PHP如何处理大文件上传？通过分片上传解决限制

File

slice()

XMLHttpRequest

fetch

temp_uploads/文件ID/块索引.part

upload_max_filesize

post_max_size

memory_limit

max_execution_time

max_input_time

File

input type="file"

FileList

File

File

slice(start, end)

Blob

// 假设 file 是用户选择的 File 对象
const chunkSize = 1024 * 1024 * 5; // 5MB per chunk
let currentChunk = 0;
const totalChunks = Math.ceil(file.size / chunkSize);
const fileId = generateUniqueId(file.name, file.size); // 生成唯一文件ID

function uploadNextChunk() {
    if (currentChunk < totalChunks) {
        const start = currentChunk * chunkSize;
        const end = Math.min(file.size, start + chunkSize);
        const chunk = file.slice(start, end); // 关键：切割文件

        const formData = new FormData();
        formData.append('fileId', fileId);
        formData.append('chunkIndex', currentChunk);
        formData.append('totalChunks', totalChunks);
        formData.append('chunk', chunk); // 发送文件块

        // 使用 fetch 或 XMLHttpRequest 发送数据到服务器
        fetch('/upload_chunk.php', {
            method: 'POST',
            body: formData
        })
        .then(response => response.json())
        .then(data => {
            if (data.success) {
                currentChunk++;
                updateProgressBar(currentChunk, totalChunks);
                uploadNextChunk(); // 递归上传下一个块
            } else {
                console.error('Chunk upload failed:', data.message);
                // 实现重试机制
            }
        })
        .catch(error => {
            console.error('Network error during chunk upload:', error);
            // 实现重试机制
        });
    } else {
        console.log('All chunks uploaded. Notifying server to merge...');
        // 通知服务器合并文件
        fetch('/merge_file.php', {
            method: 'POST',
            body: JSON.stringify({ fileId: fileId, fileName: file.name }),
            headers: { 'Content-Type': 'application/json' }
        })
        .then(response => response.json())
        .then(data => {
            if (data.success) {
                console.log('File merged successfully!');
            } else {
                console.error('File merge failed:', data.message);
            }
        });
    }
}

// 启动上传
uploadNextChunk();

$_FILES

// upload_chunk.php
if ($_SERVER['REQUEST_METHOD'] === 'POST' && isset($_FILES['chunk'])) {
    $fileId = $_POST['fileId'] ?? '';
    $chunkIndex = (int)($_POST['chunkIndex'] ?? 0);
    $totalChunks = (int)($_POST['totalChunks'] ?? 1);
    $chunkFile = $_FILES['chunk'];

    if (empty($fileId) || $chunkFile['error'] !== UPLOAD_ERR_OK) {
        echo json_encode(['success' => false, 'message' => 'Invalid request or chunk upload error.']);
        exit;
    }

    $tempDir = 'temp_uploads/' . $fileId . '/';
    if (!is_dir($tempDir)) {
        mkdir($tempDir, 0777, true); // 确保目录存在
    }

    $targetPath = $tempDir . $chunkIndex . '.part';

    if (move_uploaded_file($chunkFile['tmp_name'], $targetPath)) {
        // 记录已上传的块，例如在数据库或一个文件清单中
        // 简单示例：直接返回成功
        echo json_encode(['success' => true, 'message' => 'Chunk ' . $chunkIndex . ' uploaded.']);
    } else {
        echo json_encode(['success' => false, 'message' => 'Failed to move chunk.']);
    }
    exit;
}

// merge_file.php (当所有块上传完毕后，客户端会请求此脚本)
if ($_SERVER['REQUEST_METHOD'] === 'POST') {
    $input = json_decode(file_get_contents('php://input'), true);
    $fileId = $input['fileId'] ?? '';
    $fileName = $input['fileName'] ?? 'uploaded_file';

    if (empty($fileId)) {
        echo json_encode(['success' => false, 'message' => 'File ID missing.']);
        exit;
    }

    $tempDir = 'temp_uploads/' . $fileId . '/';
    $targetFilePath = 'uploads/' . basename($fileName); // 确保文件名安全

    if (!is_dir($tempDir)) {
        echo json_encode(['success' => false, 'message' => 'Temporary directory not found.']);
        exit;
    }

    // 假设我们知道总块数，或者可以动态扫描目录
    // 实际项目中，通常会在上传每个块时记录总块数
    $totalChunks = count(glob($tempDir . '*.part')); // 简单粗暴地统计块数

    $outputHandle = fopen($targetFilePath, 'wb');
    if (!$outputHandle) {
        echo json_encode(['success' => false, 'message' => 'Failed to open target file for writing.']);
        exit;
    }

    for ($i = 0; $i < $totalChunks; $i++) {
        $chunkPath = $tempDir . $i . '.part';
        if (file_exists($chunkPath)) {
            $chunkHandle = fopen($chunkPath, 'rb');
            if ($chunkHandle) {
                while (!feof($chunkHandle)) {
                    fwrite($outputHandle, fread($chunkHandle, 8192)); // 逐块写入
                }
                fclose($chunkHandle);
                unlink($chunkPath); // 写入成功后删除临时块
            } else {
                fclose($outputHandle);
                echo json_encode(['success' => false, 'message' => 'Failed to open chunk ' . $i . '.']);
                exit;
            }
        } else {
            fclose($outputHandle);
            echo json_encode(['success' => false, 'message' => 'Missing chunk ' . $i . '.']);
            exit;
        }
    }

    fclose($outputHandle);
    rmdir($tempDir); // 删除临时目录
    echo json_encode(['success' => true, 'message' => 'File merged successfully to ' . $targetFilePath]);
    exit;
}

glob($tempDir . '*.part')