fix de-/serialization of Connection objects. Fixes VPN auto-restart on reboot due to always-on system settings or if system killed app due to low memory

4 files changed, 47 insertions, 6 deletions

diff --git a/app/src/main/java/de/blinkt/openvpn/VpnProfile.java b/app/src/main/java/de/blinkt/openvpn/VpnProfile.java
index 41b5ddb5..922eee58 100644
--- a/app/src/main/java/de/blinkt/openvpn/VpnProfile.java
+++ b/app/src/main/java/de/blinkt/openvpn/VpnProfile.java
@@ -15,12 +15,14 @@ import android.os.Build;
 import android.preference.PreferenceManager;
 import android.security.KeyChain;
 import android.security.KeyChainException;
-import androidx.annotation.NonNull;
-import androidx.annotation.Nullable;
 import android.text.TextUtils;
 import android.util.Base64;
 
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
+
 import com.google.gson.Gson;
+import com.google.gson.GsonBuilder;
 
 import org.spongycastle.util.io.pem.PemObject;
 import org.spongycastle.util.io.pem.PemWriter;
@@ -63,8 +65,7 @@ import de.blinkt.openvpn.core.VPNLaunchHelper;
 import de.blinkt.openvpn.core.VpnStatus;
 import de.blinkt.openvpn.core.X509Utils;
 import de.blinkt.openvpn.core.connection.Connection;
-import de.blinkt.openvpn.core.connection.Obfs4Connection;
-import de.blinkt.openvpn.core.connection.OpenvpnConnection;
+import de.blinkt.openvpn.core.connection.ConnectionAdapter;
 import se.leap.bitmaskclient.BuildConfig;
 import se.leap.bitmaskclient.R;
 
@@ -1159,8 +1160,9 @@ public class VpnProfile implements Serializable, Cloneable {
 
     public static VpnProfile fromJson(String json) {
         try {
-            Gson gson = new Gson();
-            return gson.fromJson(json, VpnProfile.class);
+            GsonBuilder builder = new GsonBuilder();
+            builder.registerTypeAdapter(Connection.class, new ConnectionAdapter());
+            return builder.create().fromJson(json, VpnProfile.class);
         } catch (Exception e) {
             e.printStackTrace();
         }
diff --git a/app/src/main/java/de/blinkt/openvpn/core/OpenVPNService.java b/app/src/main/java/de/blinkt/openvpn/core/OpenVPNService.java
index 0d4a8037..2c1a65dc 100644
--- a/app/src/main/java/de/blinkt/openvpn/core/OpenVPNService.java
+++ b/app/src/main/java/de/blinkt/openvpn/core/OpenVPNService.java
@@ -333,6 +333,7 @@ public class OpenVPNService extends VpnService implements StateListener, Callbac
 
         } else {
             /* The intent is null when we are set as always-on or the service has been restarted. */
+            Log.d(TAG, "Starting VPN due to isAlwaysOn system settings or app crash.");
             mProfile = VpnStatus.getLastConnectedVpnProfile(this);
             VpnStatus.logInfo(R.string.service_restarted);
 
diff --git a/app/src/main/java/de/blinkt/openvpn/core/connection/Connection.java b/app/src/main/java/de/blinkt/openvpn/core/connection/Connection.java
index a318e55d..4cb9c0c7 100644
--- a/app/src/main/java/de/blinkt/openvpn/core/connection/Connection.java
+++ b/app/src/main/java/de/blinkt/openvpn/core/connection/Connection.java
@@ -7,9 +7,12 @@ package de.blinkt.openvpn.core.connection;
 
 import android.text.TextUtils;
 
+import com.google.gson.annotations.JsonAdapter;
+
 import java.io.Serializable;
 import java.util.Locale;
 
+@JsonAdapter(ConnectionAdapter.class)
 public abstract class Connection implements Serializable, Cloneable {
     private String mServerName = "openvpn.example.com";
     private String mServerPort = "1194";
diff --git a/app/src/main/java/de/blinkt/openvpn/core/connection/ConnectionAdapter.java b/app/src/main/java/de/blinkt/openvpn/core/connection/ConnectionAdapter.java
new file mode 100644
index 00000000..335ef34c
--- /dev/null
+++ b/app/src/main/java/de/blinkt/openvpn/core/connection/ConnectionAdapter.java
@@ -0,0 +1,35 @@
+package de.blinkt.openvpn.core.connection;
+
+import com.google.gson.JsonDeserializationContext;
+import com.google.gson.JsonDeserializer;
+import com.google.gson.JsonElement;
+import com.google.gson.JsonObject;
+import com.google.gson.JsonParseException;
+import com.google.gson.JsonSerializationContext;
+import com.google.gson.JsonSerializer;
+
+import java.lang.reflect.Type;
+
+// Adapter for Gson used to serialize and deserialize abstract Connection class, adds a property about the implemented class
+public class ConnectionAdapter implements JsonSerializer<Connection>, JsonDeserializer<Connection> {
+
+    public final static String META_TYPE = ConnectionAdapter.class.getSimpleName() + ".META_TYPE";
+    @Override
+    public Connection deserialize(JsonElement json, Type typeOfT, JsonDeserializationContext context) throws JsonParseException {
+        JsonObject jsonObject = json.getAsJsonObject();
+        String className = jsonObject.get(META_TYPE).getAsString();
+        try {
+            Class<?> clz = Class.forName(className);
+            return context.deserialize(json, clz);
+        } catch (ClassNotFoundException e) {
+            throw new JsonParseException(e);
+        }
+    }
+
+    @Override
+    public JsonElement serialize(Connection src, Type typeOfSrc, JsonSerializationContext context) {
+         JsonElement json = context.serialize(src, src.getClass());
+         json.getAsJsonObject().addProperty(META_TYPE, src.getClass().getCanonicalName());
+         return json;
+    }
+}