如何可能生成一个随机的，唯一的字符串使用数字和字母用于验证链接?就像你在一个网站上创建了一个账户，它会给你发一封带有链接的电子邮件，你必须点击那个链接才能验证你的账户
如何使用PHP生成其中一个?
当前回答
一个简单的解决方案是通过丢弃非字母数字字符将64进制转换为字母数字。
它使用random_bytes()来获得加密安全的结果。
function random_alphanumeric(int $length): string
{
$result='';
do
{
//Base 64 produces 4 characters for each 3 bytes, so most times this will give enough bytes in a single pass
$bytes=random_bytes(($length+3-strlen($result))*2);
//Discard non-alhpanumeric characters
$result.=str_replace(['/','+','='],['','',''],base64_encode($bytes));
//Keep adding characters until the string is long enough
//Add a few extra because the last 2 or 3 characters of a base 64 string tend to be less diverse
}while(strlen($result)<$length+3);
return substr($result,0,$length);
}
编辑:我只是重新审视了一下，因为我需要一些更灵活的东西。这里有一个解决方案，执行得比上面的好一点，并提供了指定ASCII字符集的任何子集的选项:
<?php
class RandomText
{
protected
$allowedChars,
//Maximum index to use
$allowedCount,
//Index values will be taken from a pool of this size
//It is a power of 2 to keep the distribution of values even
$distributionSize,
//This many characters will be generated for each output character
$ratio;
/**
* @param string $allowedChars characters to choose from
*/
public function __construct(string $allowedChars)
{
$this->allowedCount = strlen($allowedChars);
if($this->allowedCount < 1 || $this->allowedCount > 256) throw new \Exception('At least 1 and no more than 256 allowed character(s) must be specified.');
$this->allowedChars = $allowedChars;
//Find the power of 2 equal or greater than the number of allowed characters
$this->distributionSize = pow(2,ceil(log($this->allowedCount, 2)));
//Generating random bytes is the expensive part of this algorithm
//In most cases some will be wasted so it is helpful to produce some extras, but not too many
//On average, this is how many characters needed to produce 1 character in the allowed set
//50% of the time, more characters will be needed. My tests have shown this to perform well.
$this->ratio = $this->distributionSize / $this->allowedCount;
}
/**
* @param int $length string length of required result
* @return string random text
*/
public function get(int $length) : string
{
if($length < 1) throw new \Exception('$length must be >= 1.');
$result = '';
//Keep track of result length to prevent having to compute strlen()
$l = 0;
$indices = null;
$i = null;
do
{
//Bytes will be used to index the character set. Convert to integers.
$indices = unpack('C*', random_bytes(ceil(($length - $l) * $this->ratio)));
foreach($indices as $i)
{
//Reduce to the smallest range that gives an even distribution
$i %= $this->distributionSize;
//If the index is within the range of characters, add one char to the string
if($i < $this->allowedCount)
{
$l++;
$result .= $this->allowedChars[$i];
}
if($l >= $length) break;
}
}while($l < $length);
return $result;
}
}
其他回答
生成一个随机数使用 你最喜欢的随机数 发电机 乘除 得到一个与数字匹配的数字 你的代码字母表中的字符 将该索引处的项插入 你的代码字母。 重复1)，直到你有你想要的长度 想要
例如(伪代码)
int myInt = random(0, numcharacters)
char[] codealphabet = 'ABCDEF12345'
char random = codealphabet[i]
repeat until long enough
投票最多的解决方案的面向对象版本
我根据Scott的回答创建了一个面向对象的解决方案:
<?php
namespace Utils;
/**
* Class RandomStringGenerator
* @package Utils
*
* Solution taken from here:
* http://stackoverflow.com/a/13733588/1056679
*/
class RandomStringGenerator
{
/** @var string */
protected $alphabet;
/** @var int */
protected $alphabetLength;
/**
* @param string $alphabet
*/
public function __construct($alphabet = '')
{
if ('' !== $alphabet) {
$this->setAlphabet($alphabet);
} else {
$this->setAlphabet(
implode(range('a', 'z'))
. implode(range('A', 'Z'))
. implode(range(0, 9))
);
}
}
/**
* @param string $alphabet
*/
public function setAlphabet($alphabet)
{
$this->alphabet = $alphabet;
$this->alphabetLength = strlen($alphabet);
}
/**
* @param int $length
* @return string
*/
public function generate($length)
{
$token = '';
for ($i = 0; $i < $length; $i++) {
$randomKey = $this->getRandomInteger(0, $this->alphabetLength);
$token .= $this->alphabet[$randomKey];
}
return $token;
}
/**
* @param int $min
* @param int $max
* @return int
*/
protected function getRandomInteger($min, $max)
{
$range = ($max - $min);
if ($range < 0) {
// Not so random...
return $min;
}
$log = log($range, 2);
// Length in bytes.
$bytes = (int) ($log / 8) + 1;
// Length in bits.
$bits = (int) $log + 1;
// Set all lower bits to 1.
$filter = (int) (1 << $bits) - 1;
do {
$rnd = hexdec(bin2hex(openssl_random_pseudo_bytes($bytes)));
// Discard irrelevant bits.
$rnd = $rnd & $filter;
} while ($rnd >= $range);
return ($min + $rnd);
}
}
使用
<?php
use Utils\RandomStringGenerator;
// Create new instance of generator class.
$generator = new RandomStringGenerator;
// Set token length.
$tokenLength = 32;
// Call method to generate random string.
$token = $generator->generate($tokenLength);
自定义的字母
如果需要，可以使用自定义字母。 只需要向构造函数或setter传递一个支持字符的字符串:
<?php
$customAlphabet = '0123456789ABCDEF';
// Set initial alphabet.
$generator = new RandomStringGenerator($customAlphabet);
// Change alphabet whenever needed.
$generator->setAlphabet($customAlphabet);
下面是输出示例
SRniGU2sRQb2K1ylXKnWwZr4HrtdRgrM
q1sRUjNq1K9rG905aneFzyD5IcqD4dlC
I0euIWffrURLKCCJZ5PQFcNUCto6cQfD
AKwPJMEM5ytgJyJyGqoD5FQwxv82YvMr
duoRF6gAawNOEQRICnOUNYmStWmOpEgS
sdHUkEn4565AJoTtkc8EqJ6cC4MLEHUx
eVywMdYXczuZmHaJ50nIVQjOidEVkVna
baJGt7cdLDbIxMctLsEBWgAw5BByP5V0
iqT0B2obq3oerbeXkDVLjZrrLheW4d8f
OUQYCny6tj2TYDlTuu1KsnUyaLkeObwa
我希望它能帮助到一些人。干杯!
在阅读了之前的例子后，我得出了以下结论:
protected static $nonce_length = 32;
public static function getNonce()
{
$chars = array();
for ($i = 0; $i < 10; $i++)
$chars = array_merge($chars, range(0, 9), range('A', 'Z'));
shuffle($chars);
$start = mt_rand(0, count($chars) - self::$nonce_length);
return substr(join('', $chars), $start, self::$nonce_length);
}
我复制了10倍的数组[0-9,a - z]和洗牌的元素，在我得到一个随机的起始点substr()更“创造性”:) 你可以添加[a-z]和其他元素到数组中，或多或少地复制，比我更有创造力
一个简单的解决方案是通过丢弃非字母数字字符将64进制转换为字母数字。
它使用random_bytes()来获得加密安全的结果。
function random_alphanumeric(int $length): string
{
$result='';
do
{
//Base 64 produces 4 characters for each 3 bytes, so most times this will give enough bytes in a single pass
$bytes=random_bytes(($length+3-strlen($result))*2);
//Discard non-alhpanumeric characters
$result.=str_replace(['/','+','='],['','',''],base64_encode($bytes));
//Keep adding characters until the string is long enough
//Add a few extra because the last 2 or 3 characters of a base 64 string tend to be less diverse
}while(strlen($result)<$length+3);
return substr($result,0,$length);
}
编辑:我只是重新审视了一下，因为我需要一些更灵活的东西。这里有一个解决方案，执行得比上面的好一点，并提供了指定ASCII字符集的任何子集的选项:
<?php
class RandomText
{
protected
$allowedChars,
//Maximum index to use
$allowedCount,
//Index values will be taken from a pool of this size
//It is a power of 2 to keep the distribution of values even
$distributionSize,
//This many characters will be generated for each output character
$ratio;
/**
* @param string $allowedChars characters to choose from
*/
public function __construct(string $allowedChars)
{
$this->allowedCount = strlen($allowedChars);
if($this->allowedCount < 1 || $this->allowedCount > 256) throw new \Exception('At least 1 and no more than 256 allowed character(s) must be specified.');
$this->allowedChars = $allowedChars;
//Find the power of 2 equal or greater than the number of allowed characters
$this->distributionSize = pow(2,ceil(log($this->allowedCount, 2)));
//Generating random bytes is the expensive part of this algorithm
//In most cases some will be wasted so it is helpful to produce some extras, but not too many
//On average, this is how many characters needed to produce 1 character in the allowed set
//50% of the time, more characters will be needed. My tests have shown this to perform well.
$this->ratio = $this->distributionSize / $this->allowedCount;
}
/**
* @param int $length string length of required result
* @return string random text
*/
public function get(int $length) : string
{
if($length < 1) throw new \Exception('$length must be >= 1.');
$result = '';
//Keep track of result length to prevent having to compute strlen()
$l = 0;
$indices = null;
$i = null;
do
{
//Bytes will be used to index the character set. Convert to integers.
$indices = unpack('C*', random_bytes(ceil(($length - $l) * $this->ratio)));
foreach($indices as $i)
{
//Reduce to the smallest range that gives an even distribution
$i %= $this->distributionSize;
//If the index is within the range of characters, add one char to the string
if($i < $this->allowedCount)
{
$l++;
$result .= $this->allowedChars[$i];
}
if($l >= $length) break;
}
}while($l < $length);
return $result;
}
}
安全注意:在随机性质量可能影响应用程序安全性的情况下，不应使用此解决方案。特别是，rand()和uniqid()不是加密安全的随机数生成器。关于安全的替代方案，请参阅Scott的回答。
如果你不需要它随着时间的推移是绝对唯一的:
md5 (uniqid (rand()、true))
否则(假设你已经为你的用户确定了一个唯一的登录):
md5(uniqid($your_user_login, true))
