/*
* Copyright (C) 2010 The Android Open Source Project
* Modifications copyright (C) 2012-2014 Saikoa / Itsana BVBA
*
* 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.vending.licensing;
import org.apache.http.NameValuePair;
import org.apache.http.client.utils.URLEncodedUtils;
import java.net.URI;
import java.net.URISyntaxException;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import android.content.Context;
import android.content.SharedPreferences;
import android.util.Log;
/**
* Default policy. All policy decisions are based off of response data received
* from the licensing service. Specifically, the licensing server sends the
* following information: response validity period, error retry period, and
* error retry count.
* <p>
* These values will vary based on the the way the application is configured in
* the Android Market publishing console, such as whether the application is
* marked as free or is within its refund period, as well as how often an
* application is checking with the licensing service.
* <p>
* Developers who need more fine grained control over their application's
* licensing policy should implement a custom Policy.
*/
public class ServerManagedPolicy implements Policy {
private static final String TAG = "ServerManagedPolicy";
private static final String PREFS_FILE = "com.android.vending.licensing.ServerManagedPolicy";
private static final String PREF_LAST_RESPONSE = "lastResponse";
private static final String PREF_VALIDITY_TIMESTAMP = "validityTimestamp";
private static final String PREF_RETRY_UNTIL = "retryUntil";
private static final String PREF_MAX_RETRIES = "maxRetries";
private static final String PREF_RETRY_COUNT = "retryCount";
private static final String DEFAULT_VALIDITY_TIMESTAMP = "0";
private static final String DEFAULT_RETRY_UNTIL = "0";
private static final String DEFAULT_MAX_RETRIES = "0";
private static final String DEFAULT_RETRY_COUNT = "0";
private static final long MILLIS_PER_MINUTE = 60 * 1000;
private long mValidityTimestamp;
private long mRetryUntil;
private long mMaxRetries;
private long mRetryCount;
private long mLastResponseTime = 0;
private int mLastResponse;
private PreferenceObfuscator mPreferences;
/**
* @param context The context for the current application
* @param obfuscator An obfuscator to be used with preferences.
*/
public ServerManagedPolicy(Context context, Obfuscator obfuscator) {
// Import old values
SharedPreferences sp = context.getSharedPreferences(PREFS_FILE, Context.MODE_PRIVATE);
mPreferences = new PreferenceObfuscator(sp, obfuscator);
mLastResponse = Integer.parseInt(
mPreferences.getString(PREF_LAST_RESPONSE, Integer.toString(Policy.RETRY)));
mValidityTimestamp = Long.parseLong(mPreferences.getString(PREF_VALIDITY_TIMESTAMP,
DEFAULT_VALIDITY_TIMESTAMP));
mRetryUntil = Long.parseLong(mPreferences.getString(PREF_RETRY_UNTIL, DEFAULT_RETRY_UNTIL));
mMaxRetries = Long.parseLong(mPreferences.getString(PREF_MAX_RETRIES, DEFAULT_MAX_RETRIES));
mRetryCount = Long.parseLong(mPreferences.getString(PREF_RETRY_COUNT, DEFAULT_RETRY_COUNT));
}
/**
* Process a new response from the license server.
* <p>
* This data will be used for computing future policy decisions. The
* following parameters are processed:
* <ul>
* <li>VT: the timestamp that the client should consider the response
* valid until
* <li>GT: the timestamp that the client should ignore retry errors until
* <li>GR: the number of retry errors that the client should ignore
* </ul>
*
* @param response the result from validating the server response
* @param rawData the raw server response data
*/
public void processServerResponse(int response, ResponseData rawData) {
// Update retry counter
if (response != Policy.RETRY) {
setRetryCount(0);
} else {
setRetryCount(mRetryCount + 1);
}
if (response == Policy.LICENSED) {
// Update server policy data
Map<String, String> extras = decodeExtras(rawData.extra);
mLastResponse = response;
setValidityTimestamp(extras.get("VT"));
setRetryUntil(extras.get("GT"));
setMaxRetries(extras.get("GR"));
} else if (response == Policy.NOT_LICENSED) {
// Clear out stale policy data
setValidityTimestamp(DEFAULT_VALIDITY_TIMESTAMP);
setRetryUntil(DEFAULT_RETRY_UNTIL);
setMaxRetries(DEFAULT_MAX_RETRIES);
}
setLastResponse(response);
mPreferences.commit();
}
/**
* Set the last license response received from the server and add to
* preferences. You must manually call PreferenceObfuscator.commit() to
* commit these changes to disk.
*
* @param l the response
*/
private void setLastResponse(int l) {
mLastResponseTime = System.currentTimeMillis();
mLastResponse = l;
mPreferences.putString(PREF_LAST_RESPONSE, Integer.toString(l));
}
/**
* Set the current retry count and add to preferences. You must manually
* call PreferenceObfuscator.commit() to commit these changes to disk.
*
* @param c the new retry count
*/
private void setRetryCount(long c) {
mRetryCount = c;
mPreferences.putString(PREF_RETRY_COUNT, Long.toString(c));
}
public long getRetryCount() {
return mRetryCount;
}
/**
* Set the last validity timestamp (VT) received from the server and add to
* preferences. You must manually call PreferenceObfuscator.commit() to
* commit these changes to disk.
*
* @param validityTimestamp the VT string received
*/
private void setValidityTimestamp(String validityTimestamp) {
Long lValidityTimestamp;
try {
lValidityTimestamp = Long.parseLong(validityTimestamp);
} catch (NumberFormatException e) {
// No response or not parsable, expire in one minute.
Log.w(TAG, "License validity timestamp (VT) missing, caching for a minute");
lValidityTimestamp = System.currentTimeMillis() + MILLIS_PER_MINUTE;
validityTimestamp = Long.toString(lValidityTimestamp);
}
mValidityTimestamp = lValidityTimestamp;
mPreferences.putString(PREF_VALIDITY_TIMESTAMP, validityTimestamp);
}
public long getValidityTimestamp() {
return mValidityTimestamp;
}
/**
* Set the retry until timestamp (GT) received from the server and add to
* preferences. You must manually call PreferenceObfuscator.commit() to
* commit these changes to disk.
*
* @param retryUntil the GT string received
*/
private void setRetryUntil(String retryUntil) {
Long lRetryUntil;
try {
lRetryUntil = Long.parseLong(retryUntil);
} catch (NumberFormatException e) {
// No response or not parsable, expire immediately
Log.w(TAG, "License retry timestamp (GT) missing, grace period disabled");
retryUntil = "0";
lRetryUntil = 0l;
}
mRetryUntil = lRetryUntil;
mPreferences.putString(PREF_RETRY_UNTIL, retryUntil);
}
public long getRetryUntil() {
return mRetryUntil;
}
/**
* Set the max retries value (GR) as received from the server and add to
* preferences. You must manually call PreferenceObfuscator.commit() to
* commit these changes to disk.
*
* @param maxRetries the GR string received
*/
private void setMaxRetries(String maxRetries) {
Long lMaxRetries;
try {
lMaxRetries = Long.parseLong(maxRetries);
} catch (NumberFormatException e) {
// No response or not parsable, expire immediately
Log.w(TAG, "Licence retry count (GR) missing, grace period disabled");
maxRetries = "0";
lMaxRetries = 0l;
}
mMaxRetries = lMaxRetries;
mPreferences.putString(PREF_MAX_RETRIES, maxRetries);
}
public long getMaxRetries() {
return mMaxRetries;
}
/**
* {@inheritDoc}
*
* This implementation allows access if either:<br>
* <ol>
* <li>a LICENSED response was received within the validity period
* <li>a RETRY response was received in the last minute, and we are under
* the RETRY count or in the RETRY period.
* </ol>
*/
public boolean allowAccess() {
long ts = System.currentTimeMillis();
if (mLastResponse == Policy.LICENSED) {
// Check if the LICENSED response occurred within the validity timeout.
if (ts <= mValidityTimestamp) {
// Cached LICENSED response is still valid.
return true;
}
} else if (mLastResponse == Policy.RETRY &&
ts < mLastResponseTime + MILLIS_PER_MINUTE) {
// Only allow access if we are within the retry period or we haven't used up our
// max retries.
return (ts <= mRetryUntil || mRetryCount <= mMaxRetries);
}
return false;
}
private Map<String, String> decodeExtras(String extras) {
Map<String, String> results = new HashMap<String, String>();
try {
URI rawExtras = new URI("?" + extras);
List<NameValuePair> extraList = URLEncodedUtils.parse(rawExtras, "UTF-8");
for (NameValuePair item : extraList) {
results.put(item.getName(), item.getValue());
}
} catch (URISyntaxException e) {
Log.w(TAG, "Invalid syntax error while decoding extras data from server.");
}
return results;
}
}