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      1 /*
      2  * Copyright (C) 2008 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 package com.android.internal.location;
     18 
     19 import org.apache.http.HttpEntity;
     20 import org.apache.http.HttpHost;
     21 import org.apache.http.HttpResponse;
     22 import org.apache.http.StatusLine;
     23 import org.apache.http.client.HttpClient;
     24 import org.apache.http.client.methods.HttpGet;
     25 import org.apache.http.client.methods.HttpUriRequest;
     26 import org.apache.http.conn.params.ConnRouteParams;
     27 
     28 import java.io.DataInputStream;
     29 import java.io.IOException;
     30 import java.util.Properties;
     31 import java.util.Random;
     32 
     33 import android.content.Context;
     34 import android.net.Proxy;
     35 import android.net.http.AndroidHttpClient;
     36 import android.util.Config;
     37 import android.util.Log;
     38 
     39 
     40 
     41 /**
     42  * A class for downloading GPS XTRA data.
     43  *
     44  * {@hide}
     45  */
     46 public class GpsXtraDownloader {
     47 
     48     private static final String TAG = "GpsXtraDownloader";
     49 
     50     private Context mContext;
     51     private String[] mXtraServers;
     52     // to load balance our server requests
     53     private int mNextServerIndex;
     54 
     55     GpsXtraDownloader(Context context, Properties properties) {
     56         mContext = context;
     57 
     58         // read XTRA servers from the Properties object
     59         int count = 0;
     60         String server1 = properties.getProperty("XTRA_SERVER_1");
     61         String server2 = properties.getProperty("XTRA_SERVER_2");
     62         String server3 = properties.getProperty("XTRA_SERVER_3");
     63         if (server1 != null) count++;
     64         if (server2 != null) count++;
     65         if (server3 != null) count++;
     66 
     67         if (count == 0) {
     68             Log.e(TAG, "No XTRA servers were specified in the GPS configuration");
     69             return;
     70         } else {
     71             mXtraServers = new String[count];
     72             count = 0;
     73             if (server1 != null) mXtraServers[count++] = server1;
     74             if (server2 != null) mXtraServers[count++] = server2;
     75             if (server3 != null) mXtraServers[count++] = server3;
     76 
     77             // randomize first server
     78             Random random = new Random();
     79             mNextServerIndex = random.nextInt(count);
     80         }
     81     }
     82 
     83     byte[] downloadXtraData() {
     84         String proxyHost = Proxy.getHost(mContext);
     85         int proxyPort = Proxy.getPort(mContext);
     86         boolean useProxy = (proxyHost != null && proxyPort != -1);
     87         byte[] result = null;
     88         int startIndex = mNextServerIndex;
     89 
     90         if (mXtraServers == null) {
     91             return null;
     92         }
     93 
     94         // load balance our requests among the available servers
     95         while (result == null) {
     96             result = doDownload(mXtraServers[mNextServerIndex], useProxy, proxyHost, proxyPort);
     97 
     98             // increment mNextServerIndex and wrap around if necessary
     99             mNextServerIndex++;
    100             if (mNextServerIndex == mXtraServers.length) {
    101                 mNextServerIndex = 0;
    102             }
    103             // break if we have tried all the servers
    104             if (mNextServerIndex == startIndex) break;
    105         }
    106 
    107         return result;
    108     }
    109 
    110     protected static byte[] doDownload(String url, boolean isProxySet,
    111             String proxyHost, int proxyPort) {
    112         if (Config.LOGD) Log.d(TAG, "Downloading XTRA data from " + url);
    113 
    114         AndroidHttpClient client = null;
    115         try {
    116             client = AndroidHttpClient.newInstance("Android");
    117             HttpUriRequest req = new HttpGet(url);
    118 
    119             if (isProxySet) {
    120                 HttpHost proxy = new HttpHost(proxyHost, proxyPort);
    121                 ConnRouteParams.setDefaultProxy(req.getParams(), proxy);
    122             }
    123 
    124             req.addHeader(
    125                     "Accept",
    126                     "*/*, application/vnd.wap.mms-message, application/vnd.wap.sic");
    127 
    128             req.addHeader(
    129                     "x-wap-profile",
    130                     "http://www.openmobilealliance.org/tech/profiles/UAPROF/ccppschema-20021212#");
    131 
    132             HttpResponse response = client.execute(req);
    133             StatusLine status = response.getStatusLine();
    134             if (status.getStatusCode() != 200) { // HTTP 200 is success.
    135                 if (Config.LOGD) Log.d(TAG, "HTTP error: " + status.getReasonPhrase());
    136                 return null;
    137             }
    138 
    139             HttpEntity entity = response.getEntity();
    140             byte[] body = null;
    141             if (entity != null) {
    142                 try {
    143                     if (entity.getContentLength() > 0) {
    144                         body = new byte[(int) entity.getContentLength()];
    145                         DataInputStream dis = new DataInputStream(entity.getContent());
    146                         try {
    147                             dis.readFully(body);
    148                         } finally {
    149                             try {
    150                                 dis.close();
    151                             } catch (IOException e) {
    152                                 Log.e(TAG, "Unexpected IOException.", e);
    153                             }
    154                         }
    155                     }
    156                 } finally {
    157                     if (entity != null) {
    158                         entity.consumeContent();
    159                     }
    160                 }
    161             }
    162             return body;
    163         } catch (Exception e) {
    164             if (Config.LOGD) Log.d(TAG, "error " + e);
    165         } finally {
    166             if (client != null) {
    167                 client.close();
    168             }
    169         }
    170         return null;
    171     }
    172 
    173 }
    174