ios_callkit

One-to-one video call using CallKit and PushKit with flutter iOS app.

Motivation

We need to use CallKit to handle incoming VoIP notifications from iOS 13. Check the WWDC2019 video for more information. So instead of using CallKit and PushKit separately, there is a growing need to use them together. However, there are still few VoIP notification samples on the net that use CallKit and PushKit (especially for Flutter). I decided to create a flutter plugin with the minimum required functions. You can use this plugin, but the actual purpose is to help you create a VoIPKit tailored to your service.

Requirement

iOS only, not support Android.
iOS 10 or above.
one-to-one call only, not support group call.
need to a server for pushing VoIP notification with APNs.
to actually make a video or call, you need to link to a service such as WebRTC（ex: Agora, SkyWay, Amazon Kinesis Video Streams）.

Usage

1. install

Add ios_callkit as a dependency in your pubspec.yaml file.

2. setting Capability in Xcode

Select Background Modes > Voice over IP and Remote notifications is ON.
Select Push Notifications.
Changed ios/Runner/Info.plist after selected Capability.

<key>UIBackgroundModes</key>
<array>
    <string>remote-notification</string>
    <string>voip</string>
</array>

2. edit Info.plist

Edit ios/Runner/Info.plist as below.

<key>FIVKIconName</key>
<string>AppIcon-VoIPKit</string>
<key>FIVKLocalizedName</key>
<string>VoIP-Kit</string>
<key>FIVKSupportVideo</key>
<true/>
<key>FIVKSkipRecallScreen</key>
<true/>

3. add New Image set for CallKit

Add an icon（.png or .pdf） ios/Runner/Assets.xcassets/AppIcon-VoIPKit to use on the screen when a call comes in while locked iPhone.

4. create VoIP Services Certificate

Visit the Apple Developer https://developer.apple.com/certificates and create a new VoIP Services Certificate(.cer). Check Voice Over IP (VoIP) Best Practices Figure 11-2 for more information.
Create .p12 from .cer with KeyChainAccess, and .pem with openssl.

Create `.p12` from `.cer` with KeyChainAccess

openssl pkcs12 -in voip_services.p12 -out voip_services.pem -nodes -clcerts

5. request VoIP notification APNs from your server

See Apple document.
https://developer.apple.com/documentation/usernotifications/setting_up_a_remote_notification_server/sending_notification_requests_to_apns
Add data(payload) like a below.

{
    "aps": {
        "alert": {
          "uuid": <Version 4 UUID (e.g.: https://www.uuidgenerator.net/version4) >,
          "incoming_caller_id": <your service user id>,
          "incoming_caller_name": <your service user name>,
        }
    }
}

You can use curl to test VoIP notifications as follows.

curl -v \
-d '{"aps":{"alert":{"uuid":"982cf533-7b1b-4cf6-a6e0-004aab68c503","incoming_caller_id":"0123456789","incoming_caller_name":"Tester","videoType":true}}}' \
-H "apns-push-type: voip" \
-H "apns-expiration: 0" \
-H "apns-priority: 0" \
-H "apns-topic: <your app’s bundle ID>.voip" \
--http2 \
--cert ./voip_services.pem \
https://api.sandbox.push.apple.com/3/device/<VoIP device Token for your iPhone>

ios_callkit

GitHub

View Github