edu.vt.alerts.android.library.tasks.VerificationTask.java Source code

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Here is the source code for edu.vt.alerts.android.library.tasks.VerificationTask.java

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/*
 * File created on Feb 24, 2014 
 *
 * Copyright 2008-2014 Virginia Polytechnic Institute and State University
 *
 * 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 edu.vt.alerts.android.library.tasks;

import org.apache.http.HttpResponse;
import org.apache.http.StatusLine;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpGet;

import android.content.Context;
import android.os.AsyncTask;
import android.util.Log;
import edu.vt.alerts.android.library.api.Environment;
import edu.vt.alerts.android.library.callbacks.VerifyCallback;
import edu.vt.alerts.android.library.exceptions.UnexpectedNetworkResponseException;
import edu.vt.alerts.android.library.util.FileBasedKeyStoreContainer;
import edu.vt.alerts.android.library.util.HttpClientFactory;
import edu.vt.alerts.android.library.util.KeyStoreContainer;

/**
 * AsyncTask that is used to verify that the provided device is registered with
 * the VT Alerts Push Notification System.
 * 
 * Verification is made by attempting to GET the subscriber's URL, presenting
 * the certificate for the subscriber.
 * 
 * The following outcomes can occur:
 *   1) If the subscriber has no certificate or URL, verification fails.
 *   2) If the remote server returns a 401/403/404, verification fails.
 *   3) If the remote server returns a 200, verification passes.
 *   4) Any other response throws a UnexpectedNetworkResultException and is
 *      passed to the callback.
 *   
 * 
 * @author Michael Irwin
 */
public class VerificationTask extends AsyncTask<Void, Void, TaskResult<Boolean>> {

    private final Context context;
    private final VerifyCallback callback;
    private final Environment environment;
    private HttpClientFactory httpClientFactory = new HttpClientFactory();
    private KeyStoreContainer keyStoreContainer = new FileBasedKeyStoreContainer();

    /**
     * Create a new instance of the task
     * @param context The application context
     * @param environment The environment to run in
     * @param callback A callback to relay results
     */
    public VerificationTask(Context context, Environment environment, VerifyCallback callback) {
        this.context = context;
        this.callback = callback;
        this.environment = environment;
    }

    /**
     * {@inheritDoc}
     */
    @Override
    protected TaskResult<Boolean> doInBackground(Void... params) {
        try {
            if (keyStoreContainer.retrieveKeyStore(context, environment) == null)
                return new TaskResult<Boolean>(false, null);

            String subscriberUrl = environment.getRegisterUrl();
            if (subscriberUrl == null || subscriberUrl.length() == 0)
                return new TaskResult<Boolean>(false, null);

            HttpClient client = httpClientFactory.generateSubscriberClient(context, environment);
            HttpGet get = new HttpGet(subscriberUrl);
            HttpResponse response = client.execute(get);

            StatusLine statusLine = response.getStatusLine();
            int statusCode = statusLine.getStatusCode();
            Log.d("verification", "Received a " + statusCode);

            if (statusCode >= 200 || statusCode < 300) {
                return new TaskResult<Boolean>(true, null);
            } else if (statusCode == 401 || statusCode == 403 || statusCode == 404) {
                return new TaskResult<Boolean>(false, null);
            }

            throw new UnexpectedNetworkResponseException(
                    "Unexpected result while trying to verify subscription " + statusCode, statusCode,
                    statusLine.getReasonPhrase());
        } catch (Exception e) {
            return new TaskResult<Boolean>(null, e);
        }
    }

    /**
     * {@inheritDoc}
     */
    @Override
    protected void onPostExecute(TaskResult<Boolean> result) {
        if (result.exceptionThrown()) {
            callback.exceptionThrown(result.getException());
        } else if (result.getResult()) {
            callback.deviceVerified();
        } else {
            callback.deviceNotRegistered();
        }
    }

}