Metacat

/**

 *  '$RCSfile$'

 *    Purpose: A class that gets Accession Number, check for uniqueness

 *             and register it into db

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

 *             National Center for Ecological Analysis and Synthesis

 *    Authors: Jivka Bojilova, Matt Jones

 *

 *   '$Author: tao $'

 *     '$Date: 2013-04-19 17:47:14 -0700 (Fri, 19 Apr 2013) $'

 * '$Revision: 7595 $'

 *

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License as published by

 * the Free Software Foundation; either version 2 of the License, or

 * (at your option) any later version.

 *

 * This program is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 * GNU General Public License for more details.

 *

 * You should have received a copy of the GNU General Public License

 * along with this program; if not, write to the Free Software

 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

 */

package edu.ucsb.nceas.metacat.common.query;

import java.io.IOException;

import java.io.InputStream;

import java.net.MalformedURLException;

import java.net.URL;

import java.util.List;

import java.util.Map;

import java.util.Set;

import javax.xml.parsers.DocumentBuilder;

import javax.xml.parsers.DocumentBuilderFactory;

import javax.xml.parsers.ParserConfigurationException;

import javax.xml.xpath.XPathConstants;

import javax.xml.xpath.XPathFactory;

import org.apache.commons.codec.net.URLCodec;

import org.apache.commons.logging.Log;

import org.apache.commons.logging.LogFactory;

import org.apache.solr.client.solrj.impl.CommonsHttpSolrServer;

import org.apache.solr.client.solrj.util.ClientUtils;

import org.apache.solr.common.params.SolrParams;

import org.apache.solr.schema.SchemaField;

import org.dataone.configuration.Settings;

import org.dataone.service.exceptions.NotFound;

import org.dataone.service.exceptions.NotImplemented;

import org.dataone.service.types.v1.Subject;

import org.w3c.dom.Document;

import org.w3c.dom.Node;

import org.w3c.dom.NodeList;

import org.xml.sax.SAXException;

/**

 * The query service for the http solr server.

 * @author tao

 *

 */

public class HttpSolrQueryService extends SolrQueryService {

    private static final String SELECTIONPHASE = "/select";

    private static final String SOLR_SYSTEMINFO_URLAPPENDIX = "solr.systeminfo.urlappendix";

    private static final String SOLR_SCHEMA_URLAPPENDIX = "sorl.schema.urlappendix";

    private static final String SPEC_PATH = "//str[@name=\"solr-spec-version\"]";

    private String solrServerBaseURL = null;

    private CommonsHttpSolrServer httpSolrServer = null;

    private static Log log = LogFactory.getLog(HttpSolrQueryService.class);

    /**

     * Constructor

     * @param httpSolrServer

     */

    public HttpSolrQueryService(CommonsHttpSolrServer httpSolrServer) {

        if(httpSolrServer == null) {

            throw new NullPointerException("HttpSolrQueryService.constructor - The httpSolrServer parameter can't be null");

        }

        this.httpSolrServer = httpSolrServer;

        this.solrServerBaseURL = httpSolrServer.getBaseURL();

    }

    /**

     * Query the Solr server with specified query string and the user's identity. This is the for the http solr server.

     * It is hard to transform the SolrQueryReponse object to the InputStream object for the HttpSolrServer

     * since the transform needs the SolrCore. We have to open the solr url directly to get the InputStream.

     * @param query the query string

     * @param subjects the user's identity which sent the query

     * @return the response

     * @throws NotFound 

     * @throws IOException 

     * @throws Exception

     */

    /*public InputStream query(String query, Set<Subject>subjects) throws NotFound, IOException {

        StringBuffer accessFilter = generateAccessFilterParamsString(subjects);

        if(accessFilter != null && accessFilter.length() != 0) {

            query = solrServerBaseURL+"/select?"+query+"&"+FILTERQUERY+"="+accessFilter.toString();

            query = ClientUtils.escapeQueryChars(query);

        } else {

            throw new NotFound("0000", "HttpSolrQueryService.query - There is no identity (even user public) for the user who issued the query");

        }

        log.info("==========HttpSolrQueryService.query - the final url for querying the solr http server is "+query);

        URL url = new URL(query);

        return url.openStream();

    }*/

    /**

     * Query the Solr server with specified query and user's identity. 

     * It is hard to transform the SolrQueryReponse object to the InputStream object for the HttpSolrServer

     * since the transform needs the SolrCore. We have to open the solr url directly to get the InputStream.

     * @param query the query params. 

     * @param subjects the user's identity which sent the query

     * @return the response

     * @throws IOException 

     * @throws NotFound 

     * @throws Exception

     */

    public  InputStream query(SolrParams query, Set<Subject>subjects) throws IOException, NotFound {

        boolean xmlFormat = false;

        String queryString = ClientUtils.toQueryString(query, xmlFormat);

        log.info("==========HttpSolrQueryService.query - the query string after transforming from the SolrParams to the string "+queryString);

        StringBuffer accessFilter = generateAccessFilterParamsString(subjects);

        if(accessFilter != null && accessFilter.length() != 0) {

            String accessStr = accessFilter.toString();

            log.debug("==========HttpSolrQueryService.query - the access string is "+accessStr);

            URLCodec urlCodec = new URLCodec();

            accessStr = urlCodec.encode(accessStr, "UTF-8");

            log.debug("==========HttpSolrQueryService.query - the access string after escape special characters string "+accessStr);

            queryString = queryString+"&"+FILTERQUERY+"="+accessStr;

        } else {

            throw new NotFound("0000", "HttpSolrQueryService.query - There is no identity (even user public) for the user who issued the query");

        }

        //queryString = ClientUtils.escapeQueryChars(queryString);

        queryString = solrServerBaseURL+SELECTIONPHASE+queryString;

        log.info("==========HttpSolrQueryService.query - the final url for querying the solr http server is "+queryString);

        URL url = new URL(queryString);    

        return url.openStream();

        //throw new NotImplemented("0000", "HttpSolrQueryService - the method of  query(SolrParams query, Set<Subject>subjects) is not for the HttpSolrQueryService. We donot need to implemente it");

    }

    /**

     * Get the fields list of the index schema

     * @return

     * @throws Exception

     */

    public  Map<String, SchemaField> getIndexSchemaFields() throws Exception {

        return null;

    }

    /**

     * Get the list of the valid field name (moved the fields names of the CopyFieldTarget).

     * @return

     */

    public List<String> getValidSchemaField() {

        return null;

    }

    /**

     * Get the version of the solr server.

     * @return

     */

    public String getSolrServerVersion() {

        if(solrSpecVersion == null) {

            getHttpSolrServerVersion();

        }  

        return solrSpecVersion;

    }

    /*

     * Get the solr server version from the system information url. 

     */

    private void getHttpSolrServerVersion() {

        String systemInfoUrlAppendix = Settings.getConfiguration().getString(SOLR_SYSTEMINFO_URLAPPENDIX);

        String systemInfoUrl = solrServerBaseURL+systemInfoUrlAppendix;

        try {

            Document doc = transformInputStreamToDoc((new URL(systemInfoUrl)).openStream());

            NodeList nodeList = (NodeList) XPathFactory.newInstance().newXPath()

                            .evaluate(SPEC_PATH, doc, XPathConstants.NODESET);

            if(nodeList != null && nodeList.getLength() >0) {

                Node specNode = nodeList.item(0);

                solrSpecVersion = specNode.getFirstChild().getNodeValue();

            } else {

                solrSpecVersion = UNKNOWN;

            }

        } catch (Exception e) {

            log.error("HttpSolrQueryService.getHttpSolrServerVersion - can't get the solr specification version since "+e.getMessage());

            solrSpecVersion = UNKNOWN;

        }

    }

    /**

     * Generate a Document from the InputStream

     * @param input

     * @return

     * @throws ParserConfigurationException

     * @throws SAXException

     * @throws IOException

     */

    private Document transformInputStreamToDoc(InputStream input) throws ParserConfigurationException, SAXException, IOException {

        DocumentBuilderFactory dbFactory = DocumentBuilderFactory.newInstance();

        DocumentBuilder dBuilder = dbFactory.newDocumentBuilder();

        Document doc = dBuilder.parse(input);

        return doc;

    }

}