File Type Detector

A .NET library for detecting MIME types and file extensions based on file signatures (magic bytes) and predefined mappings. This project provides a robust way to identify file types from byte arrays, streams, or file paths, supporting both signature-based detection and extension-to-MIME type mappings.

Overview

The File Type Detector library is designed to help developers identify file types and MIME types accurately in .NET applications. It supports detection through file signatures (magic bytes) for precise identification and includes a comprehensive mapping of MIME types to file extensions. The library is built with extensibility in mind, allowing developers to add support for additional file formats.

NuGet Package Information

• Package Name: File Type Detector

• Version: 1.0.0

• NuGet Link: https://www.nuget.org/packages/FileTypeDetector

• Installation Command:

  dotnet add package FileTypeDetector

Features

• File Signature Detection: Detects file types by analyzing magic bytes from files, streams, or byte arrays.
• MIME Type Detection: Maps file extensions to their corresponding MIME types.
• Extensible Architecture: Easily extendable to support additional file formats through custom signature checkers.
• Thread-Safe Lazy Loading: Uses lazy-initialized collections for efficient and thread-safe access to file type and MIME type data.
• Exception Handling: Provides clear error messages for invalid or non-readable inputs.

Installation

Add the FileTypeDetector package using the .NET CLI:

dotnet add package FileTypeDetector

Usage

Detecting File Types by Signature

using MimeType.Services; using MimeType.Core.Models; var detector = new FileSignatureDetector(); byte[] fileBytes = File.ReadAllBytes("sample.png"); var fileTypes = detector.Detect(fileBytes); foreach (var fileType in fileTypes) { Console.WriteLine($"MIME: {fileType.Mime}, Extensions: {string.Join(", ", fileType.Extensions)}"); }

Supported File Signatures

The library currently supports signature-based detection for the following image formats:

• BMP (.bmp): Starts with "BM".
• GIF (.gif): Starts with "GIF87a" or "GIF89a".
• PNG (.png): Starts with 0x89 0x50 0x4E 0x47 0x0D 0x0A 0x1A 0x0A.
• TIFF (.tiff, .tif): Starts with 0x49 0x49 0x2A 0x00 (II*) or 0x4D 0x4D 0x00 0x2A (MM*).
• WebP (.webp): Starts with "RIFF" followed by "WEBP" at offset 8.
• JPEG (.jpg, .jpeg, .jpe, .jfif): Starts with 0xFF 0xD8 0xFF.
• JPEG XL (.jxl): Starts with 0xFF 0x0A (raw codestream) or a 12-byte container signature.
• DWG (.dwg): Starts with "AC" followed by version strings like "1.40", "1002", etc.

Additional file formats (e.g., audio, video, and archive formats) are supported for MIME type-to-extension mappings but lack signature detection at this time. Support for these formats will be added in future updates.

Detecting MIME Types by Extension

using MimeType.Services; var mimeDetector = new MimeTypeDetector(); var mimeTypes = mimeDetector.Detect(".png"); foreach (var mime in mimeTypes) { Console.WriteLine($"MIME Type: {mime}"); }

Detecting File Extensions by MIME Type

using MimeType.Services; var extensionDetector = new FileExtensionDetector(); var extensions = extensionDetector.Detect("image/png"); foreach (var ext in extensions) { Console.WriteLine($"Extension: {ext}"); }

Example project

Project link

[https://github.com/ibrahimekinci/FileType Detector/tree/develop/MimeType.Example](https://github.com/ibrahimekinci/FileType Detector/tree/develop/MimeType.Example)

Project Output

=== DotNetMimeType Example Console Application === === MIME Type Detection from Extension === Extension: .jpg MIME Type: image/jpeg === ************************************* === === Extension Detection from MIME Type === MIME Type: image/jpeg Extensions: jpg, jpeg, jpe, jfif === ************************************* === === File Signature Detection from File Path === File: [absolute-path]\Files\valid_file (1).png MIME: image/png, Extensions: png File: [absolute-path]\Files\valid_file (1).jpg MIME: image/jpeg, Extensions: jpg, jpeg, jpe, jfif File: [absolute-path]\Files\valid_file (1).webp MIME: image/webp, Extensions: webp === ************************************* === === File Signature Detection from Stream === File: [absolute-path]\Files\valid_file (1).png MIME: image/png, Extensions: png File: [absolute-path]\Files\valid_file (1).jpg MIME: image/jpeg, Extensions: jpg, jpeg, jpe, jfif File: [absolute-path]\Files\valid_file (1).webp MIME: image/webp, Extensions: webp === ************************************* === === File Signature Detection from Byte Array === File: [absolute-path]\Files\valid_file (1).png MIME: image/png, Extensions: png File: [absolute-path]\Files\valid_file (1).jpg MIME: image/jpeg, Extensions: jpg, jpeg, jpe, jfif File: [absolute-path]\Files\valid_file (1).webp MIME: image/webp, Extensions: webp === ************************************* === Press any key to exit...

Contributing

We welcome contributions to expand the supported file formats and improve the library! To contribute:

1. Fork the repository: https://github.com/ibrahimekinci/dotnet-FileTypeDetector
2. Add new file signature checkers or enhance existing ones in the MimeType.Infrastructure.FileSignatureCheckers namespace.
3. Update the BuiltInFileTypes class to include new file signatures and mappings.
4. Submit a pull request with a clear description of your changes.

Please ensure your code follows the existing structure and includes appropriate tests.

References

• IANA Media Types
• MIME Type Reference

License

This project is licensed under the MIT License. See the LICENSE file for details.

Author

Developed by Ibrahim Ekinci.