Frank Schwenk
7cec3030c1
Move frontend sources to frontend/, build content-hashed assets at deploy, network-first SW for shell/JS, immutable cache for /assets/, version.json update banner, and Cache-Control middleware. Docs in docs/PWA-STRATEGY.md. Co-authored-by: Cursor <cursoragent@cursor.com>
43 lines
1.4 KiB
Python
43 lines
1.4 KiB
Python
from __future__ import annotations
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from starlette.types import ASGIApp, Receive, Scope, Send
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NO_CACHE = b"no-cache, must-revalidate"
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NO_STORE = b"no-store"
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IMMUTABLE = b"public, max-age=31536000, immutable"
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def _cache_control_for_path(path: str) -> bytes | None:
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if path in ("/sw.js", "/index.html", "/manifest.json"):
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return NO_CACHE
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if path == "/version.json":
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return NO_STORE
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if path.startswith("/assets/"):
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return IMMUTABLE
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if path.endswith((".js", ".css")) and not path.startswith("/assets/"):
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return NO_CACHE
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return None
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class CacheControlMiddleware:
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def __init__(self, app: ASGIApp) -> None:
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self.app = app
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async def __call__(self, scope: Scope, receive: Receive, send: Send) -> None:
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if scope["type"] != "http":
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await self.app(scope, receive, send)
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return
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path = scope.get("path", "")
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cache_control = _cache_control_for_path(path)
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async def send_wrapper(message: dict) -> None:
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if message["type"] == "http.response.start" and cache_control is not None:
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headers = list(message.get("headers", []))
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headers = [(k, v) for k, v in headers if k.lower() != b"cache-control"]
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headers.append((b"cache-control", cache_control))
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message = {**message, "headers": headers}
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await send(message)
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await self.app(scope, receive, send_wrapper)
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