com.telenav.amazon.s3.tvmclient.AmazonTVMClient.java Source code

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Here is the source code for com.telenav.amazon.s3.tvmclient.AmazonTVMClient.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.telenav.amazon.s3.tvmclient;

import java.security.SecureRandom;
import java.util.Locale;

import org.apache.commons.codec.binary.Hex;

import android.util.Log;

/**
 * This class is uzsed to communicate with the Token Vending Machine specific for this application.
 */
public class AmazonTVMClient {
    private static final String LOG_TAG = "AmazonTVMClient";

    /**
     * The endpoint for the Token Vending Machine to connect to.
     */
    private String endpoint;

    /**
     * Use SSL when making connections to the Token Vending Machine.
     */
    private boolean useSSL;

    /**
     * The shared preferences where credentials are other aws access information is stored.
     */
    private SharedPreferences sharedPreferences;

    public AmazonTVMClient(SharedPreferences sharedPreferences, String endpoint, boolean useSSL) {
        this.endpoint = this.getEndpointDomainName(endpoint.toLowerCase(Locale.US));
        this.useSSL = useSSL;
        this.sharedPreferences = sharedPreferences;
    }

    /**
     * Anonymously register the current application/device with the Token Vending Machine.
     */
    public Response anonymousRegister() {
        Response response = Response.SUCCESSFUL;
        if (AmazonSharedPreferencesWrapper.getUidForDevice(this.sharedPreferences) == null) {
            String uid = this.generateRandomString();
            String key = this.generateRandomString();

            RegisterDeviceRequest registerDeviceRequest = new RegisterDeviceRequest(this.endpoint, this.useSSL, uid,
                    key);
            ResponseHandler handler = new ResponseHandler();

            response = this.processRequest(registerDeviceRequest, handler);
            if (response.requestWasSuccessful()) {
                AmazonSharedPreferencesWrapper.registerDeviceId(this.sharedPreferences, uid, key);
            }
        }

        return response;
    }

    /**
     * Gets a token from the Token Vending Machine. The registered key is used to secure the communication.
     */
    public Response getToken() {
        String uid = AmazonSharedPreferencesWrapper.getUidForDevice(this.sharedPreferences);
        String key = AmazonSharedPreferencesWrapper.getKeyForDevice(this.sharedPreferences);

        Request getTokenRequest = new GetTokenRequest(this.endpoint, this.useSSL, uid, key);
        ResponseHandler handler = new GetTokenResponseHandler(key);

        GetTokenResponse getTokenResponse = (GetTokenResponse) this.processRequest(getTokenRequest, handler);
        if (getTokenResponse.requestWasSuccessful()) {
            AmazonSharedPreferencesWrapper.storeCredentialsInSharedPreferences(this.sharedPreferences,
                    getTokenResponse.getAccessKey(), getTokenResponse.getSecretKey(),
                    getTokenResponse.getSecurityToken(), getTokenResponse.getExpirationDate());
        }

        return getTokenResponse;
    }

    /**
     * Process Request
     */
    protected Response processRequest(Request request, ResponseHandler handler) {
        Response response = null;
        int retries = 2;
        do {
            response = TokenVendingMachineService.sendRequest(request, handler);
            if (response.requestWasSuccessful()) {
                return response;
            } else {
                Log.w(LOG_TAG, "Request to Token Vending Machine failed with Code: [" + response.getResponseCode()
                        + "] Message: [" + response.getResponseMessage() + "]");
            }
        } while (retries-- > 0);

        return response;
    }

    /**
     * Creates a 128-bit random string.
     */
    public String generateRandomString() {
        SecureRandom random = new SecureRandom();
        byte[] randomBytes = random.generateSeed(16);
        String randomString = new String(Hex.encodeHex(randomBytes));
        return randomString;
    }

    private String getEndpointDomainName(String endpoint) {
        int startIndex = 0;
        int endIndex = 0;

        if (endpoint.startsWith("http://") || endpoint.startsWith("https://")) {
            startIndex = endpoint.indexOf("://") + 3;
        } else {
            startIndex = 0;
        }

        if (endpoint.charAt(endpoint.length() - 1) == '/') {
            endIndex = endpoint.length() - 1;
        } else {
            endIndex = endpoint.length();
        }

        return endpoint.substring(startIndex, endIndex);
    }
}