Add optional dependencies for preconf libraries

HISTORY.md

@@ -10,6 +10,7 @@
 - `pathlib.Path` is now supported by default.
   ([#81](https://github.com/python-attrs/cattrs/issues/81))
 - Add `cbor2` serialization library to the `cattr.preconf` package.
+- Add optional dependencies for `cattrs.preconf` third-party libraries. ([#337](https://github.com/python-attrs/cattrs/pull/337))
 
 ## 22.2.0 (2022-10-03)
 

docs/preconf.md

@@ -42,6 +42,17 @@ All preconf converters now have `loads` and `dumps` methods, which combine un/st
 
 Particular libraries may have additional constraints documented below.
 
+Third-party libraries can be specified as optional (extra) dependencies on `cattrs` during installation.
+Optional install targets should match the name of the {mod}`cattrs.preconf` modules.
+
+```console
+# Using pip
+pip install cattrs[ujson]
+
+# Using poetry
+poetry add --extras tomlkit cattrs
+```
+
 ## Standard Library _json_
 
 Found at {mod}`cattrs.preconf.json`.

pyproject.toml

@@ -25,9 +25,24 @@ python = ">= 3.7"
 attrs = ">= 20"
 typing_extensions = { version = "*", python = "< 3.8" }
 exceptiongroup = { version = "*", python = "< 3.11" }
+ujson = { version = "^5.4.0", optional = true }
+orjson = { version = "^3.5.2", markers = "implementation_name == 'cpython'", optional = true }
+msgpack = { version = "^1.0.2", optional = true }
+PyYAML = { version = "^6.0", optional = true }
+tomlkit = { version = "^0.11.4", python = "<4", optional = true }
+cbor2 = { version = "^5.4.6", optional = true }
+pymongo = { version = "^4.2.0", optional = true }
+
+[tool.poetry.extras]
+ujson = ["ujson"]
+orjson = ["orjson"]
+msgpack = ["msgpack"]
+pyyaml = ["PyYAML"]
+tomlkit = ["tomlkit"]
+cbor2 = ["cbor2"]
+bson = ["pymongo"]
 
 [tool.poetry.group.dev.dependencies]
-pymongo = "^4.2.0"
 flake8 = {version = "^5.0.4", python = "^3.8"}
 tox = "^3.26.0"
 Sphinx = "^5.3.0"
@@ -38,17 +53,11 @@ pendulum = "^2.1.2"
 isort = { version = "5.10.1", python = "<4" }
 black = "^22.8.0"
 immutables = "^0.18"
-ujson = "^5.4.0"
-orjson = { version = "^3.5.2", markers = "implementation_name == 'cpython'" }
-msgpack = "^1.0.2"
-PyYAML = "^6.0"
-tomlkit = { version = "^0.11.4", python = "<4" }
 furo = "^2022.9.29"
 coverage = "^6.2"
 urllib3 = { version = "^1.26.12", python = "<4" }
 sphinx-copybutton = "^0.5.0"
 myst-parser = "^0.18.1"
-cbor2 = "^5.4.6"
 
 [tool.poetry.urls]
 "Changelog" = "https://catt.rs/en/latest/history.html"
@@ -77,4 +86,4 @@ build-backend = "poetry.core.masonry.api"
 
 [tool.mypy]
 plugins = "unionize.py"
-strict = true
+strict = true

tox.ini

@@ -33,7 +33,7 @@ setenv =
 extras = dev
 allowlist_externals = poetry
 commands =
-    poetry install -v
+    poetry install -v --all-extras
     coverage run --source cattrs -m pytest tests {posargs}
 passenv = CI
 
@@ -44,7 +44,7 @@ setenv =
 extras = dev
 allowlist_externals = poetry
 commands =
-    poetry install -v
+    poetry install -v --all-extras
     coverage run --source cattrs -m pytest tests {posargs}
 passenv = CI