What potential issues can arise when transferring files from a cloud service to a web server using PHP?

One potential issue that can arise when transferring files from a cloud service to a web server using PHP is insufficient memory allocation, especially for large files. This can lead to the script timing out or crashing. To solve this issue, you can increase the memory limit in your PHP configuration settings or chunk the file transfer process to handle large files more efficiently.

// Increase memory limit
ini_set('memory_limit', '256M');

// Chunked file transfer
$chunkSize = 1024 * 1024; // 1MB
$sourceFile = 'path/to/source/file';
$destinationFile = 'path/to/destination/file';

$sourceHandle = fopen($sourceFile, 'rb');
$destinationHandle = fopen($destinationFile, 'wb');

while (!feof($sourceHandle)) {
    fwrite($destinationHandle, fread($sourceHandle, $chunkSize));
}

fclose($sourceHandle);
fclose($destinationHandle);