README.md

FileType

The file type is detected by checking signature bytes and, for some container formats, scanning the full file contents when required.

This is swift port of file-type

Documentation: Swift Package Index DocC

Installation

Requirements

• Swift 6.2+
• Xcode 26.3+ or another Swift 6.2-compatible toolchain

Swift Package Manager

import PackageDescription

let package = Package(
  name: "MyApp",
  dependencies: [
    .package(url: "https://github.com/velocityzen/FileType", branch: "main")
  ]
)

If you are consuming a tagged release instead of main, use the latest Swift 6.2-compatible tag.

Usage

Inspect mime type

import FileType

let path = "/path/to/some-file.jpg"
let url = URL(fileURLWithPath: path, isDirectory: false)
let fileType = try FileType.detect(contentsOf: url)

fileType?.type == .jpg // true
fileType // FileType(type: .jpg, ext: "jpg", mime: "image/jpeg")

Limit detection to MIME major groups when you already know the broad file family:

import FileType

let data = try Data(contentsOf: url)
let imageType = FileType.detect(in: data, matching: .image)

imageType?.mimeGroup == .image // true

Inspect the detection requirement before sampling file contents:

import FileType

switch FileType.dataRequirement(for: .docx) {
case let .prefix(byteCount):
  // Read only the prefix for simple signatures.
  print(byteCount)
case .fullFile:
  // Container formats like DOCX require the full file.
  print("Read the full file")
}

FileType.all(for: FileTypeExtension) -> [FileType]

returns all file types and mime information

FileType.all(for: FileTypeMIMEGroup) -> [FileType]

returns all file types whose mime begins with that major type

FileType.detect(in: Data) -> FileType?

returns file type detected by checking the magic number

FileType.detect(in: Data, matching: FileTypeMIMEGroup) -> FileType?

limits detection to a MIME major group such as .image, .audio, or .video

FileType.detect(contentsOf: URL) throws -> FileType?

detects the type from a file URL and only loads the full file when a detector requires it

FileType.detect(contentsOf: URL, matching: FileTypeMIMEGroup) throws -> FileType?

limits URL-based detection to one MIME major group

FileType.detect(using: FileHandle) throws -> FileType?

detects the type from a file handle positioned at the start of the file

FileType.detect(using: FileHandle, matching: FileTypeMIMEGroup) throws -> FileType?

limits file-handle detection to one MIME major group

FileType.minimumPrefixBytes(for: FileTypeExtension) -> Int

returns the minimum prefix size used by the detector for that type

FileType.minimumPrefixBytes(for: FileTypeMIMEGroup) -> Int

returns the minimum prefix size needed for that MIME major group

FileType.dataRequirement(for: FileTypeExtension) -> FileTypeDataRequirement

returns whether the detector can work from a prefix or requires the full file

FileType.dataRequirement(for: FileTypeMIMEGroup) -> FileTypeDataRequirement

returns whether that MIME major group can work from a prefix or requires the full file

FileTypeExtension.canonicalFileExtension -> String

returns the canonical on-disk extension for a public file type case

FileType.mimeGroup -> FileTypeMIMEGroup

returns the first component of the detected MIME type

UTI Detection (Apple platforms)

On Apple platforms with UniformTypeIdentifiers available (macOS 11+, iOS 14+, tvOS 14+, watchOS 7+, visionOS 1+), you can detect file types from UTI identifiers:

import FileType

// From a UTI identifier string
let fileType = FileType.detect(uti: "public.jpeg")
fileType?.type == .jpg // true

import FileType
import UniformTypeIdentifiers

// From a UTType value
let fileType = FileType.detect(utType: .png)
fileType?.type == .png // true

FileType.detect(uti: String) -> FileType?

resolves a UTI identifier string to a file type using the system's UTType mapping

FileType.detect(utType: UTType) -> FileType?

resolves a UTType value to a file type using its MIME type and file extension

Deprecated compatibility APIs

getFor(...) and getBytesCountFor(...) remain as deprecated wrappers for older callers.

Supported file types

• 3g2 - Multimedia container format defined by the 3GPP2 for 3G CDMA2000 multimedia services
• 3gp - Multimedia container format defined by the Third Generation Partnership Project (3GPP) for 3G UMTS multimedia services
• 3mf - 3D Manufacturing Format
• 7z
• aac - Advanced Audio Coding
• ac3 - ATSC A/52 Audio File
• ace
• ai - Adobe Illustrator Artwork
• aif
• alias - macOS Alias file
• amr
• ape - Monkey's Audio
• apk
• apng - Animated Portable Network Graphics
• ar
• arj
• arrow - Columnar format for tables of data
• arw - Sony Alpha Raw image file
• asar - Simple extensive tar-like archive format with indexing
• asf - Advanced Systems Format
• avi
• avif - AV1 Image File Format
• avro
• blend
• bmp
• bpg
• bz2
• cab
• cfb
• chm - Microsoft Compiled HTML Help
• cpio
• cr2 - Canon Raw image file (v2)
• cr3 - Canon Raw image file (v3)
• crx
• cur
• dat - Windows Registry hive
• dcm - DICOM Image File
• deb
• dmg
• dng - Adobe Digital Negative image file
• docm
• docx
• dotm
• dotx
• drc
• dwg
• dsf - Sony DSD Stream File (DSF)
• elf - Unix Executable and Linkable Format
• eot
• eps - Encapsulated PostScript
• epub
• exe
• f4a - Audio-only ISO base media file format used by Adobe Flash Player
• f4b - Audiobook and podcast ISO base media file format used by Adobe Flash Player
• f4p - ISO base media file format protected by Adobe Access DRM used by Adobe Flash Player
• f4v - ISO base media file format used by Adobe Flash Player
• fbx
• flac
• flif
• flv
• gif
• glb - GL Transmission Format
• gz
• heic
• icc
• icns
• ico
• ics - iCalendar
• ism - Microsoft Smooth Streaming manifest
• indd
• it - Audio module format: Impulse Tracker
• j2c - JPEG 2000 codestream
• jar
• jp2 - JPEG 2000
• jpg
• jls
• jmp - JMP data file
• jpm - JPEG 2000
• jpx - JPEG 2000
• jxl - JPEG XL image format
• jxr
• ktx
• lnk - Microsoft Windows file shortcut
• lz
• lz4
• lzh - LZH archive
• m3u - HLS playlist when HLS-specific #EXT-X- tags are present
• m4a - Audio-only MPEG-4 files
• m4b - Audiobook and podcast MPEG-4 files, which also contain metadata including chapter markers, images, and hyperlinks
• m4p - MPEG-4 files with audio streams encrypted by FairPlay Digital Rights Management as were sold through the iTunes Store
• m4v - MPEG-4 Visual bitstreams
• macho
• mid
• mie - Dedicated meta information format which supports storage of binary as well as textual meta information
• mj2 - Motion JPEG 2000
• mkv
• mobi - Mobipocket
• mov
• mp1 - MPEG-1 Audio Layer I
• mp2
• mp3
• mp4
• mpd - MPEG-DASH manifest
• mpc - Musepack (SV7 & SV8)
• mpg
• mts - MPEG-2 Transport Stream, both raw and Blu-ray Disc Audio-Video (BDAV) versions
• mxf
• nef - Nikon Electronic Format image file
• nes
• odg - OpenDocument graphics
• odp - OpenDocument for presentations
• ods - OpenDocument for spreadsheets
• odt - OpenDocument for word processing
• oga
• ogg
• ogm
• ogv
• ogx
• opus
• orf - Olympus Raw image file
• otf
• otg - OpenDocument graphics template
• otp - OpenDocument presentation template
• ots - OpenDocument spreadsheet template
• ott - OpenDocument text template
• parquet
• pcap - Libpcap File Format
• pdf
• pgp - Pretty Good Privacy
• png
• ppsm
• ppsx
• potm
• potx
• pptm
• pptx
• ps
• psd
• pst
• qcp
• raf - Fujifilm RAW image file
• rar
• reg - Windows Registry export
• rm
• rpm
• rtf
• rw2 - Panasonic RAW image file
• s3m - Audio module format: ScreamTracker 3
• sav - SPSS data file
• shp - Geospatial vector data format
• skp - SketchUp
• spx
• sqlite
• stl - Standard Tesselated Geometry File Format (ASCII only)
• swf
• tar
• tif
• ttc - TrueType Collection
• ttf
• vcf - vCard
• voc - Creative Voice File
• vsdx
• vtt
• wasm
• wav
• webm
• webp
• woff2
• woff
• wv - WavPack
• xcf - eXperimental Computing Facility
• xlsm
• xlsx
• xltm
• xltx
• xm - Audio module format: FastTracker 2
• xml
• xpi
• xz
• Z
• zip
• zst - Archive file

Pull requests are welcome for additional commonly used file types.

Testing

swift test