[jehrr]

Problem

In pyppeteer and Selenium, the proxy meter added in #11 counted every CDP loadingFinished. That included loads that never cross a proxy:

• Chrome's own chrome:// new-tab scripts;
• data: and blob: URLs;
• cache hits;
• Chrome's error page, which is reported as a finished load of the failed URL with no responseReceived.

A sibling repo's Selenium CLI, run through a stub proxy, showed the meter reading 2,779,683 bytes while the proxy carried about 6 KB. That spends the default 10 MB --proxy-budget-mb on traffic that never happened.

Separately, the pyppeteer block sent once the budget is spent used asyncio.ensure_future from whatever thread crossed the cap. A thread with no event loop raised there, the error was swallowed, and the block was never sent.

Resulting behaviour

• CdpCounter (proxy_meter.py) counts only http:// / https:// requests.
• Response bytes are counted only after a responseReceived that came over the network. A response marked requestServedFromCache, fromDiskCache, fromPrefetchCache or fromServiceWorker counts nothing, and neither does its request. Chrome's error page costs only the request that was attempted.
• responseReceived and requestServedFromCache are now subscribed (pyppeteer) and read from the performance log (Selenium).
• The pyppeteer block goes to the page's own loop with call_soon_threadsafe.
• Playwright, sidecar fields, exit codes and canary.yml are unchanged.

Evidence

• New offline checks:
  • a chrome://new-tab-page/x.js request, response and finish (2,779,683 B), plus a data: and a blob: load, count 0;
  • a cache hit via requestServedFromCache, fromDiskCache, fromPrefetchCache and fromServiceWorker counts 0;
  • Chrome's error page counts only the attempted request;
  • a budget crossed on a worker thread still sends Network.setBlockedURLs ["*"] on the page's loop.
• Planted-fault controls. Each went red on the named check and green again after restoring:
  • scheme filter removed: "chrome:// new-tab load … cost nothing" went red;
  • cache flags ignored: "a cache hit … costs nothing" went red;
  • the block sent from the tripping thread (the previous code): "a budget crossed on a worker thread …" went red.
• Suite passes in a core-only venv and in the pyppeteer and Selenium venvs (real-browser check on).
• Real browser, through a byte-counting stub proxy (opt-in check): pyppeteer still meters within 0.6% and Selenium within 0.7%.
• No proxy, no paid call, no canary dispatch.

🤖 Generated with Claude Code

https://claude.ai/code/session_01CKsd7q25N19WzUZjrAdzx8