# Changelog

This changelog is generated automatically from [GitHub Releases](https://github.com/mikeckennedy/content-types/releases).


# v0.5.7

*2026-06-17* · [GitHub](https://github.com/mikeckennedy/content-types/releases/tag/v0.5.7)


## \[0.5.7\] - 2026-06-17


### Added

- `guess_extension(content_type, with_dot=True)` -- reverse lookup from a MIME type to its canonical file extension (e.g. `application/pdf` → `.pdf`), the inverse of [get_content_type()](reference/get_content_type.html#content_types.get_content_type). Case-insensitive, and MIME parameters on a `Content-Type` header are ignored (`text/html; charset=utf-8` → `.html`). Common non-canonical / legacy spellings also resolve (e.g. `text/json` → `.json`, `image/jpg` → `.jpg`, `application/x-zip-compressed` → `.zip`). Unknown types return `None`. ([\#9](https://github.com/mikeckennedy/content-types/issues/9))
- `guess_all_extensions(content_type, with_dot=True)` -- returns every known extension for a MIME type, canonical first (e.g. `image/jpeg` → `['.jpg', '.jpeg', '.jpe']`); unknown types return `[]`. Same case-insensitivity, parameter-stripping, and alias handling as [guess_extension()](reference/guess_extension.html#content_types.guess_extension). ([\#9](https://github.com/mikeckennedy/content-types/issues/9))
- Files: `content_types/__init__.py`, `tests/test_content_types.py`, `README.md`, `great-docs.yml`, `docs/`


### Changed

- [get_content_type()](reference/get_content_type.html#content_types.get_content_type) now distinguishes an omitted `fallback` from an explicit `fallback=None`. Passing `fallback=None` returns `None` for unknown extensions (handy when you want to branch on a miss rather than receive a placeholder type), while omitting `fallback` is unchanged and still returns `application/octet-stream` (or `text/plain` with `treat_as_binary=False`) -- so existing callers are unaffected. The default keyword switched from `None` to a private sentinel to tell the two cases apart, and the return type widened to `Optional[str]`. ([\#8](https://github.com/mikeckennedy/content-types/issues/8))
- Files: `content_types/__init__.py`, `tests/test_content_types.py`, `README.md`


# v0.4.0

*2026-06-11* · [GitHub](https://github.com/mikeckennedy/content-types/releases/tag/v0.4.0)


## \[0.4.0\] - 2026-06-10


### Added

- `fallback` parameter on [get_content_type()](reference/get_content_type.html#content_types.get_content_type) to override the default MIME type returned for unknown extensions -- pass any string and it will be returned in place of `application/octet-stream` / `text/plain` ([\#8](https://github.com/mikeckennedy/content-types/issues/8))
- URL support: [get_content_type()](reference/get_content_type.html#content_types.get_content_type) now handles query strings and URL fragments
- MIME types for `.sas` (`text/x-sas`) and `.sql` (`application/sql`) extensions ([\#5](https://github.com/mikeckennedy/content-types/issues/5))
- Comprehensive test suite (35 tests) covering integration, spot tests, and negative conditions
- Documentation site built with [Great Docs](https://github.com/posit-dev/great-docs) and published at <https://mkennedy.codes/docs/content-types/> -- auto-generated API reference plus a README-driven landing page. Built locally with `scripts/build_docs.py` and served from the committed `docs/` folder (`scripts/serve_docs.py` previews it under the production subpath).
- Files: `content_types/__init__.py`, `tests/test_content_types.py`, `tests/__init__.py`, `pytest.ini`, `great-docs.yml`, `scripts/build_docs.py`, `scripts/serve_docs.py`, `pyproject.toml`, `docs/`


### Changed

- [get_content_type()](reference/get_content_type.html#content_types.get_content_type) now raises `TypeError` (instead of a bare `Exception`) when called with `None`. The message is unchanged, so existing `except Exception` handlers keep working.
- Modernized type hints (`dict[str, str]`, `Optional[str]`) and rewrote the [get_content_type()](reference/get_content_type.html#content_types.get_content_type) / `cli()` docstrings in Google style (Args/Returns/Raises) for a cleaner generated API reference.
- `.yaml`, `.yml`, and `.kubeconfig` now map to `application/yaml` (RFC 9512, registered 2024) instead of the legacy `text/yaml`. The [content_types.yaml](reference/yaml.html#content_types.yaml) shortcut constant updates to match.
- Added the `Typing :: Typed` trove classifier to advertise the existing PEP 561 `py.typed` marker on PyPI; added a test asserting the marker ships with the package.
- Dynamic version metadata: package now pulls `__version__` from distribution metadata.
- The sdist now contains only the package, change log, readme, and license -- previously it bundled every git-tracked file (the built `docs/` site, `tests/`, `scripts/`, editor config, etc.). Wheels were already minimal. (`[tool.hatch.build.targets.sdist]` in `pyproject.toml`)
- Files: `content_types/__init__.py`, `pyproject.toml`, `README.md`, `tests/test_content_types.py`


### Fixed

- `.ass` (Advanced SubStation Alpha subtitles) now maps to `text/x-ssa` -- matching its sibling `.ssa` -- instead of the incorrect `audio/aac`. `.rst` (reStructuredText, value unchanged at `text/x-rst`) moved out of the audio block into the documentation block.
- Docstring example for `get_content_type("script.js")` now shows `'text/javascript'` (the actual return value) instead of the outdated `'application/javascript'`
- Files: `content_types/__init__.py`


# v0.3.0

*2025-10-01* · [GitHub](https://github.com/mikeckennedy/content-types/releases/tag/v0.3.0)


### Added

- 137 new file extensions across 17 categories, expanding format recognition capabilities
- Comprehensive support for data-science MIME types (e.g., `application/vnd.pandas`, `application/x-ipynb+json`)
- Project now supports 360+ file formats
- Warp Project Summary / Index document for contributors and users
- Files: `content_types/__init__.py`, `WARP.md`


### Changed

- Implemented alphabetical sorting of output listings for better navigation
- Enhanced README to highlight 360+ supported file formats
- Improved docstrings throughout codebase for clarity
- Files: `content_types/__init__.py`, `README.md`


### Fixed

- Corrected CLI help text instructions for clearer usage guidance
- Adjusted code indentation for better visual consistency
- Files: `content_types/__init__.py`


# v0.2.3

*2025-02-01* · [GitHub](https://github.com/mikeckennedy/content-types/releases/tag/v0.2.3)

- Changes .js back to text/javascript
- Adds a few new types
- Adds comparison to builtin mimetypes


# v0.2.2

*2025-01-31* · [GitHub](https://github.com/mikeckennedy/content-types/releases/tag/v0.2.2)

Added [py.typed](https://github.com/mikeckennedy/content-types/blob/main/content_types/py.typed) file to suppress mypy typing warnings. Thanks [<span class="citation" cites="sanders41">@sanders41</span>](https://github.com/sanders41) Available on PyPI now.


# v0.2.1

*2025-01-31* · [GitHub](https://github.com/mikeckennedy/content-types/releases/tag/v0.2.1)

Adds many more file extensions as known types.


# v0.2.0

*2025-01-31* · [GitHub](https://github.com/mikeckennedy/content-types/releases/tag/v0.2.0)

Initial public release.