如果数据库连接失败则加载默认图像

Question

I am attempting to build a database driven site whereby images are loaded via a php script like so;

<img src="get_image.php?holderID=2">

I can get images to load from a folder outside the root directory when the database is accessible but I also want to be able to load a default image if there is a failure with making the database connection. The DB connection is initiated form a separate php connection file mysqli_template_connect.php;

DEFINE('DB_USER', 'someusername');
DEFINE('DB_PASSWORD', 'amnesia');
DEFINE('DB_HOST', 'localhost');
DEFINE('DB_NAME', 'template');
$dbc = @mysqli_connect(DB_HOST, DB_USER, DB_PASSWORD, DB_NAME);

and then config.inc.php sets some constants, one of which is for all DB connections;

define('MYSQL', '../../../dbconnect/mysqli_template_connect.php');

The get_image.php file then has a database connection conditional;

    require('includes/config.inc.php');
    REQUIRE(MYSQL);
    $holderID = $_GET['holderID'];

    if(!$dbc){
        $image_name = 'img/unavailable.png';
        $info = getimagesize($image_name);  
        header("Content-Type: {$info['mime']}
");
        readfile($image_name);
    }
    else {
        $query = "SELECT imageID FROM image_holder WHERE image_holderID = $holderID ";
        $result = @mysqli_query($dbc, $query);
        $number_rows = mysqli_num_rows($result);

        if ($number_rows == 1) {                  
          $row = mysqli_fetch_array($result, MYSQLI_NUM);
          $imageID = $row[0];
        }
        else {
          $imageID = FALSE;
        }

        if ($imageID) {
            $query = "SELECT file_name FROM image WHERE imageID = $imageID";
            $result = mysqli_query($dbc, $query);
            $number_rows = mysqli_num_rows($result);
            if ($number_rows == 1) {
                $row = mysqli_fetch_array($result, MYSQLI_NUM);
                $image_name = '../../../uploads/' . $row[0];
            }
            else {
                $image_name = 'img/unavailable.png';
            }
        }
        else {
            $image_name = 'img/unavailable.png';
        }

        $info = getimagesize($image_name);  
        header("Content-Type: {$info['mime']}
");
        readfile($image_name);
        mysqli_close($dbc);

    }

If I disable the MYSQL database in XAMP, the default image unavailable.png will not load even though the header and readfile section of code is virtually the same in the section of code that does work. I'm quite a newbie to all this so any ideas on loading the default image would be appreciated.

Answer 1

Instead of

$dbc = @mysqli_connect(DB_HOST, DB_USER, DB_PASSWORD, DB_NAME);

Use

$dbc = mysqli_connect(DB_HOST, DB_USER, DB_PASSWORD, DB_NAME);

hopefully it should work..