| name | testing-web-capture |
| description | End-to-end testing of the StreamKit web-capture gateway demo (examples/web-capture) with the native servo plugin. Use when verifying clip/cast endpoints, servo page rendering, or cross-session pixel isolation. |
| license | MPL-2.0 |
Testing the web-capture gateway demo
Setup
- Go toolchain is required for the gateway (
/usr/local/go/bin/go); install from go.dev tarball if missing.
- Build + deploy the servo plugin:
just build-plugin-native-servo && just copy-plugins-native.
- Verify freshness:
md5sum target/plugins/release/libservo_web.so .plugins/native/servo/libservo_web.so must match and have a recent timestamp. Stale .so files are a known source of white frames / cross-request corruption.
- skit loads plugins only at startup — restart
just skit after copying.
- Start backend:
just skit (127.0.0.1:4545; auth Auto disables auth on loopback, no token needed locally).
- Start gateway:
cd examples/web-capture && go run ./cmd/gateway --listen :8080 --skit-url http://127.0.0.1:4545.
Endpoints
- Finite clip:
http://127.0.0.1:8080/clip/dur=20s,res=1280x720/<target-url> → MP4 (h264-sw).
- Live cast:
http://127.0.0.1:8080/cast/<target-url> → WebM (vp9-sw). curl with -H 'Accept: video/webm' to grab raw stream.
- SSRF guard blocks loopback/private targets — use public sites (streamkit.dev is dark-themed, example.com light-themed: a good high-contrast pair for leak checks).
Verifying frames (don't trust playback alone)
- Extract frames:
ffmpeg -i clip.mp4 -vf "select='eq(n,30)+eq(n,300)'" -vsync 0 f_%d.png
- Pixel stats with PIL: min/max grey and dark-pixel fraction distinguish blank white (min≈255), blank black/pre-paint (max≈0), and real content.
- Since the first-load gate (plugin >= 0.2.2), clips/casts should show page content from frame 0 (the node holds emission until loaded+painted, capped by
load_timeout_secs, default 30s). Pre-0.2.2 builds may show all-black cold-start clips or blank lead-ins.
- Some pages (e.g. streamkit.dev) may still show a single white first frame — the page's own pre-theme paint, not a gate failure.
- Testing the load-timeout expiry path via the gateway is hard: SSRF blocks local hanging servers and public "slow" endpoints (httpstat.us sleep, closed ports) fail fast rather than hang.
Cross-session leak checks
- Sequential: capture page A then page B; sampled B frames must contain no A pixels (use dark/light pages so pixel stats catch leaks).
- Concurrent: run a cast of A and a clip of B simultaneously (two curls with
&); sample start/middle/end frames of both.
- Regression test:
cd plugins/native/servo && CARGO_TARGET_DIR=../../../target/plugins cargo test --release --test cross_session_leak (heavy; llvmpipe; pass = exit 0).
Devin Secrets Needed
None for local loopback testing (auth Auto disables auth).
