Bug 215884 – getUserMedia recurring permissions prompts in standalone when hash changes

• Component: WebRTC
• Status: RESOLVED CONFIGURATION CHANGED

Context:
I have a web app with a hash router. Once I am done analysing the camera stream and showing results my router changes the hash to a result route. When I come back to the camera view, I am prompted for the camera permissions again, even though I never left the web app. This behaviour does not happen in Safari for iOS.


Current behaviour:
In standalone mode, iOS is revoking the camera permissions every time the hash changes.

Expected behaviour:
In browser mode, once I am granted the camera use by the user, I can change the hash without loosing the camera permissions.

Steps to reproduce:
1) Add a video tag to page
2) Ask for camera permissions and attach the stream to the video tag
3) Add a <a href="#"> to page
4) click on link

In standalone mode: video stream is gone.
In browser mode: video stream is still there.

Current workaround:
Set the Vue router to abstract mode.

[Radar WebKit Bug Importer]

<rdar://problem/68001080>

[youenn fablet]

Thanks, I was able to repro with airhorner.
It seems as if there is a navigation which stops all the capture tracks and reset the permissions when doing hash navigations in Web.app but not iOS Safari.

[Alex Suzuki]

I have multiple PWAs which scan barcodes using and show the camera preview with getUserMedia. They use Angular routing.

Everything works fine in Safari, but when added to home screen (PWA), the camera permission prompt will appear every time the route changes.

Currently the only workaround we can offer to users is to provide blanket camera permissions (all web sites) in Safari.

This is probably related to this issue.

[Michal]

(In reply to Alex Suzuki from comment #3)
> 
> Everything works fine in Safari, but when added to home screen (PWA), the
> camera permission prompt will appear every time the route changes.
> 
> This is probably related to this issue.


We have exactly this problem with our PWA which is based on QR scanner. It would be nice to have this working as in Safari.

[Michal]

(In reply to Alex Suzuki from comment #3)
> I have multiple PWAs which scan barcodes using and show the camera preview
> with getUserMedia. They use Angular routing.
> 
> Currently the only workaround we can offer to users is to provide blanket
> camera permissions (all web sites) in Safari.
> 

Whad did you mean by this? Can you explain this workaround more please?

[youenn fablet]

(In reply to Michal from comment #5)
> (In reply to Alex Suzuki from comment #3)
> > I have multiple PWAs which scan barcodes using and show the camera preview
> > with getUserMedia. They use Angular routing.
> > 
> > Currently the only workaround we can offer to users is to provide blanket
> > camera permissions (all web sites) in Safari.
> > 
> 
> Whad did you mean by this? Can you explain this workaround more please?

In iOS Safari, users can persistently grant camera/microphone access from Safari UI.

[youenn fablet]

Created attachment 416332 [details]
Per site setting iOS UI

[youenn fablet]

I uploaded a screenshot that shows where to get per-site settings UI

[Michal]

(In reply to youenn fablet from comment #8)
> I uploaded a screenshot that shows where to get per-site settings UI

Yes I see, thank you for explanation of this. Of course this is working but there is need to do it manually by users. Which I don't want to delegate this problem to end-users. If you are calculating with thousands of them.

Our problem is mainly with "Installed" PWA - "Add to Home screen" (in Safari), where this permission is not persisted after you did this install of the app.

[youenn fablet]

As a temporary workaround, I wonder whether the following would work:
- Start capture
- Before navigating inside the page, stop the capture by calling stream.getTracks().forEach(t => t.stop())
- Navigate within the same page
- Restart capture (hopefully without a prompt this time).

[youenn fablet]

*** Bug 212040 has been marked as a duplicate of this bug. ***

[youenn fablet]

The fix is not in WebKit but in Safari standalone mode implementation.
I'll keep this bug open until validation is done this works as expected.

[Mauricio W]

I don't think this issue is with Safari implementation.
It also happens when running an app with WKWebView. Any changes to the path of the URL causes calls to `getUserMedia` to request permissions from the user again.

[Mauricio W]

It looks like the problem is a bit more serious in WKWebView. 

After allowing the prompt, any subsequent calls to `getUserMedia` after some period of time (looks to be about 90 seconds) will also trigger the prompt for permissions.

This happens even without navigating away from the page, regardless of if the user was active or inactive in that time.

[youenn fablet]

(In reply to Mauricio W from comment #14)
> It looks like the problem is a bit more serious in WKWebView. 
> 
> After allowing the prompt, any subsequent calls to `getUserMedia` after some
> period of time (looks to be about 90 seconds) will also trigger the prompt
> for permissions.
> 
> This happens even without navigating away from the page, regardless of if
> the user was active or inactive in that time.

This is a different bug, which might best be fixed by exposing a delegate to control getUserMedia prompt.
If capture is ongoing, prompt should not happen again until 24 hours.
If capture is not ongoing, prompt should happen again after 1 minute of inactivity.
This is the same behavior as Safari.

[Mauricio W]

Thanks for the reply, youenn. The documentation for this is rather scarce, so I wasn't sure. Thank you for clearing that up.

I don't mean to sidetrack this thread, but since you brought it up: could you explain a bit more on how I could use a delegate to handle this? Reading through the WKWebview documentation there doesn't seem to be an obvious answer to me. I also spent some time trying to understand how the UserMediaRequest gets sent out, but I couldn't really understand the flow.

[youenn fablet]

(In reply to Mauricio W from comment #16)
> Thanks for the reply, youenn. The documentation for this is rather scarce,
> so I wasn't sure. Thank you for clearing that up.
> 
> I don't mean to sidetrack this thread, but since you brought it up: could
> you explain a bit more on how I could use a delegate to handle this? Reading
> through the WKWebview documentation there doesn't seem to be an obvious
> answer to me. I also spent some time trying to understand how the
> UserMediaRequest gets sent out, but I couldn't really understand the flow.

UserMediaRequest is sent through IPC to UIProcess.
It is processed in UserMediaPermissionRequestManagerProxy which ultimately may call a WKWebView delegate dedicated to getUserMedia permission.
This delegate is not yet exposed though.

[Dan Strengier]

I too have PWAs that use the camera to scan barcodes.  It's proving very cumbersome for our users to confirm camera access every time they try and scan a QR code.

The workaround to always allow camera access across all Safari websites is a *really bad workaround* because it completely breaks user's privacy controls, just so they can seamlessly scan barcodes using our app.

[Bryce Wilson]

I can also confirm this issue via a PWA install on home screen, the camera is requested on every page there is a camera instance initiated.

[youenn fablet]

Please check this in latest iOS 14.5 beta.

[Matthias Rauch]

In 14.5 the prompt for camera permission does not show on every page anymore. That's an improvement, but the camera permission is not conserved over multiple session. That means the camera permission prompt still shows up, when the application is closed and reopend again. 

Are there any plans to resolve this behaviour too?

[Charles S]

This issue is still current with 16.3.1. User experience is miserable when multiple scans are performed more than 1 minute apart in standalone mode

[bearman]

I wonder if some can provide some insight for me. Some claim this issue is resolved, others claim the issue persists.

I've tested on MacOS 12.6.8 w/ Safari 16.6:

Visit e.g. Google.com then `getUserMedia()` and `enumerateDevices` acts as expected. 

Attempting the same with (Swift's Webkit) only enumerate an empty input device and hangs when calling `getUserMedia`.

Is this expected?

[arkraft]

I have tried this on https://whatpwacando.today/media/ and the problem still exists. I have tried it on my Mac and iPhone (16.6.1). 
On my iPhone the permission does not persist when disabling and enabling the camera or reloading the page. On Mac with Safari i get asked again after reloading the page. When using Chrome on Mac the permission is persisted after page reloads.

We are developing a PWA with a camera function, so this is really something that is halting our development. It would be great if there would be a solution for this, thanks.

[youenn fablet]

(In reply to arkraft from comment #24)
> I have tried this on https://whatpwacando.today/media/ and the problem still
> exists. I have tried it on my Mac and iPhone (16.6.1). 
> On my iPhone the permission does not persist when disabling and enabling the
> camera or reloading the page. On Mac with Safari i get asked again after
> reloading the page. When using Chrome on Mac the permission is persisted
> after page reloads.

On Safari, there is the possibility to grant persistent access to camera and/or microphone.

> We are developing a PWA with a camera function, so this is really something
> that is halting our development. It would be great if there would be a
> solution for this, thanks.

Do you mean that you would like a way for a Home Screen web app to have persistent camera/microphone access?
If so, could you file a new bug?

[juaramos]

Same problem here, any solution nowadays?

[youenn fablet]

The ask is not clear, can you clarify what the issue you would like to be solved?

[juaramos]

Is there any way to allow camera permissions one time?

Problem:

-Open app in browser mode
-Open camera component and allow permission.
-Open camera component again and it works. No permissions requested

Then

-Open app in browser mode
-Open camera component and allow permission.
-Install app as PWA
-Open PWA, then open camera component again and the permissions is requested again.


Other scenario

-Open PWA on iPad
-Open camera module and allow permissions
-While the app is alive their permissions works fine (not asked each time)
-If kill the app and cold start again the permissions are asked again.

I am experiencing this again on iOS 18.5.

I visit our PWA website in Safari, set the camera permission to "Allow".  Close the tab, close the browser, and visit the site again in Safari to confirm that the permission has persisted.

Then I open the PWA via the previously installed shortcut.  It asks for permission to use the camera again.

I return to the website in Safari, and I see that the permission has reverted to "Ask".

I don't remember this happening before upgrading to iOS 18.5, but it's also true that I haven't tested the app for a few weeks.

Why, oh why, is it so difficult to get this right, after so many years?  This (along with all the IndexedDB issues of course) is just killing us.  Fortunately, this is an internal app -- we were previously locked into iOS because our app had been developed in Xamarin, but now we finally have the chance to migrate away from Apple products.  That day can't come soon enough.