Bug 284184 – Checking for presence of request body in Service Worker causes body to be dropped from request

• Status: RESOLVED
• Resolution: FIXED
• Component: Service Workers

[Wes]

If a service worker intercepts a fetch request and checks for the presence of a body then the body will get dropped from the SW's fetch request.

NOTE: I have tried this with both "Content-Type: application/json" and "Content-Type: x-www-form-urlencoded" and both hit this bug.


> // sw code
> self.addEventListener("fetch", (event) => {
>  event.respondWith(
>    (async () => {
>      if (event.request.body) {
>        console.log("this request has a body");
>      }
>      return fetch(event.request);
>    })()
>  );
>});

I have made a repro at https://github.com/wes-goulet/webkit-service-worker-drop-body-repro

This same check of a request body causes no issue if it happens on the main thread (not in SW).

[Radar WebKit Bug Importer]

<rdar://problem/141454387>

[youenn fablet]

Submitted web-platform-tests pull request: https://github.com/web-platform-tests/wpt/pull/49923

[EWS]

Committed 288514@main (6c800745251d): <https://commits.webkit.org/288514@main>

Reviewed commits have been landed. Closing PR #38561 and removing active labels.