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Don't use DOMs as encoding signals

Instead convert UTF-16 and manipulate XML declarations
domparser
J. King 1 year ago
parent
commit
fbdd72cf7f
  1. 48
      lib/DOMParser.php

48
lib/DOMParser.php

@ -11,12 +11,22 @@ use MensBeam\Intl\Encoding;
/** The DOMParser interface allows authors to create new DOMDocument objects by parsing strings, as either HTML or XML */ /** The DOMParser interface allows authors to create new DOMDocument objects by parsing strings, as either HTML or XML */
class DOMParser { class DOMParser {
/** @var A UTF-8 byte order mark */ /** @var string A UTF-8 byte order mark */
protected const BOM_UTF8 = "\xEF\xBB\xBF"; protected const BOM_UTF8 = "\xEF\xBB\xBF";
/** @var A UTF-16 (big-endian) byte order mark */ /** @var string A UTF-16 (big-endian) byte order mark */
protected const BOM_UTF16BE = "\xFE\xFF"; protected const BOM_UTF16BE = "\xFE\xFF";
/** @var A UTF-16 (little-endian) byte order mark */ /** @var string A UTF-16 (little-endian) byte order mark */
protected const BOM_UTF16LE = "\xFF\xFE"; protected const BOM_UTF16LE = "\xFF\xFE";
/** @var string A pattern for matching an XML declaration; this matches the production listed in XML 1.0, which does not materially differ from that of XML 1.1 */
protected const XML_DECLARATION_PATTERN = <<<XMLDECL
/^
<\?xml
(\s+version=(?:"1\.[0-9]+"|'1\.[0-9]+'))
(?:\s+encoding=(?:"[A-Za-z][A-Za-z0-9\._\-]*"|'[A-Za-z][A-Za-z0-9\._\-]*'))?
(\s+standalone=(?:"yes"|"no"|'yes'|'no'))?
(\s*)\?>
/sx
XMLDECL;
/** Parses `$string` using either the HTML or XML parser, according to `$type`, and returns the resulting `DOMDocument` /** Parses `$string` using either the HTML or XML parser, according to `$type`, and returns the resulting `DOMDocument`
* *
@ -44,8 +54,9 @@ class DOMParser {
} elseif ($t->isXml) { } elseif ($t->isXml) {
// for XML we have to jump through a few hoops to deal with encoding; // for XML we have to jump through a few hoops to deal with encoding;
// if we have a known encoding we want to make sure the XML parser // if we have a known encoding we want to make sure the XML parser
// doesn't try to do its own detection. The best way to do this is // doesn't try to do its own detection. The only way to do this is
// to add a Unicode byte order mark if the string doesn't have one // to convert to UTF-8 where necessary and remove any XML
// declaration encoding information
$doc = new \DOMDocument(); $doc = new \DOMDocument();
try { try {
// first check for a byte order mark; if one exists we can go straight to parsing // first check for a byte order mark; if one exists we can go straight to parsing
@ -62,22 +73,29 @@ class DOMParser {
// accordingly; otherwise skip to parsing and let the // accordingly; otherwise skip to parsing and let the
// XML parser detect encoding // XML parser detect encoding
if ($charset) { if ($charset) {
// if the string is known to be UTF-8 or UTF-16 according to the type but has no BOM, add one // if the string is UTF-16, transcode it to UTF-8 so
if ($charset === "UTF-8") { // we're always dealing with an ASCII-compatible
$string = self::BOM_UTF8.$string; // encoding (XML's parsing rules ensure documents
} elseif ($charset === "UTF-16BE") { // in semi-ASCII-compatible encodings like Shift_JIS
$string = self::BOM_UTF16BE.$string; // or ISO 2022-JP never contain non-ASCII characters
} elseif ($charset === "UTF-16LE") { // before encoding information is seen)
$string = self::BOM_UTF16LE.$string; if ($charset === "UTF-16BE" || $charset === "UTF-16LE") {
} else {
// transcode the string to UTF-8 with a BOM where the string's encoding cannot include a BOM
$decoder = Encoding::createDecoder($charset, $string, true, false); $decoder = Encoding::createDecoder($charset, $string, true, false);
$string = self::BOM_UTF8; $string = "";
while (strlen($c = $decoder->nextChar())) { while (strlen($c = $decoder->nextChar())) {
$string .= $c; $string .= $c;
$string .= $decoder->asciiSpanNot(""); $string .= $decoder->asciiSpanNot("");
} }
unset($decoder); unset($decoder);
$charset = "UTF-8";
}
// look for an XML declaration
if (preg_match(self::XML_DECLARATION_PATTERN, $string, $match)) {
// substitute the information if one is found
$string = "<?xml".$match[1]." encoding=\"$charset\"".$match[2].$match[3]."?>".substr($string, strlen($match[0]));
} else {
// add a declaration if none is found
$string = "<?xml version=\"1.0\" encoding=\"$charset\" ?>".$string;
} }
} }
} }

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