expo: Permissions.askAsync never resolves on iOS Standalone app

With out recent app release, we have found an apparent bug in Expo in the standalone app which caused Apple to reject the submission. It turns out that the Pemissions.askAsync is often not resolving the promise when the user clicks “Allow” or “Don’t Allow” on the native dialog popup.

We were able to resolve this in two ways:

Change the screen automatically in the background and don’t wait for a resolved response.
Use a timeout around the permissions dialog (calling Permissions.getAsync to attempt to get the response).

Ensure the promise resolved with a timeout:

Note: You should probably not let the UI wait for this response.

    askNotificationPermissions_withTimeout = () => {
        // NOTE: Permissions.askAsync seems to never resolve sometimes, so using a timeout to check status

        return new Promise((resolve, reject) => {
            const timeoutId = setTimeout(async () => {
                const { status } = await Permissions.getAsync(
                    Permissions.NOTIFICATIONS
                );
                resolve(status === 'granted');
            }, 5000);

            const promise = Permissions.askAsync(
                Permissions.NOTIFICATIONS
            );

            promise.then(r => {
                clearTimeout(timeoutId);

                const { status } = r;
                resolve(status === 'granted');
            });
        });

    };

Context

Expo SDK 24.0.0
iOS Standalone

About this issue

Original URL
State: closed
Created 6 years ago
Comments: 37 (9 by maintainers)

Most upvoted comments

Hi, we just ran into the same issue with the latest version of Expo. Here are the steps to reproduce the issue:

Ask the user for notifications permissions using askAsync
Allow notification permissions
Go to Expo settings and turn off notifications permissions
Ask the user for notifications permissions again using askAsync

At that point, the app hangs waiting for the promise askAsync returns to resolve.

+10

ramshamushtaq on Apr 8, 2018

@brentvatne @bbarthec just to note: this issue was re-introduced in 'expo-permissions' (at least 6.0.0).

joraniedemagit on Aug 16, 2019

found a bit more elegant solution here: https://www.gitmemory.com/issue/expo/expo/1354/480237688

kulikalov on Dec 14, 2019

@terribleben I can confirm that this is happening on current builds too as @rmushtaq21 described. Should the issue be re-opened?

Elijen on Apr 17, 2018

@kulikalov yeah, sure. Here is the example of my custom workaround:

import { useCameraPermission } from '../hooks/useCameraPermission'

const MyComponent = () => {
  // use the variable in your component: null - still polling, true - granted, false - declined
  const hasCameraPermission = useCameraPermission()
  ...
}

Implementation:

// hooks/useCameraPermission.js
import { useState, useEffect } from 'react'
import * as Permissions from 'expo-permissions'

const STATUS_GRANTED = 'granted'
const PERMISSION_CHECK_INTERVAL = 500 // ms
var PERMISSION_INTERVAL = null // quick HACK

const clear = () => {
  if (PERMISSION_INTERVAL) {
    clearInterval(PERMISSION_INTERVAL)
    PERMISSION_INTERVAL = null
  }
}

const checkStatus = ({ status, setHasCameraPermission }) => {
  const hasCameraPermission = status === STATUS_GRANTED
  if (hasCameraPermission) clear()
  setHasCameraPermission(hasCameraPermission)
}

const detectCameraPermission = async ({ setHasCameraPermission }) => {
  // check if permissions were given previously
  const { status: initialStatus } = await Permissions.getAsync(Permissions.CAMERA)

  if (initialStatus === STATUS_GRANTED) {
    setHasCameraPermission(true)
  } else {
    // set "long polling" interval first
    PERMISSION_INTERVAL = setInterval(async () => {
      const { status } = await Permissions.getAsync(Permissions.CAMERA)
      checkStatus({ status, setHasCameraPermission })
    }, PERMISSION_CHECK_INTERVAL)

    // this one hangs
    const { status } = await Permissions.askAsync(Permissions.CAMERA)
    // doesn't hit this line
    checkStatus({ status, setHasCameraPermission })
  }
}

export const useCameraPermission = () => {
  const [hasCameraPermission, setHasCameraPermission] = useState(null)

  useEffect(() => {
    detectCameraPermission({ setHasCameraPermission })
    return () => clear()
  }, [])

  return hasCameraPermission
}

exAspArk on Dec 13, 2019

@brentvatne I get the prompt, but after I tap “allow”, the code hangs on await Permissions.askAsync and does not allow me to persist the token.

kalinchuk on Mar 14, 2019

@terribleben @watadarkstar pls reopen this issue, it’s not resolved.

kulikalov on Dec 13, 2019

@bbarthec Can you hit me with some knowledge on this issue pretty please? 😃 Thanks in advance!

jSkrills on Apr 13, 2019

there is an open WIP PR to fix this issue: https://github.com/expo/expo/pull/3737

brentvatne on Apr 6, 2019

Can confirm that SDK32 removes the hang.

However, I’m running into the issue where if the user declines the first time, askAsync will not prompt the user a second time. Is this still the standard iOS behavior as discussed here: https://forums.expo.io/t/asking-for-permissions-again-when-denied-the-first-time/10218?

yes it is

Serguzest on Feb 16, 2019

Can confirm – I observed the same thing on an app I released around the same time. Problem disappeared with a new build. Bites that it required re-approval, but it worked!

kevinjdolan on Jan 31, 2018