PHP 用户名验证
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PHP username validation
提问by Adam Thompson
I am working on writing a PHP login system. I have everything that I need working, but I would like to verify that a username entered during the registration only contains alphanumeric characters. So how could I take a variable, say $username, and ensure that it contained only alphanumeric characters?
我正在编写一个 PHP 登录系统。我有我需要工作的一切，但我想验证在注册过程中输入的用户名是否只包含字母数字字符。那么我怎样才能使用一个变量，比如 $username，并确保它只包含字母数字字符呢？
回答by Ish
if(preg_match('/^\w{5,}$/', $username)) { // \w equals "[0-9A-Za-z_]"
// valid username, alphanumeric & longer than or equals 5 chars
}
OR
或者
if(preg_match('/^[a-zA-Z0-9]{5,}$/', $username)) { // for english chars + numbers only
// valid username, alphanumeric & longer than or equals 5 chars
}
回答by Matthew Mucklo
If you don't care about the length, you can use:
如果你不在乎长度，你可以使用：
if (ctype_alnum($username)) {
// Username is valid
}
回答by ifreelancer.asia
The Best way I recommend is this :-
我推荐的最好方法是：-
$str = "";
function validate_username($str)
{
$allowed = array(".", "-", "_"); // you can add here more value, you want to allow.
if(ctype_alnum(str_replace($allowed, '', $str ))) {
return $str;
} else {
$str = "Invalid Username";
return $str;
}
}
回答by The Unicodist
If you are allowing the basic alpha-numeric username, You can check alphanumeric value with a predefined template like this:
如果您允许基本的字母数字用户名，您可以使用预定义的模板检查字母数字值，如下所示：
preg_match([[:alnum:]],$username)&&!preg_match([[:space:]],$username)
The second part returns false if the string contains any spaces.
如果字符串包含任何空格，则第二部分返回 false。
回答by muratgozel
A little bit late but I am using the following function to test usernames or other types of alphanum-like strings. It tests alphanum chars only by default but you can add more characters such as . (dot), - (dash) or _ (underscore) to the whitelist.
有点晚了，但我正在使用以下函数来测试用户名或其他类型的类似字母的字符串。默认情况下，它仅测试字母字符，但您可以添加更多字符，例如 . （点）、-（破折号）或 _（下划线）到白名单。
It will also prevent consecutive chars for the chars specified as $more_chars.
它还将防止指定为的字符的连续字符$more_chars。
function valid_alphanum_string($str, $more_chars = '') {
# check type
if (!is_string($str)) return false;
# handle allowed chars
if (mb_strlen($more_chars) > 0) {
# don't allow ^, ] and \ in allowed chars
$more_chars = str_replace(array('^', ']', '\'), '', $more_chars);
# escape dash
$escaped_chars = strpos($more_chars, '-') !== false
? str_replace('-', '\-', $more_chars)
: $more_chars;
# allowed chars must be non-consecutive
for ($i=0; $i < mb_strlen($more_chars); $i++) {
$consecutive_test = preg_match('/[' . $more_chars[$i] . '][' . $escaped_chars . ']/', $str);
if ($consecutive_test === 1) return false;
}
# allowed chars shouldn't be at the start and the end of the string
if (strpos($more_chars, $str[0]) !== false) return false;
if (strpos($more_chars, $str[mb_strlen($str) - 1])) return false;
}
else $escaped_chars = $more_chars;
$result = preg_match('/^[a-zA-Z0-9' . $escaped_chars . ']{4,}$/', $str);
return $result === 1 ? true : false;
}
回答by user516957
try this
尝试这个
function filterName ($name, $filter = "[^a-zA-Z0-9\-\_\.]"){
return preg_match("~" . $filter . "~iU", $name) ? false : true;
}
if ( !filterName ($name) ){
print "Not a valid name";
}
