com.rightscale.service.FeedScraper.java Source code

Introduction

Here is the source code for com.rightscale.service.FeedScraper.java

Source

// Dashboard: an Android front-end to the RightScale dashboard
// Copyright (C) 2009 Tony Spataro <code@tracker.xeger.net>
//
// 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.rightscale.service;

import java.net.URI;
import java.net.URISyntaxException;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

import javax.xml.parsers.SAXParser;
import javax.xml.parsers.SAXParserFactory;

import net.xeger.rest.AbstractResource;
import net.xeger.rest.Session;

import org.apache.http.HttpEntity;
import org.xml.sax.InputSource;
import org.xml.sax.XMLReader;

import com.rightscale.app.dashboard.Routes;

import android.net.Uri;
import android.util.Log;

class FeedScraper extends AbstractResource implements Runnable {
    static final int DEFAULT_POLL_PERIOD = 5000;
    static final int MAX_POLL_PERIOD = 30000;
    static final int ERROR_POLL_PERIOD = MAX_POLL_PERIOD;

    static final SimpleDateFormat ATOM_DATE_FORMAT = new SimpleDateFormat("yyyy-mm-dd'T'HH:mm:ss'Z'");
    static final Pattern RESOURCE_REGEX = Pattern
            .compile("Resource:.*<a href=\"/acct/([0-9]+)\\?path=%2F([a-z]+)%2F([0-9]+)\">([^<]*)</a");
    static final Pattern EVENT_REGEX = Pattern.compile("Event:.*<a.*>([^<]*)</a>");

    DashboardFeed _context = null;
    URI _uri = null;
    boolean _shouldStop = false;

    public FeedScraper(DashboardFeed context, Session session, URI uri) throws URISyntaxException {
        super(session, true);
        _context = context;
        _uri = uri;
    }

    protected URI getBaseURI() {
        return _uri;
    }

    protected URI getResourceURI(String relativePath, String query) {
        return _uri;
    }

    public void stop() {
        _shouldStop = true;
    }

    public void run() {
        int pollPeriod = DEFAULT_POLL_PERIOD;

        while (false == _shouldStop) {
            boolean error = false;
            int interesting = 0;

            try {
                HttpEntity response = getEntity(null, null);

                SAXParserFactory spf = SAXParserFactory.newInstance();
                SAXParser sp = spf.newSAXParser();
                XMLReader xr = sp.getXMLReader();

                AtomParser parser = new AtomParser(this);
                xr.setContentHandler(parser);
                xr.parse(new InputSource(response.getContent()));
                response.consumeContent();
                interesting = parser.getNumInteresting();
            } catch (Exception e) {
                Log.e("FeedScraper", e.getClass().getName());
                e.printStackTrace();
                error = true;
            }

            if (error) {
                pollPeriod = ERROR_POLL_PERIOD;
            } else if (interesting == 0) {
                pollPeriod = (int) (pollPeriod * 1.5);
                pollPeriod = Math.max(pollPeriod, MAX_POLL_PERIOD);
            } else {
                pollPeriod = DEFAULT_POLL_PERIOD;
            }

            try {
                Thread.sleep(pollPeriod);
            } catch (InterruptedException e) {
                //someone may have set _shouldStop on us...
            }
        }
    }

    boolean reportFeedEvent(String updated, String htmlContent) {
        Date when;
        Uri subjectUri;
        String subjectName;
        String summary;

        try {
            when = ATOM_DATE_FORMAT.parse(updated);
        } catch (ParseException e) {
            e.printStackTrace();
            Log.e("FeedScraper", htmlContent);
            return false;
        }

        Matcher m = RESOURCE_REGEX.matcher(htmlContent);
        if (m.find()) {
            String accountId = m.group(1);
            String resource = m.group(2);
            String resourceId = m.group(3);
            subjectName = m.group(4);

            if (resource.equals("servers")) {
                subjectUri = Routes.showServer(accountId, resourceId);
            } else {
                Log.w("FeedScraper", "Unknown resource type:\n" + htmlContent);
                return false;
            }
        } else {
            //Log.w("FeedScraper", "No RESOURCE_REGEX:\n" + htmlContent);
            return false;
        }

        m = EVENT_REGEX.matcher(htmlContent);
        if (m.find()) {
            summary = m.group(1);
        } else {
            //Log.w("FeedScraper", "No EVENT_REGEX:\n" + htmlContent);
            return false;
        }

        return _context.onDashboardEvent(when, subjectUri, subjectName, summary);
    }
}