eu.eubrazilcc.lvl.storage.urlshortener.UrlShortener.java Source code

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Here is the source code for eu.eubrazilcc.lvl.storage.urlshortener.UrlShortener.java

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/*
 * Copyright 2014 EUBrazilCC (EU?Brazil Cloud Connect)
 * 
 * Licensed under the EUPL, Version 1.1 or - as soon they will be approved by 
 * the European Commission - subsequent versions of the EUPL (the "Licence");
 * You may not use this work except in compliance with the Licence.
 * You may obtain a copy of the Licence at:
 * 
 *   http://ec.europa.eu/idabc/eupl
 * 
 * Unless required by applicable law or agreed to in writing, software 
 * distributed under the Licence is distributed on an "AS IS" basis,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the Licence for the specific language governing permissions and 
 * limitations under the Licence.
 * 
 * This product combines work with different licenses. See the "NOTICE" text
 * file for details on the various modules and licenses.
 * The "NOTICE" text file is part of the distribution. Any derivative works
 * that you distribute must include a readable copy of the "NOTICE" text file.
 */

package eu.eubrazilcc.lvl.storage.urlshortener;

import static com.google.common.base.Preconditions.checkArgument;
import static com.google.common.base.Preconditions.checkState;
import static com.google.common.cache.CacheBuilder.newBuilder;
import static eu.eubrazilcc.lvl.core.conf.ConfigurationManager.CONFIG_MANAGER;
import static eu.eubrazilcc.lvl.core.util.NamingUtils.urlEncodeUtf8;
import static eu.eubrazilcc.lvl.storage.mongodb.jackson.MongoDBJsonMapper.JSON_MAPPER;
import static org.apache.commons.lang.StringUtils.isNotBlank;
import static org.apache.commons.lang.StringUtils.trimToNull;
import static org.slf4j.LoggerFactory.getLogger;

import java.io.IOException;
import java.net.URI;
import java.util.HashMap;
import java.util.Map;

import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.ResponseHandler;
import org.apache.http.entity.StringEntity;
import org.apache.http.util.EntityUtils;
import org.slf4j.Logger;

import com.fasterxml.jackson.core.type.TypeReference;
import com.google.common.cache.CacheLoader;
import com.google.common.cache.LoadingCache;
import com.google.common.collect.ImmutableMap;

import eu.eubrazilcc.lvl.core.http.client.TrustedHttpsClient;

/**
 * Converts long URLs into short ones using the Google URL Shortener API.
 * @author Erik Torres <ertorser@upv.es>
 * @see <a href="https://developers.google.com/url-shortener/v1/getting_started">URL Shortener API - Getting Started</a>
 */
public class UrlShortener {

    private static final Logger LOGGER = getLogger(UrlShortener.class);

    public static final int MAX_CACHED_ELEMENTS = 2000;
    public static final String URL_SHORTENER = "https://www.googleapis.com/urlshortener/v1/url";

    private static final LoadingCache<String, String> CACHE = newBuilder().maximumSize(MAX_CACHED_ELEMENTS)
            .build(new CacheLoader<String, String>() {
                @Override
                public String load(final String key) throws Exception {
                    return loadShortenedUrl(key);
                }
            });

    public static final String shortenUrl(final String url) {
        String url2 = null;
        checkArgument(isNotBlank(url2 = trimToNull(url)), "Uninitialized or invalid url");
        String shortenedUrl = null;
        try {
            shortenedUrl = CACHE.get(normalizeUrl(url2));
        } catch (Exception e) {
            LOGGER.error("Failed to shorten URL: " + url2, e);
        }
        return shortenedUrl;
    }

    private static final String normalizeUrl(final String url) {
        String normlizedUrl = url;
        try {
            final URI uri = new URI(url).normalize();
            normlizedUrl = uri.toURL().toString();
        } catch (Exception e) {
            LOGGER.error("Failed to normalize URL: " + url, e);
        }
        return normlizedUrl;
    }

    private static final String loadShortenedUrl(final String url) throws Exception {
        String url2 = null, shortenedUrl = null;
        checkArgument(isNotBlank(url2 = trimToNull(url)), "Uninitialized or invalid url");
        try (final TrustedHttpsClient httpClient = new TrustedHttpsClient()) {
            final ResponseHandler<String> responseHandler = new ResponseHandler<String>() {
                public String handleResponse(final HttpResponse response)
                        throws ClientProtocolException, IOException {
                    final int status = response.getStatusLine().getStatusCode();
                    if (status >= 200 && status < 300) {
                        final HttpEntity entity = response.getEntity();
                        return entity != null ? EntityUtils.toString(entity) : null;
                    } else {
                        throw new ClientProtocolException("Unexpected response status: " + status);
                    }
                }
            };
            final String response = httpClient.executePost(
                    URL_SHORTENER + (isNotBlank(CONFIG_MANAGER.getGoogleAPIKey())
                            ? "?key=" + urlEncodeUtf8(CONFIG_MANAGER.getGoogleAPIKey())
                            : ""),
                    ImmutableMap.of("Accept", "application/json", "Content-type", "application/json"),
                    new StringEntity("{ \"longUrl\" : \"" + url2 + "\" }"), responseHandler);
            final Map<String, String> map = JSON_MAPPER.readValue(response,
                    new TypeReference<HashMap<String, String>>() {
                    });
            checkState(map != null, "Server response is invalid");
            shortenedUrl = map.get("id");
            checkState(isNotBlank(shortenedUrl), "No shortened URL found in server response");
        }
        return shortenedUrl;
    }

}