PHP character transcoding solves the problem of garbled data crawled by Sina

function unescape($str) {
 $str = rawurldecode($str);
 preg_match_all("/(?:%u.{4})|.+/",$str ,$r);
 $ar = $r[0];
 foreach($ar as $k=>$v) {
 if(substr($v,0,2) == '%u' && strlen ($v) == 6)
 $ar[$k] = iconv("UCS-2","utf-8",pack("H4",substr($v,-4)));
 }
 return join("",$ar);
}

has a little problem, so I changed it to another function, which seems to be more powerful.

function unescape($str) {
 $str = rawurldecode($str);
 preg_match_all("/%u.{4}|&#x.{4};|& #d+;|&#d+?|.+/U",$str,$r);
 $ar = $r[0];
 foreach($ar as $k=>$v) {
 if( substr($v,0,2) == "%u")
 $ar[$k] = iconv("UCS-2","utf-8",pack("H4",substr($v,- 4)));
 elseif(substr($v,0,3) == "")
 $ar[$k] = iconv("UCS-2","utf-8",pack(" H4",substr($v,3,-1)));
 elseif(substr($v,0,2) == "") {
 $ar[$k] = iconv("UCS-2 ","utf-8",pack("n",preg_replace("/[^d]/","",$v)));
 }
}
return join("",$ar);
 }

After using it for a while, I found that it can be used locally, but not in our online environment. Online is *nux, local is XP, and the PHP version is different. Later, I found a similar function in the manual It also supports utf8. I personally think it should be more versatile.

//php character transcoding
function utf8RawUrlDecode ($source) {
 $decodedStr = "";
 $pos = 0;
 $len = strlen ($source);
 while ($pos < $len) {
 $charAt = substr ($source, $pos, 1);
 if ($charAt == '%') {
 $pos++;
 $charAt = substr ($source, $ pos, 1);
 if ($charAt == 'u') {
 // we got a unicode character
 $pos++;
 $unicodeHexVal = substr ($source, $pos, 4);
 $unicode = hexdec ( $unicodeHexVal);
 $entity = "". $unicode . ';';
 $decodedStr .= utf8_encode ($entity);
 $pos += 4;
 }
 else {
 // we have an escaped ascii character
 $hexVal = substr ($source, $pos, 2);
 $decodedStr .= chr (hexdec ($hexVal));
 $pos += 2;
 }
 } else {
 $decodedStr .= $ charAt;
 $pos++;
 }
 }
 return $decodedStr;
}

Use this function to successfully solve the problem.