[PHP] Use openssl_random_pseudo_bytes and base64_encode functions to generate random strings_PHP tutorial

[PHP] Use openssl_random_pseudo_bytes and base64_encode functions to generate random strings

The openssl_random_pseudo_bytes function itself is used to generate a specified number of random bytes, so when using it to generate a random string, you also need to use the function base64_encode. As shown below:

<code class="language-php hljs ">public static function getRandomString($length = 42)
    {
        /*
         * Use OpenSSL (if available)
         */
        if (function_exists(&#39;openssl_random_pseudo_bytes&#39;)) {
            $bytes = openssl_random_pseudo_bytes($length * 2);

            if ($bytes === false)
                throw new RuntimeException(&#39;Unable to generate a random string&#39;);

            return substr(str_replace([&#39;/&#39;, &#39;+&#39;, &#39;=&#39;], &#39;&#39;, base64_encode($bytes)), 0, $length);
        }

        $pool = &#39;0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ&#39;;

        return substr(str_shuffle(str_repeat($pool, 5)), 0, $length);
    }</code>

After calling the base64_encode function, a replacement operation is performed on the result in order to remove unnecessary characters from the randomly generated string.

Of course, before using the openssl_random_pseudo_bytes function, it is best to use function_exists to ensure that the function is available at runtime. If not available, use Plan B:

<code class="language-php hljs ">substr(str_shuffle(str_repeat($pool, 5)), 0, $length);</code>

This function is very versatile and can be modified appropriately according to business needs and then called as a static method.

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