Add Flipper network interceptors

app/src/debug/java/org/tasks/BuildSetup.java

@@ -9,6 +9,7 @@ import com.facebook.flipper.core.FlipperClient;
 import com.facebook.flipper.plugins.databases.DatabasesFlipperPlugin;
 import com.facebook.flipper.plugins.inspector.DescriptorMapping;
 import com.facebook.flipper.plugins.inspector.InspectorFlipperPlugin;
+import com.facebook.flipper.plugins.network.NetworkFlipperPlugin;
 import com.facebook.flipper.plugins.sharedpreferences.SharedPreferencesFlipperPlugin;
 import com.facebook.soloader.SoLoader;
 import com.squareup.leakcanary.LeakCanary;
@@ -35,6 +36,7 @@ public class BuildSetup {
       FlipperClient client = AndroidFlipperClient.getInstance(context);
       client.addPlugin(new InspectorFlipperPlugin(context, DescriptorMapping.withDefaults()));
       client.addPlugin(new DatabasesFlipperPlugin(context));
+      client.addPlugin(new NetworkFlipperPlugin());
       client.addPlugin(new SharedPreferencesFlipperPlugin(context));
       client.start();
     }

app/src/debug/java/org/tasks/ChainedHttpExecuteInterceptor.java

@@ -0,0 +1,21 @@
+package org.tasks;
+
+import com.google.api.client.http.HttpExecuteInterceptor;
+import com.google.api.client.http.HttpRequest;
+import java.io.IOException;
+
+public class ChainedHttpExecuteInterceptor implements HttpExecuteInterceptor {
+
+  private final HttpExecuteInterceptor[] interceptors;
+
+  ChainedHttpExecuteInterceptor(HttpExecuteInterceptor... interceptors) {
+    this.interceptors = interceptors;
+  }
+
+  @Override
+  public void intercept(HttpRequest request) throws IOException {
+    for (HttpExecuteInterceptor interceptor : interceptors) {
+      interceptor.intercept(request);
+    }
+  }
+}

app/src/debug/java/org/tasks/DebugNetworkInterceptor.java

@@ -0,0 +1,39 @@
+package org.tasks;
+
+import android.content.Context;
+import com.facebook.flipper.android.AndroidFlipperClient;
+import com.facebook.flipper.plugins.network.FlipperOkhttpInterceptor;
+import com.facebook.flipper.plugins.network.NetworkFlipperPlugin;
+import com.google.api.client.http.HttpRequest;
+import java.io.IOException;
+import javax.inject.Inject;
+import okhttp3.OkHttpClient;
+import org.tasks.injection.ForApplication;
+
+public class DebugNetworkInterceptor {
+
+  private final Context context;
+
+  @Inject
+  public DebugNetworkInterceptor(@ForApplication Context context) {
+    this.context = context;
+  }
+
+  private static NetworkFlipperPlugin getNetworkPlugin(Context context) {
+    return AndroidFlipperClient.getInstance(context).getPlugin(NetworkFlipperPlugin.ID);
+  }
+
+  public void add(OkHttpClient.Builder builder) {
+    builder.addNetworkInterceptor(new FlipperOkhttpInterceptor(getNetworkPlugin(context)));
+  }
+
+  public <T> T execute(HttpRequest request, Class<T> responseClass) throws IOException {
+    FlipperHttpInterceptor<T> interceptor =
+        new FlipperHttpInterceptor<>(getNetworkPlugin(context), responseClass);
+    request
+        .setInterceptor(new ChainedHttpExecuteInterceptor(request.getInterceptor(), interceptor))
+        .setResponseInterceptor(interceptor)
+        .execute();
+    return interceptor.getResponse();
+  }
+}

app/src/debug/java/org/tasks/FlipperHttpInterceptor.java

@@ -0,0 +1,92 @@
+package org.tasks;
+
+import static com.todoroo.andlib.utility.DateUtilities.now;
+
+import com.facebook.flipper.plugins.network.NetworkFlipperPlugin;
+import com.facebook.flipper.plugins.network.NetworkReporter.Header;
+import com.facebook.flipper.plugins.network.NetworkReporter.RequestInfo;
+import com.facebook.flipper.plugins.network.NetworkReporter.ResponseInfo;
+import com.google.api.client.http.HttpContent;
+import com.google.api.client.http.HttpExecuteInterceptor;
+import com.google.api.client.http.HttpHeaders;
+import com.google.api.client.http.HttpRequest;
+import com.google.api.client.http.HttpResponse;
+import com.google.api.client.http.HttpResponseInterceptor;
+import com.google.api.client.json.GenericJson;
+import com.todoroo.astrid.helper.UUIDHelper;
+import java.io.ByteArrayOutputStream;
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Map;
+import timber.log.Timber;
+
+public class FlipperHttpInterceptor<T> implements HttpExecuteInterceptor, HttpResponseInterceptor {
+
+  private final Class<T> responseClass;
+  private final String requestId = UUIDHelper.newUUID();
+  private final NetworkFlipperPlugin plugin;
+  private T body;
+
+  FlipperHttpInterceptor(NetworkFlipperPlugin plugin, Class<T> responseClass) {
+    this.responseClass = responseClass;
+    this.plugin = plugin;
+  }
+
+  @Override
+  public void intercept(HttpRequest request) {
+    RequestInfo requestInfo = new RequestInfo();
+    requestInfo.method = request.getRequestMethod();
+    requestInfo.body = bodyToByteArray(request.getContent());
+    requestInfo.headers = getHeaders(request.getHeaders());
+    requestInfo.requestId = requestId;
+    requestInfo.timeStamp = now();
+    requestInfo.uri = request.getUrl().toString();
+    plugin.reportRequest(requestInfo);
+  }
+
+  @Override
+  public void interceptResponse(HttpResponse response) throws IOException {
+    ResponseInfo responseInfo = new ResponseInfo();
+    responseInfo.timeStamp = now();
+    responseInfo.headers = getHeaders(response.getHeaders());
+    responseInfo.requestId = requestId;
+    responseInfo.statusCode = response.getStatusCode();
+    responseInfo.statusReason = response.getStatusMessage();
+    body = response.parseAs(responseClass);
+    if (body instanceof GenericJson) {
+      try {
+        responseInfo.body = ((GenericJson) body).toPrettyString().getBytes();
+      } catch (IOException e) {
+        Timber.e(e);
+      }
+    }
+    plugin.reportResponse(responseInfo);
+  }
+
+  public T getResponse() {
+    return body;
+  }
+
+  private List<Header> getHeaders(HttpHeaders headers) {
+    List<Header> result = new ArrayList<>();
+    for (Map.Entry<String, Object> entry : headers.entrySet()) {
+      result.add(new Header(entry.getKey(), entry.getValue().toString()));
+    }
+    return result;
+  }
+
+  private byte[] bodyToByteArray(HttpContent content) {
+    if (content == null) {
+      return null;
+    }
+    ByteArrayOutputStream output = new ByteArrayOutputStream();
+    try {
+      content.writeTo(output);
+    } catch (IOException e) {
+      Timber.e(e);
+      return null;
+    }
+    return output.toByteArray();
+  }
+}

app/src/main/java/com/todoroo/astrid/gtasks/api/GtasksInvoker.java

@@ -1,10 +1,11 @@
 package com.todoroo.astrid.gtasks.api;
 
 import android.accounts.AccountManager;
+import android.content.Context;
 import android.os.Bundle;
 import androidx.annotation.Nullable;
 import com.google.api.client.googleapis.auth.oauth2.GoogleCredential;
-import com.google.api.client.googleapis.services.AbstractGoogleClientRequest;
+import com.google.api.client.http.HttpRequest;
 import com.google.api.client.http.HttpResponseException;
 import com.google.api.client.http.javanet.NetHttpTransport;
 import com.google.api.client.json.GenericJson;
@@ -16,10 +17,13 @@ import com.google.api.services.tasks.model.Task;
 import com.google.api.services.tasks.model.TaskList;
 import com.google.api.services.tasks.model.TaskLists;
 import com.google.common.base.Strings;
-import com.google.gson.GsonBuilder;
 import java.io.IOException;
+import javax.inject.Inject;
 import org.tasks.BuildConfig;
+import org.tasks.DebugNetworkInterceptor;
 import org.tasks.gtasks.GoogleAccountManager;
+import org.tasks.injection.ForApplication;
+import org.tasks.preferences.Preferences;
 import timber.log.Timber;
 
 /**
@@ -30,20 +34,50 @@ import timber.log.Timber;
  */
 public class GtasksInvoker {
 
-  private final String account;
+  private final Context context;
   private final GoogleAccountManager googleAccountManager;
-  private final Tasks service;
+  private final Preferences preferences;
+  private final DebugNetworkInterceptor interceptor;
   private final GoogleCredential credential = new GoogleCredential();
+  private final String account;
+  private final Tasks service;
 
-  public GtasksInvoker(String account, GoogleAccountManager googleAccountManager) {
+  @Inject
-    this.account = account;
+  public GtasksInvoker(
+      @ForApplication Context context,
+      GoogleAccountManager googleAccountManager,
+      Preferences preferences,
+      DebugNetworkInterceptor interceptor) {
+    this.context = context;
+    this.googleAccountManager = googleAccountManager;
+    this.preferences = preferences;
+    this.interceptor = interceptor;
+    account = null;
+    service = null;
+  }
+
+  private GtasksInvoker(
+      Context context,
+      GoogleAccountManager googleAccountManager,
+      Preferences preferences,
+      DebugNetworkInterceptor interceptor,
+      String account) {
+    this.context = context;
     this.googleAccountManager = googleAccountManager;
+    this.preferences = preferences;
+    this.interceptor = interceptor;
+    this.account = account;
+
     service =
         new Tasks.Builder(new NetHttpTransport(), new JacksonFactory(), credential)
             .setApplicationName(String.format("Tasks/%s", BuildConfig.VERSION_NAME))
             .build();
   }
 
+  public GtasksInvoker forAccount(String account) {
+    return new GtasksInvoker(context, googleAccountManager, preferences, interceptor, account);
+  }
+
   private void checkToken() {
     if (Strings.isNullOrEmpty(credential.getAccessToken())) {
       Bundle bundle = googleAccountManager.getAccessToken(account, TasksScopes.TASKS);
@@ -115,10 +149,15 @@ public class GtasksInvoker {
   private synchronized @Nullable <T> T execute(TasksRequest<T> request, boolean retry)
       throws IOException {
     checkToken();
-    Timber.d("%s request: %s", getCaller(retry), prettyPrint(request));
     T response;
     try {
-      response = request.execute();
+      HttpRequest httpRequest = request.buildHttpRequest();
+      Timber.d("%s", httpRequest.getUrl());
+      if (preferences.isFlipperEnabled()) {
+        response = interceptor.execute(httpRequest, request.getResponseClass());
+      } else {
+        response = httpRequest.execute().parseAs(request.getResponseClass());
+      }
     } catch (HttpResponseException e) {
       if (e.getStatusCode() == 401 && !retry) {
         googleAccountManager.invalidateToken(credential.getAccessToken());
@@ -136,8 +175,6 @@ public class GtasksInvoker {
     if (BuildConfig.DEBUG) {
       if (object instanceof GenericJson) {
         return ((GenericJson) object).toPrettyString();
-      } else if (object instanceof AbstractGoogleClientRequest) {
-        return new GsonBuilder().setPrettyPrinting().create().toJson(object);
       }
     }
     return object;

app/src/main/java/org/tasks/activities/AddCaldavAccountViewModel.java

@@ -4,7 +4,7 @@ import org.tasks.caldav.CaldavClient;
 import org.tasks.ui.CompletableViewModel;
 
 public class AddCaldavAccountViewModel extends CompletableViewModel<String> {
-  public void addAccount(String url, String username, String password) {
+  public void addAccount(CaldavClient client, String url, String username, String password) {
-    run(() -> new CaldavClient(url, username, password).getHomeSet());
+    run(() -> client.forUrl(url, username, password).getHomeSet());
   }
 }

app/src/main/java/org/tasks/activities/CreateCalendarViewModel.java

@@ -2,11 +2,10 @@ package org.tasks.activities;
 
 import org.tasks.caldav.CaldavClient;
 import org.tasks.data.CaldavAccount;
-import org.tasks.security.Encryption;
 import org.tasks.ui.CompletableViewModel;
 
 public class CreateCalendarViewModel extends CompletableViewModel<String> {
-  public void createCalendar(CaldavAccount caldavAccount, Encryption encryption, String name) {
+  public void createCalendar(CaldavClient client, CaldavAccount account, String name) {
-    run(() -> new CaldavClient(caldavAccount, encryption).makeCollection(name));
+    run(() -> client.forAccount(account).makeCollection(name));
   }
 }

app/src/main/java/org/tasks/activities/CreateListViewModel.java

@@ -2,12 +2,11 @@ package org.tasks.activities;
 
 import com.google.api.services.tasks.model.TaskList;
 import com.todoroo.astrid.gtasks.api.GtasksInvoker;
-import org.tasks.gtasks.GoogleAccountManager;
 import org.tasks.ui.CompletableViewModel;
 
 @SuppressWarnings("WeakerAccess")
 public class CreateListViewModel extends CompletableViewModel<TaskList> {
-  void createList(GoogleAccountManager googleAccountManager, String account, String name) {
+  void createList(GtasksInvoker invoker, String account, String name) {
-    run(() -> new GtasksInvoker(account, googleAccountManager).createGtaskList(name));
+    run(() -> invoker.forAccount(account).createGtaskList(name));
   }
 }

app/src/main/java/org/tasks/activities/DeleteCalendarViewModel.java

@@ -3,12 +3,10 @@ package org.tasks.activities;
 import org.tasks.caldav.CaldavClient;
 import org.tasks.data.CaldavAccount;
 import org.tasks.data.CaldavCalendar;
-import org.tasks.security.Encryption;
 import org.tasks.ui.ActionViewModel;
 
 public class DeleteCalendarViewModel extends ActionViewModel {
-  public void deleteCalendar(
+  public void deleteCalendar(CaldavClient client, CaldavAccount account, CaldavCalendar calendar) {
-      CaldavAccount caldavAccount, Encryption encryption, CaldavCalendar calendar) {
+    run(() -> client.forCalendar(account, calendar).deleteCollection());
-    run(() -> new CaldavClient(caldavAccount, calendar, encryption).deleteCollection());
   }
 }

app/src/main/java/org/tasks/activities/DeleteListViewModel.java

@@ -2,12 +2,11 @@ package org.tasks.activities;
 
 import com.todoroo.astrid.gtasks.api.GtasksInvoker;
 import org.tasks.data.GoogleTaskList;
-import org.tasks.gtasks.GoogleAccountManager;
 import org.tasks.ui.ActionViewModel;
 
 @SuppressWarnings("WeakerAccess")
 public class DeleteListViewModel extends ActionViewModel {
-  void deleteList(GoogleAccountManager googleAccountManager, GoogleTaskList list) {
+  void deleteList(GtasksInvoker invoker, GoogleTaskList list) {
-    run(() -> new GtasksInvoker(list.getAccount(), googleAccountManager).deleteGtaskList(list.getRemoteId()));
+    run(() -> invoker.forAccount(list.getAccount()).deleteGtaskList(list.getRemoteId()));
   }
 }

app/src/main/java/org/tasks/activities/GoogleTaskListSettingsActivity.java

@@ -24,6 +24,7 @@ import com.todoroo.astrid.activity.MainActivity;
 import com.todoroo.astrid.activity.TaskListFragment;
 import com.todoroo.astrid.api.GtasksFilter;
 import com.todoroo.astrid.gtasks.GtasksListService;
+import com.todoroo.astrid.gtasks.api.GtasksInvoker;
 import com.todoroo.astrid.service.TaskDeleter;
 import javax.inject.Inject;
 import org.tasks.R;
@@ -59,7 +60,7 @@ public class GoogleTaskListSettingsActivity extends ThemedInjectingAppCompatActi
   @Inject ThemeCache themeCache;
   @Inject ThemeColor themeColor;
   @Inject TaskDeleter taskDeleter;
-  @Inject GoogleAccountManager googleAccountManager;
+  @Inject GtasksInvoker gtasksInvoker;
 
   @BindView(R.id.name)
   TextInputEditText name;
@@ -206,10 +207,10 @@ public class GoogleTaskListSettingsActivity extends ThemedInjectingAppCompatActi
 
     if (isNewList) {
       showProgressIndicator();
-      createListViewModel.createList(googleAccountManager, gtasksList.getAccount(), newName);
+      createListViewModel.createList(gtasksInvoker, gtasksList.getAccount(), newName);
     } else if (nameChanged()) {
       showProgressIndicator();
-      renameListViewModel.renameList(googleAccountManager, gtasksList, newName);
+      renameListViewModel.renameList(gtasksInvoker, gtasksList, newName);
     } else {
       if (colorChanged()) {
         gtasksList.setColor(selectedTheme);
@@ -250,7 +251,7 @@ public class GoogleTaskListSettingsActivity extends ThemedInjectingAppCompatActi
             R.string.delete,
             (dialog, which) -> {
               showProgressIndicator();
-              deleteListViewModel.deleteList(googleAccountManager, gtasksList);
+              deleteListViewModel.deleteList(gtasksInvoker, gtasksList);
             })
         .setNegativeButton(android.R.string.cancel, null)
         .show();

app/src/main/java/org/tasks/activities/RenameListViewModel.java

@@ -3,15 +3,11 @@ package org.tasks.activities;
 import com.google.api.services.tasks.model.TaskList;
 import com.todoroo.astrid.gtasks.api.GtasksInvoker;
 import org.tasks.data.GoogleTaskList;
-import org.tasks.gtasks.GoogleAccountManager;
 import org.tasks.ui.CompletableViewModel;
 
 @SuppressWarnings("WeakerAccess")
 public class RenameListViewModel extends CompletableViewModel<TaskList> {
-  void renameList(GoogleAccountManager googleAccountManager, GoogleTaskList list, String name) {
+  void renameList(GtasksInvoker invoker, GoogleTaskList list, String name) {
-    run(
+    run(() -> invoker.forAccount(list.getAccount()).renameGtaskList(list.getRemoteId(), name));
-        () ->
-            new GtasksInvoker(list.getAccount(), googleAccountManager)
-                .renameGtaskList(list.getRemoteId(), name));
   }
 }

app/src/main/java/org/tasks/activities/UpdateCaldavAccountViewModel.java

@@ -4,7 +4,8 @@ import org.tasks.caldav.CaldavClient;
 import org.tasks.ui.CompletableViewModel;
 
 public class UpdateCaldavAccountViewModel extends CompletableViewModel<String> {
-  public void updateCaldavAccount(String url, String username, String password) {
+  public void updateCaldavAccount(
-    run(() -> new CaldavClient(url, username, password).getHomeSet());
+      CaldavClient client, String url, String username, String password) {
+    run(() -> client.forUrl(url, username, password).getHomeSet());
   }
 }

app/src/main/java/org/tasks/caldav/CaldavAccountSettingsActivity.java

@@ -38,6 +38,7 @@ import org.tasks.data.CaldavAccount;
 import org.tasks.data.CaldavDao;
 import org.tasks.dialogs.DialogBuilder;
 import org.tasks.injection.ActivityComponent;
+import org.tasks.injection.ForApplication;
 import org.tasks.injection.ThemedInjectingAppCompatActivity;
 import org.tasks.preferences.Preferences;
 import org.tasks.security.Encryption;
@@ -51,6 +52,7 @@ public class CaldavAccountSettingsActivity extends ThemedInjectingAppCompatActiv
 
   public static final String EXTRA_CALDAV_DATA = "caldavData"; // $NON-NLS-1$
   private static final String PASSWORD_MASK = "\u2022\u2022\u2022\u2022\u2022\u2022\u2022\u2022";
+  @Inject @ForApplication Context context;
   @Inject DialogBuilder dialogBuilder;
   @Inject Preferences preferences;
   @Inject Tracker tracker;
@@ -58,6 +60,7 @@ public class CaldavAccountSettingsActivity extends ThemedInjectingAppCompatActiv
   @Inject SyncAdapters syncAdapters;
   @Inject TaskDeleter taskDeleter;
   @Inject Encryption encryption;
+  @Inject CaldavClient client;
 
   @BindView(R.id.root_layout)
   LinearLayout root;
@@ -296,10 +299,10 @@ public class CaldavAccountSettingsActivity extends ThemedInjectingAppCompatActiv
 
     if (caldavAccount == null) {
       showProgressIndicator();
-      addCaldavAccountViewModel.addAccount(url, username, password);
+      addCaldavAccountViewModel.addAccount(client, url, username, password);
     } else if (needsValidation()) {
       showProgressIndicator();
-      updateCaldavAccountViewModel.updateCaldavAccount(url, username, password);
+      updateCaldavAccountViewModel.updateCaldavAccount(client, url, username, password);
     } else if (hasChanges()) {
       updateAccount(caldavAccount.getUrl());
     } else {

app/src/main/java/org/tasks/caldav/CaldavCalendarSettingsActivity.java

@@ -43,9 +43,9 @@ import org.tasks.data.CaldavCalendar;
 import org.tasks.data.CaldavDao;
 import org.tasks.dialogs.DialogBuilder;
 import org.tasks.injection.ActivityComponent;
+import org.tasks.injection.ForApplication;
 import org.tasks.injection.ThemedInjectingAppCompatActivity;
 import org.tasks.preferences.Preferences;
-import org.tasks.security.Encryption;
 import org.tasks.sync.SyncAdapters;
 import org.tasks.themes.ThemeCache;
 import org.tasks.themes.ThemeColor;
@@ -59,6 +59,7 @@ public class CaldavCalendarSettingsActivity extends ThemedInjectingAppCompatActi
   public static final String EXTRA_CALDAV_ACCOUNT = "extra_caldav_account";
   private static final String EXTRA_SELECTED_THEME = "extra_selected_theme";
   private static final int REQUEST_COLOR_PICKER = 10109;
+  @Inject @ForApplication Context context;
   @Inject DialogBuilder dialogBuilder;
   @Inject Preferences preferences;
   @Inject ThemeCache themeCache;
@@ -66,8 +67,8 @@ public class CaldavCalendarSettingsActivity extends ThemedInjectingAppCompatActi
   @Inject Tracker tracker;
   @Inject CaldavDao caldavDao;
   @Inject SyncAdapters syncAdapters;
-  @Inject Encryption encryption;
   @Inject TaskDeleter taskDeleter;
+  @Inject CaldavClient client;
 
   @BindView(R.id.root_layout)
   LinearLayout root;
@@ -223,7 +224,7 @@ public class CaldavCalendarSettingsActivity extends ThemedInjectingAppCompatActi
 
     if (caldavCalendar == null) {
       showProgressIndicator();
-      createCalendarViewModel.createCalendar(caldavAccount, encryption, name);
+      createCalendarViewModel.createCalendar(client, caldavAccount, name);
     } else if (hasChanges()) {
       updateAccount();
     } else {
@@ -393,7 +394,7 @@ public class CaldavCalendarSettingsActivity extends ThemedInjectingAppCompatActi
             R.string.delete,
             (dialog, which) -> {
               showProgressIndicator();
-              deleteCalendarViewModel.deleteCalendar(caldavAccount, encryption, caldavCalendar);
+              deleteCalendarViewModel.deleteCalendar(client, caldavAccount, caldavCalendar);
             })
         .setNegativeButton(android.R.string.cancel, null)
         .show();

app/src/main/java/org/tasks/caldav/CaldavClient.java

@@ -6,6 +6,7 @@ import static at.bitfire.dav4android.XmlUtils.NS_CARDDAV;
 import static at.bitfire.dav4android.XmlUtils.NS_WEBDAV;
 import static java.util.Arrays.asList;
 
+import android.content.Context;
 import at.bitfire.dav4android.BasicDigestAuthHandler;
 import at.bitfire.dav4android.DavResource;
 import at.bitfire.dav4android.DavResponse;
@@ -24,11 +25,16 @@ import java.io.StringWriter;
 import java.util.ArrayList;
 import java.util.List;
 import java.util.concurrent.TimeUnit;
+import javax.inject.Inject;
 import okhttp3.HttpUrl;
 import okhttp3.OkHttpClient;
+import okhttp3.OkHttpClient.Builder;
+import org.tasks.DebugNetworkInterceptor;
 import org.tasks.R;
 import org.tasks.data.CaldavAccount;
 import org.tasks.data.CaldavCalendar;
+import org.tasks.injection.ForApplication;
+import org.tasks.preferences.Preferences;
 import org.tasks.security.Encryption;
 import org.tasks.ui.DisplayableException;
 import org.xmlpull.v1.XmlPullParserException;
@@ -38,28 +44,43 @@ import timber.log.Timber;
 
 public class CaldavClient {
 
+  private final Context context;
+  private final Encryption encryption;
+  private final Preferences preferences;
+  private final DebugNetworkInterceptor interceptor;
   private final OkHttpClient httpClient;
   private final HttpUrl httpUrl;
 
-  public CaldavClient(CaldavAccount caldavAccount, Encryption encryption) {
+  @Inject
-    this(
-        caldavAccount.getUrl(),
-        caldavAccount.getUsername(),
-        encryption.decrypt(caldavAccount.getPassword()));
-  }
-
   public CaldavClient(
-      CaldavAccount caldavAccount, CaldavCalendar caldavCalendar, Encryption encryption) {
+      @ForApplication Context context,
-    this(
+      Encryption encryption,
-        caldavCalendar.getUrl(),
+      Preferences preferences,
-        caldavAccount.getUsername(),
+      DebugNetworkInterceptor interceptor) {
-        encryption.decrypt(caldavAccount.getPassword()));
+    this.context = context;
+    this.encryption = encryption;
+    this.preferences = preferences;
+    this.interceptor = interceptor;
+    httpClient = null;
+    httpUrl = null;
   }
 
-  public CaldavClient(String url, String username, String password) {
+  private CaldavClient(
+      Context context,
+      Encryption encryption,
+      Preferences preferences,
+      DebugNetworkInterceptor interceptor,
+      String url,
+      String username,
+      String password) {
+    this.context = context;
+    this.encryption = encryption;
+    this.preferences = preferences;
+    this.interceptor = interceptor;
+
     BasicDigestAuthHandler basicDigestAuthHandler =
         new BasicDigestAuthHandler(null, username, password);
-    httpClient =
+    Builder builder =
         new OkHttpClient()
             .newBuilder()
             .addNetworkInterceptor(basicDigestAuthHandler)
@@ -67,11 +88,26 @@ public class CaldavClient {
             .cookieJar(new MemoryCookieStore())
             .followRedirects(false)
             .followSslRedirects(true)
-            .readTimeout(30, TimeUnit.SECONDS)
+            .readTimeout(30, TimeUnit.SECONDS);
-            .build();
+    if (preferences.isFlipperEnabled()) {
+      interceptor.add(builder);
+    }
+    httpClient = builder.build();
     httpUrl = HttpUrl.parse(url);
   }
 
+  public CaldavClient forAccount(CaldavAccount account) {
+    return forUrl(account.getUrl(), account.getUsername(), account.getPassword(encryption));
+  }
+
+  public CaldavClient forCalendar(CaldavAccount account, CaldavCalendar calendar) {
+    return forUrl(calendar.getUrl(), account.getUsername(), account.getPassword(encryption));
+  }
+
+  public CaldavClient forUrl(String url, String username, String password) {
+    return new CaldavClient(context, encryption, preferences, interceptor, url, username, password);
+  }
+
   private String tryFindPrincipal() throws DavException, IOException {
     for (String link : asList("", "/.well-known/caldav")) {
       HttpUrl url = httpUrl.resolve(link);

app/src/main/java/org/tasks/caldav/CaldavSynchronizer.java

@@ -54,7 +54,6 @@ import org.tasks.data.CaldavCalendar;
 import org.tasks.data.CaldavDao;
 import org.tasks.data.CaldavTask;
 import org.tasks.injection.ForApplication;
-import org.tasks.security.Encryption;
 import timber.log.Timber;
 
 public class CaldavSynchronizer {
@@ -69,9 +68,9 @@ public class CaldavSynchronizer {
   private final LocalBroadcastManager localBroadcastManager;
   private final TaskCreator taskCreator;
   private final TaskDeleter taskDeleter;
-  private final Encryption encryption;
   private final Inventory inventory;
   private final Tracker tracker;
+  private final CaldavClient client;
   private final Context context;
 
   @Inject
@@ -82,18 +81,18 @@ public class CaldavSynchronizer {
       LocalBroadcastManager localBroadcastManager,
       TaskCreator taskCreator,
       TaskDeleter taskDeleter,
-      Encryption encryption,
       Inventory inventory,
-      Tracker tracker) {
+      Tracker tracker,
+      CaldavClient client) {
     this.context = context;
     this.caldavDao = caldavDao;
     this.taskDao = taskDao;
     this.localBroadcastManager = localBroadcastManager;
     this.taskCreator = taskCreator;
     this.taskDeleter = taskDeleter;
-    this.encryption = encryption;
     this.inventory = inventory;
     this.tracker = tracker;
+    this.client = client;
   }
 
   public void sync() {
@@ -108,7 +107,7 @@ public class CaldavSynchronizer {
         setError(account, context.getString(R.string.password_required));
         continue;
       }
-      CaldavClient caldavClient = new CaldavClient(account, encryption);
+      CaldavClient caldavClient = client.forAccount(account);
       List<DavResponse> resources;
       try {
         resources = caldavClient.getCalendars();

app/src/main/java/org/tasks/data/CaldavAccount.java

@@ -8,6 +8,7 @@ import androidx.room.ColumnInfo;
 import androidx.room.Entity;
 import androidx.room.Ignore;
 import androidx.room.PrimaryKey;
+import org.tasks.security.Encryption;
 
 @Entity(tableName = "caldav_account")
 public class CaldavAccount implements Parcelable {
@@ -109,6 +110,10 @@ public class CaldavAccount implements Parcelable {
     this.password = password;
   }
 
+  public String getPassword(Encryption encryption) {
+    return encryption.decrypt(password);
+  }
+
   public String getError() {
     return error;
   }

app/src/main/java/org/tasks/gtasks/GoogleTaskSynchronizer.java

@@ -78,6 +78,7 @@ public class GoogleTaskSynchronizer {
   private final LocalBroadcastManager localBroadcastManager;
   private final Inventory inventory;
   private final TaskDeleter taskDeleter;
+  private final GtasksInvoker gtasksInvoker;
 
   @Inject
   public GoogleTaskSynchronizer(
@@ -95,7 +96,8 @@ public class GoogleTaskSynchronizer {
       GoogleAccountManager googleAccountManager,
       LocalBroadcastManager localBroadcastManager,
       Inventory inventory,
-      TaskDeleter taskDeleter) {
+      TaskDeleter taskDeleter,
+      GtasksInvoker gtasksInvoker) {
     this.context = context;
     this.googleTaskListDao = googleTaskListDao;
     this.gtasksListService = gtasksListService;
@@ -111,6 +113,7 @@ public class GoogleTaskSynchronizer {
     this.localBroadcastManager = localBroadcastManager;
     this.inventory = inventory;
     this.taskDeleter = taskDeleter;
+    this.gtasksInvoker = gtasksInvoker;
   }
 
   public static void mergeDates(long remoteDueDate, Task local) {
@@ -182,7 +185,7 @@ public class GoogleTaskSynchronizer {
       return;
     }
 
-    GtasksInvoker gtasksInvoker = new GtasksInvoker(account.getAccount(), googleAccountManager);
+    GtasksInvoker gtasksInvoker = this.gtasksInvoker.forAccount(account.getAccount());
     pushLocalChanges(account, gtasksInvoker);
 
     List<TaskList> gtaskLists = new ArrayList<>();

app/src/main/java/org/tasks/preferences/Preferences.java

@@ -32,6 +32,7 @@ import java.util.HashMap;
 import java.util.Map;
 import java.util.Map.Entry;
 import java.util.concurrent.TimeUnit;
+import org.tasks.BuildConfig;
 import org.tasks.R;
 import org.tasks.billing.Purchase;
 import org.tasks.data.TaskAttachment;
@@ -506,4 +507,8 @@ public class Preferences {
     }
     return result;
   }
+
+  public boolean isFlipperEnabled() {
+    return BuildConfig.DEBUG && getBoolean(R.string.p_flipper, false);
+  }
 }

app/src/release/java/org/tasks/DebugNetworkInterceptor.java

@@ -0,0 +1,16 @@
+package org.tasks;
+
+import com.google.api.client.http.HttpRequest;
+import javax.inject.Inject;
+import okhttp3.OkHttpClient;
+
+public class DebugNetworkInterceptor {
+  @Inject
+  public DebugNetworkInterceptor() {}
+
+  public void add(OkHttpClient.Builder builder) {}
+
+  public <T> T execute(HttpRequest request, Class<T> responseClass) {
+    return null;
+  }
+}