#291 Server list caching

eduvpn · Aug 24, 2020 · 75c7232 · 75c7232
1 parent 47944cc
commit 75c7232
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Showing 5 changed files with 95 additions and 6 deletions.
diff --git a/app/src/main/java/nl/eduvpn/app/Constants.java b/app/src/main/java/nl/eduvpn/app/Constants.java
@@ -43,4 +43,6 @@ public class Constants {
 
     public static final Locale LOCALE = Locale.getDefault();
     public static final Locale ENGLISH_LOCALE = Locale.ENGLISH;
+
+    public static final long SERVER_LIST_VALID_FOR_MS = 3_600_000; // 1 hour
 }
diff --git a/app/src/main/java/nl/eduvpn/app/service/PreferencesService.java b/app/src/main/java/nl/eduvpn/app/service/PreferencesService.java
@@ -39,6 +39,7 @@
 import nl.eduvpn.app.entity.SavedAuthState;
 import nl.eduvpn.app.entity.SavedKeyPair;
 import nl.eduvpn.app.entity.SavedProfile;
+import nl.eduvpn.app.entity.ServerList;
 import nl.eduvpn.app.entity.Settings;
 import nl.eduvpn.app.utils.Log;
 
@@ -74,6 +75,9 @@ public class PreferencesService {
     @Deprecated
     static final String KEY_INSTANCE_LIST_INSTITUTE_ACCESS = KEY_INSTANCE_LIST_PREFIX + "institute_access";
 
+    static final String KEY_SERVER_LIST_DATA = "server_list_data";
+    static final String KEY_SERVER_LIST_TIMESTAMP = "server_list_timestamp";
+
 
     static final String KEY_SAVED_PROFILES = "saved_profiles";
     static final String KEY_SAVED_AUTH_STATES = "saved_auth_state";
@@ -625,4 +629,56 @@ public void setPreferredCountry(@Nullable String preferredCountry) {
             _getSharedPreferences().edit().putString(KEY_PREFERRED_COUNTRY, preferredCountry).apply();
         }
     }
+
+    /**
+     * Returns the server list if it is recent (see constants for exact TTL).
+     *
+     * @return The server list if it is recent, otherwise null.
+     */
+    @Nullable
+    public ServerList getServerList() {
+        long timestamp = _getSharedPreferences().getLong(KEY_SERVER_LIST_TIMESTAMP, 0L);
+        if (System.currentTimeMillis() - timestamp < Constants.SERVER_LIST_VALID_FOR_MS) {
+            String serializedServerList = _getSharedPreferences().getString(KEY_SERVER_LIST_DATA, null);
+            if (serializedServerList == null) {
+                return null;
+            }
+            try {
+                return _serializerService.deserializeServerList(new JSONObject(serializedServerList));
+            } catch (Exception ex) {
+                Log.w(TAG, "Unable to parse server list!", ex);
+                return null;
+            }
+        } else {
+            _getSharedPreferences().edit()
+                    .remove(KEY_SERVER_LIST_DATA)
+                    .remove(KEY_SERVER_LIST_TIMESTAMP)
+                    .apply();
+            return null;
+        }
+    }
+
+    /**
+     * Caches the server list. Only valid for a set amount, see constants for the exact TTL.
+     *
+     * @param serverList The server list to cache. Use null to remove previously set values.
+     */
+    public void setServerList(@Nullable ServerList serverList) {
+        if (serverList == null) {
+            _getSharedPreferences().edit().remove(KEY_SERVER_LIST_DATA)
+                    .remove(KEY_SERVER_LIST_TIMESTAMP)
+                    .apply();
+        } else {
+            try {
+                String serializedServerList = _serializerService.serializeServerList(serverList).toString();
+                _getSharedPreferences().edit()
+                        .putString(KEY_SERVER_LIST_DATA, serializedServerList)
+                        .putLong(KEY_SERVER_LIST_TIMESTAMP, System.currentTimeMillis())
+                        .apply();
+            } catch (Exception ex) {
+                Log.w(TAG, "Unable to set server list!");
+            }
+
+        }
+    }
 }
diff --git a/app/src/main/java/nl/eduvpn/app/service/SerializerService.java b/app/src/main/java/nl/eduvpn/app/service/SerializerService.java
@@ -17,7 +17,6 @@
 
 package nl.eduvpn.app.service;
 
-import android.text.TextUtils;
 import android.util.Pair;
 
 import net.openid.appauth.AuthState;
@@ -30,7 +29,6 @@
 import java.text.ParseException;
 import java.text.SimpleDateFormat;
 import java.util.ArrayList;
-import java.util.Arrays;
 import java.util.Date;
 import java.util.HashMap;
 import java.util.Iterator;
@@ -40,7 +38,6 @@
 import java.util.TimeZone;
 
 import androidx.annotation.NonNull;
-import androidx.annotation.Nullable;
 import nl.eduvpn.app.Constants;
 import nl.eduvpn.app.entity.AuthorizationType;
 import nl.eduvpn.app.entity.DiscoveredAPI;
@@ -104,7 +101,7 @@ public JSONObject serializeProfileList(@NonNull List<Profile> profileList) throw
         try {
             result.put("profile_list", data);
             data.put("data", array);
-        }catch (JSONException ex) {
+        } catch (JSONException ex) {
             throw new UnknownFormatException("Unable to create nested object for serialized profile list!");
         }
         return result;
@@ -974,6 +971,30 @@ public ServerList deserializeServerList(JSONObject jsonObject) throws UnknownFor
         }
     }
 
+    /**
+     * Serializes the server list to JSON format
+     *
+     * @param serverList The server list to serialize.
+     * @return The server list as a JSON object.
+     * @throws UnknownFormatException Thrown if there was an error while deserializing.
+     */
+    public JSONObject serializeServerList(ServerList serverList) throws UnknownFormatException {
+        try {
+            JSONObject output = new JSONObject();
+            JSONArray itemsList = new JSONArray();
+
+            output.put("server_list", itemsList);
+            output.put("v", serverList.getVersion());
+            for (int i = 0; i < serverList.getServerList().size(); ++i) {
+                JSONObject serializedItem = serializeInstance(serverList.getServerList().get(i));
+                itemsList.put(serializedItem);
+            }
+            return output;
+        } catch (JSONException ex) {
+            throw new UnknownFormatException(ex);
+        }
+    }
+
     /**
      * Returns the language of the user in a specific "country-language" format.
      *
@@ -986,6 +1007,7 @@ private String _getUserLanguage() {
 
     /**
      * Retrieves the translations from a JSON object.
+     *
      * @param translationsObject The JSON object to retrieve the translations from.
      * @return A TranslatableString instance.
      * @throws JSONException Thrown if the input is in an unexpected format.

diff --git a/app/src/main/java/nl/eduvpn/app/viewmodel/OrganizationSelectionViewModel.kt b/app/src/main/java/nl/eduvpn/app/viewmodel/OrganizationSelectionViewModel.kt
@@ -68,8 +68,14 @@ class OrganizationSelectionViewModel @Inject constructor(
             state.value = ConnectionState.FetchingServerList
             Single.just(OrganizationList(-1L, emptyList()))
         }
+        val cachedServerList = preferencesService.serverList
+        val getServerListCall = if (cachedServerList != null) {
+            Single.just(cachedServerList)
+        } else {
+            organizationService.fetchServerList()
+        }
         disposables.add(
-                Single.zip(getOrganizationsCall, organizationService.fetchServerList(), BiFunction { orgList: OrganizationList, serverList: ServerList ->
+                Single.zip(getOrganizationsCall, getServerListCall, BiFunction { orgList: OrganizationList, serverList: ServerList ->
                     Pair(orgList, serverList)
                 }).subscribe({ organizationServerListPair ->
                     val organizationList = organizationServerListPair.first

diff --git a/app/src/main/java/nl/eduvpn/app/viewmodel/ServerSelectionViewModel.kt b/app/src/main/java/nl/eduvpn/app/viewmodel/ServerSelectionViewModel.kt
@@ -24,7 +24,6 @@ import nl.eduvpn.app.R
 import nl.eduvpn.app.adapter.OrganizationAdapter
 import nl.eduvpn.app.entity.AuthorizationType
 import nl.eduvpn.app.entity.Instance
-import nl.eduvpn.app.entity.Organization
 import nl.eduvpn.app.entity.ServerList
 import nl.eduvpn.app.service.APIService
 import nl.eduvpn.app.service.ConnectionService
@@ -63,6 +62,9 @@ class ServerSelectionViewModel @Inject constructor(
 
     init {
         historyService.addObserver(this)
+        preferencesService.serverList?.let { serverList ->
+            serverListCache.value = Pair(System.currentTimeMillis(), serverList)
+        }
     }
 
     override fun onCleared() {
@@ -94,6 +96,7 @@ class ServerSelectionViewModel @Inject constructor(
                 .subscribe({
                     Log.v(TAG, "Updated server list with latest entries.")
                     serverListCache.value = Pair(System.currentTimeMillis(), it)
+                    preferencesService.serverList = it
                     refreshInstances(it)
                 }, {
                     Log.w(TAG, "Unable to fetch server list. Trying to show servers without it.", it)