不使用preg_match()在PHP中进行UTF-8验证 [英] UTF-8 validation in PHP without using preg_match()
问题描述
我需要验证一些以UTF-8编码的用户输入.许多建议使用以下代码:
I need to validate some user input that is encoded in UTF-8. Many have recommended using the following code:
preg_match('/\A(
[\x09\x0A\x0D\x20-\x7E]
| [\xC2-\xDF][\x80-\xBF]
| \xE0[\xA0-\xBF][\x80-\xBF]
| [\xE1-\xEC\xEE\xEF][\x80-\xBF]{2}
| \xED[\x80-\x9F][\x80-\xBF]
| \xF0[\x90-\xBF][\x80-\xBF]{2}
| [\xF1-\xF3][\x80-\xBF]{3}
| \xF4[\x80-\x8F][\x80-\xBF]{2}
)*\z/x', $string);
这是来自 http://www.w3的正则表达式.org/International/questions/qa-forms-utf-8 .一切正常，直到我发现PHP的一个错误至少在2006年以来就存在.如果$ string太长，则Preg_match()会导致段错误.似乎没有任何解决方法.您可以在此处查看错误提交: http://bugs.php.net/bug. php?id = 36463
It's a regular expression taken from http://www.w3.org/International/questions/qa-forms-utf-8 . Everything was ok until I discovered a bug in PHP that seems to have been around at least since 2006. Preg_match() causes a seg fault if the $string is too long. There doesn't seem to be any workaround. You can view the bug submission here: http://bugs.php.net/bug.php?id=36463
现在，为了避免使用preg_match，我创建了一个函数，其功能与上述正则表达式完全相同.我不知道这个问题在Stack Overflow上是否合适，但我想知道我做的功能是否正确.在这里:
Now, to avoid using preg_match I've created a function that does the exact same thing as the regular expression above. I don't know if this question is appropriate here at Stack Overflow, but I would like to know if the function I've made is correct. Here it is:
编辑[13.01.2010]: 如果有人感兴趣，我发布的先前版本中有几个错误.下面是我函数的最终版本.
EDIT [13.01.2010]: If anyone is interested, there were several bugs in the previous version I've posted. Below is the final version of my function.
function check_UTF8_string(&$string) {
$len = mb_strlen($string, "ISO-8859-1");
$ok = 1;
for ($i = 0; $i < $len; $i++) {
$o = ord(mb_substr($string, $i, 1, "ISO-8859-1"));
if ($o == 9 || $o == 10 || $o == 13 || ($o >= 32 && $o <= 126)) {
}
elseif ($o >= 194 && $o <= 223) {
$i++;
$o2 = ord(mb_substr($string, $i, 1, "ISO-8859-1"));
if (!($o2 >= 128 && $o2 <= 191)) {
$ok = 0;
break;
}
}
elseif ($o == 224) {
$o2 = ord(mb_substr($string, $i + 1, 1, "ISO-8859-1"));
$o3 = ord(mb_substr($string, $i + 2, 1, "ISO-8859-1"));
$i += 2;
if (!($o2 >= 160 && $o2 <= 191) || !($o3 >= 128 && $o3 <= 191)) {
$ok = 0;
break;
}
}
elseif (($o >= 225 && $o <= 236) || $o == 238 || $o == 239) {
$o2 = ord(mb_substr($string, $i + 1, 1, "ISO-8859-1"));
$o3 = ord(mb_substr($string, $i + 2, 1, "ISO-8859-1"));
$i += 2;
if (!($o2 >= 128 && $o2 <= 191) || !($o3 >= 128 && $o3 <= 191)) {
$ok = 0;
break;
}
}
elseif ($o == 237) {
$o2 = ord(mb_substr($string, $i + 1, 1, "ISO-8859-1"));
$o3 = ord(mb_substr($string, $i + 2, 1, "ISO-8859-1"));
$i += 2;
if (!($o2 >= 128 && $o2 <= 159) || !($o3 >= 128 && $o3 <= 191)) {
$ok = 0;
break;
}
}
elseif ($o == 240) {
$o2 = ord(mb_substr($string, $i + 1, 1, "ISO-8859-1"));
$o3 = ord(mb_substr($string, $i + 2, 1, "ISO-8859-1"));
$o4 = ord(mb_substr($string, $i + 3, 1, "ISO-8859-1"));
$i += 3;
if (!($o2 >= 144 && $o2 <= 191) ||
!($o3 >= 128 && $o3 <= 191) ||
!($o4 >= 128 && $o4 <= 191)) {
$ok = 0;
break;
}
}
elseif ($o >= 241 && $o <= 243) {
$o2 = ord(mb_substr($string, $i + 1, 1, "ISO-8859-1"));
$o3 = ord(mb_substr($string, $i + 2, 1, "ISO-8859-1"));
$o4 = ord(mb_substr($string, $i + 3, 1, "ISO-8859-1"));
$i += 3;
if (!($o2 >= 128 && $o2 <= 191) ||
!($o3 >= 128 && $o3 <= 191) ||
!($o4 >= 128 && $o4 <= 191)) {
$ok = 0;
break;
}
}
elseif ($o == 244) {
$o2 = ord(mb_substr($string, $i + 1, 1, "ISO-8859-1"));
$o3 = ord(mb_substr($string, $i + 2, 1, "ISO-8859-1"));
$o4 = ord(mb_substr($string, $i + 3, 1, "ISO-8859-1"));
$i += 5;
if (!($o2 >= 128 && $o2 <= 143) ||
!($o3 >= 128 && $o3 <= 191) ||
!($o4 >= 128 && $o4 <= 191)) {
$ok = 0;
break;
}
}
else {
$ok = 0;
break;
}
}
return $ok;
}
是的，很长.我希望我已经正确理解了该正则表达式是如何工作的.也希望对其他人有帮助.
Yes, it's very long. I hope I've understood correctly how that regular expression works. Also hope it will be of help to others.
提前谢谢！
推荐答案
您始终可以使用如果您想经常使用它并可能在某个时候进行更改:
If you want to use it a lot and possibly change it at sometime:
1)首先在配置文件中设置要使用的编码
1) First set the encoding you want to use in your config file
/* Set internal character encoding to UTF-8 */
mb_internal_encoding("UTF-8");
2)检查字符串
if(mb_check_encoding($string))
{
// do something
}
或者，如果您不打算对其进行更改，则始终可以直接将编码直接放入函数中:
Or, if you don't plan on changing it, you can always just put the encoding straight into the function:
if(mb_check_encoding($string, 'UTF-8'))
{
// do something
}
这篇关于不使用preg_match()在PHP中进行UTF-8验证的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
