com.hhscyber.nl.tweets.url.URLUnshortener.java Source code

Introduction

Here is the source code for com.hhscyber.nl.tweets.url.URLUnshortener.java

Source

/*
 * To change this license header, choose License Headers in Project Properties.
 * To change this template file, choose Tools | Templates
 * and open the template in the editor.
 */
package com.hhscyber.nl.tweets.url;

import java.io.IOException;
import java.net.HttpURLConnection;
import java.net.Proxy;
import java.net.URL;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import com.google.common.io.Closeables;

/**
 * Expand short urls. Works with all the major url shorteners (t.co, bit.ly, fb.me, is.gd, goo.gl, etc).
 * @author Pedro Oliveira
 *
 */
public class URLUnshortener {

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

    public static final int DEFAULT_CONNECT_TIMEOUT = 1000;
    public static final int DEFAULT_READ_TIMEOUT = 1000;
    public static final int DEFAULT_CACHE_SIZE = 10000;

    private final int connectTimeout;
    private final int readTimeout;
    private final LRUCache<URL, URL> cache;

    public URLUnshortener() {
        this(DEFAULT_CONNECT_TIMEOUT, DEFAULT_READ_TIMEOUT, DEFAULT_CACHE_SIZE);
    }

    /**
     * @param connectTimeout HTTP connection timeout, in ms
     * @param readTimeout HTTP read timeout, in ms
     * @param cacheSize Number of resolved URLs to maintain in cache
     */
    public URLUnshortener(int connectTimeout, int readTimeout, int cacheSize) {
        this.connectTimeout = connectTimeout;
        this.readTimeout = readTimeout;
        this.cache = LRUCache.build(cacheSize);
    }

    /**
     * Expand the given short {@link URL}
     * @param address
     * @return
     */
    public URL expand(URL address) {

        //Check cache
        URL inCache = cache.get(address);
        if (inCache != null) {
            return inCache;
        }

        //Connect & check for the location field
        HttpURLConnection connection = null;
        try {
            connection = (HttpURLConnection) address.openConnection(Proxy.NO_PROXY);
            connection.setConnectTimeout(connectTimeout);
            connection.setInstanceFollowRedirects(false);
            connection.setReadTimeout(readTimeout);
            connection.connect();
            String expandedURL = connection.getHeaderField("Location");
            if (expandedURL != null) {
                URL expanded = new URL(expandedURL);
                cache.put(address, expanded);
                return expanded;
            }
        } catch (Throwable e) {
            LOGGER.warn("Problem while expanding {}", address, e);
        } finally {
            try {
                if (connection != null) {
                    Closeables.closeQuietly(connection.getInputStream());
                }
            } catch (IOException e) {
                LOGGER.warn("Unable to close connection stream", e);
            }
        }

        return address;
    }
}