Bug 199906 – REGRESSION: WebSockets no longer work in Service Workers

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

[James Lees]

It seems Websocket connections no longer work in service workers. I created a small demo app to demonstrate the issue

https://service-worker-example-zzobdmsvlg.now.sh (src: https://github.com/leesio/service-worker-example)

Alternatively, a simple way recreate

Open the safari developer tools in any service worker context on an iOS device running 12.3+
Try to create a websocket connection

e.g.

const wsUrl = 'wss://ws-test1.staging.pusher.com:443/app/9f35c4ed36479d45cbea?protocol=7&client=js&version=4.4.0&flash=false';
const handler = (event) => console.log('event', event.type, event.data)
let socket = new WebSocket(wsUrl);
socket.onerror = handler;
socket.onopen = handler;
socket.onmessage = handler;
socket.onclose = handler;

Observe the results

macOS Safari - 10.14.5 (18F132)

[Log] event – "open" – undefined
[Log] event – "message" – "{\"event\":\"pusher:connection_established\",\"data\":\"{\\\"socket_id\\\":\\\"5234.586038\\\",\\\"activity_timeout\\\":120}\"}"

Safari on iOS 12.3.1 on iPhone SE

[Log] event – "error" – undefined
[Log] event – "close" – undefined

It's not clear to me whether this was a deliberate change, or a regression. The example app shows websockets work fine on my Xcode simulator running iOS 12.2, but not on any real devices running 12.3.1 (tried iphone 6s and iPhone SE)

[youenn fablet]

Hi James,

Thanks for the report.
Can you confirm that WebSocket connections work for you on MacOSX but not on iOS?

I tried your example and I got a 1006 error on both MacOS and iOS.

[James Lees]

Created attachment 374452 [details]
A screengrab of the test application working on macOS Safari

Hi Youenn,

Thanks for getting back to me so quickly. I can confirm that the demo app works fine for me in macOS Safari. I've attached a screengrab showing the results. Note that the close events are expected - service worker closes the connection 2s after opening it!)

My macOS version is 10.14.5 (18F132). If there's anything else you need from me please don't hesitate to get in touch.

James

[Radar WebKit Bug Importer]

<rdar://problem/53516732>

[youenn fablet]

I did some debugging and it seems that this may be a regression from https://bugs.webkit.org/show_bug.cgi?id=193529.

[youenn fablet]

Created attachment 375097 [details]
Patch

[Geoffrey Garen]

Comment on attachment 375097 [details]
Patch

Can we regression test this? Seems like a pretty serious failure not to test.

[youenn fablet]

(In reply to Geoffrey Garen from comment #6)
> Comment on attachment 375097 [details]
> Patch
> 
> Can we regression test this? Seems like a pretty serious failure not to test.

The current test was bogus as it was passing while it should not.
The test is now covering this properly.

[Geoffrey Garen]

Comment on attachment 375097 [details]
Patch

r=me

[WebKit Commit Bot]

Comment on attachment 375097 [details]
Patch

Clearing flags on attachment: 375097

Committed r247923: <https://trac.webkit.org/changeset/247923>

[WebKit Commit Bot]

All reviewed patches have been landed.  Closing bug.

[James Lees]

Great news.
This is the first time I've reported a WebKit bug so I don't know much about the release cycles etc.
When is this fix likely to make it into iOS Safari? Apologies if this isn't the right place for this question.

[Alexey Proskuryakov]

Indeed, we do not comment on Apple's release schedules or plans.

However, any information on customer impact would be used for prioritization. Are there any live websites, apps, or release plans that you are aware of that are impacted by this?

[James Lees]

Alexey,

Understood.
It may be a little bit difficult for me to provide end-user impact. We're a bit of a middleperson in all of this - we provide a set of libraries/APIs that allow our customers to add realtime functionality to *their* websites/apps. As a result it's hard to know if other users have been affected and haven't raised a support issue.

We first noticed this bug when a customer reported our pusher-js library no longer worked in service-workers on iOS. I've asked that customer for more information about how this issue is affecting them.

I'll also add a note to our github issue asking for more input from users.

Thanks for your help on this