# Using universal links

You can improve the security of your app with Apple's universal links (opens new window) feature that securely communicates information between apps. If you set up a universal link, LINE tries to open your app with the universal link first. If the universal link is invalid, LINE falls back to a URL based on your iOS bundle ID (see Linking your app to your channel.

Universal links are recommended

Although universal links are optional, we recommend using them to make your app more secure.

Universal links are supported on LINE 8.16 or later for iOS. To enable users to open your app with a universal link, follow these steps:

  1. Create an association between your app and your server.
  2. Set up a universal link on the LINE Developers Console.
  3. Set up the universal link in the Info.plist file.
  4. Handle the login result after your app is opened by the universal link.

# 1. Create an association between your app and your server

For this step, see Allowing Apps and Websites to Link to Your Content (opens new window) by Apple.

Complete these tasks:

  • Create an apple-app-site-association file that contains JSON data about the URLs that your app can handle and put it in your HTTPS server.
  • Add an Associated Domains entitlement to your app.

This section assumes that you use https://yourdomain.com/line-auth/ as the universal link to handle a LINE authorization response.

Include /line-auth/* in the paths field of your apple-app-site-association file. An example of a valid Apple App Site Association file looks like below:

{
    "applinks": {
        "apps": [],
        "details": [
            {
                "appID": "YOUR_TEAM_ID.com.yourcompany.yourapp",
                "paths": [ "/line-auth/*" ]
            }
        ]
    }
}

Note that you can test universal links only on a real iOS device. You need to set up your app ID and profile correctly. If your universal links don’t work, see Troubleshooting Universal Links (opens new window) on Apple's developer site. Ensure that your universal links work before you proceed with the next steps.

# 2. Set up a universal link on the LINE Developers Console

For the procedure, see Linking your app to your channel. In this example, we set it to https://yourdomain.com/line-auth/.

# 3. Set up the universal link in the Info.plist file

In your app's Info.plist file, add a UniversalLink key and set it to the value you want in the LineSDKConfig dictionary as below. It should be at the same level as your ChannelID key.

<key>LineSDKConfig</key>
<dict>
    <key>ChannelID</key>
    <string>1234567890</string>
    <key>UniversalLink</key>
    <string>https://yourdomain.com/line-auth/</string>
</dict>

# 4. Handle the login result after your app is opened by the universal link

Add the code below in the AppDelegate file.

- (BOOL)application:(UIApplication *)application continueUserActivity:(NSUserActivity *)userActivity restorationHandler:(void (^)(NSArray<id<UIUserActivityRestoring>> * _Nullable))restorationHandler
{
    if ([[LineSDKLogin sharedInstance] handleOpenURL:userActivity.webpageURL]) {
        return YES;
    }
    // Your other code to handle universal links and/or user activities.
}

Now LINE can open your app with the universal link and your app can handle the login result.