Build a file format detector

Here is a Python-based file format detector that can identify common file types by inspecting their file signatures (also known as magic numbers). This script reads the first few bytes of a file and matches them against known signatures.

python
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import os

# Define known file signatures
FILE_SIGNATURES = {
    b'xFFxD8xFF': 'JPEG image',
    b'x89PNGrnx1an': 'PNG image',
    b'GIF87a': 'GIF image',
    b'GIF89a': 'GIF image',
    b'%PDF-': 'PDF document',
    b'x25x21': 'PostScript document',
    b'PKx03x04': 'ZIP archive',
    b'x1Fx8Bx08': 'GZIP archive',
    b'Rar!x1Ax07x00': 'RAR archive',
    b'x42x4D': 'BMP image',
    b'x49x44x33': 'MP3 audio',
    b'OggS': 'OGG audio/video',
    b'fLaC': 'FLAC audio',
    b'x00x00x00x18ftyp': 'MP4 video',
    b'x00x00x00x14ftyp': 'MP4 video',
    b'x00x00x01xBA': 'MPEG video',
    b'x00x00x01xB3': 'MPEG video',
    b'x52x49x46x46': 'AVI or WAV (needs more context)',
    b'x4Dx5A': 'Windows executable (EXE)',
}

def detect_file_format(file_path):
    try:
        with open(file_path, 'rb') as f:
            header = f.read(16)

        for signature, filetype in FILE_SIGNATURES.items():
            if header.startswith(signature):
                return filetype

        return "Unknown file type"

    except FileNotFoundError:
        return "File not found"
    except IOError as e:
        return f"I/O error: {e}"

# Example usage
if __name__ == "__main__":
    path = input("Enter file path: ").strip()
    if os.path.isfile(path):
        result = detect_file_format(path)
        print(f"Detected file type: {result}")
    else:
        print("Invalid file path.")

Features:

• Detects common formats: JPEG, PNG, PDF, MP3, ZIP, MP4, EXE, and more.

• Uses file headers (magic numbers) for identification, not file extensions.

• Lightweight and easily extendable with more signatures.

To Extend:

You can add more file signatures by expanding the FILE_SIGNATURES dictionary with known hex patterns.

Would you like a web interface or command-line enhancements for this detector?