com.neocotic.blingaer.link.LinkServiceImpl.java Source code

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/* Copyright (C) 2011 Alasdair Mercer, http://neocotic.com/
 * 
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 * 
 * The above copyright notice and this permission notice shall be included in all
 * copies or substantial portions of the Software.
 * 
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */
package com.neocotic.blingaer.link;

import java.io.File;
import java.io.InputStreamReader;
import java.io.Reader;
import java.io.UnsupportedEncodingException;
import java.net.URL;
import java.util.List;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

import org.apache.commons.lang3.StringEscapeUtils;
import org.apache.commons.lang3.StringUtils;
import org.apache.log4j.Logger;

import com.maxmind.geoip.Country;
import com.maxmind.geoip.LookupService;
import com.neocotic.blingaer.account.Account;
import com.neocotic.blingaer.application.Application;
import com.neocotic.blingaer.common.HashUtils;
import com.neocotic.blingaer.common.IOUtils;
import com.neocotic.blingaer.common.dao.DAOLocator;
import com.neocotic.blingaer.common.validation.ValidationResult;
import com.neocotic.blingaer.common.validation.ValidationRule;
import com.neocotic.blingaer.common.validation.Validator;
import com.neocotic.blingaer.common.validation.rule.StringValidationRule;
import com.neocotic.blingaer.common.validation.rule.URLValidationRule;
import com.neocotic.blingaer.link.dao.LinkDAO;

/**
 * An implementation of {@link LinkService} that provides the promised
 * functionality.
 * 
 * @author Alasdair Mercer
 */
// TODO: Test code
public class LinkServiceImpl implements LinkService {

    /** The {@code Logger} instance for {@link LinkServiceImpl}. */
    private static final Logger LOG = Logger.getLogger(LinkServiceImpl.class);

    /** The path to MaxMind's GeoIP API data {@code File}. */
    private static final String DATA_FILE_PATH = "/WEB-INF/GeoIP.dat";

    private LookupService lookup;
    private List<ValidationRule> urlValidationRules;

    /**
     * Provides quick and easy access to the {@link LinkDAO}.
     * 
     * @return an instance of {@code LinkDAO}
     */
    private LinkDAO dao() {
        return DAOLocator.getInstance().getDAO(LinkDAO.class);
    }

    /*
     * @see LinkService#fetchClick(Long)
     */
    @Override
    public Click fetchClick(Long id) {
        LOG.trace("Entered method - fetchClick");

        Click click = null;

        try {
            click = dao().getClickForId(id);
        } catch (LinkServiceException e) {
            LOG.debug("Swallowed exception", e);
        }

        LOG.trace("Exiting method - fetchClick");

        return click;
    }

    /*
     * @see LinkService#fetchClicks(Link)
     */
    @Override
    public List<Click> fetchClicks(Link link) {
        return dao().getClicksForLink(link);
    }

    /*
     * @see LinkService#fetchGlobalLink(Link)
     */
    @Override
    public Link fetchGlobalLink(Link link) {
        LOG.trace("Entered method - fetchGlobalLink");

        Link globalLink = null;

        if (link.getParent() != null) {
            try {
                globalLink = dao().getParentLink(link);
            } catch (LinkServiceException e) {
                LOG.debug("Swallowed exception", e);
            }
        }

        LOG.trace("Exiting method - fetchGlobalLink");

        return globalLink;
    }

    /*
     * @see LinkService#fetchCountry(String)
     */
    @Override
    public Country fetchCountry(String ipAddress) throws LinkServiceException {
        return lookup().getCountry(ipAddress);
    }

    /*
     * @see LinkService#fetchGlobalLink(String)
     */
    @Override
    public Link fetchGlobalLink(String url) throws IllegalArgumentException {
        if (validateUrl(url).hasErrors()) {
            throw new IllegalArgumentException("Invalid URL");
        }

        return dao().getGlobalLinkForUrl(url);
    }

    /*
     * @see LinkService#fetchLink(Long)
     */
    @Override
    public Link fetchLink(Long id) {
        LOG.trace("Entered method - fetchLink");

        Link link = null;

        try {
            link = dao().getLinkForId(id);
        } catch (LinkServiceException e) {
            LOG.debug("Swallowed exception", e);
        }

        LOG.trace("Exiting method - fetchLink");

        return link;
    }

    /*
     * @see LinkService#fetchLinkForHash(String)
     */
    @Override
    public Link fetchLinkForHash(String hash) {
        return LinkServiceFactory.getLinkService().fetchLink(HashUtils.toNumber(hash));
    }

    /*
     * @see LinkService#fetchLinkForShortUrl(String)
     */
    @Override
    public Link fetchLinkForShortUrl(String shortUrl) throws IllegalArgumentException {
        if (validateUrl(shortUrl).hasErrors()) {
            throw new IllegalArgumentException("Invalid URL");
        }

        return LinkServiceFactory.getLinkService()
                .fetchLink(HashUtils.toNumber(StringUtils.substringAfterLast(shortUrl, "/")));
    }

    /*
     * @see LinkService#fetchLinks(Account)
     */
    @Override
    public List<Link> fetchLinks(Account account) {
        return dao().getLinksForAccount(account);
    }

    /*
     * @see LinkService#fetchLinks(Application)
     */
    @Override
    public List<Link> fetchLinks(Application application) {
        return dao().getLinksForApplication(application);
    }

    /*
     * @see LinkService#fetchLinks(String)
     */
    @Override
    public List<Link> fetchLinks(String url) throws IllegalArgumentException {
        if (validateUrl(url).hasErrors()) {
            throw new IllegalArgumentException("Invalid URL");
        }

        return dao().getLinksForUrl(url);
    }

    /*
     * @see LinkService#fetchTitle(String)
     */
    @Override
    public String fetchTitle(String url) throws IllegalArgumentException {
        LOG.trace("Entered method - fetchTitle");

        if (validateUrl(url).hasErrors()) {
            throw new IllegalArgumentException("Invalid URL");
        }

        String content = null;
        Reader reader = null;

        try {
            reader = new InputStreamReader(new URL(url).openStream());

            content = IOUtils.toString(reader);

            reader.close();
        } catch (Exception e) {
            LOG.debug("Swallowed exception", e);
        } finally {
            IOUtils.closeQuietly(reader);
        }

        // Use URL if content could not be retrieved
        if (content == null) {
            return url;
        }

        // Attempts to extract charset declared in the HTML
        String charSet = null;
        Matcher matcher = Pattern.compile("/<meta[^>]*?charset=([^>]*?)\\/?>/is").matcher(content);

        while (matcher.find()) {
            charSet = StringUtils.trimToNull(matcher.group());
            break;
        }

        // Attempts to extract title declared in the HTML
        String title = null;
        matcher = Pattern.compile("/<title>(.*?)<\\/title>/is").matcher(content);

        while (matcher.find()) {
            title = StringUtils.trimToNull(matcher.group());
            break;
        }

        // If title wasn't found uses an error message (if applicable) or URL
        if (title == null) {
            title = (content.indexOf("Error") == 0) ? content : url;
        }

        // Attempts charset conversion to UTF-8
        try {
            if (charSet == null) {
                title = new String(title.getBytes(), "UTF-8");
            } else {
                title = new String(title.getBytes(charSet), "UTF-8");
            }
        } catch (UnsupportedEncodingException e) {
            LOG.debug("Swallowed exception", e);
        }

        // Removes HTML entities
        title = StringEscapeUtils.unescapeHtml4(title);

        // Removes all tags
        title = title.replaceAll("<(.|\\n)*?>", StringUtils.EMPTY);

        LOG.trace("Exiting method - fetchTitle");

        return title;
    }

    /**
     * Returns the {@code LookupService} used by MaxMind's GeoIP API to query
     * their data {@code File}.
     * <p>
     * The result is cached internally by this {@link LikeServiceImpl} to
     * improve performance of subsequent calls to this method.
     * 
     * @return the GeoIP {@code LookupService}
     * @throws LinkServiceException
     *             If the data {@code File} could not be accessed.
     */
    private LookupService lookup() throws LinkServiceException {
        LOG.trace("Entered method - lookup");

        if (lookup == null) {
            try {
                // TODO: Confirm GEOIP_MEMORY_CACHE is best option for GAE
                lookup = new LookupService(new File(LinkServiceImpl.class.getResource(DATA_FILE_PATH).toURI()),
                        LookupService.GEOIP_MEMORY_CACHE);
            } catch (Exception e) {
                LOG.debug("Throwing exception", e);

                throw new LinkServiceException(e);
            }
        }

        LOG.trace("Exiting method - lookup");

        return lookup;
    }

    /*
     * @see LinkService#removeLink(Link)
     */
    @Override
    public void removeLink(Link link) {
        dao().deleteLink(link);
    }

    /*
     * @see LinkService#storeLink(Link)
     */
    @Override
    public Link storeLink(Link link) {
        return dao().updateLink(link);
    }

    /**
     * Validates the specified URL specification.
     * 
     * @param url
     *            the URL to be validated
     * @return the {@link ValidationResult result} of the validation
     */
    private ValidationResult validateUrl(String url) {
        if (urlValidationRules == null) {
            urlValidationRules.add(new StringValidationRule());
            urlValidationRules.add(new URLValidationRule());
        }

        return Validator.validate(url, urlValidationRules);
    }
}