Issue 5010 - Allow to preload subscription files

libadblockplus-android/src/org/adblockplus/libadblockplus/android/AndroidWebRequestResourceWrapper.java

+/*
+ * This file is part of Adblock Plus <https://adblockplus.org/>,
+ * Copyright (C) 2006-2016 Eyeo GmbH
+ *
+ * Adblock Plus is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 3 as
+ * published by the Free Software Foundation.
+ *
+ * Adblock Plus is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with Adblock Plus.  If not, see <http://www.gnu.org/licenses/>.
+ */
+package org.adblockplus.libadblockplus.android;
+
+import android.content.Context;
+import android.content.SharedPreferences;
+import android.util.Log;
+
+import org.adblockplus.libadblockplus.HeaderEntry;
+import org.adblockplus.libadblockplus.ServerResponse;
+import org.adblockplus.libadblockplus.WebRequest;
+
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.InputStreamReader;
+import java.util.Collections;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+
+/**
+ * WebRequest wrapper to return request response from android resources for selected URLs
+ */
+public class AndroidWebRequestResourceWrapper extends WebRequest
+{
+  private static final String TAG = Utils.getTag(AndroidWebRequestResourceWrapper.class);
+
+  public static final String EASYLIST =
+    "https://easylist-downloads.adblockplus.org/easylist.txt";
+  public static final String EASYLIST_INDONESIAN =
+    "https://easylist-downloads.adblockplus.org/abpindo+easylist.txt";
+  public static final String EASYLIST_BULGARIAN =
+    "https://easylist-downloads.adblockplus.org/bulgarian_list+easylist.txt";
+  public static final String EASYLIST_CHINESE =
+    "https://easylist-downloads.adblockplus.org/easylistchina+easylist.txt";
+  public static final String EASYLIST_CZECH_SLOVAK =
+    "https://easylist-downloads.adblockplus.org/easylistczechslovak+easylist.txt";
+  public static final String EASYLIST_DUTCH =
+    "https://easylist-downloads.adblockplus.org/easylistdutch+easylist.txt";
+  public static final String EASYLIST_GERMAN =
+    "https://easylist-downloads.adblockplus.org/easylistgermany+easylist.txt";
+  public static final String EASYLIST_ISRAELI =
+    "https://easylist-downloads.adblockplus.org/israellist+easylist.txt";
+  public static final String EASYLIST_ITALIAN =
+    "https://easylist-downloads.adblockplus.org/easylistitaly+easylist.txt";
+  public static final String EASYLIST_LITHUANIAN =
+    "https://easylist-downloads.adblockplus.org/easylistlithuania+easylist.txt";
+  public static final String EASYLIST_LATVIAN =
+    "https://easylist-downloads.adblockplus.org/latvianlist+easylist.txt";
+  public static final String EASYLIST_ARABIAN_FRENCH =
+    "https://easylist-downloads.adblockplus.org/liste_ar+liste_fr+easylist.txt";
+  public static final String EASYLIST_FRENCH =
+    "https://easylist-downloads.adblockplus.org/liste_fr+easylist.txt";
+  public static final String EASYLIST_ROMANIAN =
+    "https://easylist-downloads.adblockplus.org/rolist+easylist.txt";
+  public static final String EASYLIST_RUSSIAN =
+    "https://easylist-downloads.adblockplus.org/ruadlist+easylist.txt";
+  public static final String ACCEPTABLE_ADS =
+    "https://easylist-downloads.adblockplus.org/exceptionrules.txt";
+
+  private Context context;
+  private WebRequest request;
+  private Map<String, Integer> URLtoResouceIdMap;
+  private Storage storage;
+  private Listener listener;
+
+  /**
+   * Constructor
+   * @param context android context
+   * @param request wrapped request to perform the request if it's not preloaded subscription requested
+   * @param URLtoResourceIdMap map URL -> android resource id for preloaded subscriptions
+   *                           See AndroidWebRequestResourceWrapper.EASYLIST_... constants
+   * @param storage Storage impl to remember served interceptions
+   */
+  public AndroidWebRequestResourceWrapper(Context context, WebRequest request,
+                                          Map<String, Integer> URLtoResourceIdMap,

[anton, 2017/03/20 08:28:46]

using map allows to pass multiple mappings and describe preloaded subscriptions
for multiple locales

+                                          Storage storage)
+  {
+    this.context = context;
+    this.request = request;
+    this.URLtoResouceIdMap = Collections.synchronizedMap(URLtoResourceIdMap);
+    this.storage = storage;
+  }
+
+  public Listener getListener()
+  {
+    return listener;
+  }
+
+  public void setListener(Listener listener)
+  {
+    this.listener = listener;
+  }
+
+  @Override
+  public ServerResponse httpGET(String url, List<HeaderEntry> headers)
+  {
+    // since parameters may vary we need to ignore them
+    String urlWithoutParams = url.substring(0, url.indexOf("?"));
+    Integer resourceId = URLtoResouceIdMap.get(urlWithoutParams);
+
+    if (resourceId != null)
+    {
+      if (!storage.contains(urlWithoutParams))
+      {
+        Log.w(TAG, "Intercepting request for " + url + " with resource #" + resourceId.intValue());
+        ServerResponse response = buildResourceContentResponse(resourceId);
+        storage.put(urlWithoutParams);
+
+        if (listener != null)
+        {
+          listener.onIntercepted(url, resourceId);
+        }
+
+        return response;
+      }
+      else
+      {
+        Log.d(TAG, "Skip intercepting");
+      }
+    }
+
+    // delegate to wrapper request
+    return request.httpGET(url, headers);
+  }
+
+  protected String readResourceContent(int resourceId) throws IOException
+  {
+    Log.d(TAG, "Reading from resource ...");
+
+    InputStream is = null;
+
+    try
+    {
+      is = context.getResources().openRawResource(resourceId);
+      BufferedReader br = new BufferedReader(new InputStreamReader(is));
+      StringBuilder sb = new StringBuilder();
+      String line;
+      boolean firstLine = true;
+      while ((line = br.readLine()) != null)
+      {
+        if (firstLine)
+        {
+          firstLine = false;
+        }
+        else
+        {
+          sb.append("\r\n");
+        }
+        sb.append(line);
+      }
+
+      Log.d(TAG, "Resource read (" + sb.length() + " bytes)");
+      return sb.toString();
+    }
+    finally
+    {
+      if (is != null)
+      {
+        is.close();
+      }
+    }
+  }
+
+  protected ServerResponse buildResourceContentResponse(int resourceId)
+  {
+    ServerResponse response = new ServerResponse();
+    try
+    {
+      response.setResponse(readResourceContent(resourceId));
+      response.setResponseStatus(200);
+      response.setStatus(ServerResponse.NsStatus.OK);
+    }
+    catch (IOException e)
+    {
+      Log.e(TAG, "Error injecting response", e);
+      response.setStatus(ServerResponse.NsStatus.ERROR_FAILURE);
+    }
+
+    return response;
+  }
+
+  @Override
+  public void dispose()
+  {
+    request.dispose();
+    super.dispose();
+  }
+
+  /**
+   * Listener for events
+   */
+  public interface Listener

[anton, 2017/03/20 08:28:45]

listener is introduced for the only purpose - we need to force update
subscriptions right after we returned preloaded response.
I decided not to pass FilterEngine instance here directly and not to have this
strong logics, but delegate the required actions to app.
So it's up to app logics if we need to force update or not. BTW listener is
optional

+  {
+    void onIntercepted(String url, int resourceId);
+  }
+
+  /**
+   * Interface to remember intercepted subscription requests
+   */
+  public interface Storage
+  {
+    void put(String url);
+    boolean contains(String url);
+  }
+
+  /**
+   * Storage impl in Shared Preferences
+   */
+  public static class SharedPrefsStorage implements Storage

[anton, 2017/03/20 08:28:46]

The only iml for now. Since we use SharedPrefsStorage for adblock settings too,
i assume we don't need another impls for now.

+  {
+    private static final String URLS = "urls";
+
+    private SharedPreferences prefs;
+    private Set<String> urls;
+
+    public SharedPrefsStorage(SharedPreferences prefs)
+    {
+      this.prefs = prefs;
+      this.urls = prefs.getStringSet(URLS, new HashSet<String>());
+    }
+
+    @Override
+    public synchronized void put(String url)
+    {
+      urls.add(url);
+
+      prefs
+        .edit()
+        .putStringSet(URLS, urls)
+        .commit();
+    }
+
+    @Override
+    public synchronized boolean contains(String url)
+    {
+      return urls.contains(url);
+    }
+  }
+}