Implemented HTTP caching and updates on wwwroot, much faster page loads.

cista/app.py

@@ -2,15 +2,21 @@ import mimetypes
 from importlib.resources import files
 from urllib.parse import unquote
 
+import sanic.helpers
 import asyncio
 import brotli
-from sanic import Blueprint, Sanic, raw
+from blake3 import blake3
+from sanic import Blueprint, Sanic, raw, empty
 from sanic.exceptions import Forbidden, NotFound
+from wsgiref.handlers import format_date_time
 
 from cista import auth, config, session, watching
 from cista.api import bp
 from cista.util.apphelpers import handle_sanic_exception
 
+# Workaround until Sanic PR #2824 is merged
+sanic.helpers._ENTITY_HEADERS = frozenset()
+
 app = Sanic("cista", strict_slashes=True)
 app.blueprint(auth.bp)
 app.blueprint(bp)
@@ -63,8 +69,12 @@ www = {}
 
 
 @app.before_server_start
-def load_wwwroot(app):
+async def load_wwwroot(*_ignored):
     global www
+    www = await asyncio.get_event_loop().run_in_executor(None, _load_wwwroot, www)
+
+
+def _load_wwwroot(www):
     wwwnew = {}
     base = files("cista") / "wwwroot"
     paths = ["."]
@@ -77,36 +87,71 @@ def load_wwwroot(app):
                 continue
             name = p.relative_to(base).as_posix()
             mime = mimetypes.guess_type(name)[0] or "application/octet-stream"
+            mtime = p.stat().st_mtime
             data = p.read_bytes()
+            etag = blake3(data).hexdigest(length=8)
+            if name == "index.html":
+                name = ""
             # Use old data if not changed
-            if name in www and www[name][0] == data:
+            if name in www and www[name][2]["etag"] == etag:
                 wwwnew[name] = www[name]
                 continue
+            cached = name.startswith("assets/")
+            headers = {
+                "etag": etag,
+                "last-modified": format_date_time(mtime),
+                "cache-control": "max-age=31536000, immutable"
+                if cached
+                else "no-cache",
+                "content-type": mime,
+            }
             # Precompress with Brotli
             br = brotli.compress(data)
             if len(br) >= len(data):
                 br = False
-            wwwnew[name] = data, br, mime
-    www = wwwnew
+            wwwnew[name] = data, br, headers
+    return wwwnew
 
 
 @app.add_task
 async def refresh_wwwroot():
-    while app.debug:
+    while True:
+        try:
+            wwwold = www
+            await load_wwwroot()
+            changes = ""
+            for name in sorted(www):
+                attr = www[name]
+                if wwwold.get(name) == attr:
+                    continue
+                headers = attr[2]
+                changes += f"{headers['last-modified']} {headers['etag']} /{name}\n"
+            for name in sorted(set(wwwold) - set(www)):
+                changes += f"Deleted /{name}\n"
+            if changes:
+                print(f"Updated wwwroot:\n{changes}", end="", flush=True)
+        except Exception as e:
+            print("Error loading wwwroot", e)
+        if not app.debug:
+            return
         await asyncio.sleep(0.5)
-        load_wwwroot(app)
 
 
-@app.get("/<path:path>", static=True)
+@app.route("/<path:path>", methods=["GET", "HEAD"])
 async def wwwroot(req, path=""):
     """Frontend files only"""
-    name = unquote(path) or "index.html"
+    name = unquote(path)
     if name not in www:
         raise NotFound(f"File not found: /{path}", extra={"name": name})
-    data, br, mime = www[name]
-    headers = {}
+    data, br, headers = www[name]
+    if req.headers.if_none_match == headers["etag"]:
+        # The client has it cached, respond 304 Not Modified
+        return empty(304, headers=headers)
     # Brotli compressed?
     if br and "br" in req.headers.accept_encoding.split(", "):
-        headers["content-encoding"] = "br"
+        headers = {
+            **headers,
+            "content-encoding": "br",
+        }
         data = br
-    return raw(data, content_type=mime, headers=headers)
+    return raw(data, headers=headers)

pyproject.toml

@@ -15,6 +15,7 @@ classifiers = [
 ]
 dependencies = [
     "argon2-cffi",
+    "blake3",
     "brotli",
     "docopt",
     "inotify",