+ //return true;
+ }
+
+ /**
+ * xml charset encoding guessing helper function.
+ * Tries to determine the charset encoding of an XML chunk received over HTTP.
+ * NB: according to the spec (RFC 3023), if text/xml content-type is received over HTTP without a content-type,
+ * we SHOULD assume it is strictly US-ASCII. But we try to be more tolerant of non conforming (legacy?) clients/servers,
+ * which will be most probably using UTF-8 anyway...
+ * In order of importance checks:
+ * 1. http headers
+ * 2. BOM
+ * 3. XML declaration
+ * 4. guesses using mb_detect_encoding()
+ *
+ * @param string $httpHeader the http Content-type header
+ * @param string $xmlChunk xml content buffer
+ * @param string $encodingPrefs comma separated list of character encodings to be used as default (when mb extension is enabled).
+ * This can also be set globally using PhpXmlRpc::$xmlrpc_detectencodings
+ * @return string the encoding determined. Null if it can't be determined and mbstring is enabled,
+ * PhpXmlRpc::$xmlrpc_defencoding if it can't be determined and mbstring is not enabled
+ *
+ * @todo explore usage of mb_http_input(): does it detect http headers + post data? if so, use it instead of hand-detection!!!
+ */
+ public static function guessEncoding($httpHeader = '', $xmlChunk = '', $encodingPrefs = null)
+ {
+ // discussion: see http://www.yale.edu/pclt/encoding/
+ // 1 - test if encoding is specified in HTTP HEADERS
+
+ // Details:
+ // LWS: (\13\10)?( |\t)+
+ // token: (any char but excluded stuff)+
+ // quoted string: " (any char but double quotes and control chars)* "
+ // header: Content-type = ...; charset=value(; ...)*
+ // where value is of type token, no LWS allowed between 'charset' and value
+ // Note: we do not check for invalid chars in VALUE:
+ // this had better be done using pure ereg as below
+ // Note 2: we might be removing whitespace/tabs that ought to be left in if
+ // the received charset is a quoted string. But nobody uses such charset names...
+
+ /// @todo this test will pass if ANY header has charset specification, not only Content-Type. Fix it?
+ $matches = array();
+ if (preg_match('/;\s*charset\s*=([^;]+)/i', $httpHeader, $matches)) {
+ return strtoupper(trim($matches[1], " \t\""));
+ }
+
+ // 2 - scan the first bytes of the data for a UTF-16 (or other) BOM pattern
+ // (source: http://www.w3.org/TR/2000/REC-xml-20001006)
+ // NOTE: actually, according to the spec, even if we find the BOM and determine
+ // an encoding, we should check if there is an encoding specified
+ // in the xml declaration, and verify if they match.
+ /// @todo implement check as described above?
+ /// @todo implement check for first bytes of string even without a BOM? (It sure looks harder than for cases WITH a BOM)
+ if (preg_match('/^(\x00\x00\xFE\xFF|\xFF\xFE\x00\x00|\x00\x00\xFF\xFE|\xFE\xFF\x00\x00)/', $xmlChunk)) {
+ return 'UCS-4';
+ } elseif (preg_match('/^(\xFE\xFF|\xFF\xFE)/', $xmlChunk)) {
+ return 'UTF-16';
+ } elseif (preg_match('/^(\xEF\xBB\xBF)/', $xmlChunk)) {
+ return 'UTF-8';
+ }
+
+ // 3 - test if encoding is specified in the xml declaration
+ // Details:
+ // SPACE: (#x20 | #x9 | #xD | #xA)+ === [ \x9\xD\xA]+
+ // EQ: SPACE?=SPACE? === [ \x9\xD\xA]*=[ \x9\xD\xA]*
+ if (preg_match('/^<\?xml\s+version\s*=\s*' . "((?:\"[a-zA-Z0-9_.:-]+\")|(?:'[a-zA-Z0-9_.:-]+'))" .
+ '\s+encoding\s*=\s*' . "((?:\"[A-Za-z][A-Za-z0-9._-]*\")|(?:'[A-Za-z][A-Za-z0-9._-]*'))/",
+ $xmlChunk, $matches)) {
+ return strtoupper(substr($matches[2], 1, -1));
+ }
+
+ // 4 - if mbstring is available, let it do the guesswork
+ if (extension_loaded('mbstring')) {
+ if ($encodingPrefs == null && PhpXmlRpc::$xmlrpc_detectencodings != null) {
+ $encodingPrefs = PhpXmlRpc::$xmlrpc_detectencodings;
+ }
+ if ($encodingPrefs) {
+ $enc = mb_detect_encoding($xmlChunk, $encodingPrefs);
+ } else {
+ $enc = mb_detect_encoding($xmlChunk);
+ }
+ // NB: mb_detect likes to call it ascii, xml parser likes to call it US_ASCII...
+ // IANA also likes better US-ASCII, so go with it
+ if ($enc == 'ASCII') {
+ $enc = 'US-' . $enc;
+ }
+
+ return $enc;
+ } else {
+ // no encoding specified: as per HTTP1.1 assume it is iso-8859-1?
+ // Both RFC 2616 (HTTP 1.1) and 1945 (HTTP 1.0) clearly state that for text/xxx content types
+ // this should be the standard. And we should be getting text/xml as request and response.
+ // BUT we have to be backward compatible with the lib, which always used UTF-8 as default...
+ return PhpXmlRpc::$xmlrpc_defencoding;
+ }