feat: add WSGI adapter

examples/wsgi/app.py

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+from slack_bolt import App
+from slack_bolt.adapter.wsgi import SlackRequestHandler
+
+app = App()
+
+
+@app.event("app_mention")
+def handle_app_mentions(body, say, logger):
+    logger.info(body)
+    say("What's up?")
+
+
+api = SlackRequestHandler(app)
+
+# pip install -r requirements.txt
+# export SLACK_SIGNING_SECRET=***
+# export SLACK_BOT_TOKEN=xoxb-***
+# gunicorn app:api -b 0.0.0.0:3000 --log-level debug
+# ngrok http 3000

examples/wsgi/oauth_app.py

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+from slack_bolt import App
+from slack_bolt.adapter.wsgi import SlackRequestHandler
+
+app = App()
+
+
+@app.event("app_mention")
+def handle_app_mentions(body, say, logger):
+    logger.info(body)
+    say("What's up?")
+
+
+api = SlackRequestHandler(app)
+
+# pip install -r requirements.txt
+
+# # -- OAuth flow -- #
+# export SLACK_SIGNING_SECRET=***
+# export SLACK_CLIENT_ID=111.111
+# export SLACK_CLIENT_SECRET=***
+# export SLACK_SCOPES=app_mentions:read,channels:history,im:history,chat:write
+
+# gunicorn oauth_app:api -b 0.0.0.0:3000 --log-level debug

examples/wsgi/requirements.txt

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+gunicorn<23

slack_bolt/adapter/wsgi/__init__.py

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+from .handler import SlackRequestHandler
+
+__all__ = ["SlackRequestHandler"]

slack_bolt/adapter/wsgi/handler.py

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+from typing import Any, Callable, Dict, Iterable, List, Tuple
+from slack_bolt.oauth.oauth_flow import OAuthFlow
+from slack_bolt.adapter.wsgi.http_request import WsgiHttpRequest
+from slack_bolt.adapter.wsgi.http_response import WsgiHttpResponse
+
+from slack_bolt import App
+
+from slack_bolt.request import BoltRequest
+from slack_bolt.response import BoltResponse
+
+
+class SlackRequestHandler:
+    def __init__(self, app: App, path: str = "/slack/events"):
+        """Setup Bolt as a WSGI web framework, this will make your application compatible with WSGI web servers.
+        This can be used for production deployments.
+
+        With the default settings, `http://localhost:3000/slack/events`
+        Run Bolt with [gunicorn](https://gunicorn.org/)
+
+        # Python
+            app = App()
+
+            api = SlackRequestHandler(app)
+
+        # bash
+            export SLACK_SIGNING_SECRET=***
+
+            export SLACK_BOT_TOKEN=xoxb-***
+
+            gunicorn app:api -b 0.0.0.0:3000 --log-level debug
+
+        Args:
+            app: Your bolt application
+            path: The path to handle request from Slack (Default: `/slack/events`)
+        """
+        self.path = path
+        self.app = app
+
+    def dispatch(self, request: WsgiHttpRequest) -> BoltResponse:
+        return self.app.dispatch(
+            BoltRequest(body=request.get_body(), query=request.query_string, headers=request.get_headers())
+        )
+
+    def handle_installation(self, request: WsgiHttpRequest) -> BoltResponse:
+        oauth_flow: OAuthFlow = self.app.oauth_flow
+        return oauth_flow.handle_installation(
+            BoltRequest(body=request.get_body(), query=request.query_string, headers=request.get_headers())
+        )
+
+    def handle_callback(self, request: WsgiHttpRequest) -> BoltResponse:
+        oauth_flow: OAuthFlow = self.app.oauth_flow
+        return oauth_flow.handle_callback(
+            BoltRequest(body=request.get_body(), query=request.query_string, headers=request.get_headers())
+        )
+
+    def _get_http_response(self, method: str, path: str, request: WsgiHttpRequest) -> WsgiHttpResponse:
+        if method == "GET":
+            if self.app.oauth_flow is not None:
+                if path == self.app.oauth_flow.install_path:
+                    bolt_response: BoltResponse = self.handle_installation(request)
+                    return WsgiHttpResponse(
+                        status=bolt_response.status, headers=bolt_response.headers, body=bolt_response.body
+                    )
+                if path == self.app.oauth_flow.redirect_uri_path:
+                    bolt_response: BoltResponse = self.handle_callback(request)
+                    return WsgiHttpResponse(
+                        status=bolt_response.status, headers=bolt_response.headers, body=bolt_response.body
+                    )
+        if method == "POST" and path == self.path:
+            bolt_response: BoltResponse = self.dispatch(request)
+            return WsgiHttpResponse(status=bolt_response.status, headers=bolt_response.headers, body=bolt_response.body)
+        return WsgiHttpResponse(status=404, headers={"content-type": ["text/plain;charset=utf-8"]}, body="Not Found")
+
+    def __call__(
+        self,
+        environ: Dict[str, Any],
+        start_response: Callable[[str, List[Tuple[str, str]]], None],
+    ) -> Iterable[bytes]:
+        if "HTTP" in environ.get("SERVER_PROTOCOL", ""):
+            response: WsgiHttpResponse = self._get_http_response(
+                method=environ.get("REQUEST_METHOD", "GET"),
+                path=environ.get("PATH_INFO", ""),
+                request=WsgiHttpRequest(environ),
+            )
+            start_response(response.status, response.headers)
+            return response.body
+        raise TypeError(f"Unsupported SERVER_PROTOCOL: {environ['SERVER_PROTOCOL']}")

slack_bolt/adapter/wsgi/http_request.py

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+from typing import Any, Dict
+
+from .utils import ENCODING
+
+
+class WsgiHttpRequest:
+    __slots__ = ("query_string", "environ")
+
+    def __init__(self, environ: Dict[str, Any]):
+        self.query_string = environ.get("QUERY_STRING", "")
+        self.environ = environ
+
+    def get_headers(self) -> Dict[str, str]:
+        headers = {}
+        for key, value in self.environ.items():
+            if key in {"CONTENT_LENGTH", "CONTENT_TYPE"}:
+                name = key.lower().replace("_", "-")
+                headers[name] = value
+            if key.startswith("HTTP_"):
+                name = key[len("HTTP_") :].lower().replace("_", "-")
+                headers[name] = value
+        return headers
+
+    def get_body(self) -> str:
+        if "wsgi.input" not in self.environ:
+            return ""
+        content_length = int(self.environ.get("CONTENT_LENGTH", 0))
+        return self.environ["wsgi.input"].read(content_length).decode(ENCODING)

slack_bolt/adapter/wsgi/http_response.py

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+from typing import Sequence, Tuple, Dict, List
+from http import HTTPStatus
+
+from .utils import ENCODING
+
+
+class WsgiHttpResponse:
+    __slots__ = ("status", "headers", "body")
+
+    def __init__(self, status: int, headers: Dict[str, Sequence[str]] = {}, body: str = ""):
+        _status = HTTPStatus(status)
+        self.status = f"{_status.value} {_status.phrase}"
+
+        self.headers: List[Tuple[str, str]] = []
+        for key, value in headers.items():
+            if key.lower() == "content-length":
+                continue
+            self.headers.append((key, value[0]))
+
+        _body = bytes(body, ENCODING)
+        self.headers.append(("content-length", str(len(_body))))
+        self.body = [_body]

slack_bolt/adapter/wsgi/utils.py

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+ENCODING = "utf-8"  # should always be utf-8