Add deep linking support

[csduarte]

Summary

Allow permalinks to open the mobile app.

The app checks for platform specific configuration on app install. If no configuration is found then the deep linking code sits silently and permalinks act as just regular links.

Setup for iOS

• Create an apple-app-site-association file in the .well-known directory at the root of your server. It should be accessible by navigating to https://<your-site-name>/.well-known/apple-app-site-association. *** There should NOT be a file extension ***
• In order to handle permalink deep links paste the following JSON into the apple-app-site-association file. Make sure to place your app ID in the appID property:

{
    "applinks": {
        "apps": [],
        "details": [
            {
                "appID": "<your-app-id-here>",
                "paths": ["**/pl/*"]
            }
        ]
    }
}

• Make sure to add the associated domains entitlement to your app via the Apple developer portal
• Add an entitlement that specifies the domains your app supports via the Xcode entitlements manager.

Before installing the app with the new entitlement make sure that you can view the contents of the apple-app-site-association file via a browser by navigating to https://<your-site-name>/.well-known/apple-app-site-association. The app will check for this file on install and if found will allow outside permalinks to open the app.

Official documentation can be found using the following link:

• iOS universal links

Setup for Android

Configuring deep links for Android is done much easier when using the App Links Assistant in Android Studio. Please refer to the following link for adding deep links via the App Links Assistant:

• Android App Links Assistant

Screenshots

[enahum]

@jarredwitt is there documentation needed for this?

[jarredwitt]

@enahum updated the PR description to include some instructions for setup. The setup is pretty specific for each platform since it deals with the app ID's as well as some required file uploads to the server. The good thing about the setup is that it sits silently in the background if a configuration is not found. Let me know if you need help/have issues testing.

[enahum]

It would be great to submit the PR to the docs and the developer docs ;)

[enahum]

Will this work with multiple servers if the app id is the one we provide or people wanting to use this will need to build their own apps?

[jarredwitt]

@enahum sorry for the late response, not sure on the multiple servers front. My guess is maybe? For iOS the apple-app-site-association file it only requires that the appID be present so I think if users are using the build from the app store then they would only need to upload the apple-app-site-association file to their server with the MM appID set and I think it'll work. Not sure on Android, but I think if the file is signed using the MM keystore then it should work the same way as long as that file is also uploaded to the server.

[jarredwitt]

@enahum actually forgot that comment. It'll require users to build their own app if they want to support other servers since you have to specify the site url in the entitlements file at build time for iOS and Android.

[enahum]

just one minor comment, also can you please submit a PR to the https://github.com/mattermost/mattermost-developer-documentation repo on how to set up universal links when building from source?

[enahum]

is there a reason for this?

[jarredwitt]

Yes, I was getting some setState on unmounted component warnings from this:

https://github.com/uber-uchat/mattermost-mobile/blob/ca1659c65835eb0c3a0d632811eaa860c1585f73/app/screens/channel/channel_post_list/channel_post_list.js#L63

[enahum]

Plz don’t forget about the docs for this feature