Metacat

/**

 *      Name: MetaCatServlet.java

 *   Purpose: A Class that implements a metadata catalog as a java Servlet

 * Copyright: 2000 Regents of the University of California and the

 *            National Center for Ecological Analysis and Synthesis

 *   Authors: Matt Jones, Dan Higgins

 *

 *   Version: '$Id: MetaCatServlet.java 184 2000-06-21 02:57:19Z jones $'

 */

package edu.ucsb.nceas.metacat;

import java.io.PrintWriter;

import java.io.IOException;

import java.io.Reader;

import java.io.StringReader;

import java.io.BufferedReader;

import java.util.Enumeration;

import java.util.Hashtable;

import java.util.ResourceBundle;

import java.util.PropertyResourceBundle;

import java.net.URL;

import java.net.MalformedURLException;

import java.sql.PreparedStatement;

import java.sql.ResultSet;

import java.sql.Connection;

import java.sql.SQLException;

import javax.servlet.ServletConfig;

import javax.servlet.ServletContext;

import javax.servlet.ServletException;

import javax.servlet.ServletInputStream;

import javax.servlet.http.HttpServlet;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

import javax.servlet.http.HttpUtils;

import oracle.xml.parser.v2.XSLStylesheet;

import oracle.xml.parser.v2.XSLException;

import oracle.xml.parser.v2.XMLDocumentFragment;

import oracle.xml.parser.v2.XSLProcessor;

import oracle.xml.parser.v2.*;    

import java.io.File;

import java.io.FileInputStream;

/**

 * A metadata catalog server implemented as a Java Servlet

 *

 * <p>Valid parameters are:<br>

 * action=query -- query the values of all elements and attributes

 *                     and return a result set of nodes<br>

 * action=squery -- structured query (@see pathquery.dtd)

 * doctype -- document type list returned by the query (publicID)

 * qformat=xml -- display resultset from query in XML<br>

 * qformat=html -- display resultset from query in HTML<br>

 * action=getdocument -- display an XML document in XML or HTML<br>

 * docid=34 -- display the document with the document ID number 34<br>

 * action=putdocument -- load an XML document into the database store<br>

 * doctext -- XML text ofthe document to load into the database<br>

 * query -- actual query text (to go with 'action=query' or 'action=squery')<br>

 * action=validate -- vallidate the xml contained in validatetext<br>

 * valtext -- XML text to be validated

 * action=getdatadoc -- retreive a stored datadocument

 * datadoc -- data document name (id)

 */

public class MetaCatServlet extends HttpServlet {

  private ServletConfig		config = null;

  private ServletContext	context = null;

  private Connection 		conn = null;

  private DBQuery		queryobj = null;

  private DBReader		docreader = null;

  private DBTransform		dbt = null;

  private String 		resultStyleURL = null;

  private String 		xmlcatalogfile = null;

  private String 		saxparser = null;

  private String    		defaultdatapath = null; 

					// path to directory where data files 

					// that can be downloaded will be stored

  private String    		executescript  = null;  

					// script to get data file and put it 

                                    	// in defaultdocpath dir

  private PropertyResourceBundle options = null;

  private MetaCatUtil util = null;

  /**

   * Initialize the servlet by creating appropriate database connections

   */

  public void init( ServletConfig config ) throws ServletException {

    try {

      super.init( config );

      this.config = config;

      this.context = config.getServletContext();

      System.out.println("MetaCatServlet Initialize");

      util = new MetaCatUtil();

      // Get the configuration file information

      resultStyleURL = util.getOption("resultStyleURL");

      xmlcatalogfile = util.getOption("xmlcatalogfile");

      saxparser = util.getOption("saxparser");

      defaultdatapath = util.getOption("defaultdatapath");

      executescript = util.getOption("executescript");

      try {

        // Open a connection to the database

        conn = util.openDBConnection();

        queryobj = new DBQuery(conn,saxparser);

        docreader = new DBReader(conn);

        dbt = new DBTransform(conn);

      } catch (Exception e) {

        System.err.println("Error opening database connection");

      }

    } catch ( ServletException ex ) {

      throw ex;

    }

  }

  /** Handle "GET" method requests from HTTP clients */

  public void doGet (HttpServletRequest request, HttpServletResponse response)

    throws ServletException, IOException {

    // Process the data and send back the response

    handleGetOrPost(request, response);

  }

  /** Handle "POST" method requests from HTTP clients */

  public void doPost( HttpServletRequest request, HttpServletResponse response)

    throws ServletException, IOException {

    // Process the data and send back the response

    handleGetOrPost(request, response);

  }

  /**

   * Control servlet response depending on the action parameter specified

   */

  private void handleGetOrPost(HttpServletRequest request, 

    HttpServletResponse response) 

    throws ServletException, IOException {

    if (conn == null) {

      System.err.println("Connection to database lost.  Reopening...");

      try {

        // Open a connection to the database

        conn = util.openDBConnection();

        queryobj = new DBQuery(conn, saxparser);

        docreader = new DBReader(conn);

        dbt = new DBTransform(conn);

      } catch (Exception e) {

        System.err.println("Error opening database connection");

      }

    }

    // Get a handle to the output stream back to the client

    PrintWriter out = response.getWriter();

    //response.setContentType("text/html");

    String name = null;

    String[] value = null;

    String[] docid = new String[3];

    Hashtable params = new Hashtable();

    Enumeration paramlist = request.getParameterNames();

    while (paramlist.hasMoreElements()) {

      name = (String)paramlist.nextElement();

      value = request.getParameterValues(name);

      // Decode the docid and mouse click information

      if (name.endsWith(".y")) {

        docid[0] = name.substring(0,name.length()-2);

        //out.println("docid => " + docid[0]);

        params.put("docid", docid);

        name = "ypos";

      }

      if (name.endsWith(".x")) {

        name = "xpos";

      }

      //out.println(name + " => " + value[0]);

      params.put(name,value);

    }

    // Determine what type of request the user made

    // if the action parameter is set, use it as a default

    // but if the ypos param is set, calculate the action needed

    String action = ((String[])params.get("action"))[0];

    long ypos = 0;

    try {

      ypos = (new Long(((String[])params.get("ypos"))[0]).longValue());

      //out.println("<P>YPOS IS " + ypos);

      if (ypos <= 13) {

        action = "getdocument";

      } else if (ypos > 13 && ypos <= 27) {

        action = "validate";

      } else if (ypos > 27) {

        action = "transform";

      } else {

        action = "";

      }

    } catch (Exception npe) {

      //out.println("<P>Caught exception looking for Y value.");

    }

    if (action.equals("query") || action.equals("squery")) {

      handleQueryAction(out, params, response);

    } else if (action.equals("getdocument")) {

      try {

        handleGetDocumentAction(out, params, response);

      } catch (ClassNotFoundException e) {

        out.println(e.getMessage());

      } catch (SQLException se) {

        out.println(se.getMessage());

      }

    } else if (action.equals("putdocument")) {

      handlePutDocumentAction(out, params, response);

    } else if (action.equals("validate")) {

      handleValidateAction(out, params, response);  

    } else if (action.equals("getdatadoc")) {

      handleGetDataDocumentAction(out, params, response);  

    } else {

      out.println("Error: action not registered.  Please report this error.");

    }

    // Close the stream to the client

    out.close();

  }

  /** 

   * Handle the database query request and return a result set, possibly

   * transformed from XML into HTML

   */

  private void handleQueryAction(PrintWriter out, Hashtable params, 

               HttpServletResponse response) {

      String action = ((String[])params.get("action"))[0];

      String query = ((String[])params.get("query"))[0]; 

      Hashtable doclist = null;

      String[] doctypeArr = null;

      String doctype = null;

      Reader xmlquery = null;

      // Run the query if it is a structured query

      // or, if it is a free-text, simple query,

      // format it first as a structured query and then run it

      if (action.equals("query")) {

        doctypeArr = (String[])params.get("doctype");

        doctype = null;

        if (doctypeArr != null) {

          doctype = ((String[])params.get("doctype"))[0]; 

        }

        if (doctype != null) {

          xmlquery = new StringReader(DBQuery.createQuery(query,doctype));

        } else {

          xmlquery = new StringReader(DBQuery.createQuery(query));

        }

      } else if (action.equals("squery")) {

        xmlquery = new StringReader(query);

      } else {

        System.err.println("Error handling query -- illegal action value");

      }

      if (queryobj != null) {

          doclist = queryobj.findDocuments(xmlquery);

      } else {

        out.println("Query Object Init failed.");

        return;

      }

      // Create a buffer to hold the xml result

      StringBuffer resultset = new StringBuffer();

      // Print the resulting root nodes

      String docid;

      String document = null;

      resultset.append("<?xml version=\"1.0\"?>\n");

      //resultset.append("<!DOCTYPE resultset PUBLIC " +

      //               "\"-//NCEAS//resultset//EN\" \"resultset.dtd\">\n");

      resultset.append("<resultset>\n");

      resultset.append("  <query>" + query + "</query>");

      Enumeration doclistkeys = doclist.keys(); 

      while (doclistkeys.hasMoreElements()) {

        docid = (String)doclistkeys.nextElement();

        document = (String)doclist.get(docid);

        resultset.append("  <document>" + document + "</document>");

      }

      resultset.append("</resultset>");

      String qformat = ((String[])params.get("qformat"))[0]; 

      if (qformat.equals("xml")) {

        // set content type and other response header fields first

        response.setContentType("text/xml");

        out.println(resultset.toString());

      } else if (qformat.equals("html")) {

        // set content type and other response header fields first

        response.setContentType("text/html");

        //out.println("Converting to HTML...");

        XMLDocumentFragment htmldoc = null;

        try {

          XSLStylesheet style = new XSLStylesheet(new URL(resultStyleURL), null);

          htmldoc = (new XSLProcessor()).processXSL(style, 

                     (Reader)(new StringReader(resultset.toString())),null);

          htmldoc.print(out);

        } catch (Exception e) {

          out.println("Error transforming document:\n" + e.getMessage());

        }

      }

  }

  /** 

   * Handle the database getdocument request and return a XML document, 

   * possibly transformed from XML into HTML

   */

  private void handleGetDocumentAction(PrintWriter out, Hashtable params, 

               HttpServletResponse response) 

               throws ClassNotFoundException, IOException, SQLException {

    String docidstr = null;

    String docid = null;

    String doc = null;

    try {

      // Find the document id number

      docidstr = ((String[])params.get("docid"))[0]; 

      //docid = (new Long(docidstr)).longValue();

      docid = docidstr;

      // Get the document indicated fromthe db

      doc = docreader.readXMLDocument(docid);

    } catch (NullPointerException npe) {

      response.setContentType("text/html");

      out.println("Error getting document ID: " + docidstr +" (" + docid + ")");

    }

      // Return the document in XML or HTML format

      String qformat = ((String[])params.get("qformat"))[0]; 

      if (qformat.equals("xml")) {

        // set content type and other response header fields first

        response.setContentType("text/xml");

        out.println(doc);

      } else if (qformat.equals("html")) {

        // set content type and other response header fields first

        response.setContentType("text/html");

        // Look up the document type

        String sourcetype = docreader.getDoctypeInfo(docid).getDoctype();

        // Transform the document to the new doctype

        dbt.transformXMLDocument(doc, sourcetype, "-//W3C//HTML//EN", out);

      }

  }

  /** 

   * Handle the database putdocument request and write an XML document 

   * to the database connection

   */

  private void handlePutDocumentAction(PrintWriter out, Hashtable params, 

               HttpServletResponse response) {

      // Get the document indicated

      String[] doctext = (String[])params.get("doctext");

      StringReader xml = new StringReader(doctext[0]);

      // write the document to the database

      try {

        DBWriter dbw = new DBWriter(xml, conn);

      } catch (SQLException e1) {

          out.println("Error 1 loading document:<p>\n" + e1.getMessage());

      }catch (IOException e2) {

          out.println("Error 2 loading document:<p>\n" + e2.getMessage());

      }catch (ClassNotFoundException e3) {

          out.println("Error 3 loading document:<p>\n" + e3.getMessage());

      }

      // set content type and other response header fields first

      response.setContentType("text/xml");

      out.println(doctext[0]);

  }

  /** 

   * Handle the validtion request and return the results 

   * to the requestor

   */

  private void handleValidateAction(PrintWriter out, Hashtable params, HttpServletResponse response) {

    // Get the document indicated

    String valtext = null;

    try {

      valtext = ((String[])params.get("valtext"))[0];

    } catch (Exception nullpe) {

      String docidstr = null;

      String docid = null;

      try {

        // Find the document id number

        docidstr = ((String[])params.get("docid"))[0]; 

        //docid = (new Long(docidstr)).longValue();

        docid = docidstr;

        // Get the document indicated fromthe db

        valtext = docreader.readXMLDocument(docid);

      } catch (NullPointerException npe) {

        response.setContentType("text/html");

        out.println("Error getting document ID: " + 

                     docidstr +" (" + docid + ")");

      }

    }

    SAXParser parser = new SAXParser();  // works for both Xerces and Oracle

    parser.setValidationMode(true);      // Oracle

    try {

      GenericXMLValidate gxv = new GenericXMLValidate(parser, xmlcatalogfile);

      boolean valid = gxv.validateString(valtext);

      // set content type and other response header fields first

      response.setContentType("text/html");

      out.println("<html>");

      out.println("<head><link rel=\"stylesheet\" type=\"text/css\" " +

                  "href=\"/xmltodb/rowcol.css\" /></head>");

      out.println("<body class=\"emlbody\">");

      if (valid) {

        out.println("The input XML is VALID!");

      } else {

        out.println("The input XML is NOT VALID<br />\n<pre>\n" 

                    + gxv.returnErrors() + "\n</pre>\n");

        //response.setContentType("text/xml");

        //out.println(valtext);

      } 

      out.println("</body></html>");

    } catch (NullPointerException npe2) {

      // set content type and other response header fields first

      response.setContentType("text/html");

      //out.println(valtext); 

      out.println("Error validating document."); 

    }

  }

  /** 

   * Look up the document type from the database

   *

   * @param docid the id of the document to look up

   */

  private String OldgetDoctype(long docid) {

    PreparedStatement pstmt;

    String doctype = null;

    try {

      pstmt =

        conn.prepareStatement("SELECT doctype " + 

                                "FROM xml_documents " +

                               "WHERE docid = ?");

      // Bind the values to the query

      pstmt.setLong(1, new Long(docid).longValue());

      pstmt.execute();

      try {

        ResultSet rs = pstmt.getResultSet();

        try {

          boolean tableHasRows = rs.next();

          if (tableHasRows) {

            try {

              doctype  = rs.getString(1);

            } catch (SQLException e) {

              System.out.println("Error with getString: " + e.getMessage());

            }

          }

        } catch (SQLException e) {

          System.out.println("Error with next: " + e.getMessage());

        }

      } catch (SQLException e) {

        System.out.println("Error with getrset: " + e.getMessage());

      }

      pstmt.close();

    } catch (SQLException e) {

      System.out.println("Error getting id: " + e.getMessage());

    }

    return doctype;

  }

  /** 

   * Handle the document request and return the results 

   * to the requestor

   */

  private void handleGetDataDocumentAction(PrintWriter out, Hashtable params, HttpServletResponse response) {

      boolean error_flag = false;

      String error_message = "";

      // Get the document indicated

      String[] datadoc = (String[])params.get("datadoc");

  //    defaultdatapath = "C:\\Temp\\";    // for testing only!!!

   //   executescript = "test.bat";        // for testing only!!!

      // set content type and other response header fields first

      response.setContentType("application/octet-stream");

   if (defaultdatapath!=null) {

        if(!defaultdatapath.endsWith(System.getProperty("file.separator"))) defaultdatapath=defaultdatapath+System.getProperty("file.separator");

      System.out.println("Path= "+defaultdatapath+datadoc[0]);

      if (executescript!=null) {

        String command = null;

        File scriptfile = new File(executescript);

        if (scriptfile.exists()) {

            command=executescript+" "+datadoc[0]; }  // execute script includes path

        else {     // look in defaultdatapath

                command = defaultdatapath+executescript+" "+datadoc[0];  // on Win98 one MUST include the .bat extender

        }

      System.out.println(command);

      try {

      Process proc = Runtime.getRuntime().exec(command);

      proc.waitFor();

      }

      catch (Exception eee) {

        System.out.println("Error running process!");

        error_flag = true;

        error_message = "Error running process!";}

      } // end executescript not null if

      File datafile = new File(defaultdatapath+datadoc[0]);

      try {

      FileInputStream fw = new FileInputStream(datafile);

      int x;

     while ((x = fw.read())!=-1) {

        out.write(x); }

      fw.close();

      }

      catch (Exception e) {

        System.out.println("Error in returning file\n"+e.getMessage());

        error_flag=true;

        error_message = error_message+"\nError in returning file\n"+e.getMessage();}

   } // end defaultdatapath not null if

  }

}