Allow HTTPFetcher to pass through 304 responses by sonnyb9 · Pull Request #4120 · MagicMirrorOrg/MagicMirror

sonnyb9 · 2026-04-24T12:57:14Z

Summary

This updates js/http_fetcher.js so HTTP 304 Not Modified responses are emitted through the normal response event instead of being treated as errors.

That aligns the core fetcher with the built-in yr weather provider in v2.35.0, which already includes explicit logic to handle 304 and reuse cached data.

Closes #4119.

Root cause

HTTPFetcher currently treats all non-OK responses as errors. Since 304 is not an OK response, it never reaches providers listening on the response event.

At the same time, defaultmodules/weather/providers/yr.js expects to receive 304 and handle it by reusing cached data.

What changed

special-case HTTP 304 in HTTPFetcher
emit 304 through the normal response event
preserve the existing error path for other non-OK statuses

Validation

confirmed defaultmodules/weather/providers/yr.js already expects response.status === 304
compared the unpatched v2.35.0 HTTPFetcher behavior to the provider logic
ran node --check js/http_fetcher.js

rejas · 2026-04-24T18:23:42Z

Please base your PR against the develop branch

sonnyb9 · 2026-04-25T15:32:32Z

Thanks for the reply.

Retargeted this PR to develop and force-pushed a rebased branch so the diff stays limited to the HTTPFetcher change.

I also updated the implementation to treat 304 as part of the successful response path, which preserves the existing serverErrorCount / networkErrorCount reset behavior, and added a focused unit test for that case.

Validation on this checkout: node --check js/http_fetcher.js. I also attempted npm test -- --run tests/unit/functions/http_fetcher_spec.js, but vitest is not installed locally in this environment.

KristjanESPERANTO · 2026-04-25T18:55:00Z

but vitest is not installed locally in this environment.

Once you run npm run install, you can run the tests.

Is there a reason why the PR is still marked as a draft?

sonnyb9 · 2026-04-25T19:21:58Z

Tests are passing locally now after installing the repo dependencies.

Ran:
./node_modules/.bin/vitest run tests/unit/functions/http_fetcher_spec.js

Result:
Test Files 1 passed (1)
Tests 20 passed (20)

Marked the PR ready for review.

KristjanESPERANTO · 2026-04-25T20:16:02Z

Looks good, thank! 🙂 Even though there are plenty of clear indications of this, let me ask specifically: This is all Vibe Coded, right?

It’s not a problem for me; I’d just like to have it explicitly stated. Maybe we should include this in our PR requirements, like other projects - specifying how much of the process was handled by AI.

sonnyb9 · 2026-04-25T22:10:12Z

Yes, it was coded with codex/gpt-5.4.

@cgillinger

## Release Notes Thanks to: @cgillinger, @khassel, @KristjanESPERANTO, @sonnyb9 > ⚠️ This release needs nodejs version >=22.21.1 <23 || >=24 (no change to previous release) [Compare to previous Release v2.35.0](v2.35.0...v2.36.0) This release falls outside the quarterly schedule. We opted for an early release due to: - Security fix for the internal cors proxy - API change of the weather provider smi - Several bug fixes ### Breaking Changes The cors proxy is now disabled by default. If required, it must be explicitly enabled in the `config.js` file. See the [documentation](https://docs.magicmirror.builders/configuration/cors.html). ### ⚠️ Security You can find several publicly accessible MagicMirror² instances. This should never be done. Doing so makes your entire configuration, including secrets and API keys, publicly visible. Furthermore, it allows attackers to target the host; this is only prevented beginning with this release. Public MagicMirror² instances should always run behind a reverse proxy with authentication. ### [core] - Prepare Release 2.36.0 (#4126) - Allow HTTPFetcher to pass through 304 responses (#4120) - fix(http-fetcher): fall back to reloadInterval after retries exhausted (#4113) - config endpoint must handle functions in module configs (#4106) - fix replaceSecretPlaceholder (#4104) - restrict replaceSecretPlaceholder to cors with allowWhitelist (#4102) - fix: prevent crash when config is undefined in socket handler (#4096) - fix cors function for alpine linux (#4091) - fix(cors): prevent SSRF via DNS rebinding (#4090) - add option to disable or restrict cors endpoint (#4087) - fix: prevent SSRF via /cors endpoint by blocking private/reserved IPs (#4084) - chore: add permissions section to enforce pull-request rules workflow (#4079) - update version for develop ### [dependencies] - update dependencies (#4124) - chore: update dependencies (#4088) - refactor: enable ESLint rule "no-unused-vars" and handle related issues (#4080) ### [modules/newsfeed] - fix(newsfeed): prevent duplicate parse error callback when using pipeline (#4083) ### [modules/updatenotification] - fix(updatenotification): harden git command execution + simplify checkUpdates (#4115) - fix(tests): correct import path for git_helper module in updatenotification tests (#4078) ### [modules/weather] - fix(weather): use nearest openmeteo hourly data (#4123) - fix(weather): avoid loading state after reconnect (#4121) - weather: fix UV index display and add WeatherFlow precipitation (#4108) - fix(weather): restore OpenWeatherMap v2.5 support (#4101) - fix(weather): use stable instanceId to prevent duplicate fetchers (#4092) - SMHI: migrate to SNOW1gv1 API (replace deprecated PMP3gv2) (#4082) ### [testing] - ci(actions): set explicit token permissions (#4114) - fix(http_fetcher): use undici.fetch when dispatcher is present (#4097) - ci(codeql): also scan develop branch on push and PR (#4086) - refactor: replace implicit global config with explicit global.config (#4085) --------- Signed-off-by: dependabot[bot] <support@github.com> Co-authored-by: sam detweiler <sdetweil@gmail.com> Co-authored-by: Kristjan ESPERANTO <35647502+KristjanESPERANTO@users.noreply.github.com> Co-authored-by: Veeck <github@veeck.de> Co-authored-by: veeck <gitkraken@veeck.de> Co-authored-by: Magnus <34011212+MagMar94@users.noreply.github.com> Co-authored-by: Ikko Eltociear Ashimine <eltociear@gmail.com> Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com> Co-authored-by: DevIncomin <56730075+Developer-Incoming@users.noreply.github.com> Co-authored-by: Nathan <n8nyoung@gmail.com> Co-authored-by: mixasgr <mixasgr@users.noreply.github.com> Co-authored-by: Savvas Adamtziloglou <savvas-gr@greeklug.gr> Co-authored-by: Konstantinos <geraki@gmail.com> Co-authored-by: OWL4C <124401812+OWL4C@users.noreply.github.com> Co-authored-by: BugHaver <43462320+bughaver@users.noreply.github.com> Co-authored-by: BugHaver <43462320+lsaadeh@users.noreply.github.com> Co-authored-by: Bugsounet - Cédric <github@bugsounet.fr> Co-authored-by: Koen Konst <koenspero@gmail.com> Co-authored-by: Koen Konst <c.h.konst@avisi.nl> Co-authored-by: dathbe <github@beffa.us> Co-authored-by: Marcel <m-idler@users.noreply.github.com> Co-authored-by: Kevin G. <crazylegstoo@gmail.com> Co-authored-by: Jboucly <33218155+jboucly@users.noreply.github.com> Co-authored-by: Jboucly <contact@jboucly.fr> Co-authored-by: Jarno <54169345+jarnoml@users.noreply.github.com> Co-authored-by: Jordan Welch <JordanHWelch@gmail.com> Co-authored-by: Blackspirits <blackspirits@gmail.com> Co-authored-by: Samed Ozdemir <samed@xsor.io> Co-authored-by: in-voker <58696565+in-voker@users.noreply.github.com> Co-authored-by: Andrés Vanegas Jiménez <142350+angeldeejay@users.noreply.github.com> Co-authored-by: cgillinger <christian.gillinger@gmail.com> Co-authored-by: Sonny B <43247590+sonnyb9@users.noreply.github.com> Co-authored-by: sonnyb9 <sonnyb9@users.noreply.github.com>

After #4120 was merged, here's a bit of polish on top. - docs: Optimize JSDoc and comments. - test: The existing 304 test is moved to the dedicated status code block and extended with an `errorSpy` to also verify that no `error` event is emitted. - refactor: The success branch is moved before the error branch in `fetch()`. This is more intuitive. The bottom line is that this PR improves maintainability. For users, this PR doesn't change anything.

When a calendar server responds with 304 (nothing changed since last fetch), the response has no body. CalendarFetcher was parsing it anyway, which produced an empty event list - clearing all previously loaded events and showing nothing on screen. The bug was hidden until MagicMirrorOrg#4120 started forwarding 304 responses through HTTPFetcher instead of silently dropping them. Fix: skip parsing on 304 and re-broadcast the cached events as-is. Also adding unit tests for CalendarFetcher: 304 handling, HTTP error forwarding, parse error resilience, and shouldRefetch boundaries.

When a server responds with 304 (nothing changed since last fetch), the response has no body. Several modules were trying to parse that empty body anyway - which either cleared their cached data or threw an exception. The result: a blank calendar, empty newsfeed, or missing weather data after the next refresh cycle. This was reported in the forum: https://forum.magicmirror.builders/topic/20250/calendar-events-broadcasting-nothing-showing The bug was "introduced" by #4120, which correctly started forwarding 304s to consumers - but not all were ready for it. ### Fix Skip parsing on 304 and keep the existing data as-is: - **calendar** - re-broadcasts cached events - **newsfeed** - re-broadcasts cached items - **buienradar, openmeteo, weatherflow, weathergov** - return early before calling `response.json()`

KristjanESPERANTO reviewed Apr 25, 2026

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Comment thread js/http_fetcher.js Outdated

Handle HTTP 304 as a successful fetch

4484407

sonnyb9 force-pushed the codex/httpfetcher-304-pass-through branch from e34dcb7 to 4484407 Compare April 25, 2026 15:30

sonnyb9 changed the base branch from master to develop April 25, 2026 15:31

sonnyb9 marked this pull request as ready for review April 25, 2026 19:21

KristjanESPERANTO approved these changes Apr 25, 2026

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khassel approved these changes Apr 27, 2026

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khassel merged commit b8548f2 into MagicMirrorOrg:develop Apr 27, 2026

khassel mentioned this pull request Apr 30, 2026

Release 2.36.0 #4127

Merged

KristjanESPERANTO mentioned this pull request Apr 30, 2026

polish HTTP 304 docs/test/handling #4129

Merged

KristjanESPERANTO mentioned this pull request Jun 5, 2026

fix: modules losing data after HTTP 304 responses #4180

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Allow HTTPFetcher to pass through 304 responses#4120

Allow HTTPFetcher to pass through 304 responses#4120
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sonnyb9 commented Apr 24, 2026

Summary

Root cause

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