PHP网站性能优化：如何优化文件上传流程以提高访问速度？

<?php
$targetDir = "uploads/";
$chunkSize = 2 * 1024 * 1024; // 2MB
$fileName = $_REQUEST["name"];
$chunkIndex = intval($_REQUEST["chunk"]);
$chunksCount = intval($_REQUEST["chunks"]);
$file = $_FILES["file"]["tmp_name"];

if (!file_exists($targetDir)) {
    mkdir($targetDir, 0755, true);
}

$targetPath = $targetDir . $fileName;

if ($chunkIndex === 0) {
    move_uploaded_file($file, $targetPath);
} else {
    file_put_contents($targetPath, file_get_contents($file), FILE_APPEND);
}

if ($chunkIndex === $chunksCount - 1) {
    // 文件上传完毕，进行后续处理
    // ...
    echo "文件上传成功！";
}
?>

<?php
$targetDir = "uploads/";
$fileName = $_FILES["file"]["name"];
$file = $_FILES["file"]["tmp_name"];

if (!file_exists($targetDir)) {
    mkdir($targetDir, 0755, true);
}

$targetPath = $targetDir . $fileName;

$bufferSize = 8192; // 8KB
$handle = fopen($file, "rb");
$buffer = '';

while (!feof($handle)) {
    $buffer = fread($handle, $bufferSize);
    file_put_contents($targetPath, $buffer, FILE_APPEND);
}

fclose($handle);

// 文件上传完毕，进行后续处理
// ...
echo "文件上传成功！";
?>