Files
libretro/website/tools/lighthouse.py
T
Abdessamad Derraz abe240073c feat: pass the Starlight gate on dense pages
Pages of cards under one or two headings drop the table of contents,
whose script watched every block of a 400-card page: 2 x 430 ms of
main thread on a throttled phone. Tables are measured once the page is
idle, skipping those in closed blocks, so a scrolling table is a tab
stop anywhere on the page. The 12 heaviest pages score 97 to 100 in
Lighthouse mobile, axe reports nothing on 16 pages in both themes, and
the search answers the ten gate queries.
2026-10-22 17:21:14 +02:00

69 lines
3.0 KiB
Python

#!/usr/bin/env python3
"""Lighthouse mobile (default form factor) on a list of pages, one summary line each.
python lighthouse.py [--performance-only] <out dir> <name>=<base url> ... -- <page> ...
With all four categories, Lighthouse runs its accessibility checks inside the
page during the same load, and those tasks count toward Total Blocking Time
on a page of 15,000 elements. --performance-only measures the page alone.
Needs `npx lighthouse` and Chrome at /usr/bin/google-chrome.
"""
from __future__ import annotations
import json
import os
import subprocess
import sys
from pathlib import Path
CATEGORIES = ("performance", "accessibility", "best-practices", "seo")
def main() -> int:
args = sys.argv[1:]
categories = CATEGORIES
if args[0] == "--performance-only":
args.pop(0)
categories = ("performance",)
out = Path(args.pop(0))
split = args.index("--")
engines = dict(item.split("=", 1) for item in args[:split])
pages = args[split + 1:]
out.mkdir(parents=True, exist_ok=True)
env = {**os.environ, "CHROME_PATH": "/usr/bin/google-chrome"}
for name, base in engines.items():
for page in pages:
slug = page.strip("/").replace("/", "_") or "home"
report = out / f"{name}-{slug}.json"
# Under WSL chrome-launcher names its profile folder with a Windows path,
# created relative to the working directory: run it inside the output folder.
subprocess.run(
["npx", "--prefix", str(Path(__file__).resolve().parent.parent), "lighthouse", base + page,
"--quiet", "--output=json", f"--output-path={report.resolve()}",
"--chrome-flags=--headless=new --no-sandbox",
f"--only-categories={','.join(categories)}",
# Extra flags for one experiment, space separated.
*os.environ.get("LIGHTHOUSE_FLAGS", "").split()],
env=env, cwd=out, check=False, stdout=subprocess.DEVNULL, stderr=subprocess.DEVNULL)
data = json.loads(report.read_text())
cats, audits = data["categories"], data["audits"]
failed = [k for k, a in audits.items()
if a.get("score") is not None and a["score"] < 1 and a.get("scoreDisplayMode") == "binary"]
print(json.dumps({
"engine": name, "page": page or "/",
**{c: round(cats[c]["score"] * 100) for c in categories},
"lcp": audits["largest-contentful-paint"]["displayValue"],
"tbt": audits["total-blocking-time"]["displayValue"],
"cls": audits["cumulative-layout-shift"]["displayValue"],
"bytes": audits["total-byte-weight"]["displayValue"],
# Lighthouse 13 moved the DOM size audit into an insight.
"dom": (audits.get("dom-size") or audits.get("dom-size-insight") or {}).get("displayValue", ""),
"failed": failed,
}))
return 0
if __name__ == "__main__":
sys.exit(main())