Database connection error
The system could not connect to the database. Please try again later.
set_charset("utf8mb4");
// Optional: set default timezone (adjust if you prefer another)
if (function_exists('date_default_timezone_set')) {
date_default_timezone_set('America/New_York');
}
/**
* Helper to check if a table exists in the current database.
*/
function tableExists(mysqli $conn, string $tableName): bool
{
static $cache = [];
if (isset($cache[$tableName])) {
return $cache[$tableName];
}
$sql = "SELECT 1 FROM information_schema.TABLES
WHERE TABLE_SCHEMA = ? AND TABLE_NAME = ?
LIMIT 1";
if ($stmt = $conn->prepare($sql)) {
$dbName = $conn->real_escape_string($conn->query("SELECT DATABASE()")->fetch_row()[0] ?? '');
$stmt->bind_param('ss', $dbName, $tableName);
if ($stmt->execute()) {
$stmt->store_result();
$exists = $stmt->num_rows > 0;
$stmt->close();
$cache[$tableName] = $exists;
return $exists;
}
$stmt->close();
}
$cache[$tableName] = false;
return false;
}
/**
* Centralized Audit Log helper.
* Records field-level changes into audit_log table if it exists.
*
* @param mysqli $conn
* @param string $entityType e.g. 'customer', 'order', 'invoice'
* @param int $entityId
* @param string $fieldName
* @param mixed $oldValue
* @param mixed $newValue
*/
function logAuditChange(mysqli $conn, $entityType, $entityId, $fieldName, $oldValue, $newValue): void
{
// If nothing changed, skip
if ($oldValue === $newValue) {
return;
}
// Only log if the table exists
if (!tableExists($conn, 'audit_log')) {
return;
}
// Resolve who changed it
$changedBy = 'system';
if (session_status() === PHP_SESSION_ACTIVE) {
if (!empty($_SESSION['username'])) {
$changedBy = $_SESSION['username'];
} elseif (!empty($_SESSION['email'])) {
$changedBy = $_SESSION['email'];
}
}
// Normalize complex values
if (is_array($oldValue) || is_object($oldValue)) {
$oldValue = json_encode($oldValue);
}
if (is_array($newValue) || is_object($newValue)) {
$newValue = json_encode($newValue);
}
$sql = "INSERT INTO audit_log (entity_type, entity_id, field_name, old_value, new_value, changed_by)
VALUES (?, ?, ?, ?, ?, ?)";
if ($stmt = $conn->prepare($sql)) {
$entityType = (string)$entityType;
$fieldName = (string)$fieldName;
$oldValueStr = (string)$oldValue;
$newValueStr = (string)$newValue;
$changedBy = (string)$changedBy;
$stmt->bind_param(
'sissss',
$entityType,
$entityId,
$fieldName,
$oldValueStr,
$newValueStr,
$changedBy
);
$stmt->execute();
$stmt->close();
}
}
/**
* Centralized error logger.
* Creates a short error_code and stores technical details in error_reports.
* Returns the generated error_code so you can show it to the user.
*
* Usage example in any page:
*
* $code = logErrorAndGetCode($conn, "Prepare failed: " . $conn->error);
* echo "";
*/
function logErrorAndGetCode(mysqli $conn, string $errorMessage, ?string $pageUrl = null, ?int $userId = null): string
{
// Generate a human-readable error code, e.g. ER-20251211-ABC123
$random = substr(bin2hex(random_bytes(4)), 0, 6);
$code = 'ER-' . date('Ymd') . '-' . strtoupper($random);
if ($pageUrl === null && isset($_SERVER['REQUEST_URI'])) {
$pageUrl = $_SERVER['REQUEST_URI'];
}
$browserInfo = $_SERVER['HTTP_USER_AGENT'] ?? '';
// Only log if table exists, to avoid 500s on fresh installs
if (!tableExists($conn, 'error_reports')) {
return $code;
}
$sql = "INSERT INTO error_reports (user_id, error_code, page_url, error_message, browser_info)
VALUES (?, ?, ?, ?, ?)";
if ($stmt = $conn->prepare($sql)) {
// Try to pick user_id from session if not passed
if (($userId === null || $userId === '') && isset($_SESSION['user_id'])) {
$userId = $_SESSION['user_id'];
}
$stmt->bind_param(
'issss',
$userId,
$code,
$pageUrl,
$errorMessage,
$browserInfo
);
$stmt->execute();
$stmt->close();
}
return $code;
}
?>