我试图在PHP中创建一个随机字符串，我得到绝对没有输出:
<?php
function RandomString()
{
$characters = '0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ';
$randstring = '';
for ($i = 0; $i < 10; $i++) {
$randstring = $characters[rand(0, strlen($characters))];
}
return $randstring;
}
RandomString();
echo $randstring;
我做错了什么?
当前回答
这将创建一个20个字符的十六进制字符串:
$string = bin2hex(openssl_random_pseudo_bytes(10)); // 20 chars
在PHP 7 (random_bytes())中:
$string = base64_encode(random_bytes(10)); // ~14 characters, includes /=+
// or
$string = substr(str_replace(['+', '/', '='], '', base64_encode(random_bytes(32))), 0, 32); // 32 characters, without /=+
// or
$string = bin2hex(random_bytes(10)); // 20 characters, only 0-9a-f
其他回答
一个完整的解决方案(课程加测试)，部分基于上面的一些建议…
class TokenFactory
{
private const LENGTH = 12;
private const ALLOWED = '123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNPQRSTUVWXYZ~!@#$%^&*{}';
private const MIN_NUMBER_OF_DIGITS = 1;
private const MIN_NUMBER_OF_CAPS = 1;
private const MIN_NUMBER_OF_SPECIALS = 1;
private const MIN_NUMBER_OF_LETTERS = 1;
/**
* @return string
* @throws \Exception
*/
public function make(): string
{
$pass = $this->generateToken();
if ($this->isTokenValid($pass)) {
return $pass;
} else {
return $this->make();
}
}
/**
* @return string
* @throws \Exception
*/
private function generateToken(): string
{
$allowedCharacters = self::ALLOWED;
$token = '';
$max = mb_strlen($allowedCharacters, '8bit') - 1;
for ($i = 0; $i < self::LENGTH; ++$i) {
$token .= $allowedCharacters[random_int(0, $max)];
}
return $token;
}
/**
* @param $token
* @return bool
*/
private function isTokenValid($token): bool
{
$numberOfDigits = preg_match_all("/[0-9]/", $token);
$numberOfCaps = preg_match_all("/[A-Z]/", $token);
$numberOfSpecials = preg_match_all("/[~!@#\$%^&*{}]/", $token);
$numberOfLetters = preg_match_all("/[a-z]/", $token);
return
$numberOfDigits > self::MIN_NUMBER_OF_DIGITS
&& $numberOfCaps > self::MIN_NUMBER_OF_CAPS
&& $numberOfSpecials > self::MIN_NUMBER_OF_SPECIALS
&& $numberOfLetters > self::MIN_NUMBER_OF_LETTERS
;
}
}
class TokenFactoryTest
{
public function test_correct_syntax()
{
/**
* Arrange
*/
$length = 12;
$numberOfChecks = 1000;
/**
* Act & Assert
*/
$class = new TokenFactory();
$i = 0;
while ($i < $numberOfChecks) {
$generatedToken = $class->make();
$numberOfDigits = preg_match_all( "/[0-9]/", $generatedToken );
$numberOfCaps = preg_match_all( "/[A-Z]/", $generatedToken );
$numberOfSpecials = preg_match_all("/[~!@#\$%^&*{}]/", $generatedToken);
$numberOfLetters = preg_match_all("/[a-z]/", $generatedToken);
Assert::assertEquals($length, strlen($generatedToken));
Assert::assertTrue($numberOfDigits >= 1, 'Digit error: ' . $generatedToken);
Assert::assertTrue($numberOfCaps >= 1, 'Caps error: ' . $generatedToken);
Assert::assertTrue($numberOfSpecials >= 1, 'Specials error: ' . $generatedToken);
Assert::assertTrue($numberOfLetters >= 1, 'Letters error: ' . $generatedToken);
$i++;
}
}
}
顺便说一句，请确保在适合您需要的地方捕获该异常!
注意:str_shuffle()内部使用rand()，不适合用于加密目的(例如生成随机密码)。你需要一个安全的随机数生成器。它也不允许字符重复。
还有一种方法。
UPDATED(现在这会生成任意长度的字符串):
function generateRandomString($length = 10) {
return substr(str_shuffle(str_repeat($x='0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ', ceil($length/strlen($x)) )),1,$length);
}
echo generateRandomString(); // OR: generateRandomString(24)
就是这样。：）
来自yii2框架
/**
* Generates a random string of specified length.
* The string generated matches [A-Za-z0-9_-]+ and is transparent to URL-encoding.
*
* @param int $length the length of the key in characters
* @return string the generated random key
*/
function generateRandomString($length = 10) {
$bytes = random_bytes($length);
return substr(strtr(base64_encode($bytes), '+/', '-_'), 0, $length);
}
function generateRandomString($length = 15)
{
return substr(sha1(rand()), 0, $length);
}
哒哒！
这将创建一个20个字符的十六进制字符串:
$string = bin2hex(openssl_random_pseudo_bytes(10)); // 20 chars
在PHP 7 (random_bytes())中:
$string = base64_encode(random_bytes(10)); // ~14 characters, includes /=+
// or
$string = substr(str_replace(['+', '/', '='], '', base64_encode(random_bytes(32))), 0, 32); // 32 characters, without /=+
// or
$string = bin2hex(random_bytes(10)); // 20 characters, only 0-9a-f
