feat: lazy-load issue capture workflow (Closes #537)

src/frontend_bundle.py

@@ -13,11 +13,20 @@ import rjsmin
 
 SCRIPT_TAG = re.compile(r'^<script src="(static/[^"?]+\.js)"></script>$', re.MULTILINE)
 WORKER_RUNTIME_SOURCE = "static/background-issue-sync.js"
+FEATURE_SOURCES = {"issue-capture": ("static/create-issue-sheet.js",)}
 CACHE_DECLARATION = re.compile(
     r"const CACHE = 'stackchain-dashboard-shell-(?:v\d+|[0-9a-f]{16})';"
 )
 
 
+@dataclass(frozen=True)
+class RuntimeBundle:
+    runtime_bytes: bytes
+    runtime_gzip_bytes: bytes
+    runtime_digest: str
+    runtime_name: str
+
+
 @dataclass(frozen=True)
 class FrontendBuild:
     dashboard_html: str
@@ -27,6 +36,7 @@ class FrontendBuild:
     runtime_name: str
     shell_digest: str
     page_sources: tuple[str, ...]
+    feature_bundles: dict[str, RuntimeBundle]
     service_worker_source: str
 
 
@@ -41,6 +51,17 @@ def _bundle(frontend_dir: Path, sources: tuple[str, ...]) -> bytes:
     return minified + f';"source-sha256:{revision}";'.encode()
 
 
+def _runtime(frontend_dir: Path, sources: tuple[str, ...], prefix: str) -> RuntimeBundle:
+    content = _bundle(frontend_dir, sources)
+    digest = hashlib.sha256(content).hexdigest()[:16]
+    return RuntimeBundle(
+        runtime_bytes=content,
+        runtime_gzip_bytes=gzip.compress(content, compresslevel=6, mtime=0),
+        runtime_digest=digest,
+        runtime_name=f"{prefix}-{digest}.js",
+    )
+
+
 def build_frontend(frontend_dir: Path) -> FrontendBuild:
     """Return one internally consistent HTML, runtime, and offline-worker build."""
     source_html = (frontend_dir / "index.html").read_text()
@@ -48,13 +69,21 @@ def build_frontend(frontend_dir: Path) -> FrontendBuild:
     if not sources:
         raise ValueError("dashboard entry document has no page scripts")
 
-    runtime = _bundle(frontend_dir, sources)
-    runtime_gzip = gzip.compress(runtime, compresslevel=6, mtime=0)
-    digest = hashlib.sha256(runtime).hexdigest()[:16]
-    runtime_name = f"runtime-{digest}.js"
+    feature_source_names = {source for group in FEATURE_SOURCES.values() for source in group}
+    core_sources = tuple(source for source in sources if source not in feature_source_names)
+    core = _runtime(frontend_dir, core_sources, "runtime")
+    feature_bundles = {
+        name: _runtime(frontend_dir, feature_sources, f"feature-{name}")
+        for name, feature_sources in FEATURE_SOURCES.items()
+    }
     dashboard_html = SCRIPT_TAG.sub("", source_html)
+    feature_metadata = "\n".join(
+        f'<meta name="stackchain-feature-{name}" content="{bundle.runtime_name}">'
+        for name, bundle in feature_bundles.items()
+    )
+    dashboard_html = dashboard_html.replace("</head>", feature_metadata + "\n</head>")
     dashboard_html = dashboard_html.replace(
-        "</body>", f'<script src="{runtime_name}"></script>\n</body>'
+        "</body>", f'<script src="{core.runtime_name}"></script>\n</body>'
     )
 
     worker = (frontend_dir / "service-worker.js").read_text()
@@ -63,7 +92,9 @@ def build_frontend(frontend_dir: Path) -> FrontendBuild:
             worker = worker.replace(f"  BASE + '{source}',\n", "")
     worker = worker.replace(
         "  BASE + 'static/dashboard.css',\n",
-        f"  BASE + 'static/dashboard.css',\n  BASE + '{runtime_name}',\n",
+        "  BASE + 'static/dashboard.css',\n"
+        + f"  BASE + '{core.runtime_name}',\n"
+        + "".join(f"  BASE + '{bundle.runtime_name}',\n" for bundle in feature_bundles.values()),
     )
     worker = CACHE_DECLARATION.sub(
         "const CACHE = 'stackchain-dashboard-shell-BUILD';", worker, count=1
@@ -72,7 +103,8 @@ def build_frontend(frontend_dir: Path) -> FrontendBuild:
     shell_hasher = hashlib.sha256()
     shell_inputs = (
         ("dashboard.html", dashboard_html.encode()),
-        (runtime_name, runtime),
+        (core.runtime_name, core.runtime_bytes),
+        *((bundle.runtime_name, bundle.runtime_bytes) for bundle in feature_bundles.values()),
         ("static/dashboard.css", (frontend_dir / "dashboard.css").read_bytes()),
         ("manifest.webmanifest", (frontend_dir / "manifest.webmanifest").read_bytes()),
         (
@@ -105,11 +137,12 @@ def build_frontend(frontend_dir: Path) -> FrontendBuild:
 
     return FrontendBuild(
         dashboard_html=dashboard_html,
-        runtime_bytes=runtime,
-        runtime_gzip_bytes=runtime_gzip,
-        runtime_digest=digest,
-        runtime_name=runtime_name,
+        runtime_bytes=core.runtime_bytes,
+        runtime_gzip_bytes=core.runtime_gzip_bytes,
+        runtime_digest=core.runtime_digest,
+        runtime_name=core.runtime_name,
         shell_digest=shell_digest,
         page_sources=sources,
+        feature_bundles=feature_bundles,
         service_worker_source=worker,
     )

src/views.py

@@ -69,3 +69,20 @@ async def runtime_bundle(digest: str, request: Request) -> Response:
             **({"Content-Encoding": "gzip"} if accepts_gzip else {}),
         },
     )
+
+
+@router.get("/feature-{name}-{digest}.js")
+async def feature_bundle(name: str, digest: str, request: Request) -> Response:
+    bundle = FRONTEND_BUILD.feature_bundles.get(name)
+    if bundle is None or digest != bundle.runtime_digest:
+        raise HTTPException(status_code=404, detail="Feature revision not found")
+    accepts_gzip = _quality(request.headers.get("Accept-Encoding", ""), "gzip") > 0
+    return Response(
+        bundle.runtime_gzip_bytes if accepts_gzip else bundle.runtime_bytes,
+        media_type="application/javascript",
+        headers={
+            "Cache-Control": "public, max-age=31536000, immutable",
+            "Vary": "Accept-Encoding",
+            **({"Content-Encoding": "gzip"} if accepts_gzip else {}),
+        },
+    )