如何在PHP的fwrite()函数中写入PHP代码？

你遇到的核心问题是双引号字符串会被PHP自动解析内部变量，同时存在引号嵌套冲突的问题，导致代码提前执行或触发语法错误，无法原样写入目标文件。

方案1：使用单引号包裹内容 #

单引号内的变量和特殊字符不会被PHP解析，只需转义字符串内部的单引号（用\'）即可：

$fp = fopen('../blogs/' . $url . '.php', 'w');
fwrite($fp, '
  <p>This is a paragraph</p>
  <?php 
     $conn = mysqli_connect(\'server\', \'username\', \'password\', \'database\');
     if(!$conn){
        echo \'<h3 class="container bg-dark p-3 text-center text-warning rounded-lg mt-5">Not able to establish Database Connection</h3>\';
     }
     // Get data to display on index page
     $sql = \'SELECT * FROM blog WHERE id = $id\';
     $result = $conn->query($sql);
     while($row = $result->fetch_assoc()){
        $content = $row[\'content\'];
        echo $content;
     }
  ?>
');
fclose($fp);

方案2：使用NOWDOC语法（推荐） #

NOWDOC是PHP专为大段纯文本设计的语法，用<<<'标识'开头、标识;结尾，内部内容完全原样输出，无需转义变量或引号：

$fp = fopen('../blogs/' . $url . '.php', 'w');
$phpCode = <<<'CODE'
  <p>This is a paragraph</p>
  <?php 
     $conn = mysqli_connect('server', 'username', 'password', 'database');
     if(!$conn){
        echo '<h3 class="container bg-dark p-3 text-center text-warning rounded-lg mt-5">Not able to establish Database Connection</h3>';
     }
     // Get data to display on index page
     $sql = 'SELECT * FROM blog WHERE id = $id';
     $result = $conn->query($sql);
     while($row = $result->fetch_assoc()){
        $content = $row['content'];
        echo $content;
     }
  ?>
CODE;
fwrite($fp, $phpCode);
fclose($fp);

方案3：转义双引号内的变量 #

如果坚持使用双引号，需给所有不想被解析的变量前添加\，同时处理引号嵌套冲突：

$fp = fopen('../blogs/' . $url . '.php', 'w');
fwrite($fp, "
  <p>This is a paragraph</p>
  <?php 
     \$conn = mysqli_connect('server', 'username', 'password', 'database');
     if(!\$conn){
        echo '<h3 class=\"container bg-dark p-3 text-center text-warning rounded-lg mt-5\">Not able to establish Database Connection</h3>';
     }
     // Get data to display on index page
     \$sql = 'SELECT * FROM blog WHERE id = \$id';
     \$result = \$conn->query(\$sql);
     while(\$row = \$result->fetch_assoc()){
        \$content = \$row['content'];
        echo \$content;
     }
  ?>
");
fclose($fp);

额外修复点 #

• 原代码中$result_->fetch_assoc()多了下划线，已修正为$result->fetch_assoc()
• 补充了未闭合的<h3>标签
• 添加fclose($fp)确保文件句柄正常关闭，写入操作完成

内容的提问来源于stack exchange，提问作者JohannesDev