Make maubot http server serve frontend for production

maubot/server.py

@@ -18,6 +18,7 @@ import asyncio
 
 from aiohttp import web
 from aiohttp.abc import AbstractAccessLogger
+import pkg_resources
 
 from mautrix.api import PathBuilder, Method
 
@@ -35,21 +36,56 @@ class AccessLogger(AbstractAccessLogger):
 class MaubotServer:
     log: logging.Logger = logging.getLogger("maubot.server")
 
-    def __init__(self, config: Config, management: web.Application,
-                 loop: asyncio.AbstractEventLoop) -> None:
+    def __init__(self, config: Config, loop: asyncio.AbstractEventLoop) -> None:
         self.loop = loop or asyncio.get_event_loop()
         self.app = web.Application(loop=self.loop)
         self.config = config
 
-        path = PathBuilder(config["server.base_path"])
-        self.add_route(Method.GET, path.version, self.version)
-        self.app.add_subapp(config["server.base_path"], management)
-
         as_path = PathBuilder(config["server.appservice_base_path"])
         self.add_route(Method.PUT, as_path.transactions, self.handle_transaction)
 
+        self.setup_management_ui()
+
         self.runner = web.AppRunner(self.app, access_log_class=AccessLogger)
 
+    def setup_management_ui(self) -> None:
+        ui_base = self.config["server.ui_base_path"]
+        if ui_base == "/":
+            ui_base = ""
+        directory = (self.config["server.override_resource_path"]
+                     or pkg_resources.resource_filename("maubot", "management/frontend/build"))
+        self.app.router.add_static(f"{ui_base}/static", f"{directory}/static")
+        self.setup_static_root_files(directory, ui_base)
+
+        with open(f"{directory}/index.html", "r") as file:
+            index_html = file.read()
+
+        @web.middleware
+        async def frontend_404_middleware(request, handler):
+            if hasattr(handler, "__self__") and isinstance(handler.__self__, web.StaticResource):
+                try:
+                    return await handler(request)
+                except web.HTTPNotFound:
+                    return web.Response(body=index_html, content_type="text/html")
+            return await handler(request)
+
+        self.app.middlewares.append(frontend_404_middleware)
+        self.app.router.add_get(f"{ui_base}/", lambda _: web.Response(body=index_html,
+                                                                      content_type="text/html"))
+        self.app.router.add_get(ui_base, lambda _: web.HTTPFound(f"{ui_base}/"))
+
+    def setup_static_root_files(self, directory: str, ui_base: str) -> None:
+        files = {
+            "asset-manifest.json": "application/json",
+            "manifest.json": "application/json",
+            "favicon.png": "image/png",
+        }
+        for file, mime in files.items():
+            with open(f"{directory}/{file}", "rb") as stream:
+                data = stream.read()
+            self.app.router.add_get(f"{ui_base}/{file}", lambda _: web.Response(body=data,
+                                                                                content_type=mime))
+
     def add_route(self, method: Method, path: PathBuilder, handler) -> None:
         self.app.router.add_route(method.value, str(path), handler)