/*
* Copyright 2014 Google Inc. All rights reserved.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.google.samples.apps.iosched.gcm;
import android.content.Context;
import android.content.SharedPreferences;
import android.content.SharedPreferences.Editor;
import android.text.TextUtils;
import com.google.samples.apps.iosched.Config;
import com.google.samples.apps.iosched.util.AccountUtils;
import java.io.IOException;
import java.io.OutputStream;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.*;
import java.util.Map.Entry;
import static com.google.samples.apps.iosched.util.LogUtils.*;
/**
* Helper class used to communicate with the demo server.
*/
public final class ServerUtilities {
private static final String TAG = makeLogTag("GCMs");
private static final String PREFERENCES = "com.google.samples.apps.iosched.gcm";
private static final String PROPERTY_REGISTERED_TS = "registered_ts";
private static final String PROPERTY_REG_ID = "reg_id";
private static final String PROPERTY_GCM_KEY = "gcm_key";
private static final int MAX_ATTEMPTS = 5;
private static final int BACKOFF_MILLI_SECONDS = 2000;
private static final Random sRandom = new Random();
private static boolean checkGcmEnabled() {
if (TextUtils.isEmpty(Config.GCM_SERVER_URL)) {
LOGD(TAG, "GCM feature disabled (no URL configured)");
return false;
} else if (TextUtils.isEmpty(Config.GCM_API_KEY)) {
LOGD(TAG, "GCM feature disabled (no API key configured)");
return false;
} else if (TextUtils.isEmpty(Config.GCM_SENDER_ID)) {
LOGD(TAG, "GCM feature disabled (no sender ID configured)");
return false;
}
return true;
}
/**
* Register this account/device pair within the server.
*
* @param context Current context
* @param gcmId The GCM registration ID for this device
* @param gcmKey The GCM key with which to register.
* @return whether the registration succeeded or not.
*/
public static boolean register(final Context context, final String gcmId, final String gcmKey) {
if (!checkGcmEnabled()) {
return false;
}
LOGI(TAG, "registering device (gcm_id = " + gcmId + ")");
String serverUrl = Config.GCM_SERVER_URL + "/register";
LOGI(TAG, "registering on GCM with GCM key: " + AccountUtils.sanitizeGcmKey(gcmKey));
Map<String, String> params = new HashMap<String, String>();
params.put("gcm_id", gcmId);
params.put("gcm_key", gcmKey);
long backoff = BACKOFF_MILLI_SECONDS + sRandom.nextInt(1000);
// Once GCM returns a registration id, we need to register it in the
// demo server. As the server might be down, we will retry it a couple
// times.
for (int i = 1; i <= MAX_ATTEMPTS; i++) {
LOGV(TAG, "Attempt #" + i + " to register");
try {
post(serverUrl, params, Config.GCM_API_KEY);
setRegisteredOnServer(context, true, gcmId, gcmKey);
return true;
} catch (IOException e) {
// Here we are simplifying and retrying on any error; in a real
// application, it should retry only on unrecoverable errors
// (like HTTP error code 503).
LOGE(TAG, "Failed to register on attempt " + i, e);
if (i == MAX_ATTEMPTS) {
break;
}
try {
LOGV(TAG, "Sleeping for " + backoff + " ms before retry");
Thread.sleep(backoff);
} catch (InterruptedException e1) {
// Activity finished before we complete - exit.
LOGD(TAG, "Thread interrupted: abort remaining retries!");
Thread.currentThread().interrupt();
return false;
}
// increase backoff exponentially
backoff *= 2;
}
}
return false;
}
/**
* Unregister this account/device pair within the server.
*
* @param context Current context
* @param gcmId The GCM registration ID for this device
*/
static void unregister(final Context context, final String gcmId) {
if (!checkGcmEnabled()) {
return;
}
LOGI(TAG, "unregistering device (gcmId = " + gcmId + ")");
String serverUrl = Config.GCM_SERVER_URL + "/unregister";
Map<String, String> params = new HashMap<String, String>();
params.put("gcm_id", gcmId);
try {
post(serverUrl, params, Config.GCM_API_KEY);
setRegisteredOnServer(context, false, gcmId, null);
} catch (IOException e) {
// At this point the device is unregistered from GCM, but still
// registered in the server.
// We could try to unregister again, but it is not necessary:
// if the server tries to send a message to the device, it will get
// a "NotRegistered" error message and should unregister the device.
LOGD(TAG, "Unable to unregister from application server", e);
} finally {
// Regardless of server success, clear local preferences
setRegisteredOnServer(context, false, null, null);
}
}
/**
* Request user data sync.
*
* @param context Current context
*/
public static void notifyUserDataChanged(final Context context) {
if (!checkGcmEnabled()) {
return;
}
LOGI(TAG, "Notifying GCM that user data changed");
String serverUrl = Config.GCM_SERVER_URL + "/send/self/sync_user";
try {
String gcmKey = AccountUtils.getGcmKey(context, AccountUtils.getActiveAccountName(context));
if (gcmKey != null) {
post(serverUrl, new HashMap<String, String>(), gcmKey);
}
} catch (IOException e) {
LOGE(TAG, "Unable to notify GCM about user data change", e);
}
}
/**
* Sets whether the device was successfully registered in the server side.
*
* @param context Current context
* @param flag True if registration was successful, false otherwise
* @param gcmId True if registration was successful, false otherwise
*/
private static void setRegisteredOnServer(Context context, boolean flag, String gcmId, String gcmKey) {
final SharedPreferences prefs = context.getSharedPreferences(
PREFERENCES, Context.MODE_PRIVATE);
LOGD(TAG, "Setting registered on server status as: " + flag + ", gcmKey="
+ AccountUtils.sanitizeGcmKey(gcmKey));
Editor editor = prefs.edit();
if (flag) {
editor.putLong(PROPERTY_REGISTERED_TS, new Date().getTime());
editor.putString(PROPERTY_GCM_KEY, gcmKey == null ? "" : gcmKey);
editor.putString(PROPERTY_REG_ID, gcmId);
} else {
editor.remove(PROPERTY_REG_ID);
}
editor.commit();
}
/**
* Checks whether the device was successfully registered in the server side.
*
* @param context Current context
* @return True if registration was successful, false otherwise
*/
public static boolean isRegisteredOnServer(Context context, String gcmKey) {
final SharedPreferences prefs = context.getSharedPreferences(
PREFERENCES, Context.MODE_PRIVATE);
// Find registration threshold
Calendar cal = Calendar.getInstance();
cal.add(Calendar.DATE, -1);
long yesterdayTS = cal.getTimeInMillis();
long regTS = prefs.getLong(PROPERTY_REGISTERED_TS, 0);
gcmKey = gcmKey == null ? "" : gcmKey;
if (regTS > yesterdayTS) {
LOGV(TAG, "GCM registration current. regTS=" + regTS + " yesterdayTS=" + yesterdayTS);
final String registeredGcmKey = prefs.getString(PROPERTY_GCM_KEY, "");
if (registeredGcmKey.equals(gcmKey)) {
LOGD(TAG, "GCM registration is valid and for the correct gcm key: "
+ AccountUtils.sanitizeGcmKey(registeredGcmKey));
return true;
}
LOGD(TAG, "GCM registration is for DIFFERENT gcm key "
+ AccountUtils.sanitizeGcmKey(registeredGcmKey) + ". We were expecting "
+ AccountUtils.sanitizeGcmKey(gcmKey));
return false;
} else {
LOGV(TAG, "GCM registration expired. regTS=" + regTS + " yesterdayTS=" + yesterdayTS);
return false;
}
}
public static String getGcmId(Context context) {
final SharedPreferences prefs = context.getSharedPreferences(PREFERENCES, Context.MODE_PRIVATE);
return prefs.getString(PROPERTY_REG_ID, null);
}
/**
* Unregister the current GCM ID when we sign-out
*
* @param context Current context
*/
public static void onSignOut(Context context) {
String gcmId = getGcmId(context);
if (gcmId != null) {
unregister(context, gcmId);
}
}
/**
* Issue a POST request to the server.
*
* @param endpoint POST address.
* @param params request parameters.
* @throws java.io.IOException propagated from POST.
*/
private static void post(String endpoint, Map<String, String> params, String key)
throws IOException {
URL url;
try {
url = new URL(endpoint);
} catch (MalformedURLException e) {
throw new IllegalArgumentException("invalid url: " + endpoint);
}
params.put("key", key);
StringBuilder bodyBuilder = new StringBuilder();
Iterator<Entry<String, String>> iterator = params.entrySet().iterator();
// constructs the POST body using the parameters
while (iterator.hasNext()) {
Entry<String, String> param = iterator.next();
bodyBuilder.append(param.getKey()).append('=')
.append(param.getValue());
if (iterator.hasNext()) {
bodyBuilder.append('&');
}
}
String body = bodyBuilder.toString();
LOGV(TAG, "Posting '" + body + "' to " + url);
HttpURLConnection conn = null;
try {
conn = (HttpURLConnection) url.openConnection();
conn.setDoOutput(true);
conn.setUseCaches(false);
conn.setChunkedStreamingMode(0);
conn.setRequestMethod("POST");
conn.setRequestProperty("Content-Type",
"application/x-www-form-urlencoded;charset=UTF-8");
conn.setRequestProperty("Content-Length",
Integer.toString(body.length()));
// post the request
OutputStream out = conn.getOutputStream();
out.write(body.getBytes());
out.close();
// handle the response
int status = conn.getResponseCode();
if (status != 200) {
throw new IOException("Post failed with error code " + status);
}
} finally {
if (conn != null) {
conn.disconnect();
}
}
}
}