feat: compress dashboard shell over HTTP (#417)

tests/test_frontend_bundle.py

@@ -3,8 +3,10 @@ import re
 import shutil
 from pathlib import Path
 
+import httpx
 import pytest
 
+from src import main
 from src.frontend_bundle import build_frontend
 from src.views import dashboard, runtime_bundle, service_worker
 
@@ -37,6 +39,62 @@ def test_page_runtime_is_one_deterministic_content_addressed_bundle(tmp_path):
     assert changed.runtime_bytes != first.runtime_bytes
 
 
+@pytest.mark.anyio
+async def test_runtime_is_transferred_as_gzip_when_the_client_accepts_it():
+    transport = httpx.ASGITransport(app=main.app)
+
+    async with httpx.AsyncClient(transport=transport, base_url="http://test") as client:
+        response = await client.get(
+            f"/{main.FRONTEND_BUILD.runtime_name}",
+            headers={"Accept-Encoding": "gzip"},
+        )
+
+    assert response.status_code == 200
+    assert response.headers["content-encoding"] == "gzip"
+    assert response.headers["vary"] == "Accept-Encoding"
+    assert int(response.headers["content-length"]) <= 100 * 1024
+    assert response.content == main.FRONTEND_BUILD.runtime_bytes
+    assert response.headers["cache-control"] == "public, max-age=31536000, immutable"
+
+
+@pytest.mark.anyio
+@pytest.mark.parametrize("accept_encoding", ["identity", "gzip;q=0, identity;q=1"])
+async def test_runtime_stays_unencoded_when_the_client_declines_gzip(accept_encoding):
+    transport = httpx.ASGITransport(app=main.app)
+
+    async with httpx.AsyncClient(transport=transport, base_url="http://test") as client:
+        response = await client.get(
+            f"/{main.FRONTEND_BUILD.runtime_name}",
+            headers={"Accept-Encoding": accept_encoding},
+        )
+
+    assert response.status_code == 200
+    assert "content-encoding" not in response.headers
+    assert int(response.headers["content-length"]) == len(main.FRONTEND_BUILD.runtime_bytes)
+    assert response.content == main.FRONTEND_BUILD.runtime_bytes
+
+
+@pytest.mark.anyio
+async def test_dashboard_shell_is_compressed_without_losing_response_policies():
+    transport = httpx.ASGITransport(app=main.app)
+
+    async with httpx.AsyncClient(transport=transport, base_url="http://test") as client:
+        page = await client.get("/", headers={"Accept-Encoding": "gzip"})
+        stylesheet = await client.get(
+            "/static/dashboard.css", headers={"Accept-Encoding": "gzip"}
+        )
+        health = await client.get("/healthz", headers={"Accept-Encoding": "gzip"})
+
+    assert page.headers["content-encoding"] == "gzip"
+    assert page.headers["cache-control"] == "no-cache"
+    assert page.headers["content-security-policy"]
+    assert main.FRONTEND_BUILD.runtime_name in page.text
+    assert stylesheet.headers["content-encoding"] == "gzip"
+    assert "mobile-task-dock" in stylesheet.text
+    assert health.json() == {"service": "stackchain-dashboard", "status": "ok"}
+    assert "content-encoding" not in health.headers
+
+
 def test_offline_shell_precaches_exact_runtime_without_superseded_page_modules():
     build = build_frontend(FRONTEND)