/**
* Copyright (C) 2015 Monitordroid 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.
*
* @author Tyler Butler
**/
package com.monitordroid.app;
import static com.monitordroid.app.CommonUtilities.SERVER_URL;
import static com.monitordroid.app.CommonUtilities.displayMessage;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
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 android.content.Context;
import com.google.android.gcm.GCMRegistrar;
public final class ServerUtilities {
private static final int MAX_ATTEMPTS = 5;
private static final int BACKOFF_MILLI_SECONDS = 2000;
private static final Random random = new Random();
/**
* Register this account/device pair within the server using Account
* Name/Email Strings from registration screen.
*/
static void register(final Context context, String name, String email,
final String regId) {
String serverUrl = SERVER_URL;
Map<String, String> params = new HashMap<String, String>();
params.put("regId", regId);
params.put("name", name);
params.put("email", email);
boolean deviceAdded;
long backoff = BACKOFF_MILLI_SECONDS + random.nextInt(1000);
// Retry connection 5 times
for (int i = 1; i <= MAX_ATTEMPTS; i++) {
try {
displayMessage(context, context.getString(
R.string.server_registering, i, MAX_ATTEMPTS));
// Post method will return true or false depending on whether
// the device was added successfully on the server
// If false, it is probably because the input account
// email/username is not an active account
deviceAdded = post(serverUrl, params);
if (deviceAdded) {
GCMRegistrar.setRegisteredOnServer(context, true);
String message = context
.getString(R.string.server_registered)
+ " \""
+ name
+ "\" "
+ context.getString(R.string.to_account)
+ " \""
+ email + "\".";
CommonUtilities.displayMessage(context, message);
}
else {
GCMRegistrar.setRegisteredOnServer(context, false);
String message = context
.getString(R.string.server_not_added)
+ " \""
+ name
+ "\" "
+ context.getString(R.string.to_account)
+ " \""
+ email
+ "\". "
+ context.getString(R.string.ensure_spelling);
CommonUtilities.displayMessage(context, message);
}
return;
}
catch (IOException e) {
if (i == MAX_ATTEMPTS) {
break;
}
try {
Thread.sleep(backoff);
}
catch (InterruptedException e1) {
// Activity finished before completed - exit.
Thread.currentThread().interrupt();
return;
}
// increase backoff exponentially
backoff *= 2;
}
}
String message = context.getString(R.string.server_register_error,
MAX_ATTEMPTS);
CommonUtilities.displayMessage(context, message);
}
/**
* Unregister this account/device pair within the server.
*/
static void unregister(final Context context, final String regId) {
String serverUrl = SERVER_URL + "/unregister";
Map<String, String> params = new HashMap<String, String>();
params.put("regId", regId);
try {
post(serverUrl, params);
GCMRegistrar.setRegisteredOnServer(context, false);
String message = context.getString(R.string.server_unregistered);
CommonUtilities.displayMessage(context, message);
}
catch (IOException e) {
}
}
/**
* Issue a POST request to the server.
*
* @param endpoint
* POST address.
* @param params
* request parameters containing the new GCM ID, account name,
* and device name
*
* @throws IOException
* propagated from POST.
*
* @return boolean indicating whether the device was successfully added to
* the server's database.
*/
private static boolean post(String endpoint, Map<String, String> params)
throws IOException {
URL url;
boolean deviceAdded = false;
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();
byte[] bytes = body.getBytes();
HttpURLConnection conn = null;
try {
conn = (HttpURLConnection) url.openConnection();
conn.setDoOutput(true);
conn.setUseCaches(false);
conn.setFixedLengthStreamingMode(bytes.length);
conn.setRequestMethod("POST");
conn.setRequestProperty("Content-Type",
"application/x-www-form-urlencoded;charset=UTF-8");
// post the request
OutputStream out = conn.getOutputStream();
out.write(bytes);
out.close();
// Input reader from Monitordroid Server Servers response will
// either be "existsandcompleted" indicating the device was
// succesfully added to the database or "didnotcomplete", indicating
// that the device was not successfully added.
// If adding the device is not successful, it is probably due to the
// user entering a non-existent account into the "Account Email"
// field.
BufferedReader in = new BufferedReader(new InputStreamReader(
conn.getInputStream()));
String inputLine;
while ((inputLine = in.readLine()) != null) {
if (inputLine.contains("existsandcompleted")) {
deviceAdded = true;
}
if (inputLine.contains("didnotcomplete")) {
deviceAdded = false;
}
}
in.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();
}
}
return deviceAdded;
}
}