[PHP] openssl_random_pseudo_bytes 関数と Base64_encode 関数を使用してランダムな文字列を生成する

<code class="language-php hljs "><span class="hljs-keyword">public</span> <span class="hljs-keyword">static</span> <span class="hljs-function"><span class="hljs-keyword">function</span> <span class="hljs-title">getRandomString</span><span class="hljs-params">(<span class="hljs-variable">$length</span> = <span class="hljs-number">42</span>)</span>    {</span>        <span class="hljs-comment">/*         * Use OpenSSL (if available)         */</span>        <span class="hljs-keyword">if</span> (function_exists(<span class="hljs-string">'openssl_random_pseudo_bytes'</span>)) {            <span class="hljs-variable">$bytes</span> = openssl_random_pseudo_bytes(<span class="hljs-variable">$length</span> * <span class="hljs-number">2</span>);            <span class="hljs-keyword">if</span> (<span class="hljs-variable">$bytes</span> === <span class="hljs-keyword">false</span>)                <span class="hljs-keyword">throw</span> <span class="hljs-keyword">new</span> RuntimeException(<span class="hljs-string">'Unable to generate a random string'</span>);            <span class="hljs-keyword">return</span> substr(str_replace([<span class="hljs-string">'/'</span>, <span class="hljs-string">'+'</span>, <span class="hljs-string">'='</span>], <span class="hljs-string">''</span>, base64_encode(<span class="hljs-variable">$bytes</span>)), <span class="hljs-number">0</span>, <span class="hljs-variable">$length</span>);        }        <span class="hljs-variable">$pool</span> = <span class="hljs-string">'0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ'</span>;        <span class="hljs-keyword">return</span> substr(str_shuffle(str_repeat(<span class="hljs-variable">$pool</span>, <span class="hljs-number">5</span>)), <span class="hljs-number">0</span>, <span class="hljs-variable">$length</span>);    }</code>

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