michaelschiemer/src/Framework/LiveComponents/docs/UPLOAD-GUIDE.md

# LiveComponents Upload Guide

Comprehensive guide for implementing chunked, resumable file uploads with progress tracking and virus scanning.

## Table of Contents

- [Overview](#overview)
- [Quick Start](#quick-start)
- [Chunked Upload Architecture](#chunked-upload-architecture)
- [Backend Implementation](#backend-implementation)
- [Client-Side Implementation](#client-side-implementation)
- [Progress Tracking](#progress-tracking)
- [Quarantine & Virus Scanning](#quarantine--virus-scanning)
- [Resume Capability](#resume-capability)
- [Security](#security)
- [Testing](#testing)
- [Production Deployment](#production-deployment)

---

## Overview

LiveComponents provides a **production-ready chunked upload system** with:

✅ **Chunked Uploads** - Split large files into manageable chunks (512KB default)
✅ **Resume Capability** - Resume interrupted uploads from last chunk
✅ **Integrity Verification** - SHA-256 hashing on client and server
✅ **Progress Tracking** - Real-time progress via Server-Sent Events (SSE)
✅ **Quarantine System** - Automatic virus scanning integration
✅ **Parallel Uploads** - Concurrent chunk uploads (3 parallel by default)
✅ **Retry Logic** - Automatic retry with exponential backoff
✅ **Memory Efficient** - Stream-based chunk assembly

### Use Cases

- **Large File Uploads**: Videos, images, documents (>100MB)
- **Unreliable Networks**: Mobile connections, slow networks
- **Background Uploads**: Long-running uploads with resume capability
- **Secure Uploads**: Virus scanning and integrity verification

---

## Quick Start

### 1. HTML Template

```html
<div data-lc-component="file-uploader" data-lc-id="{component_id}">
    <h3>Upload Files</h3>

    <!-- File input -->
    <input
        type="file"
        id="file-upload-input"
        accept="image/*,video/*,.pdf,.doc,.docx"
        multiple
    />

    <!-- Upload button -->
    <button id="upload-btn" disabled>Upload</button>

    <!-- Progress display -->
    <div id="upload-progress" class="hidden">
        <div class="progress-bar">
            <div id="progress-fill" style="width: 0%"></div>
        </div>
        <p id="progress-text">0%</p>
        <p id="upload-status">Preparing upload...</p>
    </div>

    <!-- Uploaded files list -->
    <div id="uploaded-files">
        <h4>Uploaded Files</h4>
        <ul data-lc-fragment="file-list">
            <for items="uploaded_files" as="file">
                <li>
                    {file.name} ({file.size_formatted})
                    <span class="status">{file.status}</span>
                </li>
            </for>
        </ul>
    </div>
</div>
```

### 2. JavaScript Integration

```javascript
import { ChunkedUploader } from '@js/modules/livecomponent';

const fileInput = document.getElementById('file-upload-input');
const uploadBtn = document.getElementById('upload-btn');
const progressBar = document.getElementById('progress-fill');
const progressText = document.getElementById('progress-text');

// Enable button when file selected
fileInput.addEventListener('change', (e) => {
    uploadBtn.disabled = e.target.files.length === 0;
});

// Initialize uploader
const uploader = new ChunkedUploader('file-uploader:main', {
    chunkSize: 512 * 1024,     // 512KB chunks
    maxConcurrentChunks: 3,    // 3 parallel uploads
    maxRetries: 3,             // Retry failed chunks 3 times
    enableSSE: true,           // Real-time progress via SSE

    // Progress callback
    onProgress: (progress) => {
        progressBar.style.width = `${progress}%`;
        progressText.textContent = `${progress.toFixed(1)}%`;
    },

    // Complete callback
    onComplete: (result) => {
        alert(`Upload complete! File ID: ${result.fileId}`);
        fileInput.value = '';
        uploadBtn.disabled = true;
    },

    // Error callback
    onError: (error) => {
        alert(`Upload failed: ${error.message}`);
    }
});

// Upload on button click
uploadBtn.addEventListener('click', async () => {
    const file = fileInput.files[0];
    if (!file) return;

    try {
        const result = await uploader.uploadFile(file);
        console.log('Upload successful:', result);
    } catch (error) {
        console.error('Upload failed:', error);
    }
});
```

### 3. Component Backend

```php
<?php

namespace App\Application\LiveComponents\FileUploader;

use App\Framework\LiveComponents\Attributes\Action;
use App\Framework\LiveComponents\Attributes\LiveComponent;
use App\Framework\LiveComponents\Contracts\LiveComponentContract;
use App\Framework\LiveComponents\ValueObjects\ComponentId;

#[LiveComponent('file-uploader')]
final readonly class FileUploaderComponent implements LiveComponentContract
{
    public function __construct(
        public ComponentId $id,
        public FileUploaderState $state,
        private FileRepository $fileRepository
    ) {}

    #[Action]
    public function refreshFileList(): FileUploaderState
    {
        $files = $this->fileRepository->findByUser($this->state->userId);

        return $this->state->withFiles($files);
    }

    public function render(): string
    {
        return 'components/file-uploader';
    }
}
```

**That's it!** The framework handles chunking, hashing, upload, assembly, and progress tracking automatically.

---

## Chunked Upload Architecture

### Upload Lifecycle

```
1. Initialize Session
   ├─ Generate unique session ID
   ├─ Calculate total chunks
   ├─ Store session metadata
   └─ Return session ID to client

2. Upload Chunks (parallel)
   ├─ Hash chunk on client (SHA-256)
   ├─ Upload chunk with hash
   ├─ Verify hash on server
   ├─ Store chunk temporarily
   └─ Update session progress

3. Complete Upload
   ├─ Assemble all chunks
   ├─ Verify final file hash
   ├─ Move to quarantine
   ├─ Trigger virus scan
   └─ Return file ID

4. Post-Processing
   ├─ Virus scan (async)
   ├─ Move from quarantine
   ├─ Generate thumbnails
   └─ Update component state
```

### API Endpoints

| Endpoint | Method | Purpose |
|----------|--------|---------|
| `/live-component/upload/init` | POST | Initialize upload session |
| `/live-component/upload/chunk` | POST | Upload single chunk |
| `/live-component/upload/complete` | POST | Finalize upload |
| `/live-component/upload/abort` | POST | Cancel upload |
| `/live-component/upload/status/{sessionId}` | GET | Get upload status |

---

## Backend Implementation

### Upload Session Management

The framework automatically manages upload sessions via `UploadSessionStore`:

```php
use App\Framework\LiveComponents\Upload\UploadSession;
use App\Framework\LiveComponents\Upload\UploadSessionId;
use App\Framework\Core\ValueObjects\Duration;

// Framework creates sessions automatically
// You can query session status:

$sessionId = UploadSessionId::fromString($sessionIdString);
$session = $this->uploadSessionStore->get($sessionId);

if ($session === null) {
    // Session expired or doesn't exist
}

// Session contains:
$session->id;              // UploadSessionId
$session->fileName;        // Original filename
$session->totalSize;       // Total file size
$session->totalChunks;     // Number of chunks
$session->uploadedChunks;  // Array of uploaded chunk indices
$session->componentId;     // Associated component ID
$session->userId;          // User ID (if authenticated)
$session->createdAt;       // Session creation time
$session->expiresAt;       // Session expiration
```

### Chunk Integrity Verification

```php
use App\Framework\LiveComponents\Upload\IntegrityValidator;
use App\Framework\LiveComponents\Upload\ChunkHash;

// Framework automatically verifies chunk integrity
// But you can also use IntegrityValidator manually:

$validator = $container->get(IntegrityValidator::class);

// Verify chunk hash
$expectedHash = ChunkHash::fromHex($clientProvidedHash);
$isValid = $validator->verifyChunkHash($chunkPath, $expectedHash);

if (!$isValid) {
    throw new ChunkIntegrityException('Chunk hash mismatch');
}

// Verify final file hash
$fileHash = $validator->hashFile($assembledFilePath);
$isValid = $validator->verifyFileHash(
    $assembledFilePath,
    ChunkHash::fromHex($expectedFileHash)
);
```

### Custom Post-Processing

```php
use App\Framework\LiveComponents\Upload\ChunkedUploadManager;
use App\Framework\Event\EventHandler;
use App\Framework\LiveComponents\Upload\Events\UploadCompletedEvent;

#[EventHandler]
final readonly class ProcessUploadedFileHandler
{
    public function handle(UploadCompletedEvent $event): void
    {
        // File is in quarantine, waiting for virus scan
        // You can process metadata here

        $file = new File(
            id: $event->fileId,
            originalName: $event->originalFileName,
            size: $event->fileSize,
            uploadedBy: $event->userId,
            componentId: $event->componentId
        );

        $this->fileRepository->save($file);

        // Generate thumbnails (if image)
        if ($this->isImage($event->mimeType)) {
            $this->thumbnailGenerator->generate($event->filePath);
        }

        // Extract metadata (if video)
        if ($this->isVideo($event->mimeType)) {
            $this->videoMetadataExtractor->extract($event->filePath);
        }
    }
}
```

### Storage Configuration

```php
// Environment configuration
UPLOAD_TEMP_DIR=/var/www/storage/uploads/temp
UPLOAD_QUARANTINE_DIR=/var/www/storage/uploads/quarantine
UPLOAD_FINAL_DIR=/var/www/storage/uploads/files
UPLOAD_MAX_FILE_SIZE=2147483648  # 2GB
UPLOAD_CHUNK_SIZE=524288          # 512KB
UPLOAD_SESSION_TTL=3600           # 1 hour
```

---

## Client-Side Implementation

### Basic Upload

```javascript
import { ChunkedUploader } from '@js/modules/livecomponent';

const uploader = new ChunkedUploader('file-uploader:main');

// Upload a file
const result = await uploader.uploadFile(file);

console.log('File uploaded:', result.fileId);
```

### Advanced Configuration

```javascript
const uploader = new ChunkedUploader('file-uploader:main', {
    // Chunk configuration
    chunkSize: 512 * 1024,         // 512KB chunks (default)
    maxConcurrentChunks: 3,        // 3 parallel uploads (default)

    // Retry configuration
    maxRetries: 3,                 // Retry failed chunks (default: 3)
    retryDelay: 1000,              // Initial retry delay (default: 1s)
    retryBackoffMultiplier: 2,     // Exponential backoff (default: 2)

    // Progress tracking
    enableSSE: true,               // Real-time progress via SSE (default: true)
    progressUpdateInterval: 100,   // Progress callback interval (default: 100ms)

    // Callbacks
    onProgress: (progress) => {
        console.log(`Upload: ${progress.toFixed(2)}%`);
    },

    onChunkUpload: (chunkIndex, totalChunks) => {
        console.log(`Chunk ${chunkIndex + 1}/${totalChunks} uploaded`);
    },

    onComplete: (result) => {
        console.log('Upload complete:', result);
    },

    onError: (error) => {
        console.error('Upload failed:', error);
    }
});
```

### Multiple File Upload

```javascript
const files = Array.from(fileInput.files);

// Sequential uploads
for (const file of files) {
    try {
        const result = await uploader.uploadFile(file);
        console.log(`${file.name} uploaded successfully`);
    } catch (error) {
        console.error(`${file.name} failed:`, error);
    }
}

// Parallel uploads (careful with concurrency)
const uploads = files.map(file => uploader.uploadFile(file));
const results = await Promise.allSettled(uploads);

results.forEach((result, index) => {
    if (result.status === 'fulfilled') {
        console.log(`${files[index].name} uploaded`);
    } else {
        console.error(`${files[index].name} failed:`, result.reason);
    }
});
```

### Custom Progress UI

```javascript
const uploader = new ChunkedUploader('file-uploader:main', {
    onProgress: (progress) => {
        // Update progress bar
        progressBar.style.width = `${progress}%`;
        progressText.textContent = `${progress.toFixed(1)}%`;

        // Update status text
        if (progress < 25) {
            statusText.textContent = 'Starting upload...';
        } else if (progress < 75) {
            statusText.textContent = 'Uploading...';
        } else if (progress < 100) {
            statusText.textContent = 'Almost done...';
        }
    },

    onChunkUpload: (chunkIndex, totalChunks) => {
        chunksText.textContent = `${chunkIndex + 1} / ${totalChunks} chunks`;
    },

    onComplete: (result) => {
        progressBar.classList.add('complete');
        statusText.textContent = 'Upload complete!';

        // Show success message
        setTimeout(() => {
            resetUploadUI();
        }, 2000);
    }
});
```

---

## Progress Tracking

### Real-Time Progress via SSE

The framework automatically broadcasts upload progress via Server-Sent Events:

```javascript
// SSE automatically enabled by default
const uploader = new ChunkedUploader('file-uploader:main', {
    enableSSE: true,  // Real-time progress

    onProgress: (progress) => {
        // Called automatically as chunks upload
        console.log(`Progress: ${progress}%`);
    }
});

// Progress events are automatically synchronized between:
// - Chunk upload completion
// - Server-side progress updates
// - SSE broadcasts
```

### Manual Progress Polling

```javascript
// Disable SSE and poll manually
const uploader = new ChunkedUploader('file-uploader:main', {
    enableSSE: false  // Disable automatic SSE
});

// Poll upload status
const sessionId = 'upload-session-id';

async function pollUploadStatus() {
    const response = await fetch(`/live-component/upload/status/${sessionId}`);
    const status = await response.json();

    console.log('Upload progress:', {
        uploaded: status.uploaded_chunks,
        total: status.total_chunks,
        progress: (status.uploaded_chunks / status.total_chunks) * 100
    });

    if (status.uploaded_chunks < status.total_chunks) {
        setTimeout(pollUploadStatus, 1000);  // Poll every second
    }
}
```

### Progress Events

```javascript
// Listen to granular progress events
uploader.on('upload:started', (data) => {
    console.log('Upload started:', data.fileName);
});

uploader.on('chunk:uploaded', (data) => {
    console.log(`Chunk ${data.chunkIndex} uploaded`);
});

uploader.on('upload:progress', (data) => {
    console.log(`Progress: ${data.progress}%`);
});

uploader.on('upload:complete', (data) => {
    console.log('Upload complete:', data.fileId);
});

uploader.on('upload:error', (error) => {
    console.error('Upload error:', error);
});
```

---

## Quarantine & Virus Scanning

### How Quarantine Works

```
1. Upload Complete
   ↓
2. File Assembled
   ↓
3. Move to Quarantine (automatic)
   ├─ File stored in quarantine directory
   ├─ QuarantineStatus: PENDING
   └─ Virus scan triggered (async)
   ↓
4. Virus Scan
   ├─ ClamAV / VirusTotal integration
   ├─ QuarantineStatus: SCANNING
   └─ Scan result returned
   ↓
5. Post-Scan
   ├─ Clean → Move to final storage, QuarantineStatus: RELEASED
   └─ Infected → Delete file, QuarantineStatus: QUARANTINED
```

### Virus Scanner Integration

```php
use App\Framework\LiveComponents\Upload\QuarantineService;
use App\Framework\LiveComponents\Upload\ScanResult;
use App\Framework\LiveComponents\Upload\ScanStatus;

// Custom virus scanner implementation
final readonly class ClamAVScanner implements VirusScanner
{
    public function scan(string $filePath): ScanResult
    {
        // Execute ClamAV scan
        $output = shell_exec("clamscan --no-summary {$filePath}");

        $isClean = str_contains($output, 'OK');

        if ($isClean) {
            return ScanResult::clean();
        }

        // Extract virus signature
        preg_match('/FOUND: (.+)/', $output, $matches);
        $signature = $matches[1] ?? 'Unknown';

        return ScanResult::infected($signature);
    }
}

// Register scanner
$container->singleton(VirusScanner::class, new ClamAVScanner());
```

### VirusTotal Integration

```php
final readonly class VirusTotalScanner implements VirusScanner
{
    public function __construct(
        private string $apiKey,
        private HttpClient $httpClient
    ) {}

    public function scan(string $filePath): ScanResult
    {
        // Upload file to VirusTotal
        $response = $this->httpClient->post('https://www.virustotal.com/api/v3/files', [
            'file' => new CURLFile($filePath)
        ], [
            'x-apikey' => $this->apiKey
        ]);

        $data = json_decode($response->body, true);

        // Check scan results
        $positives = $data['data']['attributes']['last_analysis_stats']['malicious'] ?? 0;

        if ($positives > 0) {
            return ScanResult::infected(
                signature: "{$positives} engines detected malware"
            );
        }

        return ScanResult::clean();
    }
}
```

### Quarantine Status Tracking

```php
use App\Framework\LiveComponents\Upload\QuarantineStatus;

// Check quarantine status
$status = $this->quarantineService->getStatus($fileId);

match ($status) {
    QuarantineStatus::PENDING => 'Waiting for scan...',
    QuarantineStatus::SCANNING => 'Scanning for viruses...',
    QuarantineStatus::QUARANTINED => 'File infected and quarantined',
    QuarantineStatus::RELEASED => 'File clean and available',
};

// Listen to scan completion
$this->eventDispatcher->listen(FileScanCompletedEvent::class, function($event) {
    if ($event->scanResult->isClean()) {
        // File is safe - notify user
        $this->notificationService->send(
            $event->userId,
            "Your file '{$event->fileName}' has been uploaded successfully"
        );
    } else {
        // File infected - alert security team
        $this->securityLogger->alert('Infected file uploaded', [
            'file_id' => $event->fileId,
            'user_id' => $event->userId,
            'signature' => $event->scanResult->signature
        ]);
    }
});
```

---

## Resume Capability

### How Resume Works

1. **Upload Interrupted** (network failure, browser close, etc.)
2. **User Returns** and selects same file
3. **Framework Detects** existing session by file hash
4. **Resume Upload** from last successfully uploaded chunk

### Resume Implementation

```javascript
const uploader = new ChunkedUploader('file-uploader:main', {
    enableResume: true  // Enable resume (default: true)
});

// Framework automatically:
// 1. Hashes file to generate consistent session ID
// 2. Checks server for existing session
// 3. Resumes from last uploaded chunk
// 4. Continues upload seamlessly

// Manual resume control
uploader.on('upload:resuming', (data) => {
    console.log(`Resuming from chunk ${data.lastChunkIndex}`);
    console.log(`${data.uploadedChunks}/${data.totalChunks} chunks already uploaded`);

    // Show resume message to user
    showNotification(`Resuming upload from ${data.progress}%`);
});
```

### Session Expiration

```php
// Configure session TTL
UPLOAD_SESSION_TTL=3600  # 1 hour

// Sessions expire after TTL
// After expiration, upload must restart from beginning
```

### Resume Best Practices

```javascript
// 1. Always use same file (don't modify between uploads)
const file = fileInput.files[0];
const result = await uploader.uploadFile(file);

// 2. Don't change filename (affects session ID)
// ❌ Bad
const renamedFile = new File([file], 'new-name.jpg', { type: file.type });

// ✅ Good
const originalFile = fileInput.files[0];

// 3. Handle resume gracefully
uploader.on('upload:resuming', (data) => {
    // Inform user
    alert(`Resuming upload from ${data.progress.toFixed(1)}%`);
});

uploader.on('upload:cannot-resume', (reason) => {
    // Session expired or file changed
    alert(`Cannot resume: ${reason}. Starting new upload...`);
});
```

---

## Security

### Upload Security Checklist

- [x] **File Size Limits** - Enforce max file size (2GB default)
- [x] **File Type Validation** - MIME type and extension checking
- [x] **Integrity Verification** - SHA-256 hashing client and server
- [x] **Virus Scanning** - Automatic quarantine and scan
- [x] **Rate Limiting** - Prevent upload abuse
- [x] **Authentication** - Only authenticated users can upload
- [x] **CSRF Protection** - Token validation on all uploads
- [x] **Idempotency** - Prevent duplicate uploads

### File Type Validation

```php
// Configure allowed file types
$allowedMimeTypes = [
    'image/jpeg',
    'image/png',
    'image/gif',
    'image/webp',
    'video/mp4',
    'application/pdf',
    'application/msword',
    'application/vnd.openxmlformats-officedocument.wordprocessingml.document'
];

$allowedExtensions = [
    'jpg', 'jpeg', 'png', 'gif', 'webp',
    'mp4', 'pdf', 'doc', 'docx'
];

// Validation happens automatically in ChunkedUploadController
// But you can also validate manually:
if (!in_array($file->getMimeType(), $allowedMimeTypes)) {
    throw new InvalidFileTypeException('File type not allowed');
}

if (!in_array($file->getExtension(), $allowedExtensions)) {
    throw new InvalidFileTypeException('File extension not allowed');
}
```

### Size Limits

```javascript
// Client-side validation (before upload)
const MAX_FILE_SIZE = 2 * 1024 * 1024 * 1024; // 2GB

if (file.size > MAX_FILE_SIZE) {
    alert('File too large. Maximum size is 2GB.');
    return;
}

// Server-side enforcement (automatic)
// Configured via UPLOAD_MAX_FILE_SIZE environment variable
```

### Rate Limiting

```php
use App\Framework\LiveComponents\Attributes\Action;

#[Action(
    rateLimit: 10,           // Max 10 upload requests
    rateLimitWindow: 3600    // Per hour
)]
public function uploadChunk(UploadChunkRequest $request): JsonResult
{
    // Rate limiting applied automatically by framework
}
```

---

## Testing

### Unit Tests

```php
use function Pest\LiveComponents\mountComponent;
use function Pest\LiveComponents\callAction;

describe('FileUploaderComponent', function () {
    it('initializes upload session', function () {
        $manager = container()->get(ChunkedUploadManager::class);

        $session = $manager->initializeSession(
            componentId: 'file-uploader:test',
            fileName: 'test.pdf',
            fileSize: 1024 * 1024,  // 1MB
            totalChunks: 2,
            userId: '123'
        );

        expect($session->fileName)->toBe('test.pdf');
        expect($session->totalChunks)->toBe(2);
    });

    it('verifies chunk integrity', function () {
        $validator = container()->get(IntegrityValidator::class);

        $chunkPath = __DIR__ . '/fixtures/chunk.bin';
        $expectedHash = ChunkHash::fromHex(hash_file('sha256', $chunkPath));

        $isValid = $validator->verifyChunkHash($chunkPath, $expectedHash);

        expect($isValid)->toBeTrue();
    });
});
```

### Integration Tests

```javascript
// JavaScript tests with Jest
describe('ChunkedUploader', () => {
    it('uploads file in chunks', async () => {
        const file = new File(['test content'], 'test.txt', {
            type: 'text/plain'
        });

        const uploader = new ChunkedUploader('test:uploader', {
            chunkSize: 512
        });

        const result = await uploader.uploadFile(file);

        expect(result.fileId).toBeDefined();
        expect(result.success).toBe(true);
    });

    it('resumes interrupted upload', async () => {
        const file = new File(['test content'], 'test.txt');
        const uploader = new ChunkedUploader('test:uploader');

        // Start upload
        const uploadPromise = uploader.uploadFile(file);

        // Simulate interruption
        uploader.abort();

        // Resume
        const result = await uploader.uploadFile(file);

        expect(result.resumed).toBe(true);
    });
});
```

---

## Production Deployment

### Infrastructure Setup

```bash
# Create upload directories
mkdir -p /var/www/storage/uploads/{temp,quarantine,files}

# Set permissions
chown -R www-data:www-data /var/www/storage/uploads
chmod -R 755 /var/www/storage/uploads

# Install ClamAV
apt-get install clamav clamav-daemon
systemctl start clamav-daemon

# Update virus definitions
freshclam
```

### Environment Configuration

```env
# Upload settings
UPLOAD_TEMP_DIR=/var/www/storage/uploads/temp
UPLOAD_QUARANTINE_DIR=/var/www/storage/uploads/quarantine
UPLOAD_FINAL_DIR=/var/www/storage/uploads/files
UPLOAD_MAX_FILE_SIZE=2147483648
UPLOAD_CHUNK_SIZE=524288
UPLOAD_SESSION_TTL=3600

# Virus scanning
CLAMAV_SOCKET=/var/run/clamav/clamd.ctl
VIRUSTOTAL_API_KEY=your-api-key-here

# Cleanup
UPLOAD_CLEANUP_ENABLED=true
UPLOAD_CLEANUP_INTERVAL=3600  # Clean up old sessions every hour
```

### Monitoring

```php
// Track upload metrics
$this->metrics->increment('upload.sessions.created');
$this->metrics->increment('upload.chunks.uploaded');
$this->metrics->increment('upload.completed');
$this->metrics->increment('upload.failed');

// Track virus scan results
$this->metrics->increment('virus_scan.clean');
$this->metrics->increment('virus_scan.infected');

// Track performance
$this->metrics->timing('upload.session.duration', $duration);
$this->metrics->timing('upload.chunk.duration', $chunkDuration);
```

---

## Summary

LiveComponents Chunked Upload System:

✅ **Production-Ready** - Battle-tested with large files (>2GB)
✅ **Resumable** - Automatic resume from interruptions
✅ **Secure** - Hash verification + virus scanning + quarantine
✅ **Fast** - Parallel chunk uploads (3 concurrent)
✅ **Reliable** - Retry logic with exponential backoff
✅ **User-Friendly** - Real-time progress via SSE
✅ **Memory-Efficient** - Stream-based chunk assembly

Perfect for applications requiring **large file uploads** with **reliability** and **security**.