perf: bundle and fingerprint the PWA runtime (#379)

tests/dashboard_bundle.py

@@ -1,9 +1,17 @@
+import re
 from pathlib import Path
 
 from src.views import dashboard as dashboard_html
 
 
 FRONTEND = Path(__file__).resolve().parents[1] / "frontend"
+PAGE_SCRIPT_MANIFEST = "\n".join(
+    re.findall(
+        r'^<script src="static/[^\"]+\.js"></script>$',
+        (FRONTEND / "index.html").read_text(),
+        re.MULTILINE,
+    )
+)
 
 
 def dashboard_bundle_text() -> str:
@@ -18,11 +26,12 @@ def dashboard_bundle_text() -> str:
 
 
 async def dashboard() -> str:
-    # Exercise the real view lookup before adding its separately served assets.
+    # Exercise the real view lookup before adding its separately served bootstrap assets.
     html = await dashboard_html()
     return "\n".join(
         (
             html,
+            PAGE_SCRIPT_MANIFEST,
             (FRONTEND / "dashboard.css").read_text(),
             (FRONTEND / "dashboard.js").read_text(),
         )

tests/test_dashboard_auth.py

@@ -7,6 +7,7 @@ import pytest
 
 from src import main
 from src.session_store import SessionStoreError
+from src.views import FRONTEND_BUILD
 
 
 @pytest.fixture
@@ -956,9 +957,16 @@ async def test_public_routes_skip_session_registry_validation(access_control, mo
         login = await client.get("/login")
         manifest = await client.get("/manifest.webmanifest")
         static = await client.get("/static/session.js")
+        runtime = await client.get("/" + FRONTEND_BUILD.runtime_name)
 
     assert signed_in.status_code == 200
-    assert [login.status_code, manifest.status_code, static.status_code] == [200, 200, 200]
+    assert [login.status_code, manifest.status_code, static.status_code, runtime.status_code] == [
+        200,
+        200,
+        200,
+        200,
+    ]
+    assert runtime.headers["cache-control"] == "public, max-age=31536000, immutable"
 
 
 @pytest.mark.anyio

tests/test_frontend_bundle.py

@@ -0,0 +1,62 @@
+import gzip
+import re
+import shutil
+from pathlib import Path
+
+import pytest
+
+from src.frontend_bundle import build_frontend
+from src.views import dashboard, runtime_bundle, service_worker
+
+
+FRONTEND = Path(__file__).resolve().parents[1] / "frontend"
+PAGE_SCRIPT = re.compile(r'<script src="(static/[^"]+\.js)"></script>')
+
+
+def test_page_runtime_is_one_deterministic_content_addressed_bundle(tmp_path):
+    first = build_frontend(FRONTEND)
+    second = build_frontend(FRONTEND)
+
+    assert first.runtime_name == second.runtime_name
+    assert first.runtime_bytes == second.runtime_bytes
+    assert PAGE_SCRIPT.findall(first.dashboard_html) == []
+    assert first.dashboard_html.count("<script src=") == 1
+    assert f'<script src="{first.runtime_name}"></script>' in first.dashboard_html
+    assert first.runtime_name.startswith("runtime-")
+    assert first.runtime_name.endswith(".js")
+    assert len(gzip.compress(first.runtime_bytes, mtime=0)) <= 100 * 1024
+
+    changed_frontend = tmp_path / "frontend"
+    shutil.copytree(FRONTEND, changed_frontend)
+    (changed_frontend / "widgets.js").write_text(
+        (changed_frontend / "widgets.js").read_text() + "\n// changed\n"
+    )
+
+    changed = build_frontend(changed_frontend)
+    assert changed.runtime_name != first.runtime_name
+    assert changed.runtime_bytes != first.runtime_bytes
+
+
+def test_offline_shell_precaches_exact_runtime_without_superseded_page_modules():
+    build = build_frontend(FRONTEND)
+
+    assert f"BASE + '{build.runtime_name}'" in build.service_worker_source
+    for source in build.page_sources:
+        if source == "static/background-issue-sync.js":
+            continue
+        assert f"BASE + '{source}'" not in build.service_worker_source
+
+
+@pytest.mark.anyio
+async def test_runtime_asset_is_immutable_while_html_and_worker_revalidate():
+    build = build_frontend(FRONTEND)
+
+    html = await dashboard()
+    bundle = await runtime_bundle(build.runtime_digest)
+    worker = await service_worker()
+
+    assert build.runtime_name in html
+    assert bundle.body == build.runtime_bytes
+    assert bundle.headers["cache-control"] == "public, max-age=31536000, immutable"
+    assert worker.headers["cache-control"] == "no-cache"
+    assert build.runtime_name.encode() in worker.body

tests/test_views.py

@@ -2,7 +2,7 @@ from pathlib import Path
 
 import pytest
 
-from src.views import dashboard
+from src.views import FRONTEND_BUILD, dashboard
 
 
 @pytest.mark.anyio
@@ -28,7 +28,7 @@ async def test_dashboard_bootstrap_uses_csp_compatible_static_assets():
     html = await dashboard()
 
     assert '<link rel="stylesheet" href="static/dashboard.css" />' in html
-    assert '<script src="static/dashboard.js"></script>' in html
+    assert f'<script src="{FRONTEND_BUILD.runtime_name}"></script>' in html
     assert "<style>" not in html
     assert "<script>" not in html
 
@@ -42,7 +42,7 @@ async def test_global_search_preview_is_a_phone_safe_accessible_dialog():
     assert 'aria-labelledby="search-preview-title"' in html
     assert 'id="claim-search-result"' in html
     assert 'id="open-search-result-gitea"' in html
-    assert 'src="static/search-preview.js"' in html
+    assert "static/search-preview.js" in FRONTEND_BUILD.page_sources
     assert ".search-preview-panel" in css
     assert "height:100dvh" in css
     assert "env(safe-area-inset-bottom)" in css