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0.2.0 (2026-04-21)

Custom signatures

  • Define your own MIME types via use MagicBytes.DefineSignatures and wire them in with config :magic_bytes, extra_signatures: MyModule
  • defsignature/2 registers a prefix-based signature
  • guards: true option generates guard macros on the custom module (e.g. MyModule.is_application_x_cld/1)
  • Custom signatures are checked before built-ins; unmatched bytes fall through to built-in detection

Configuration

  • config :magic_bytes, read_bytes: N — bytes read from input; defaults to 16, which satisfies all built-in signatures. Only needed if you define custom signatures whose prefix exceeds 16 bytes.
  • config :magic_bytes, only: [...] — restrict detection to a specific set of MIME types; others return {:error, :unknown}
  • config :magic_bytes, exclude: [...] — suppress specific MIME types

New built-in signatures

  • image/jp2 (JPEG 2000)
  • image/jxl (JPEG XL — bare codestream and ISO BMFF container)
  • image/flif
  • application/x-lz4
  • application/vnd.apache.parquet
  • application/vnd.apache.arrow.file
  • application/vnd.android.dex

0.1.0 (2026-04-09)

Initial release.

  • MagicBytes.from_path/1, from_binary/1, from_stream/1 for MIME detection
  • Guard macros generated for all prefix-based signatures (is_image_jpeg/1, is_application_pdf/1, etc.)
  • Support for 40+ MIME types across images, audio, video, documents, archives, executables, fonts, and databases