/*
* Copyright 2016 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 org.physical_web.physicalweb.ble;
import android.annotation.TargetApi;
import android.bluetooth.le.AdvertiseData;
import android.bluetooth.le.AdvertiseSettings;
import android.os.ParcelUuid;
import android.util.Log;
import android.util.SparseArray;
import android.webkit.URLUtil;
import java.nio.ByteBuffer;
import java.nio.ByteOrder;
import java.util.Locale;
import java.util.UUID;
/**
*Helper class to simplify Eddystone URL encoding.
**/
public class AdvertiseDataUtils {
private static final String TAG = "AdvertiseDataUtils";
private static final ParcelUuid EDDYSTONE_BEACON_UUID = ParcelUuid.fromString(
"0000FEAA-0000-1000-8000-00805F9B34FB");
/**
* URI Scheme maps a byte code into the scheme and an optional scheme specific prefix.
*/
private static final SparseArray<String> URI_SCHEMES = new SparseArray<String>() {{
put((byte) 0, "http://www.");
put((byte) 1, "https://www.");
put((byte) 2, "http://");
put((byte) 3, "https://");
put((byte) 4, "urn:uuid:"); // RFC 2141 and RFC 4122};
}};
/**
* Expansion strings for "http" and "https" schemes. These contain strings appearing
* anywhere in a URL. Restricted to Generic TLDs. <p/> Note: this is a scheme specific encoding.
*/
private static final SparseArray<String> URL_CODES = new SparseArray<String>() {{
put((byte) 0, ".com/");
put((byte) 1, ".org/");
put((byte) 2, ".edu/");
put((byte) 3, ".net/");
put((byte) 4, ".info/");
put((byte) 5, ".biz/");
put((byte) 6, ".gov/");
put((byte) 7, ".com");
put((byte) 8, ".org");
put((byte) 9, ".edu");
put((byte) 10, ".net");
put((byte) 11, ".info");
put((byte) 12, ".biz");
put((byte) 13, ".gov");
}};
private static final byte URL_FRAME_TYPE = 0x10;
private static final byte FAT_BEACON = 0x0e;
/**
* Creates the Uri string with embedded expansion codes.
*
* @param uri to be encoded
* @return the Uri string with expansion codes.
*/
public static byte[] encodeUri(String uri) {
if (uri == null || uri.length() == 0) {
Log.i(TAG, "null or empty uri");
return new byte[0];
}
ByteBuffer bb = ByteBuffer.allocate(uri.length());
// UUIDs are ordered as byte array, which means most significant first
bb.order(ByteOrder.BIG_ENDIAN);
int position = 0;
// Add the byte code for the scheme or return null if none
Byte schemeCode = encodeUriScheme(uri);
if (schemeCode == null) {
Log.i(TAG, "null scheme code");
return null;
}
String scheme = URI_SCHEMES.get(schemeCode);
bb.put(schemeCode);
position += scheme.length();
if (URLUtil.isNetworkUrl(scheme)) {
Log.i(TAG, "is network URL");
return encodeUrl(uri, position, bb);
} else if ("urn:uuid:".equals(scheme)) {
Log.i(TAG, "is UUID");
return encodeUrnUuid(uri, position, bb);
}
return null;
}
/**
* Finds the longest expansion from the uri at the current position.
*
* @param uriString the Uri
* @param pos start position
* @return an index in URI_MAP or 0 if none.
*/
private static byte findLongestExpansion(String uriString, int pos) {
byte expansion = -1;
int expansionLength = 0;
for (int i = 0; i < URL_CODES.size(); i++) {
// get the key and value.
int key = URL_CODES.keyAt(i);
String value = URL_CODES.valueAt(i);
if (value.length() > expansionLength && uriString.startsWith(value, pos)) {
expansion = (byte) key;
expansionLength = value.length();
}
}
return expansion;
}
private static Byte encodeUriScheme(String uri) {
String lowerCaseUri = uri.toLowerCase(Locale.ENGLISH);
for (int i = 0; i < URI_SCHEMES.size(); i++) {
// get the key and value.
int key = URI_SCHEMES.keyAt(i);
String value = URI_SCHEMES.valueAt(i);
if (lowerCaseUri.startsWith(value)) {
return (byte) key;
}
}
return null;
}
private static byte[] encodeUrl(String url, int position, ByteBuffer bb) {
while (position < url.length()) {
byte expansion = findLongestExpansion(url, position);
if (expansion >= 0) {
bb.put(expansion);
position += URL_CODES.get(expansion).length();
} else {
bb.put((byte) url.charAt(position++));
}
}
return byteBufferToArray(bb);
}
private static byte[] encodeUrnUuid(String urn, int position, ByteBuffer bb) {
String uuidString = urn.substring(position, urn.length());
UUID uuid;
try {
uuid = UUID.fromString(uuidString);
} catch (IllegalArgumentException e) {
//Log.w(TAG, "encodeUrnUuid invalid urn:uuid format - " + urn);
return null;
}
// UUIDs are ordered as byte array, which means most significant first
bb.order(ByteOrder.BIG_ENDIAN);
bb.putLong(uuid.getMostSignificantBits());
bb.putLong(uuid.getLeastSignificantBits());
return byteBufferToArray(bb);
}
private static byte[] byteBufferToArray(ByteBuffer bb) {
byte[] bytes = new byte[bb.position()];
bb.rewind();
bb.get(bytes, 0, bytes.length);
return bytes;
}
// Generate the advertising bytes for the given URL
@TargetApi(21)
public static AdvertiseData getAdvertisementData(byte[] urlData) {
AdvertiseData.Builder builder = new AdvertiseData.Builder();
builder.setIncludeTxPowerLevel(false); // reserve advertising space for URI
// Manually build the advertising info
// See https://github.com/google/eddystone/tree/master/eddystone-url
if (urlData == null || urlData.length == 0) {
return null;
}
byte[] beaconData = new byte[urlData.length + 2];
System.arraycopy(urlData, 0, beaconData, 2, urlData.length);
beaconData[0] = URL_FRAME_TYPE; // frame type: url
beaconData[1] = (byte) 0xBA; // calibrated tx power at 0 m
builder.addServiceData(EDDYSTONE_BEACON_UUID, beaconData);
// Adding 0xFEAA to the "Service Complete List UUID 16" (0x3) for iOS compatibility
builder.addServiceUuid(EDDYSTONE_BEACON_UUID);
return builder.build();
}
// Build and return the advertising bytes for the given FatBeacon advertisement
@TargetApi(21)
public static AdvertiseData getFatBeaconAdvertisementData(byte[] fatBeaconAdvertisement) {
// Manually build the advertising info
int length = Math.min(fatBeaconAdvertisement.length, 17);
byte[] beaconData = new byte[length + 3];
System.arraycopy(fatBeaconAdvertisement, 0, beaconData, 3, length);
beaconData[0] = URL_FRAME_TYPE;
beaconData[1] = (byte) 0xBA;
beaconData[2] = FAT_BEACON;
return new AdvertiseData.Builder()
.setIncludeTxPowerLevel(false) // reserve advertising space for URI
.addServiceData(EDDYSTONE_BEACON_UUID, beaconData)
// Adding 0xFEAA to the "Service Complete List UUID 16" (0x3) for iOS compatibility
.addServiceUuid(EDDYSTONE_BEACON_UUID)
.build();
}
// Build and return the ble advertising settings
@TargetApi(21)
public static AdvertiseSettings getAdvertiseSettings(boolean connectable) {
AdvertiseSettings.Builder builder = new AdvertiseSettings.Builder();
builder.setAdvertiseMode(AdvertiseSettings.ADVERTISE_MODE_LOW_POWER);
builder.setTxPowerLevel(AdvertiseSettings.ADVERTISE_TX_POWER_MEDIUM);
builder.setConnectable(connectable);
return builder.build();
}
}
