Add async optional dependency extra

Author: Cr1stal

README.md

@@ -150,18 +150,19 @@ Most of the app's functionality will be inside listener functions (the `fn` para
 
 ## Creating an async app
 
-If you'd prefer to build your app with [asyncio](https://docs.python.org/3/library/asyncio.html), you can import the [AIOHTTP](https://docs.aiohttp.org/en/stable/) library and call the `AsyncApp` constructor. Within async apps, you can use the async/await pattern.
+If you'd prefer to build your app with [asyncio](https://docs.python.org/3/library/asyncio.html), you can install the async extra to include [AIOHTTP](https://docs.aiohttp.org/en/stable/) and call the `AsyncApp` constructor. Within async apps, you can use the async/await pattern.
 
 ```bash
-# Python 3.7+ required
+# Python 3.9+ required for the async extra
 python -m venv .venv
 source .venv/bin/activate
 
 pip install -U pip
-# aiohttp is required
-pip install slack_bolt aiohttp
+pip install "slack_bolt[async]"
 ```
 
+If you're using Python 3.7 or 3.8, install an `aiohttp` version compatible with your Python runtime separately.
+
 In async apps, all middleware/listeners must be async functions. When calling utility methods (like `ack` and `say`) within these functions, it's required to use the `await` keyword.
 
 ```python

docs/english/concepts/async.md

@@ -1,11 +1,11 @@
 # Using async (asyncio)
 
-To use the async version of Bolt, you can import and initialize an `AsyncApp` instance (rather than `App`). `AsyncApp` relies on [AIOHTTP](https://docs.aiohttp.org) to make API requests, which means you'll need to install `aiohttp` (by adding to `requirements.txt` or running `pip install aiohttp`).
+To use the async version of Bolt, you can import and initialize an `AsyncApp` instance (rather than `App`). `AsyncApp` relies on [AIOHTTP](https://docs.aiohttp.org) to make API requests. On Python 3.9 and newer, install the async extra by running `pip install "slack_bolt[async]"`. If you're using Python 3.7 or 3.8, install an `aiohttp` version compatible with your Python runtime separately.
 
 Sample async projects can be found within the repository's [examples](https://github.com/slackapi/bolt-python/tree/main/examples) folder.
 
 ```python
-# Requirement: install aiohttp
+# Requirement: pip install "slack_bolt[async]"
 from slack_bolt.async_app import AsyncApp
 app = AsyncApp()
 

docs/japanese/concepts/async.md

@@ -1,11 +1,11 @@
 # Async（asyncio）の使用
 
-非同期バージョンの Bolt を使用する場合は、`App` の代わりに `AsyncApp` インスタンスをインポートして初期化します。`AsyncApp` では [AIOHTTP](https://docs.aiohttp.org/) を使って API リクエストを行うため、`aiohttp` をインストールする必要があります（`requirements.txt` に追記するか、`pip install aiohttp` を実行します）。
+非同期バージョンの Bolt を使用する場合は、`App` の代わりに `AsyncApp` インスタンスをインポートして初期化します。`AsyncApp` では [AIOHTTP](https://docs.aiohttp.org/) を使って API リクエストを行います。Python 3.9 以降では、`pip install "slack_bolt[async]"` を実行して async extra をインストールしてください。Python 3.7 または 3.8 を使用している場合は、その Python ランタイムと互換性のある `aiohttp` のバージョンを別途インストールしてください。
 
 非同期バージョンのプロジェクトのサンプルは、リポジトリの [`examples` フォルダ](https://github.com/slackapi/bolt-python/tree/main/examples)にあります。
 
 ```python
-# aiohttp のインストールが必要です
+# 必要条件: pip install "slack_bolt[async]"
 from slack_bolt.async_app import AsyncApp
 app = AsyncApp()
 

pyproject.toml

@@ -4,7 +4,7 @@ build-backend = "setuptools.build_meta"
 
 [project]
 name = "slack_bolt"
-dynamic = ["version", "readme", "authors"]
+dynamic = ["version", "readme", "authors", "optional-dependencies"]
 description = "The Bolt Framework for Python"
 license = { text = "MIT" }
 classifiers = [
@@ -34,6 +34,7 @@ include = ["slack_bolt*"]
 [tool.setuptools.dynamic]
 version = { attr = "slack_bolt.version.__version__" }
 readme = { file = ["README.md"], content-type = "text/markdown" }
+optional-dependencies.async = { file = ["requirements/async.txt"] }
 
 [tool.distutils.bdist_wheel]
 universal = true

requirements/async.txt

@@ -0,0 +1,2 @@
+# pip install -r requirements/async.txt
+aiohttp>=3,<4; python_version >= "3.9"

slack_bolt/async_app.py

@@ -2,18 +2,19 @@
 
 ### Creating an async app
 
-If you'd prefer to build your app with [asyncio](https://docs.python.org/3/library/asyncio.html), you can import the [AIOHTTP](https://docs.aiohttp.org/en/stable/) library and call the `AsyncApp` constructor. Within async apps, you can use the async/await pattern.
+If you'd prefer to build your app with [asyncio](https://docs.python.org/3/library/asyncio.html), you can install the async extra to include [AIOHTTP](https://docs.aiohttp.org/en/stable/) and call the `AsyncApp` constructor. Within async apps, you can use the async/await pattern.
 
 ```bash
-# Python 3.7+ required
+# Python 3.9+ required for the async extra
 python -m venv .venv
 source .venv/bin/activate
 
 pip install -U pip
-# aiohttp is required
-pip install slack_bolt aiohttp
+pip install "slack_bolt[async]"
 ```
 
+If you're using Python 3.7 or 3.8, install an `aiohttp` version compatible with your Python runtime separately.
+
 In async apps, all middleware/listeners must be async functions. When calling utility methods (like `ack` and `say`) within these functions, it's required to use the `await` keyword.
 
 ```python