Intent to prototype: Network Error Logging
Valentin Gosu
Summary: In bug 1911759 we plan to land a preffed off prototype of (a subset of) NEL. This mechanism can be used by website operators to monitor the success and failure rates of requests.
Bug: 1911759
Specification: Network Error Logging
Standards Body: W3C
Platform coverage: All
Preference: network.http.network_error_logging.enabled
DevTools bug: NEL requests can be observed using the Browser Console (make sure to check Enable Network Monitoring)
Link to standards-positions discussion: Network Error Logging (NEL) · Issue #99 · mozilla/standards-positions · GitHub
Other browsers:
Blink: Chrome Platform Status Shipped since Chrome 71
WebKit: No support according to MDN
web-platform-tests: testing/web-platform/tests/network-error-logging - mozsearch
Network Error Logging is a useful mechanism that website operators use to monitor network request success rates. Currently it is only shipping in Chromium based browsers. Implementing it in Firefox has the potential to improve the visibility of Firefox users in the operator's metrics and to receive advance notice when a specific change (either in the website or the browser) is causing network requests to fail.
The prototype in bug 1911759 does not use the existing (also preffed off Reporting API implementation) as that interface isn't usable from the parent process at the moment.
Security & Privacy Concerns: We have previously raised concerns regarding some of the privacy properties of NEL, but we believe that these can be overcome by selectively deciding what information to send to the reporting endpoint. Cloudflare has shared a document describing the NEL information that is actually being used, and this initial implementation is restricted to that. We don't intend to enable this feature until we are confident that our implementation does a good job preserving user privacy.