
if (isset($this->_special_ent2dec[$matches[3]])) return $entity;
|
|
if (!$this->_entity_lookup) {
|
|
require_once 'HTMLPurifier/EntityLookup.php';
|
|
$this->_entity_lookup = HTMLPurifier_EntityLookup::instance();
|
|
}
|
|
if (isset($this->_entity_lookup->table[$matches[3]])) {
|
|
return $this->_entity_lookup->table[$matches[3]];
|
|
} else {
|
|
return $entity;
|
|
}
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Contains a copy of the EntityLookup table.
|
|
* @protected
|
|
*/
|
|
var $_entity_lookup;
|
|
|
|
/**
|
|
* Translates CDATA sections into regular sections (through escaping).
|
|
*
|
|
* @protected
|
|
* @param $string HTML string to process.
|
|
* @returns HTML with CDATA sections escaped.
|
|
*/
|
|
function escapeCDATA($string) {
|
|
return preg_replace_callback(
|
|
'/<!\[CDATA\[(.+?)\]\]>/',
|
|
array('HTMLPurifier_Lexer', 'CDATACallback'),
|
|
$string
|
|
);
|
|
}
|
|
|
|
/**
|
|
* Callback function for escapeCDATA() that does the work.
|
|
*
|
|
* @warning Though this is public in order to let the callback happen,
|
|
* calling it directly is not recommended.
|
|
* @params $matches PCRE matches array, with index 0 the entire match
|
|
* and 1 the inside of the CDATA section.
|
|
* @returns Escaped internals of the CDATA section.
|
|
*/
|
|
function CDATACallback($matches) {
|
|
// not exactly sure why the character set is needed, but whatever
|
|
return htmlspecialchars($matches[1], ENT_COMPAT, 'UTF-8');
|
|
}
|
|
|
|
/**
|
|
* Takes a string of HTML (fragment or document) and returns the content
|
|
*/
|
|
function extractBody($html, $return_bool = false) {
|
|
$matches = array();
|
|
$result = preg_match('!<body[^>]*>(.+?)</body>!is', $html, $matches);
|
|
if ($return_bool) return $result;
|
|
if ($result) {
|
|
return $matches[1];
|
|
} else {
|
|
return $html;
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Cleans a UTF-8 string for well-formedness and SGML validity
|
|
*
|
|
* It will parse according to UTF-8 and return a valid UTF8 string, with
|
|
* non-SGML codepoints excluded.
|
|
*
|
|
* @warning This function can find a lot of use, so we may be moving
|
|
* it to a dedicated class.
|
|
*
|
|
* @note Just for reference, the non-SGML code points are 0 to 31 and
|
|
* 127 to 159, inclusive. However, we allow code points 9, 10
|
|
* and 13, which are the tab, line feed and carriage return
|
|
* respectively. 128 and above the code points map to multibyte
|
|
* UTF-8 representations.
|
|
*
|
|
* @note The functionality provided by the original function could be
|
|
* implemented with iconv using 'UTF-8//IGNORE', mbstring, or
|
|
* even the PCRE modifier 'u', these do not allow us to strip
|
|
* control characters or disallowed code points, and the latter
|
|
* does not allow invalid UTF8 characters to be ignored.
|
|
*
|
|
* @note Decomposing the string into Unicode code points is necessary
|
|
* because SGML disallows the use of specific code points, not
|
|
* necessarily bytes. A naive implementation that simply strtr
|
|
* disallowed code points as bytes will break other Unicode
|
|
* characters in which using such bytes is valid.
|
|
*
|
|
* @note Code adapted from utf8ToUnicode by Henri Sivonen and
|
|
* hsivonen@iki.fi at <http://iki.fi/hsivonen/php-utf8/> under the
|
|
* LGPL license. Notes on what changed are inside.
|
|
*/
|
|
function cleanUTF8($str) {
|
|
$mState = 0; // cached expected number of octets after the current octet
|
|
// until the beginning of the next UTF8 character sequence
|
|
$mUcs4 = 0; // cached Unicode character
|
|
$mBytes = 1; // cached expected number of octets in the current sequence
|
|
|
|
// original code involved an $out that was an array of Unicode
|
|
// codepoints. Instead of having to convert back into UTF-8, we've
|
|
// decided to directly append valid UTF-8 characters onto a string
|
|
// $out once they're done. $char accumulates raw bytes, while $mUcs4
|
|
// turns into the Unicode code point, so there's some redundancy.
|
|
|
|
$out = '';
|
|
$char = '';
|
|
|
|
$len = strlen($str);
|
|
for($i = 0; $i < $len; $i++) {
|
|
$in = ord($str{$i});
|
|
$char .= $str[$i]; // append byte to char
|
|
if (0 == $mState) {
|
|
// When mState is zero we expect either a US-ASCII character
|
|
// or a multi-octet sequence.
|
|
if (0 == (0x80 & ($in))) {
|
|
// US-ASCII, pass straight through.
|
|
if (($in <= 31 || $in == 127) &&
|
|
!($in == 9 || $in == 13 || $in == 10) // save \r\t\n
|
|
) {
|
|
// control characters, remove
|
|
} else {
|
|
$out .= $char;
|
|
}
|
|
// reset
|
|
$char = '';
|
|
$mBytes = 1;
|
|
} elseif (0xC0 == (0xE0 & ($in))) {
|
|
// First octet of 2 octet sequence
|
|
$mUcs4 = ($in);
|
|
$mUcs4 = ($mUcs4 & 0x1F) << 6;
|
|
$mState = 1;
|
|
$mBytes = 2;
|
|
} elseif (0xE0 == (0xF0 & ($in))) {
|
|
// First octet of 3 octet sequence
|
|
$mUcs4 = ($in);
|
|
$mUcs4 = ($mUcs4 & 0x0F) << 12;
|
|
$mState = 2;
|
|
$mBytes = 3;
|
|
} elseif (0xF0 == (0xF8 & ($in))) {
|
|
// First octet of 4 octet sequence
|
|
$mUcs4 = ($in);
|
|
$mUcs4 = ($mUcs4 & 0x07) << 18;
|
|
$mState = 3;
|
|
$mBytes = 4;
|
|
} elseif (0xF8 == (0xFC & ($in))) {
|
|
// First octet of 5 octet sequence.
|
|
//
|
|
// This is illegal because the encoded codepoint must be
|
|
// either:
|
|
// (a) not the shortest form or
|
|
// (b) outside the Unicode range of 0-0x10FFFF.
|
|
// Rather than trying to resynchronize, we will carry on
|
|
// until the end of the sequence and let the later error
|
|
// handling code catch it.
|
|
$mUcs4 = ($in);
|
|
$mUcs4 = ($mUcs4 & 0x03) << 24;
|
|
$mState = 4;
|
|
$mBytes = 5;
|
|
} elseif (0xFC == (0xFE & ($in))) {
|
|
// First octet of 6 octet sequence, see comments for 5
|
|
// octet sequence.
|
|
$mUcs4 = ($in);
|
|
$mUcs4 = ($mUcs4 & 1) << 30;
|
|
$mState = 5;
|
|
$mBytes = 6;
|
|
} else {
|
|
// Current octet is neither in the US-ASCII range nor a
|
|
// legal first octet of a multi-octet sequence.
|
|
$mState = 0;
|
|
$mUcs4 = 0;
|
|
$mBytes = 1;
|
|
$char = '';
|
|
}
|
|
} else {
|
|
// When mState is non-zero, we expect a continuation of the
|
|
// multi-octet sequence
|
|
if (0x80 == (0xC0 & ($in))) {
|
|
// Legal continuation.
|
|
$shift = ($mState - 1) * 6;
|
|
$tmp = $in;
|
|
$tmp = ($tmp & 0x0000003F) << $shift;
|
|
$mUcs4 |= $tmp;
|
|
|
|
if (0 == --$mState) {
|
|
// End of the multi-octet sequence. mUcs4 now contains
|
|
// the final Unicode codepoint to be output
|
|
|
|
// Check for illegal sequences and codepoints.
|
|
|
|
// From Unicode 3.1, non-shortest form is illegal
|
|
if (((2 == $mBytes) && ($mUcs4 < 0x0080)) ||
|
|
((3 == $mBytes) && ($mUcs4 < 0x0800)) ||
|
|
((4 == $mBytes) && ($mUcs4 < 0x10000)) ||
|
|
(4 < $mBytes) ||
|
|
// From Unicode 3.2, surrogate characters = illegal
|
|
(($mUcs4 & 0xFFFFF800) == 0xD800) ||
|
|
// Codepoints outside the Unicode range are illegal
|
|
($mUcs4 > 0x10FFFF)
|
|
) {
|
|
|
|
} elseif (0xFEFF != $mUcs4 && // omit BOM
|
|
!($mUcs4 >= 128 && $mUcs4 <= 159) // omit non-SGML
|
|
) {
|
|
$out .= $char;
|
|
}
|
|
// initialize UTF8 cache (reset)
|
|
$mState = 0;
|
|
$mUcs4 = 0;
|
|
$mBytes = 1;
|
|
$char = '';
|
|
}
|
|
} else {
|
|
// ((0xC0 & (*in) != 0x80) && (mState != 0))
|
|
// Incomplete multi-octet sequence.
|
|
// used to result in complete fail, but we'll reset
|
|
$mState = 0;
|
|
$mUcs4 = 0;
|
|
$mBytes = 1;
|
|
$char ='';
|
|
}
|
|
}
|
|
}
|
|
return $out;
|
|
}
|
|
|
|
}
|
|
|
|
?>
|