uri-resolver-manager/src/main/java/org/gcube/portlets/user/uriresolvermanager/resolvers/CatalogueResolver.java

package org.gcube.portlets.user.uriresolvermanager.resolvers;

import java.io.BufferedInputStream;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.net.HttpURLConnection;
import java.net.URL;
import java.util.Map;

import org.gcube.portlets.user.uriresolvermanager.entity.GenericResolver;
import org.gcube.portlets.user.uriresolvermanager.util.UrlEncoderUtil;
import org.gcube.portlets.user.urlshortener.UrlShortener;
import org.json.JSONObject;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * The Class CatalogueResolver.
 *
 * @author Francesco Mangiacrapa at ISTI-CNR francesco.mangiacrapa@isti.cnr.it
 * 
 *         Apr 4, 2024
 */
public class CatalogueResolver extends GenericResolver {

	private static final int _60SEC = 60000;
	public static final Logger LOG = LoggerFactory.getLogger(CatalogueResolver.class);

	/**
	 * Instantiates a new catalogue resolver wrapper.
	 *
	 * @param resourceName the resource name
	 * @param entryName    the entry name
	 */
	public CatalogueResolver(String resourceName, String entryName) {
		super(resourceName, entryName);
	}

	/**
	 * Gets the link.
	 *
	 * @param baseURI    the base URI
	 * @param parameters the parameters
	 * @return the link
	 * @throws Exception the exception
	 */
	@Override
	public String getLink(String baseURI, Map<String, String> parameters) throws Exception {
		LOG.debug("called getLink: " + baseURI + " parameters: " + parameters);

		HttpURLConnection con = null;
		String theResponse = null;
		try {

			URL urlObj = new URL(baseURI);
			con = (HttpURLConnection) urlObj.openConnection();
			con.setRequestMethod("POST");
			con.setRequestProperty("Content-Type", "application/json; charset=UTF-8");
			// con.setRequestProperty("Accept", "application/json");

			con.setDoOutput(true);
			con.setReadTimeout(_60SEC);
			con.setConnectTimeout(_60SEC);

			JSONObject jObj = new org.json.JSONObject();
			for (String key : parameters.keySet()) {
				jObj.put(key, parameters.get(key));
			}

//			if (queryStringParameters != null) {
//				String queryString = UrlEncoderUtil.toQueryString(queryStringParameters);
//				jObj.put(CatalogueResolverQueryStringBuilder.QUERY_STRING_PARAMETER, queryString);
//			}

			String toJSON = jObj.toString();
			LOG.info("Submitting JSON: " + toJSON);
			Integer code = null;
			try {

				OutputStream os = con.getOutputStream();
				os.write(toJSON.getBytes("UTF-8"));
				os.close();

				code = con.getResponseCode();
				theResponse = readResponse(con.getInputStream());

				if (!((200 <= code) && (code <= 208))) {
					throw new Exception(CatalogueResolver.class.getSimpleName()+" returned code: " + code + ". Response is: " + theResponse);
				}
			} catch (IOException e) {
				theResponse = readResponse(con.getInputStream());
				LOG.error(CatalogueResolver.class.getSimpleName()+" returned code: " + code + ". Response is: " + theResponse);
				throw e;
			}

		} catch (Exception e) {
			LOG.error(CatalogueResolver.class.getSimpleName() + " error:  ", e);
			throw e;
		} finally {
			try {
				if (con != null)
					con.disconnect();
			} catch (Exception e) {
				// silent
			}
		}
		LOG.info("Got Link: " + theResponse);
		return theResponse;

	}

	/**
	 * Short link.
	 *
	 * @param theLink    the the link
	 * @param parameters the parameters
	 * @return the string
	 * @throws Exception the exception
	 */
	@Override
	public String shortLink(String theLink, Map<String, String> parameters) throws Exception {
		LOG.info("specific shortLink called");

		String linkDecoded = theLink;

		String[] queryStringArray = theLink.split("\\?");
		if (queryStringArray.length > 1) {
			String queryString = queryStringArray[1];
			String queryStringEncoded = UrlEncoderUtil.encodeQuery(queryString);
			theLink = String.format("%s?%s", queryStringArray[0], queryStringEncoded);
		}

		try {
			LOG.info("Encoded link is: " + theLink);
			LOG.info("Shortner starts..");
			String shortLink = shortTheLink(theLink);
			LOG.info("Shorted link is: " + shortLink);
			if (shortLink != null && shortLink.equals(theLink)) {
				// here the short link and the input link are identical
				// so the shortening did not work
				// I'm returning the decoded link because it is directly consumable via browser
				LOG.debug("Shorted link is equal to input link, returning decoded link: " + linkDecoded);
				theLink = linkDecoded;
			} else {
				// here the link is really shorted
				LOG.debug("The link is really short, returning it");
				theLink = shortLink;
			}

		} catch (Exception e) {
			LOG.warn("An error occurred during link shortening: ", e);
			// here I'm returning the decoded link in case of error on shortening it
			theLink = linkDecoded;
		}

		return theLink;

	}

	/**
	 * Short the link.
	 *
	 * @param link the link
	 * @return the string
	 */
	private String shortTheLink(String link) {

		String toReturnLink = link;
		try {
			UrlShortener shortener = new UrlShortener();
			String shortedLink = shortener.shorten(link);
			LOG.info("Shorted link is: " + shortedLink);
			toReturnLink = shortedLink;
		} catch (Exception e) {
			LOG.warn("Returning source link, an error occurred during link shortening: ", e);
		}
		return toReturnLink;
	}

	/**
	 * Read response.
	 *
	 * @param ris the ris
	 * @return the string
	 * @throws IOException Signals that an I/O exception has occurred.
	 */
	private String readResponse(InputStream ris) throws IOException {
		// Receive the response from the server
		InputStream in = new BufferedInputStream(ris);
		BufferedReader reader = new BufferedReader(new InputStreamReader(in));
		StringBuilder result = new StringBuilder();
		String line;
		while ((line = reader.readLine()) != null) {
			result.append(line);
		}

		return result.toString();
	}

}