/*
* Copyright 2012 Google Inc.
*
* 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.android.apps.iosched.gcm;
import com.google.android.apps.iosched.Config;
import com.google.android.gcm.GCMRegistrar;
import android.content.Context;
import java.io.IOException;
import java.io.OutputStream;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import java.util.Map.Entry;
import java.util.Random;
import static com.google.android.apps.iosched.util.LogUtils.LOGD;
import static com.google.android.apps.iosched.util.LogUtils.LOGE;
import static com.google.android.apps.iosched.util.LogUtils.LOGI;
import static com.google.android.apps.iosched.util.LogUtils.LOGV;
import static com.google.android.apps.iosched.util.LogUtils.makeLogTag;
/**
* Helper class used to communicate with the demo server.
*/
public final class ServerUtilities {
private static final String TAG = makeLogTag("GCM");
private static final int MAX_ATTEMPTS = 5;
private static final int BACKOFF_MILLIS = 2000;
private static final Random sRandom = new Random();
/**
* Register this account/device pair within the server.
*
* @param context Current context
* @param regId The GCM registration ID for this device
* @return whether the registration succeeded or not.
*/
public static boolean register(final Context context, final String regId) {
LOGI(TAG, "registering device (regId = " + regId + ")");
String serverUrl = Config.GCM_SERVER_URL + "/register";
Map<String, String> params = new HashMap<String, String>();
params.put("regId", regId);
long backoff = BACKOFF_MILLIS + 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);
GCMRegistrar.setRegisteredOnServer(context, true);
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 regId The GCM registration ID for this device
*/
static void unregister(final Context context, final String regId) {
LOGI(TAG, "unregistering device (regId = " + regId + ")");
String serverUrl = Config.GCM_SERVER_URL + "/unregister";
Map<String, String> params = new HashMap<String, String>();
params.put("regId", regId);
try {
post(serverUrl, params);
GCMRegistrar.setRegisteredOnServer(context, false);
} 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);
}
}
/**
* 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)
throws IOException {
URL url;
try {
url = new URL(endpoint);
} catch (MalformedURLException e) {
throw new IllegalArgumentException("invalid url: " + endpoint);
}
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();
}
}
}
}