NestJS Upload Library

A comprehensive library for uploading images and files to AWS S3 or Google Cloud Storage with advanced validation, image optimization, rate limiting, and caching for NestJS applications.

📋 Table of Contents

• Features
• Installation
• Quick Start
• Configuration
• API Endpoints
• Service Usage
• Validation
• Image Optimization
• Rate Limiting
• Caching
• Types and Interfaces
• Error Handling
• Usage Examples

✨ Features

• ✅ AWS S3 and Google Cloud Storage Support - Flexible provider choice
• ✅ Advanced File Validation - Size, MIME type, format validation
• ✅ Image Validation - Dimensions, aspect ratio, format validation
• ✅ Automatic Image Optimization - Size reduction, WebP conversion
• ✅ Rate Limiting - Protection against abuse (in-memory or Redis)
• ✅ Presigned URL Caching - Performance improvement
• ✅ Private File Support - Presigned URLs for secure access
• ✅ Batch Operations - Upload/delete multiple files simultaneously
• ✅ Stream Upload - Support for large files
• ✅ File Metadata - Custom headers and metadata
• ✅ Full TypeScript Support - Typed methods and interfaces
• ✅ Swagger/OpenAPI Documentation - Automatic documentation generation
• ✅ REST API Endpoints - Ready-to-use endpoints for upload/delete
• ✅ Operation Logging - Detailed logging of all operations

📦 Installation

npm install nestjs-upload

Dependencies

The library requires the following peer dependencies:

npm install @nestjs/common @nestjs/config @nestjs/platform-express

For Swagger documentation (optional):

npm install @nestjs/swagger

For image optimization (optional, but recommended):

npm install sharp

For Redis rate limiting (optional):

npm install ioredis

🚀 Quick Start

1. AWS S3 Configuration

Using Default Credentials (Recommended):

AWS SDK automatically uses credentials from:

• Environment variables (AWS_ACCESS_KEY_ID, AWS_SECRET_ACCESS_KEY)
• ~/.aws/credentials file
• IAM roles (on EC2 instances)

import { Module } from '@nestjs/common';
import { UploadModule, StorageProvider } from 'nestjs-upload';

@Module({
  imports: [
    UploadModule.forRoot({
      provider: StorageProvider.AWS,
      aws: {
        bucket: 'my-bucket-name',
        region: 'us-east-1',
        // Credentials will be automatically loaded from ~/.aws/credentials
        // or environment variables
      },
      validation: {
        maxFileSize: 5 * 1024 * 1024, // 5MB
        allowedMimeTypes: ['image/jpeg', 'image/png', 'image/webp'],
        imageValidation: {
          minWidth: 100,
          maxWidth: 2000,
          minHeight: 100,
          maxHeight: 2000,
          aspectRatio: {
            width: 16,
            height: 9,
            tolerance: 0.1,
          },
          allowedFormats: ['jpeg', 'png', 'webp'],
        },
      },
      imageOptimization: {
        enabled: true,
        maxWidth: 1920,
        maxHeight: 1080,
        quality: 85,
        format: 'auto', // or ImageFormat.WEBP, ImageFormat.JPEG, ImageFormat.PNG
        convertToWebP: false,
      },
      defaultPublic: true,
      rateLimit: {
        enabled: true,
        type: 'memory', // or 'redis'
        windowMs: 60000, // 1 minute
        maxRequests: 10,
      },
      cache: {
        enabled: true,
        ttl: 3600, // 1 hour
        maxSize: 1000,
      },
    }),
  ],
})
export class AppModule {}

2. Google Cloud Storage Configuration

Using Application Default Credentials (Recommended):

Google Cloud SDK automatically uses credentials from:

• GOOGLE_APPLICATION_CREDENTIALS environment variable
• ~/.config/gcloud/application_default_credentials.json (after gcloud auth application-default login)
• GCE/Cloud Run metadata service

import { Module } from '@nestjs/common';
import { UploadModule, StorageProvider } from 'nestjs-upload';

@Module({
  imports: [
    UploadModule.forRoot({
      provider: StorageProvider.GCS,
      gcs: {
        bucket: 'my-bucket-name',
        projectId: 'my-project-id',
        // Credentials will be automatically loaded from Application Default Credentials
      },
      validation: {
        maxFileSize: 10 * 1024 * 1024, // 10MB
        allowedMimeTypes: ['image/jpeg', 'image/png'],
        imageValidation: {
          minWidth: 200,
          maxWidth: 4000,
          minHeight: 200,
          maxHeight: 4000,
        },
      },
    }),
  ],
})
export class AppModule {}

Setting Up Credentials

AWS Credentials

Option 1: Using ~/.aws/credentials file (Recommended for local development)

Create ~/.aws/credentials file:

[default]
aws_access_key_id = YOUR_ACCESS_KEY_ID
aws_secret_access_key = YOUR_SECRET_ACCESS_KEY

Option 2: Using environment variables

export AWS_ACCESS_KEY_ID=your_access_key_id
export AWS_SECRET_ACCESS_KEY=your_secret_access_key
export AWS_REGION=us-east-1

Option 3: Using explicit credentials in config (not recommended)

aws: {
  bucket: 'my-bucket',
  region: 'us-east-1',
  accessKey: 'your-access-key',
  secretKey: 'your-secret-key',
}

Google Cloud Credentials

Option 1: Using Application Default Credentials (Recommended)

gcloud auth application-default login

This creates credentials at ~/.config/gcloud/application_default_credentials.json

Option 2: Using GOOGLE_APPLICATION_CREDENTIALS environment variable

export GOOGLE_APPLICATION_CREDENTIALS=/path/to/service-account-key.json

Option 3: Using explicit key file in config

gcs: {
  bucket: 'my-bucket',
  projectId: 'my-project-id',
  keyFilename: './path/to/service-account-key.json',
}

⚙️ Configuration

Full Configuration with All Options

import { UploadModule, StorageProvider, ImageFormat } from 'nestjs-upload';

UploadModule.forRoot({
  // Required parameters
  provider: StorageProvider.AWS, // or StorageProvider.GCS
  
  // AWS configuration (if provider === StorageProvider.AWS)
  aws: {
    bucket: 'my-bucket',
    region: 'us-east-1',
    // Optional: Explicit credentials (if not provided, uses default credential chain)
    // accessKey: process.env.AWS_ACCESS_KEY_ID,
    // secretKey: process.env.AWS_SECRET_ACCESS_KEY,
  },
  
  // GCS configuration (if provider === StorageProvider.GCS)
  gcs: {
    bucket: 'my-bucket',
    projectId: 'my-project-id',
    // Optional: Explicit credentials (if not provided, uses Application Default Credentials)
    // keyFilename: './path/to/service-account-key.json',
    // or
    // credentials: { client_email: '...', private_key: '...', project_id: '...' }
  },
  
  // File validation
  validation: {
    maxFileSize: 5 * 1024 * 1024, // Maximum size in bytes
    allowedMimeTypes: ['image/jpeg', 'image/png', 'image/webp'],
    imageValidation: {
      minWidth: 100,
      maxWidth: 2000,
      minHeight: 100,
      maxHeight: 2000,
      aspectRatio: {
        width: 16,
        height: 9,
        tolerance: 0.1, // 10% deviation
      },
      allowedFormats: ['jpeg', 'png', 'webp'],
    },
  },
  
  // Image optimization
  imageOptimization: {
    enabled: true,
    maxWidth: 1920,
    maxHeight: 1080,
    quality: 85, // 1-100
    format: ImageFormat.AUTO, // 'auto' | ImageFormat.JPEG | ImageFormat.PNG | ImageFormat.WEBP
    convertToWebP: false, // If true, all images are converted to WebP
  },
  
  // Files are public by default
  defaultPublic: true,
  
  // Rate Limiting
  rateLimit: {
    enabled: true,
    type: 'memory', // 'memory' | 'redis'
    windowMs: 60000, // Time window in milliseconds
    maxRequests: 10, // Maximum number of requests in the window
    // Redis configuration (if type === 'redis')
    redis: {
      host: 'localhost',
      port: 6379,
      // or
      // client: redisClient, // Existing Redis client
    },
  },
  
  // Presigned URL caching
  cache: {
    enabled: true,
    ttl: 3600, // Time to live in seconds
    maxSize: 1000, // Maximum number of entries in cache
  },
})

🌐 API Endpoints

POST /upload

Uploads a file to the selected storage with validation and optional optimization.

Request:

• Content-Type: multipart/form-data
• file (required): File to upload
• folder (optional): Folder path in bucket (e.g., images/products)
• isPublic (optional): Whether the file is public (default: true)
• metadata (optional): Object with metadata:
  • contentType: File MIME type
  • cacheControl: Cache-Control header value
  • contentDisposition: Content-Disposition header value
  • contentEncoding: Content-Encoding header value
  • metadata: Custom metadata (key-value pairs)

Response:

{
  "imgUrl": "https://bucket.s3.region.amazonaws.com/uuid.jpg",
  "key": "images/products/uuid.jpg",
  "bucket": "my-bucket-name",
  "isPublic": true
}

Example with curl:

curl -X POST http://localhost:3000/upload \
  -F "[email protected]" \
  -F "folder=images/products" \
  -F "isPublic=true" \
  -F "metadata[contentType]=image/jpeg" \
  -F "metadata[cacheControl]=public, max-age=3600"

Example with FormData (JavaScript):

const formData = new FormData();
formData.append('file', fileInput.files[0]);
formData.append('folder', 'images/products');
formData.append('isPublic', 'true');
formData.append('metadata[contentType]', 'image/jpeg');
formData.append('metadata[cacheControl]', 'public, max-age=3600');

fetch('http://localhost:3000/upload', {
  method: 'POST',
  body: formData,
});

DELETE /upload/:key

Deletes a file from storage by key.

Parameters:

• key (path parameter): File key/path in storage

Response:

{
  "success": true,
  "message": "File deleted successfully"
}

Example:

curl -X DELETE http://localhost:3000/upload/images/products/uuid.jpg

GET /upload/presigned-url/:key

Generates a presigned URL for accessing a private file.

Parameters:

• key (path parameter): File key/path in storage

Query Parameters:

• expiresIn (optional): URL expiration time in seconds (default: 3600, max: 604800)
• contentType (optional): Content-Type for the presigned URL

Response:

{
  "url": "https://bucket.s3.region.amazonaws.com/file.jpg?X-Amz-Algorithm=...",
  "key": "images/products/uuid.jpg",
  "expiresIn": 3600
}

Example:

curl "http://localhost:3000/upload/presigned-url/images/products/uuid.jpg?expiresIn=7200&contentType=image/jpeg"

💻 Service Usage

Injecting the Service

import { Injectable } from '@nestjs/common';
import { UploadService } from 'nestjs-upload';

@Injectable()
export class MyService {
  constructor(private readonly uploadService: UploadService) {}
}

UploadService Methods

uploadFile()

Uploads a file from buffer with validation and optional optimization.

async uploadFile(
  dataBuffer: Buffer,
  filename: string,
  folder?: string,
  options?: UploadOptions,
): Promise<{ imgUrl: string; key: string; bucket: string; isPublic?: boolean }>

Parameters:

• dataBuffer: Buffer with file data
• filename: Original filename
• folder: Optional folder in bucket
• options: Upload options:
  • isPublic: Whether the file is public (default: true)
  • metadata: File metadata:
    • contentType: MIME type
    • cacheControl: Cache-Control header
    • contentDisposition: Content-Disposition header
    • contentEncoding: Content-Encoding header
    • metadata: Custom metadata (Record<string, string>)

Example:

const result = await this.uploadService.uploadFile(
  buffer,
  'image.jpg',
  'images/products',
  {
    isPublic: true,
    metadata: {
      contentType: 'image/jpeg',
      cacheControl: 'public, max-age=3600',
      metadata: {
        author: 'John Doe',
        category: 'product',
      },
    },
  },
);

console.log(result.imgUrl); // File URL
console.log(result.key); // File key
console.log(result.bucket); // Bucket name

uploadPublicFile()

Uploads a public file (backward compatibility method).

async uploadPublicFile(
  dataBuffer: Buffer,
  filename: string,
  folder?: string,
): Promise<{ imgUrl: string; key: string; bucket: string }>

Example:

const result = await this.uploadService.uploadPublicFile(
  buffer,
  'image.jpg',
  'images/products',
);

uploadFileStream()

Uploads a file from stream (useful for large files).

async uploadFileStream(
  stream: Readable,
  filename: string,
  folder?: string,
  options?: UploadOptions,
): Promise<{ imgUrl: string; key: string; bucket: string; isPublic?: boolean }>

Example:

import { createReadStream } from 'fs';

const stream = createReadStream('./large-file.zip');
const result = await this.uploadService.uploadFileStream(
  stream,
  'large-file.zip',
  'downloads',
  { isPublic: false },
);

uploadFiles()

Uploads multiple files simultaneously (batch upload).

async uploadFiles(
  files: Array<{ buffer: Buffer; filename: string; folder?: string }>,
  options?: UploadOptions,
): Promise<Array<{ imgUrl: string; key: string; bucket: string; isPublic?: boolean }>>

Example:

const files = [
  { buffer: buffer1, filename: 'image1.jpg', folder: 'images' },
  { buffer: buffer2, filename: 'image2.png', folder: 'images' },
  { buffer: buffer3, filename: 'document.pdf', folder: 'documents' },
];

const results = await this.uploadService.uploadFiles(files, {
  isPublic: true,
});

results.forEach((result, index) => {
  console.log(`File ${index + 1}: ${result.imgUrl}`);
});

deleteFile()

Deletes a file from storage.

async deleteFile(
  key: string,
  ignoreNotFound?: boolean,
): Promise<boolean>

Parameters:

• key: File key/path in storage
• ignoreNotFound: If true, doesn't throw error if file not found (default: false)

Example:

// With error thrown if file not found
await this.uploadService.deleteFile('images/products/uuid.jpg');

// Without error thrown
const deleted = await this.uploadService.deleteFile(
  'images/products/uuid.jpg',
  true,
);
if (deleted) {
  console.log('File deleted');
} else {
  console.log('File not found');
}

deleteFiles()

Deletes multiple files simultaneously (batch delete).

async deleteFiles(
  keys: string[],
  ignoreNotFound?: boolean,
): Promise<boolean[]>

Example:

const keys = [
  'images/products/uuid1.jpg',
  'images/products/uuid2.png',
  'images/products/uuid3.webp',
];

const results = await this.uploadService.deleteFiles(keys, true);
// results = [true, true, false] - last file not found

getPresignedUrl()

Generates a presigned URL for accessing a private file.

async getPresignedUrl(
  key: string,
  options?: PresignedUrlOptions,
): Promise<string>

Parameters:

• key: File key/path in storage
• options: Presigned URL options:
  • expiresIn: URL expiration time in seconds (default: 3600)
  • contentType: Content-Type for URL

Example:

// Basic presigned URL (1 hour)
const url = await this.uploadService.getPresignedUrl(
  'private/documents/file.pdf',
);

// With custom expiration and Content-Type
const url = await this.uploadService.getPresignedUrl(
  'private/images/photo.jpg',
  {
    expiresIn: 7200, // 2 hours
    contentType: 'image/jpeg',
  },
);

fileExists()

Checks if a file exists in storage.

async fileExists(key: string): Promise<boolean>

Example:

const exists = await this.uploadService.fileExists('images/products/uuid.jpg');
if (exists) {
  console.log('File exists');
}

getFileMetadata()

Gets file metadata.

async getFileMetadata(key: string): Promise<FileMetadata | null>

Example:

const metadata = await this.uploadService.getFileMetadata(
  'images/products/uuid.jpg',
);

if (metadata) {
  console.log('Size:', metadata.size);
  console.log('Content-Type:', metadata.contentType);
  console.log('Last Modified:', metadata.lastModified);
  console.log('ETag:', metadata.etag);
  console.log('Custom metadata:', metadata.metadata);
}

✅ Validation

File Validation

validation: {
  maxFileSize: 5 * 1024 * 1024, // Maximum size in bytes
  allowedMimeTypes: ['image/jpeg', 'image/png', 'image/webp'], // Allowed MIME types
}

Image Validation

imageValidation: {
  minWidth: 100,        // Minimum width in pixels
  maxWidth: 2000,       // Maximum width in pixels
  minHeight: 100,       // Minimum height in pixels
  maxHeight: 2000,      // Maximum height in pixels
  aspectRatio: {        // Aspect ratio
    width: 16,
    height: 9,
    tolerance: 0.1,     // Allowed deviation (10%)
  },
  allowedFormats: ['jpeg', 'png', 'webp'], // Allowed formats
}

Example validation error:

{
  "statusCode": 400,
  "message": "Image validation failed: Image width must be at least 100px, Image aspect ratio must be 16:9"
}

🖼️ Image Optimization

The library supports automatic image optimization using Sharp.

Configuration

imageOptimization: {
  enabled: true,
  maxWidth: 1920,        // Maximum width after optimization
  maxHeight: 1080,       // Maximum height after optimization
  quality: 85,           // Image quality (1-100)
  format: 'auto',         // Output format: 'auto' | ImageFormat.JPEG | ImageFormat.PNG | ImageFormat.WEBP
  convertToWebP: false,   // If true, all images are converted to WebP
}

Image Formats

import { ImageFormat } from 'nestjs-upload';

// Available formats
ImageFormat.JPEG // 'jpeg'
ImageFormat.JPG  // 'jpg' (maps to JPEG)
ImageFormat.PNG  // 'png'
ImageFormat.WEBP // 'webp'

Optimization Examples

Automatic format (preserves original format):

imageOptimization: {
  enabled: true,
  format: 'auto',
  maxWidth: 1920,
  quality: 85,
}

Force WebP conversion:

imageOptimization: {
  enabled: true,
  convertToWebP: true,
  quality: 85,
}

Convert to JPEG:

imageOptimization: {
  enabled: true,
  format: ImageFormat.JPEG,
  quality: 90,
}

Without resizing (compression only):

imageOptimization: {
  enabled: true,
  quality: 85,
  // maxWidth and maxHeight not specified
}

Using ImageOptimizer Directly

import { ImageOptimizer } from 'nestjs-upload';

const optimizer = new ImageOptimizer({
  enabled: true,
  maxWidth: 1920,
  quality: 85,
});

const result = await optimizer.optimize(buffer, 'image/jpeg');
console.log(`Original: ${buffer.length} bytes`);
console.log(`Optimized: ${result.size} bytes`);
console.log(`Reduction: ${((1 - result.size / buffer.length) * 100).toFixed(1)}%`);

🚦 Rate Limiting

The library supports rate limiting to protect against abuse.

In-Memory Rate Limiter

rateLimit: {
  enabled: true,
  type: 'memory',
  windowMs: 60000,    // 1 minute
  maxRequests: 10,    // Maximum 10 requests per minute
}

Redis Rate Limiter

rateLimit: {
  enabled: true,
  type: 'redis',
  windowMs: 60000,
  maxRequests: 10,
  redis: {
    host: 'localhost',
    port: 6379,
    // or use existing client
    // client: redisClient,
  },
}

Response When Limit Exceeded

{
  "statusCode": 429,
  "message": "Too Many Requests",
  "retryAfter": 30
}

💾 Caching

The library supports caching of presigned URLs to improve performance.

Configuration

cache: {
  enabled: true,
  ttl: 3600,      // Time to live in seconds (1 hour)
  maxSize: 1000,  // Maximum number of entries in cache
}

Using PresignedUrlCacheService Directly

import { PresignedUrlCacheService } from 'nestjs-upload';

const cache = new PresignedUrlCacheService(3600, 1000);

// Store URL
cache.set('key', 'https://...', 3600);

// Get URL
const url = cache.get('key');

// Delete from cache
cache.delete('key');

// Clear entire cache
cache.clear();

📚 Types and Interfaces

Exported Types

import {
  // Enums
  StorageProvider,
  ImageFormat,
  ImageMimeType,
  
  // Interfaces
  UploadConfig,
  AwsConfig,
  GcsConfig,
  ValidationConfig,
  ImageValidationConfig,
  ImageOptimizationConfig,
  CacheConfig,
  RateLimitConfig,
  
  // Services
  UploadService,
  ImageOptimizer,
  PresignedUrlCacheService,
  
  // Validators
  FileValidator,
  ImageValidator,
  
  // Providers
  AwsS3Provider,
  GcsProvider,
  IStorageProvider,
  
  // Guards
  RateLimitGuard,
  
  // Utils
  getMimeType,
  isImageMimeType,
  validateFileKey,
  buildSafeKey,
} from 'nestjs-upload';

Main Interfaces

UploadOptions

interface UploadOptions {
  isPublic?: boolean;
  metadata?: FileMetadataOptions;
}

interface FileMetadataOptions {
  contentType?: string;
  cacheControl?: string;
  contentDisposition?: string;
  contentEncoding?: string;
  metadata?: Record<string, string>;
}

PresignedUrlOptions

interface PresignedUrlOptions {
  expiresIn?: number;    // Expiration time in seconds
  contentType?: string; // Content-Type
}

FileMetadata

interface FileMetadata {
  key: string;
  size?: number;
  contentType?: string;
  lastModified?: Date;
  etag?: string;
  metadata?: Record<string, string>;
}

⚠️ Error Handling

The library throws the following error types:

BadRequestException

Thrown when:

• Invalid files (size, MIME type)
• Invalid images (dimensions, aspect ratio)
• Invalid parameters (file key, folder)

Example:

try {
  await uploadService.uploadFile(buffer, 'file.jpg');
} catch (error) {
  if (error instanceof BadRequestException) {
    console.error('Validation error:', error.message);
  }
}

InternalServerErrorException

Thrown when:

• Upload/delete errors
• Storage connection errors
• Other internal errors

Example:

try {
  await uploadService.uploadFile(buffer, 'file.jpg');
} catch (error) {
  if (error instanceof InternalServerErrorException) {
    console.error('Server error:', error.message);
  }
}

Custom Error Handling

import { Catch, ExceptionFilter, ArgumentsHost } from '@nestjs/common';
import { BadRequestException, InternalServerErrorException } from '@nestjs/common';

@Catch(BadRequestException, InternalServerErrorException)
export class UploadExceptionFilter implements ExceptionFilter {
  catch(exception: BadRequestException | InternalServerErrorException, host: ArgumentsHost) {
    const response = host.switchToHttp().getResponse();
    const status = exception.getStatus();
    
    response.status(status).json({
      statusCode: status,
      message: exception.message,
      timestamp: new Date().toISOString(),
    });
  }
}

📖 Usage Examples

Uploading Image with Optimization

import { Injectable } from '@nestjs/common';
import { UploadService } from 'nestjs-upload';

@Injectable()
export class ImageService {
  constructor(private readonly uploadService: UploadService) {}

  async uploadProductImage(buffer: Buffer, filename: string) {
    const result = await this.uploadService.uploadFile(
      buffer,
      filename,
      'images/products',
      {
        isPublic: true,
        metadata: {
          contentType: 'image/jpeg',
          cacheControl: 'public, max-age=31536000',
          metadata: {
            category: 'product',
          },
        },
      },
    );
    
    return result.imgUrl;
  }
}

Uploading Private Document

async uploadPrivateDocument(buffer: Buffer, filename: string, userId: string) {
  const result = await this.uploadService.uploadFile(
    buffer,
    filename,
    `documents/${userId}`,
    {
      isPublic: false,
      metadata: {
        contentType: 'application/pdf',
        metadata: {
          userId,
          type: 'document',
        },
      },
    },
  );
  
  // Generate presigned URL for access
  const presignedUrl = await this.uploadService.getPresignedUrl(
    result.key,
    { expiresIn: 3600 },
  );
  
  return {
    key: result.key,
    url: presignedUrl,
  };
}

Batch Upload with Error Handling

async uploadMultipleImages(files: Array<{ buffer: Buffer; filename: string }>) {
  const uploadPromises = files.map(file =>
    this.uploadService.uploadFile(
      file.buffer,
      file.filename,
      'images/gallery',
      { isPublic: true },
    ).catch(error => {
      console.error(`Failed to upload ${file.filename}:`, error.message);
      return null;
    }),
  );
  
  const results = await Promise.all(uploadPromises);
  const successful = results.filter(r => r !== null);
  
  return {
    total: files.length,
    successful: successful.length,
    failed: files.length - successful.length,
    urls: successful.map(r => r!.imgUrl),
  };
}

Deleting Files by Pattern

async deleteUserFiles(userId: string) {
  // Get list of user files (requires implementation)
  const userFiles = await this.getUserFiles(userId);
  
  // Delete all files
  const results = await this.uploadService.deleteFiles(
    userFiles.map(f => f.key),
    true, // ignoreNotFound
  );
  
  const deletedCount = results.filter(r => r === true).length;
  
  return {
    total: userFiles.length,
    deleted: deletedCount,
  };
}

Check and Update File

async updateFileIfExists(key: string, newBuffer: Buffer) {
  const exists = await this.uploadService.fileExists(key);
  
  if (!exists) {
    throw new NotFoundException('File not found');
  }
  
  // Delete old file
  await this.uploadService.deleteFile(key);
  
  // Upload new file
  const result = await this.uploadService.uploadFile(
    newBuffer,
    key.split('/').pop()!,
    key.split('/').slice(0, -1).join('/'),
  );
  
  return result;
}

Usage with Express Multer

import { Controller, Post, UploadedFile, UseInterceptors } from '@nestjs/common';
import { FileInterceptor } from '@nestjs/platform-express';
import { UploadService } from 'nestjs-upload';

@Controller('api/files')
export class FilesController {
  constructor(private readonly uploadService: UploadService) {}

  @Post('upload')
  @UseInterceptors(FileInterceptor('file'))
  async upload(@UploadedFile() file: Express.Multer.File) {
    if (!file) {
      throw new BadRequestException('File is required');
    }

    const result = await this.uploadService.uploadFile(
      file.buffer,
      file.originalname,
      'uploads',
    );

    return {
      success: true,
      url: result.imgUrl,
      key: result.key,
    };
  }
}

🔍 Logging

The library uses NestJS built-in logger for logging:

• ✅ Successful upload/delete operations
• ✅ Validation errors
• ✅ Storage operation errors
• ✅ Image optimization (before/after size)
• ✅ Presigned URL caching

Example logs:

[UploadService] File uploaded successfully: images/products/uuid.jpg (public)
[ImageOptimizer] Image optimized: 2048576 -> 512384 bytes (75.0% reduction)
[UploadService] Presigned URL generated for: private/documents/file.pdf

📝 Swagger Documentation

If you use @nestjs/swagger, all endpoints will be automatically documented in Swagger UI.

Example configuration:

import { DocumentBuilder, SwaggerModule } from '@nestjs/swagger';

const config = new DocumentBuilder()
  .setTitle('My API')
  .setDescription('API description')
  .setVersion('1.0')
  .addTag('upload')
  .build();

const document = SwaggerModule.createDocument(app, config);
SwaggerModule.setup('api', app, document);

🛠️ Extending Functionality

Creating Custom Storage Provider

import { IStorageProvider, UploadResult, UploadOptions } from 'nestjs-upload';
import { Readable } from 'stream';

export class CustomStorageProvider implements IStorageProvider {
  async upload(
    dataBuffer: Buffer,
    filename: string,
    folder?: string,
    options?: UploadOptions,
  ): Promise<UploadResult> {
    // Your implementation
  }

  // Implement other methods...
}

Using Custom Provider

// In your module
const customProvider = new CustomStorageProvider();

const uploadService = new UploadService(
  customProvider,
  fileValidator,
  imageValidator,
  imageOptimizer,
  urlCache,
);

📄 License

MIT

🤝 Support

If you have questions or issues, please create an issue in the project repository.