android: support app links via simplex.chat (#545)

* update manifest

* autoverify domain

* add path prefix to intent filter

* support contact links

* add android app readme

* only allow a single simplex task at a time to avoid opening simplex 'on top' of app with link

apps/android/app/src/main/AndroidManifest.xml

@@ -1,33 +1,35 @@
 <?xml version="1.0" encoding="utf-8"?>
 <manifest xmlns:android="http://schemas.android.com/apk/res/android"
-  package="chat.simplex.app">
+    package="chat.simplex.app">
 
   <uses-feature android:name="android.hardware.camera" />
+
   <uses-permission android:name="android.permission.CAMERA" />
   <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
-  <uses-permission android:name="android.permission.FOREGROUND_SERVICE"/>
-  <uses-permission android:name="android.permission.WAKE_LOCK"/>
-  <uses-permission android:name="android.permission.RECEIVE_BOOT_COMPLETED"/>
-  <uses-permission android:name="android.permission.VIBRATE"/>
+  <uses-permission android:name="android.permission.FOREGROUND_SERVICE" />
+  <uses-permission android:name="android.permission.WAKE_LOCK" />
+  <uses-permission android:name="android.permission.RECEIVE_BOOT_COMPLETED" />
+  <uses-permission android:name="android.permission.VIBRATE" />
   <uses-permission android:name="android.permission.INTERNET" />
   <uses-permission android:name="android.permission.ACCESS_WIFI_STATE" />
   <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
 
   <application
-    android:name="SimplexApp"
-    android:allowBackup="true"
-    android:icon="@mipmap/icon"
-    android:label="@string/app_name"
-    android:supportsRtl="true"
-    android:theme="@style/Theme.SimpleX">
+      android:name="SimplexApp"
+      android:allowBackup="true"
+      android:icon="@mipmap/icon"
+      android:label="@string/app_name"
+      android:supportsRtl="true"
+      android:theme="@style/Theme.SimpleX">
 
     <!-- Main activity -->
     <activity
-      android:name=".MainActivity"
-      android:exported="true"
-      android:label="@string/app_name"
-      android:windowSoftInputMode="adjustResize"
-      android:theme="@style/Theme.SimpleX">
+        android:name=".MainActivity"
+        android:launchMode="singleTask"
+        android:exported="true"
+        android:label="@string/app_name"
+        android:windowSoftInputMode="adjustResize"
+        android:theme="@style/Theme.SimpleX">
       <intent-filter>
         <action android:name="android.intent.action.MAIN" />
         <category android:name="android.intent.category.LAUNCHER" />
@@ -36,10 +38,24 @@
       <!-- open simplex:/ connection URI -->
       <intent-filter>
         <action android:name="android.intent.action.VIEW" />
+
         <category android:name="android.intent.category.DEFAULT" />
         <category android:name="android.intent.category.BROWSABLE" />
+
         <data android:scheme="simplex" />
       </intent-filter>
+      <intent-filter android:autoVerify="true">
+        <action android:name="android.intent.action.VIEW" />
+
+        <category android:name="android.intent.category.DEFAULT" />
+        <category android:name="android.intent.category.BROWSABLE" />
+
+        <data android:scheme="http" />
+        <data android:scheme="https" />
+        <data android:host="simplex.chat" />
+        <data android:pathPrefix="/invitation" />
+        <data android:pathPrefix="/contact" />
+      </intent-filter>
     </activity>
 
     <provider
@@ -49,7 +65,7 @@
         android:grantUriPermissions="true">
       <meta-data
           android:name="android.support.FILE_PROVIDER_PATHS"
-          android:resource="@xml/file_paths"/>
+          android:resource="@xml/file_paths" />
     </provider>
 
     <!-- SimplexService foreground service -->
@@ -57,8 +73,7 @@
         android:name=".SimplexService"
         android:enabled="true"
         android:exported="false"
-        android:stopWithTask="false">
-    </service>
+        android:stopWithTask="false"></service>
 
     <!-- SimplexService restart on reboot -->
     <receiver
@@ -66,7 +81,7 @@
         android:enabled="true"
         android:exported="true">
       <intent-filter>
-        <action android:name="android.intent.action.BOOT_COMPLETED"/>
+        <action android:name="android.intent.action.BOOT_COMPLETED" />
       </intent-filter>
     </receiver>
 
@@ -74,6 +89,6 @@
     <receiver
         android:name=".SimplexService$AutoRestartReceiver"
         android:enabled="true"
-        android:exported="false"/>
+        android:exported="false" />
   </application>
 </manifest>

apps/android/app/src/main/java/chat/simplex/app/MainActivity.kt

@@ -39,7 +39,6 @@ class MainActivity: ComponentActivity() {
   override fun onCreate(savedInstanceState: Bundle?) {
     super.onCreate(savedInstanceState)
 //    testJson()
-    processIntent(intent, vm.chatModel)
     setContent {
       SimpleXTheme {
         Surface(
@@ -54,6 +53,11 @@ class MainActivity: ComponentActivity() {
     schedulePeriodicServiceRestartWorker()
   }
 
+  override fun onNewIntent(intent: Intent?) {
+    super.onNewIntent(intent)
+    processIntent(intent, vm.chatModel)
+  }
+
   private fun schedulePeriodicServiceRestartWorker() {
     val workerVersion = chatController.getAutoRestartWorkerVersion()
     val workPolicy = if (workerVersion == SimplexService.SERVICE_START_WORKER_VERSION) {

apps/android/readme.md

@@ -0,0 +1,25 @@
+# Android App Development
+
+This readme is currently a stub and as such is in development.
+
+Ultimately, this readme will act as a guide to contributing to the develop of the SimpleX android app.
+
+
+## Gotchas
+
+#### SHA Signature for verification for app links/deep links
+
+In order for the SimpleX app to be automatically adopted for opening links from https://simplex.chat the SHA certificate fingerprint for the App installed on the phone must be in the hosted [assetlinks.json](https://simplex.chat/.well-known/assetlinks.json) file on simplex.chat.
+
+The accepted fingerprints are in the `sha256_cert_fingerprints` list.
+
+To find your SHA certificate fingerprint perform the following steps.
+
+1. Build and install your development version of the app as usual
+2. From the terminal in Android studio run `adb shell pm get-app-links chat.simplex.app`
+3. Copy the signature listed in `signatures` in the result
+4. Add your signature to [assetlinks.json](https://github.com/simplex-chat/website/blob/master/.well-known/assetlinks.json) in the [website repo](https://github.com/simplex-chat/website) and make a PR. On approval, wait a few minutes for the changes to propagate to the public website and then you should be able to verify SimpleX.
+
+More information is available [here](https://developer.android.com/training/app-links/verify-site-associations#manual-verification). If there is no response when running the `pm get-app-links` command, the intents in `AndroidManifest.xml` are likely misspecified. A verification attempt can be triggered using `adb shell pm verify-app-links --re-verify chat.simplex.app`. 
+
+Note that this is not an issue for the app store build of the app as this is signed with our app store credentials and thus there is a stable signature over users. Developers do not have general access to these credentials for development and testing.