com.nadmm.airports.notams.NotamService.java Source code

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Here is the source code for com.nadmm.airports.notams.NotamService.java

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/*
 * FlightIntel for Pilots
 *
 * Copyright 2012-2015 Nadeem Hasan <nhasan@nadmm.com>
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

package com.nadmm.airports.notams;

import android.app.IntentService;
import android.content.Intent;
import android.support.v4.content.LocalBroadcastManager;
import android.text.format.DateUtils;

import com.nadmm.airports.utils.SystemUtils;
import com.nadmm.airports.utils.UiUtils;

import java.io.BufferedOutputStream;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.ArrayList;
import java.util.Date;
import java.util.Locale;

import javax.net.ssl.HttpsURLConnection;

public class NotamService extends IntentService {

    private static final String SERVICE_NAME = "notam";

    public static final String ACTION_GET_NOTAM = "flightintel.intent.action.GET_NOTAM";

    public static final String ICAO_CODE = "ICAO_CODE";
    public static final String NOTAM_PATH = "NOTAM_PATH";
    private static final long NOTAM_CACHE_MAX_AGE = 15 * DateUtils.MINUTE_IN_MILLIS;

    private final URL NOTAM_URL = new URL(
            "https://pilotweb.nas.faa.gov" + "/PilotWeb/notamRetrievalByICAOAction.do?method=displayByICAOs");
    private final String NOTAM_PARAM = "formatType=ICAO&retrieveLocId=%s&reportType=RAW"
            + "&actionType=notamRetrievalByICAOs&openItems=&submit=View%%20NOTAMs";

    private File mDataDir;

    public NotamService() throws MalformedURLException {
        super(SERVICE_NAME);
    }

    @Override
    public void onCreate() {
        super.onCreate();

        mDataDir = SystemUtils.getExternalDir(this, SERVICE_NAME);

        cleanupCache();
    }

    @Override
    protected void onHandleIntent(Intent intent) {
        String icaoCode = intent.getStringExtra(ICAO_CODE);
        File notamFile = new File(mDataDir, "NOTAM_" + icaoCode + ".txt");
        if (!notamFile.exists()) {
            try {
                fetchNotams(icaoCode, notamFile);
            } catch (IOException e) {
                UiUtils.showToast(this, e.getMessage());
            }
        }
        sendResult(notamFile);
    }

    private void fetchNotams(String icaoCode, File notamFile) throws IOException {
        String params = String.format(NOTAM_PARAM, icaoCode);

        HttpsURLConnection conn = (HttpsURLConnection) NOTAM_URL.openConnection();
        conn.setRequestProperty("Connection", "close");
        conn.setDoInput(true);
        conn.setDoOutput(true);
        conn.setUseCaches(false);
        conn.setConnectTimeout(30 * 1000);
        conn.setReadTimeout(30 * 1000);
        conn.setRequestMethod("POST");
        conn.setRequestProperty("User-Agent", "Mozilla/5.0 (X11; U; Linux i686; en-US)");
        conn.setRequestProperty("Content-Type", "application/x-www-form-urlencoded");
        conn.setRequestProperty("Content-Length", Integer.toString(params.length()));

        // Write out the form parameters as the request body
        OutputStream faa = conn.getOutputStream();
        faa.write(params.getBytes("UTF-8"));
        faa.close();

        int response = conn.getResponseCode();
        if (response == HttpURLConnection.HTTP_OK) {
            // Request was successful, parse the html to extract notams
            InputStream in = conn.getInputStream();
            ArrayList<String> notams = parseNotamsFromHtml(in);
            in.close();

            // Write the NOTAMS to the cache file
            BufferedOutputStream cache = new BufferedOutputStream(new FileOutputStream(notamFile));
            for (String notam : notams) {
                cache.write(notam.getBytes());
                cache.write('\n');
            }
            cache.close();
        }
    }

    private ArrayList<String> parseNotamsFromHtml(InputStream in) throws IOException {
        ArrayList<String> notams = new ArrayList<>();

        BufferedReader reader = new BufferedReader(new InputStreamReader(in));

        String line;
        boolean inside = false;
        StringBuilder builder = null;
        while ((line = reader.readLine()) != null) {
            if (!inside) {
                // Inspect the contents of all <pre> tags to find NOTAMs
                if (line.toUpperCase(Locale.US).contains("<PRE>")) {
                    builder = new StringBuilder();
                    inside = true;
                }
            }
            if (inside) {
                builder.append(line);
                builder.append(" ");
                if (line.toUpperCase(Locale.US).contains("</PRE>")) {
                    inside = false;
                    int start = builder.indexOf("!");
                    if (start >= 0) {
                        // Now get the actual inner contents
                        int end = builder.indexOf("SOURCE:");
                        String notam = builder.substring(start, end).trim();
                        // Normalize the whitespaces
                        //notam = whitespaces.matcher( notam ).replaceAll( " " );
                        notams.add(notam);
                    }
                }
            }
        }

        return notams;
    }

    protected void sendResult(File notamFile) {
        Intent result = new Intent();
        result.setAction(ACTION_GET_NOTAM);
        if (notamFile.exists()) {
            result.putExtra(NOTAM_PATH, notamFile.getAbsolutePath());
        }
        LocalBroadcastManager bm = LocalBroadcastManager.getInstance(this);
        bm.sendBroadcast(result);
    }

    private void cleanupCache() {
        Date now = new Date();
        File[] files = mDataDir.listFiles();
        for (File file : files) {
            long age = now.getTime() - file.lastModified();
            if (age > NOTAM_CACHE_MAX_AGE) {
                file.delete();
            }
        }
    }

}