com.experiment.trax.services.tvmclient.AWSSharedPreferencesWrapper.java Source code

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Here is the source code for com.experiment.trax.services.tvmclient.AWSSharedPreferencesWrapper.java

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/*
 * Copyright 2010-2013 Amazon.com, Inc. or its affiliates. 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.
 * A copy of the License is located at
 *
 *  http://aws.amazon.com/apache2.0
 *
 * or in the "license" file accompanying this file. This file 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.experiment.trax.services.tvmclient;

import android.content.SharedPreferences;
import com.amazonaws.auth.AWSCredentials;
import com.amazonaws.auth.BasicSessionCredentials;

/**
 * This utility class is used to store content in Android's Shared Preferences.
 * For maximum security the preferences should be private.
 */
public class AWSSharedPreferencesWrapper {

    private static final String AWS_ACCESS_KEY = "AWS_ACCESS_KEY";
    private static final String AWS_SECRET_KEY = "AWS_SECRET_KEY";
    private static final String AWS_SECURITY_TOKEN = "AWS_SECURITY_TOKEN";
    private static final String AWS_EXPIRATION_DATE = "AWS_EXPIRATION_DATE";

    private static final String AWS_DEVICE_UID = "AWS_DEVICE_UID";
    private static final String AWS_DEVICE_KEY = "AWS_DEVICE_KEY";

    /**
     * Set all of the Shared Preferences used by the Token Vending Machine to null.
     * This function is useful if the user needs/wants to log out to clear any user specific information.
     */
    public static void wipe(SharedPreferences sharedPreferences) {
        AWSSharedPreferencesWrapper.storeValueInSharedPreferences(sharedPreferences, AWS_DEVICE_UID, null);
        AWSSharedPreferencesWrapper.storeValueInSharedPreferences(sharedPreferences, AWS_DEVICE_KEY, null);
        AWSSharedPreferencesWrapper.storeValueInSharedPreferences(sharedPreferences, AWS_ACCESS_KEY, null);
        AWSSharedPreferencesWrapper.storeValueInSharedPreferences(sharedPreferences, AWS_SECRET_KEY, null);
        AWSSharedPreferencesWrapper.storeValueInSharedPreferences(sharedPreferences, AWS_SECURITY_TOKEN, null);
        AWSSharedPreferencesWrapper.storeValueInSharedPreferences(sharedPreferences, AWS_EXPIRATION_DATE, null);
    }

    /**
     * Stores the UID and Key that were registered in the Shared Preferences.
     * The UID and Key and used to encrypt/decrypt the Token that is returned from the Token Vending Machine.
     */
    public static void registerDeviceId(SharedPreferences sharedPreferences, String uid, String key) {
        AWSSharedPreferencesWrapper.storeValueInSharedPreferences(sharedPreferences, AWS_DEVICE_UID, uid);
        AWSSharedPreferencesWrapper.storeValueInSharedPreferences(sharedPreferences, AWS_DEVICE_KEY, key);
    }

    /**
     * Returns the current UID stored in Shared Preferences.
     */
    public static String getUidForDevice(SharedPreferences sharedPreferences) {
        return AWSSharedPreferencesWrapper.getValueFromSharedPreferences(sharedPreferences, AWS_DEVICE_UID);
    }

    /**
     * Returns the current Key stored in Shared Preferences.
     */
    public static String getKeyForDevice(SharedPreferences sharedPreferences) {
        return AWSSharedPreferencesWrapper.getValueFromSharedPreferences(sharedPreferences, AWS_DEVICE_KEY);
    }

    /**
     * Gets the AWS Access Key, AWS Secret Key and Security Token currently stored in Shared Preferences.  Then creates a Credentials object
     * and returns that object.
     */
    public static AWSCredentials getCredentialsFromSharedPreferences(SharedPreferences sharedPreferences) {
        String accessKey = AWSSharedPreferencesWrapper.getValueFromSharedPreferences(sharedPreferences,
                AWS_ACCESS_KEY);
        String secretKey = AWSSharedPreferencesWrapper.getValueFromSharedPreferences(sharedPreferences,
                AWS_SECRET_KEY);
        String securityToken = AWSSharedPreferencesWrapper.getValueFromSharedPreferences(sharedPreferences,
                AWS_SECURITY_TOKEN);

        return new BasicSessionCredentials(accessKey, secretKey, securityToken);
    }

    /**
     * Checks if the current Token's expiration date stored in Shared Preferences has expired.
     * A token that has expired or will expire in fifteen minutes or less is considered expired.
     */
    public static boolean areCredentialsExpired(SharedPreferences sharedPreferences) {
        String expirationDate = AWSSharedPreferencesWrapper.getValueFromSharedPreferences(sharedPreferences,
                AWS_EXPIRATION_DATE);
        if (expirationDate == null) {
            return true;
        } else {
            long timeInSeconds = Long.parseLong(expirationDate);
            return (timeInSeconds < (System.currentTimeMillis() + 15 * 60 * 100));
        }
    }

    /**
     * Stores the four pieces of information associated with a Token in the Shared Preferences.
     */
    public static void storeCredentialsInSharedPreferences(SharedPreferences sharedPreferences, String accessKey,
            String secretKey, String securityToken, String expirationDate) {
        AWSSharedPreferencesWrapper.storeValueInSharedPreferences(sharedPreferences, AWS_ACCESS_KEY, accessKey);
        AWSSharedPreferencesWrapper.storeValueInSharedPreferences(sharedPreferences, AWS_SECRET_KEY, secretKey);
        AWSSharedPreferencesWrapper.storeValueInSharedPreferences(sharedPreferences, AWS_SECURITY_TOKEN,
                securityToken);
        AWSSharedPreferencesWrapper.storeValueInSharedPreferences(sharedPreferences, AWS_EXPIRATION_DATE,
                expirationDate);
    }

    protected static void storeValueInSharedPreferences(SharedPreferences sharedPreferences, String key,
            String value) {
        SharedPreferences.Editor editor = sharedPreferences.edit();
        editor.putString(key, value);
        editor.commit();
    }

    protected static String getValueFromSharedPreferences(SharedPreferences sharedPreferences, String key) {
        return sharedPreferences.getString(key, null);
    }
}