| /* |
| * Copyright (C) 2008 The Android Open Source Project |
| * |
| * 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.android.server.location; |
| |
| import android.content.Context; |
| import android.text.TextUtils; |
| import android.util.Log; |
| |
| import java.net.HttpURLConnection; |
| import java.net.URL; |
| import libcore.io.IoUtils; |
| |
| import java.io.ByteArrayOutputStream; |
| import java.io.InputStream; |
| import java.io.IOException; |
| import java.util.Properties; |
| import java.util.Random; |
| |
| /** |
| * A class for downloading GPS XTRA data. |
| * |
| * {@hide} |
| */ |
| public class GpsXtraDownloader { |
| |
| private static final String TAG = "GpsXtraDownloader"; |
| private static final boolean DEBUG = Log.isLoggable(TAG, Log.DEBUG); |
| private static final long MAXIMUM_CONTENT_LENGTH_BYTES = 1000000; // 1MB. |
| private static final String DEFAULT_USER_AGENT = "Android"; |
| |
| private final String[] mXtraServers; |
| // to load balance our server requests |
| private int mNextServerIndex; |
| private final String mUserAgent; |
| |
| GpsXtraDownloader(Properties properties) { |
| // read XTRA servers from the Properties object |
| int count = 0; |
| String server1 = properties.getProperty("XTRA_SERVER_1"); |
| String server2 = properties.getProperty("XTRA_SERVER_2"); |
| String server3 = properties.getProperty("XTRA_SERVER_3"); |
| if (server1 != null) count++; |
| if (server2 != null) count++; |
| if (server3 != null) count++; |
| |
| // Set User Agent from properties, if possible. |
| String agent = properties.getProperty("XTRA_USER_AGENT"); |
| if (TextUtils.isEmpty(agent)) { |
| mUserAgent = DEFAULT_USER_AGENT; |
| } else { |
| mUserAgent = agent; |
| } |
| |
| if (count == 0) { |
| Log.e(TAG, "No XTRA servers were specified in the GPS configuration"); |
| mXtraServers = null; |
| } else { |
| mXtraServers = new String[count]; |
| count = 0; |
| if (server1 != null) mXtraServers[count++] = server1; |
| if (server2 != null) mXtraServers[count++] = server2; |
| if (server3 != null) mXtraServers[count++] = server3; |
| |
| // randomize first server |
| Random random = new Random(); |
| mNextServerIndex = random.nextInt(count); |
| } |
| } |
| |
| byte[] downloadXtraData() { |
| byte[] result = null; |
| int startIndex = mNextServerIndex; |
| |
| if (mXtraServers == null) { |
| return null; |
| } |
| |
| // load balance our requests among the available servers |
| while (result == null) { |
| result = doDownload(mXtraServers[mNextServerIndex]); |
| |
| // increment mNextServerIndex and wrap around if necessary |
| mNextServerIndex++; |
| if (mNextServerIndex == mXtraServers.length) { |
| mNextServerIndex = 0; |
| } |
| // break if we have tried all the servers |
| if (mNextServerIndex == startIndex) break; |
| } |
| |
| return result; |
| } |
| |
| protected byte[] doDownload(String url) { |
| if (DEBUG) Log.d(TAG, "Downloading XTRA data from " + url); |
| |
| HttpURLConnection connection = null; |
| try { |
| connection = (HttpURLConnection) (new URL(url)).openConnection(); |
| connection.setRequestProperty( |
| "Accept", |
| "*/*, application/vnd.wap.mms-message, application/vnd.wap.sic"); |
| connection.setRequestProperty( |
| "x-wap-profile", |
| "http://www.openmobilealliance.org/tech/profiles/UAPROF/ccppschema-20021212#"); |
| |
| connection.connect(); |
| int statusCode = connection.getResponseCode(); |
| if (statusCode != HttpURLConnection.HTTP_OK) { |
| if (DEBUG) Log.d(TAG, "HTTP error downloading gps XTRA: " + statusCode); |
| return null; |
| } |
| |
| try (InputStream in = connection.getInputStream()) { |
| ByteArrayOutputStream bytes = new ByteArrayOutputStream(); |
| byte[] buffer = new byte[1024]; |
| int count; |
| while ((count = in.read(buffer)) != -1) { |
| bytes.write(buffer, 0, count); |
| if (bytes.size() > MAXIMUM_CONTENT_LENGTH_BYTES) { |
| if (DEBUG) Log.d(TAG, "XTRA file too large"); |
| return null; |
| } |
| } |
| return bytes.toByteArray(); |
| } |
| } catch (IOException ioe) { |
| if (DEBUG) Log.d(TAG, "Error downloading gps XTRA: ", ioe); |
| } finally { |
| if (connection != null) { |
| connection.disconnect(); |
| } |
| } |
| return null; |
| } |
| |
| } |
| |