Metacat

/**

 * Copyright 2006 OCLC Online Computer Library Center Licensed under the Apache

 * License, Version 2.0 (the "License"); you may not use this file except in

 * compliance with the License. You may obtain a copy of the License at

 * http://www.apache.org/licenses/LICENSE-2.0 Unless required by applicable law or

 * agreed to in writing, software distributed under the License is distributed on

 * an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express

 * or implied. See the License for the specific language governing permissions and

 * limitations under the License.

 */

package edu.ucsb.nceas.metacat.oaipmh.provider.server;

import java.io.FileInputStream;

import java.io.FileNotFoundException;

import java.io.IOException;

import java.io.InputStream;

import java.io.OutputStreamWriter;

import java.io.Writer;

import java.net.SocketException;

import java.util.Date;

import java.util.Enumeration;

import java.util.HashMap;

import java.util.Properties;

import java.util.zip.DeflaterOutputStream;

import java.util.zip.GZIPOutputStream;

import javax.servlet.ServletConfig;

import javax.servlet.ServletContext;

import javax.servlet.ServletException;

import javax.servlet.http.HttpServlet;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

import javax.xml.transform.Transformer;

import javax.xml.transform.TransformerException;

import javax.xml.transform.TransformerFactory;

import javax.xml.transform.stream.StreamSource;

import org.apache.log4j.Logger;

import org.apache.log4j.PropertyConfigurator;

import edu.ucsb.nceas.metacat.oaipmh.provider.server.crosswalk.Eml2oai_dc;

import edu.ucsb.nceas.metacat.properties.PropertyService;

import edu.ucsb.nceas.metacat.shared.ServiceException;

import ORG.oclc.oai.server.catalog.AbstractCatalog;

import ORG.oclc.oai.server.verb.BadVerb;

import ORG.oclc.oai.server.verb.GetRecord;

import ORG.oclc.oai.server.verb.Identify;

import ORG.oclc.oai.server.verb.ListIdentifiers;

import ORG.oclc.oai.server.verb.ListMetadataFormats;

import ORG.oclc.oai.server.verb.ListRecords;

import ORG.oclc.oai.server.verb.ListSets;

import ORG.oclc.oai.server.verb.OAIInternalServerError;

import ORG.oclc.oai.server.verb.ServerVerb;

/**

 * OAIHandler is the primary Servlet for OAICat.

 * 

 * @author Jeffrey A. Young, OCLC Online Computer Library Center

 */

public class OAIHandler extends HttpServlet {

  /*

   * Class fields

   */

  private static final Logger log = Logger.getLogger(OAIHandler.class);

  private static final long serialVersionUID = 1L;

  private static final String VERSION = "1.5.57";

  private static boolean debug = false;

  // Set to false when developing and testing code outside of Metacat

  private static boolean integratedWithMetacat = true;

  /*

   * Class methods

   */

  /**

   * Get the VERSION number

   */

  public static String getVERSION() {

    return VERSION;

  }

  /**

   * Boolean to determine whether the Data Provider code is executing in a

   * Metacat application. This is normally true, but the 

   * 'integratedWithMetacat' value can be set to

   * false by a developer when testing the code outside of Metacat. This

   * eliminates dependencies on Metacat property settings.

   * 

   * @return

   */

  public static boolean isIntegratedWithMetacat() {

    return integratedWithMetacat;

  }

  /*

   * Instance fields

   */

  protected HashMap attributesMap = new HashMap();

  private final String CONFIG_DIR = "WEB-INF";

  private final String CONFIG_NAME = "metacat.properties";

  private final String LOG4J_NAME = "log4j.properties";

  private final String XSLT_DIR = "oaipmh";

  /*

   * Instance methods

   */

  /**

   * Peform the http GET action. Note that POST is shunted to here as well. The

   * verb widget is taken from the request and used to invoke an OAIVerb object

   * of the corresponding kind to do the actual work of the verb.

   * 

   * @param request

   *          the servlet's request information

   * @param response

   *          the servlet's response information

   * @exception IOException

   *              an I/O error occurred

   */

  public void doGet(HttpServletRequest request, HttpServletResponse response)

      throws IOException, ServletException {

    ServletConfig servletConfig = this.getServletConfig();

    //init_debug(servletConfig); // used when debugging the init() method

    String pathInfo = request.getPathInfo();

    HashMap attributes = getAttributes(pathInfo);

    Properties properties;

    if (!filterRequest(request, response)) { return; }

    log.debug("attributes=" + attributes);

    properties = (Properties) attributes.get("OAIHandler.properties");

    boolean monitor = false;

    if (properties.getProperty("OAIHandler.monitor") != null) {

      monitor = true;

    }

    boolean serviceUnavailable = isServiceUnavailable(properties);

    HashMap serverVerbs = ServerVerb.getVerbs(properties);

    Transformer transformer = 

                         (Transformer) attributes.get("OAIHandler.transformer");

    boolean forceRender = false;

    if ("true".equals(properties.getProperty("OAIHandler.forceRender"))) {

      forceRender = true;

    }

    // try {

    request.setCharacterEncoding("UTF-8");

    // } catch (UnsupportedEncodingException e) {

    // e.printStackTrace();

    // throw new IOException(e.getMessage());

    // }

    Date then = null;

    if (monitor) then = new Date();

    if (debug) {

      Enumeration headerNames = request.getHeaderNames();

      System.out.println("OAIHandler.doGet: ");

      while (headerNames.hasMoreElements()) {

        String headerName = (String) headerNames.nextElement();

        System.out.print(headerName);

        System.out.print(": ");

        System.out.println(request.getHeader(headerName));

      }

    }

    if (serviceUnavailable) {

      response.sendError(HttpServletResponse.SC_SERVICE_UNAVAILABLE,

          "Sorry. This server is down for maintenance");

    } 

    else {

      try {

        String userAgent = request.getHeader("User-Agent");

        if (userAgent == null) {

          userAgent = "";

        } else {

          userAgent = userAgent.toLowerCase();

        }

        Transformer serverTransformer = null;

        if (transformer != null) {

          // return HTML if the client is an old browser

          if (forceRender

              || userAgent.indexOf("opera") != -1

              || (userAgent.startsWith("mozilla") && userAgent

                  .indexOf("msie 6") == -1

              /* && userAgent.indexOf("netscape/7") == -1 */)) {

            serverTransformer = transformer;

          }

        }

        String result = getResult(attributes, request, response,

                                  serverTransformer, serverVerbs);

        // log.debug("result=" + result);

        // if (serverTransformer) { // render on the server

        // response.setContentType("text/html; charset=UTF-8");

        // StringReader stringReader = new StringReader(getResult(request));

        // StreamSource streamSource = new StreamSource(stringReader);

        // StringWriter stringWriter = new StringWriter();

        // transformer.transform(streamSource, new StreamResult(stringWriter));

        // result = stringWriter.toString();

        // } else { // render on the client

        // response.setContentType("text/xml; charset=UTF-8");

        // result = getResult(request);

        // }

        Writer out = getWriter(request, response);

        out.write(result);

        out.close();

      } 

      catch (FileNotFoundException e) {

        if (debug) {

          e.printStackTrace();

          System.out.println("SC_NOT_FOUND: " + e.getMessage());

        }

        response.sendError(HttpServletResponse.SC_NOT_FOUND, e.getMessage());

      } 

      catch (TransformerException e) {

        response.sendError(HttpServletResponse.SC_INTERNAL_SERVER_ERROR, 

                           e.getMessage()

                          );

      } 

      catch (OAIInternalServerError e) {

        response.sendError(HttpServletResponse.SC_INTERNAL_SERVER_ERROR, 

                           e.getMessage()

                          );

      } 

      catch (SocketException e) {

        System.out.println(e.getMessage());

        response.sendError(HttpServletResponse.SC_INTERNAL_SERVER_ERROR, 

                           e.getMessage()

                          );

      } 

      catch (Throwable e) {

        e.printStackTrace();

        response.sendError(HttpServletResponse.SC_INTERNAL_SERVER_ERROR, 

                           e.getMessage()

                          );

      }

    }

    if (monitor) {

      StringBuffer reqUri = new StringBuffer(request.getRequestURI().toString());

      String queryString = request.getQueryString(); // d=789

      if (queryString != null) {

        reqUri.append("?").append(queryString);

      }

      Runtime rt = Runtime.getRuntime();

      System.out.println(rt.freeMemory() + "/" + rt.totalMemory() + " "

          + ((new Date()).getTime() - then.getTime()) + "ms: "

          + reqUri.toString());

    }

  }

  /**

   * Perform a POST action. Actually this gets shunted to GET.

   * 

   * @param request

   *          the servlet's request information

   * @param response

   *          the servlet's response information

   * @exception IOException

   *              an I/O error occurred

   */

  public void doPost(HttpServletRequest request, HttpServletResponse response)

      throws IOException, ServletException {

    doGet(request, response);

  }

  /**

   * Override to do any pre-qualification; return false if the response should be

   * returned immediately, without further action.

   * 

   * @param request

   * @param response

   * @return false=return immediately, true=continue

   */

  protected boolean filterRequest(HttpServletRequest request,

      HttpServletResponse response) {

    return true;

  }

  public HashMap getAttributes(Properties properties) 

          throws Throwable {

    HashMap attributes = new HashMap();

    Enumeration attrNames = getServletContext().getAttributeNames();

    String serviceUnavailable;

    while (attrNames.hasMoreElements()) {

      String attrName = (String) attrNames.nextElement();

      Object attrValue = getServletContext().getAttribute(attrName);

      attributes.put(attrName, attrValue);

    }

    attributes.put("OAIHandler.properties", properties);

    String missingVerbClassName = properties.getProperty(

        "OAIHandler.missingVerbClassName", "ORG.oclc.oai.server.verb.BadVerb");

    Class missingVerbClass = Class.forName(missingVerbClassName);

    attributes.put("OAIHandler.missingVerbClass", missingVerbClass);

    serviceUnavailable = properties.getProperty("OAIHandler.serviceUnavailable");

    if (!"true".equals(serviceUnavailable)) {

      attributes.put("OAIHandler.version", VERSION);

      AbstractCatalog metacatCatalog = 

                       AbstractCatalog.factory(properties, getServletContext());

      attributes.put("OAIHandler.catalog", metacatCatalog);

    }

    boolean forceRender = false;

    if ("true".equals(properties.getProperty("OAIHandler.forceRender"))) {

      forceRender = true;

    }

    String styleSheet = properties.getProperty("OAIHandler.styleSheet");

    String appBase = properties.getProperty("OAIHandler.appBase");

    if (appBase == null) appBase = "webapps";

    String render = properties.getProperty("OAIHandler.renderForOldBrowsers");

    if ((styleSheet != null) && 

        ("true".equalsIgnoreCase(render) || forceRender)

       ) {

      InputStream is;

      try {

        is = new FileInputStream(appBase + "/" + styleSheet);

      } 

      catch (FileNotFoundException e) {

        // This is a silly way to skip the context name in the styleSheet name

        is = new FileInputStream(getServletContext().getRealPath(

            styleSheet.substring(styleSheet.indexOf("/", 1) + 1)));

      }

      StreamSource xslSource = new StreamSource(is);

      TransformerFactory tFactory = TransformerFactory.newInstance();

      Transformer transformer = tFactory.newTransformer(xslSource);

      attributes.put("OAIHandler.transformer", transformer);

    }

    return attributes;

  }

  public HashMap getAttributes(String pathInfo) {

    HashMap attributes = null;

    log.debug("pathInfo=" + pathInfo);

    if (pathInfo != null && pathInfo.length() > 0) {

      if (attributesMap.containsKey(pathInfo)) {

        log.debug("attributesMap containsKey");

        attributes = (HashMap) attributesMap.get(pathInfo);

      } 

      else {

        log.debug("!attributesMap containsKey");

        try {

          String fileName = pathInfo.substring(1) + ".properties";

          log.debug("attempting load of " + fileName);

          Thread thread = Thread.currentThread();

          ClassLoader classLoader = thread.getContextClassLoader();

          InputStream in = classLoader.getResourceAsStream(fileName);

          if (in != null) {

            log.debug("file found");

            Properties properties = new Properties();

            properties.load(in);

            attributes = getAttributes(properties);

          } 

          else {

            log.debug("file not found");

          }

          attributesMap.put(pathInfo, attributes);

        } 

        catch (Throwable e) {

          log.debug("Couldn't load file", e);

          // do nothing

        }

      }

    }

    if (attributes == null) log.debug("use global attributes");

    attributes = (HashMap) attributesMap.get("global");

    return attributes;

  }

  public static String getResult(HashMap attributes,

                                 HttpServletRequest request, 

                                 HttpServletResponse response,

                                 Transformer serverTransformer, 

                                 HashMap serverVerbs

                                ) 

      throws Throwable {

    String verb = request.getParameter("verb");

    log.debug("verb: " + verb);

    String result = null;

    if (verb != null) {

      if (verb.equals("GetRecord")) {

        result = GetRecord.construct(attributes, request, response,

          serverTransformer);

      } 

      else if (verb.equals("Identify")) {

        result = Identify.construct(attributes, request, response,

          serverTransformer);

      } 

      else if (verb.equals("ListIdentifiers")) {

        result = ListIdentifiers.construct(attributes, request, response,

          serverTransformer);

      } 

      else if (verb.equals("ListMetadataFormats")) {

        result = ListMetadataFormats.construct(attributes, request, response,

          serverTransformer);

      } 

      else if (verb.equals("ListRecords")) {

        result = ListRecords.construct(attributes, request, response,

          serverTransformer);

      } 

      else if (verb.equals("ListSets")) {

        result = ListSets.construct(attributes, request, response,

          serverTransformer);

      } 

      else {

        result = BadVerb.construct(attributes, request, response,

          serverTransformer);

      }

    }

    else {

      // Return a 'badVerb' response when the verb is missing from the request

      result = BadVerb.construct(attributes, request, response,

          serverTransformer);

    }

    return result;

    /*

     * } catch (NoSuchMethodException e) { throw new

     * OAIInternalServerError(e.getMessage()); } catch (IllegalAccessException

     * e) { throw new OAIInternalServerError(e.getMessage()); }

     */

  }

  /**

   * Get a response Writer depending on acceptable encodings

   * 

   * @param request

   *          the servlet's request information

   * @param response

   *          the servlet's response information

   * @exception IOException

   *              an I/O error occurred

   */

  public static Writer getWriter(HttpServletRequest request,

      HttpServletResponse response) throws IOException {

    Writer out;

    String encodings = request.getHeader("Accept-Encoding");

    if (debug) { System.out.println("encodings=" + encodings); }

    if (encodings != null && encodings.indexOf("gzip") != -1) {

      // System.out.println("using gzip encoding");

      // log.debug("using gzip encoding");

      response.setHeader("Content-Encoding", "gzip");

      out = new OutputStreamWriter(new GZIPOutputStream(response

          .getOutputStream()), "UTF-8");

      // } else if (encodings != null && encodings.indexOf("compress") != -1) {

      // // System.out.println("using compress encoding");

      // response.setHeader("Content-Encoding", "compress");

      // ZipOutputStream zos = new ZipOutputStream(response.getOutputStream());

      // zos.putNextEntry(new ZipEntry("dummy name"));

      // out = new OutputStreamWriter(zos, "UTF-8");

    } 

    else if (encodings != null && encodings.indexOf("deflate") != -1) {

      // System.out.println("using deflate encoding");

      // log.debug("using deflate encoding");

      response.setHeader("Content-Encoding", "deflate");

      out = new OutputStreamWriter(new DeflaterOutputStream(response

          .getOutputStream()), "UTF-8");

    } 

    else {

      // log.debug("using no encoding");

      out = response.getWriter();

    }

    return out;

  }

  /**

   * init is called one time when the Servlet is loaded. This is the place where

   * one-time initialization is done. Specifically, we load the properties file

   * for this application, and create the AbstractCatalog object for subsequent

   * use.

   * 

   * @param config

   *          servlet configuration information

   * @exception ServletException

   *              there was a problem with initialization

   */

  //public void init_debug(ServletConfig config) throws ServletException {

  public void init(ServletConfig config) throws ServletException {

    super.init(config);

    if (isIntegratedWithMetacat()) {

      try {

        PropertyService.getInstance();

      } 

      catch (ServiceException se) {

        System.err.println("Error in loading properties: " + se.getMessage());

      }

    }

    ServletContext servletContext = config.getServletContext();

    String configDirPath = servletContext.getRealPath(CONFIG_DIR);

    String configPath = configDirPath + "/" + CONFIG_NAME;

    // Initialize the properties file for log4j

    String log4jPath = configDirPath + "/" + LOG4J_NAME;

    PropertyConfigurator.configureAndWatch(log4jPath);

    // Initialize the directory path to the crosswalk XSLT files

    String xsltDirPath = servletContext.getRealPath(XSLT_DIR);

    Eml2oai_dc.setDirPath(xsltDirPath);

    try {

      HashMap attributes = null;

      Properties properties = null;

      InputStream in;

      try {

        log.debug("configPath=" + configPath);

        in = new FileInputStream(configPath);

      } 

      catch (FileNotFoundException e) {

        log.debug("configPath not found. Try the classpath: " + configPath);

        Thread thread = Thread.currentThread();

        ClassLoader classLoader = thread.getContextClassLoader();

        in = classLoader.getResourceAsStream(configPath);

      }

      if (in != null) {

        log.debug("configPath '" + configPath + "' found. Loading properties");

        properties = new Properties();

        properties.load(in);

        attributes = getAttributes(properties);

      }

      attributesMap.put("global", attributes);

    }

    catch (FileNotFoundException e) {

      e.printStackTrace();

      throw new ServletException(e.getMessage());

    } 

    catch (ClassNotFoundException e) {

      e.printStackTrace();

      throw new ServletException(e.getMessage());

    } 

    catch (IllegalArgumentException e) {

      e.printStackTrace();

      throw new ServletException(e.getMessage());

    } 

    catch (IOException e) {

      e.printStackTrace();

      throw new ServletException(e.getMessage());

    } 

    catch (Throwable e) {

      e.printStackTrace();

      throw new ServletException(e.getMessage());

    }

  }

  /**

   * Should the server report itself down for maintenance? Override this method

   * if you want to do this check another way.

   * 

   * @param properties

   * @return true=service is unavailable, false=service is available

   */

  protected boolean isServiceUnavailable(Properties properties) {

    if (properties.getProperty("OAIHandler.serviceUnavailable") != null) {

      return true;

    }

    return false;

  }

}