<?php
/**
* Removes all unrecognized tags from the list of tokens.
*
* This strategy iterates through all the tokens and removes unrecognized
* tokens. If a token is not recognized but a TagTransform is defined for
* that element, the element will be transformed accordingly.
*/
class HTMLPurifier_Strategy_RemoveForeignElements extends HTMLPurifier_Strategy
{
/**
* @param HTMLPurifier_Token[] $tokens
* @param HTMLPurifier_Config $config
* @param HTMLPurifier_Context $context
* @return array|HTMLPurifier_Token[]
*/
public function execute($tokens, $config, $context)
{
$definition = $config->getHTMLDefinition();
$generator = new HTMLPurifier_Generator($config, $context);
$result = array();
$escape_invalid_tags = $config->get('Core.EscapeInvalidTags');
$remove_invalid_img = $config->get('Core.RemoveInvalidImg');
// currently only used to determine if comments should be kept
$trusted = $config->get('HTML.Trusted');
$comment_lookup = $config->get('HTML.AllowedComments');
$comment_regexp = $config->get('HTML.AllowedCommentsRegexp');
$check_comments = $comment_lookup !== array() || $comment_regexp !== null;
$remove_script_contents = $config->get('Core.RemoveScriptContents');
$hidden_elements = $config->get('Core.HiddenElements');
// remove script contents compatibility
if ($remove_script_contents === true) {
$hidden_elements['script'] = true;
} elseif ($remove_script_contents === false && isset($hidden_elements['script'])) {
unset($hidden_elements['script']);
}
$attr_validator = new HTMLPurifier_AttrValidator();
// removes tokens until it reaches a closing tag with its value
$remove_until = false;
// converts comments into text tokens when this is equal to a tag name
$textify_comments = false;
$token = false;
$context->register('CurrentToken', $token);
$e = false;
if ($config->get('Core.CollectErrors')) {
$e =& $context->get('ErrorCollector');
}
foreach ($tokens as $token) {
if ($remove_until) {
if (empty($token->is_tag) || $token->name !== $remove_until) {
continue;
}
}
if (!empty($token->is_tag)) {
// DEFINITION CALL
// before any processing, try to transform the element
if (isset($definition->info_tag_transform[$token->name])) {
$original_name = $token->name;
// there is a transformation for this tag
// DEFINITION CALL
$token = $definition->
info_tag_transform[$token->name]->transform($token, $config, $context);
if ($e) {
$e->send(E_NOTICE, 'Strategy_RemoveForeignElements: Tag transform', $original_name);
}
}
if (isset($definition->info[$token->name])) {
// mostly everything's good, but
// we need to make sure required attributes are in order
if (($token instanceof HTMLPurifier_Token_Start || $token instanceof HTMLPurifier_Token_Empty) &&
$definition->info[$token->name]->required_attr &&
($token->name != 'img' || $remove_invalid_img) // ensure config option still works
) {
$attr_validator->validateToken($token, $config, $context);
$ok = true;
foreach ($definition->info[$token->name]->required_attr as $name) {
if (!isset($token->attr[$name])) {
$ok = false;
break;
}
}
if (!$ok) {
if ($e) {
$e->send(
E_ERROR,
'Strategy_RemoveForeignElements: Missing required attribute',
$name
);
}
continue;
}
$token->armor['ValidateAttributes'] = true;
}
if (isset($hidden_elements[$token->name]) && $token instanceof HTMLPurifier_Token_Start) {
$textify_comments = $token->name;
} elseif ($token->name === $textify_comments && $token instanceof HTMLPurifier_Token_End) {
$textify_comments = false;
}
} elseif ($escape_invalid_tags) {
// invalid tag, generate HTML representation and insert in
if ($e) {
$e->send(E_WARNING, 'Strategy_RemoveForeignElements: Foreign element to text');
}
$token = new HTMLPurifier_Token_Text(
$generator->generateFromToken($token)
);
} else {
// check if we need to destroy all of the tag's children
// CAN BE GENERICIZED
if (isset($hidden_elements[$token->name])) {
if ($token instanceof HTMLPurifier_Token_Start) {
$remove_until = $token->name;
} elseif ($token instanceof HTMLPurifier_Token_Empty) {
// do nothing: we're still looking
} else {
$remove_until = false;
}
if ($e) {
$e->send(E_ERROR, 'Strategy_RemoveForeignElements: Foreign meta element removed');
}
} else {
if ($e) {
$e->send(E_ERROR, 'Strategy_RemoveForeignElements: Foreign element removed');
}
}
continue;
}
} elseif ($token instanceof HTMLPurifier_Token_Comment) {
// textify comments in script tags when they are allowed
if ($textify_comments !== false) {
$data = $token->data;
$token = new HTMLPurifier_Token_Text($data);
} elseif ($trusted || $check_comments) {
// always cleanup comments
$trailing_hyphen = false;
if ($e) {
// perform check whether or not there's a trailing hyphen
if (substr($token->data, -1) == '-') {
$trailing_hyphen = true;
}
}
$token->data = rtrim($token->data, '-');
$found_double_hyphen = false;
while (strpos($token->data, '--') !== false) {
$found_double_hyphen = true;
$token->data = str_replace('--', '-', $token->data);
}
if ($trusted || !empty($comment_lookup[trim($token->data)]) ||
($comment_regexp !== null && preg_match($comment_regexp, trim($token->data)))) {
// OK good
if ($e) {
if ($trailing_hyphen) {
$e->send(
E_NOTICE,
'Strategy_RemoveForeignElements: Trailing hyphen in comment removed'
);
}
if ($found_double_hyphen) {
$e->send(E_NOTICE, 'Strategy_RemoveForeignElements: Hyphens in comment collapsed');
}
}
} else {
if ($e) {
$e->send(E_NOTICE, 'Strategy_RemoveForeignElements: Comment removed');
}
continue;
}
} else {
// strip comments
if ($e) {
$e->send(E_NOTICE, 'Strategy_RemoveForeignElements: Comment removed');
}
continue;
}
} elseif ($token instanceof HTMLPurifier_Token_Text) {
} else {
continue;
}
$result[] = $token;
}
if ($remove_until && $e) {
// we removed tokens until the end, throw error
$e->send(E_ERROR, 'Strategy_RemoveForeignElements: Token removed to end', $remove_until);
}
$context->destroy('CurrentToken');
return $result;
}
}
// vim: et sw=4 sts=4
