source: main/trunk/greenstone3/src/java/org/greenstone/gsdl3/service/IViaRetrieve.java@ 26215

package org.greenstone.gsdl3.service;

// Greenstone classes
import org.greenstone.gsdl3.core.GSException;
import org.greenstone.util.Misc;
import org.greenstone.gsdl3.util.*;

// XML classes
import org.w3c.dom.Element; 
import org.w3c.dom.Document;
import org.w3c.dom.NodeList; 

import java.util.HashMap;
import java.util.ArrayList;
import java.io.File;
import java.io.InputStream;
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.IOException;
import java.net.HttpURLConnection;
import java.net.URLConnection;
import java.net.URL;
import java.net.Authenticator;
import java.net.MalformedURLException;

import org.apache.log4j.*;

/**
 *
 * @author Katherine Don
 * @version $Revision: 26215 $
 * Modified by  <a href="mailto:[email protected]">Chi-Yu Huang</a>
 */

public class IViaRetrieve 
    extends AbstractDocumentRetrieve {

      static Logger logger = Logger.getLogger(org.greenstone.gsdl3.service.IViaRetrieve.class.getName());
    

    protected String ivia_server_url = null;
    
    public IViaRetrieve() {
    does_structure = false;
    }
    
    //Configure IViaRetrieve Service
    public boolean configure(Element info, Element extra_info) 
    {
    if (!super.configure(info, extra_info)) {
        return false;
    }
    
    Element server_elem = (Element)GSXML.getChildByTagName(info, "iViaServer");
    if (server_elem == null) {
        logger.error("no iViaServer element found");
        return false;
    }
    ivia_server_url = server_elem.getAttribute("url");
    if (ivia_server_url.equals("")) {
        logger.error("no url for the iViaServer element");
        return false;
    }
    return true;
    
    }
        
    /** gets a document by sending a request to iVia, then processes it and creates a documentNode around the text */
    protected Element getNodeContent(String doc_id, String lang) 
    throws GSException {

    String url_string = ivia_server_url+"/cgi-bin/view_record?theme=gsdl3&record_id="+doc_id;

    StringBuffer buffer = new StringBuffer();
    try {
        BufferedReader reader = Misc.makeHttpConnection(url_string);
            String line;
        while((line = reader.readLine())!= null) {
        buffer.append(line);
        }
    } catch (java.net.MalformedURLException e) {
        throw new GSException("Malformed URL: "+url_string, GSXML.ERROR_TYPE_SYSTEM);
    } catch (java.io.IOException e) {
        throw new GSException("IOException during connection to "+url_string+": "+e.toString(),GSXML.ERROR_TYPE_SYSTEM);
    }

    String node_content = buffer.toString(); 

    String escaped_content = GSXML.xmlSafe(node_content);
    
    StringBuffer processed_content = new StringBuffer(escaped_content.length());
    processed_content.append("<nodeContent>");
    int pos = 0;
    int lastpos = 0;
    while ((pos = escaped_content.indexOf("&lt;a ", lastpos))!= -1) {
        processed_content.append(escaped_content.substring(lastpos, pos));
        int endpos = escaped_content.indexOf("&lt;/a&gt;", pos);
        if (endpos == -1) {
        break;
        }
        String link = escaped_content.substring(pos, endpos+10);
        link = convertLink(link);
        processed_content.append(link);
        lastpos = endpos+10;
    }
    processed_content.append(escaped_content.substring(lastpos)); // get the last bit
    processed_content.append("</nodeContent>");
        
    Document content_doc = this.converter.getDOM(processed_content.toString());
    if (content_doc == null) {
        logger.error("Couldn't parse node content");
        logger.error(processed_content.toString());
        return null;
    }
    
    Element content_element = content_doc.getDocumentElement();

    return (Element)this.doc.importNode(content_element,true);
    }
    
    /** converts a url from an <a> element into a greenstone suitable one */
    protected String convertLink(String aref) {
    if (aref.indexOf("href=&quot;http") != -1) {
        return aref; // an external link
    }
    String type = "other";
    if (aref.indexOf("/cgi-bin/canned_search")!=-1) {
        type="query";
    } else if (aref.indexOf("/cgi-bin/click_through") != -1) {
        type = "external";
    } else if (aref.indexOf("/cgi-bin/view_record") != -1) {
        type="document";
    } 
    
    int href_start = aref.indexOf("href=&quot;")+11;
    int href_end = aref.indexOf("&gt;", href_start);
    String href = aref.substring(href_start, href_end);
    String link_content = aref.substring(href_end+4, aref.length()-10);
    
    if (type.equals("external")) {
        // the external link is everything after the http at the end.
        String address = href.substring(href.lastIndexOf("http"));
        address = address.replaceAll("%3[aA]", ":");
        address = address.replaceAll("%2[fF]", "/");

        return "&lt;a href=\""+address+"\"&gt;"+link_content+"&lt;/a&gt;";
    }
    if (type.equals("other")) {
        return "other type of link ("+link_content+")";
    }
    StringBuffer result = new StringBuffer();
    result.append("<link type='");
    result.append(type);
    result.append("'");
    if (type.equals("query")) {
        result.append(" service='TextQuery'");
    }
    result.append(">");
    // add in the parameters
    href = href.substring(href.indexOf("?")+1);
    String [] params = href.split("&amp;");
    for (int i=0; i<params.length; i++) {
        String param = params[i];
        int eq_pos = param.indexOf("=");
        if (eq_pos != -1) {
        
        result.append("<param name='"+param.substring(0, eq_pos)+"' value='"+param.substring(eq_pos+1)+"'/>");
        }
    }
    result.append(link_content);
    result.append("</link>");

    return result.toString();
    }

    // iVia craps out if we ask for a metadata which is not valid. So need
    // to make sure we only ask for acceptable fields.
    protected boolean isAcceptableMetadata(String meta) {
    String valid_metadata = ",title,url,ivia_description,keywords,subjects,";
    if (valid_metadata.indexOf(","+meta+",")!=-1) {
        return true;
    }
    return false;
    }

    protected String translateId(String oid){
    int p = oid.lastIndexOf('.');
    if (p != oid.length()-3) {
        logger.info("translateoid error: '.' is not the third to last char!!");
        return oid;
    }
    String top = oid.substring(0, p);
    return top;
    }

    protected String translateExternalId(String id){
    return id;
    }

    protected String getDocType(String node_id){
        return GSXML.DOC_TYPE_SIMPLE;
    }
    protected String getRootId(String node_id){
    return node_id; 
    }

    protected ArrayList<String> getChildrenIds(String node_id){
    return null; 
    }
    
    protected String getParentId(String node_id){
    return null;
    }
    
    protected Element getMetadataList (String doc_id,
                       boolean all_metadata,
                       ArrayList<String> metadata_names,
                       String lang) 
    throws GSException {
    
    Element meta_list = this.doc.createElement(GSXML.METADATA_ELEM+GSXML.LIST_MODIFIER);

    // do the query to the iVia server
    StringBuffer field_list= new StringBuffer();
    boolean metadata_found = false;

    for (int i=0; i<metadata_names.size();i++){
        if (isAcceptableMetadata(metadata_names.get(i))){
        metadata_found = true;
        field_list.append(metadata_names.get(i));
        field_list.append(",");
        }
    }
    if (!metadata_found){
        return meta_list;
    }
    
    String url_string = ivia_server_url+"/cgi-bin/view_record_set?theme=gsdl3&record_id_list="+doc_id+"&field_list="+field_list.toString(); 
    try {
        BufferedReader reader = Misc.makeHttpConnection(url_string);
        String line;
        while  ((line = reader.readLine()) != null) {
        //metadata entry
        int col_pos = line.indexOf(':');
        if (col_pos == -1) {
            // end of the metadata for this doc
            break; 
        }
        String name = line.substring(0,col_pos);
        String value = line.substring(col_pos+2); // includes a space
        GSXML.addMetadata(this.doc, meta_list, name, value);
        }
    } catch (java.net.MalformedURLException e) {
        throw new GSException("Malformed URL: "+url_string, GSXML.ERROR_TYPE_SYSTEM);
    } catch (java.io.IOException e) {
        throw new GSException("IOException: "+e.toString(), GSXML.ERROR_TYPE_SYSTEM);
    }
    return meta_list;
    }
    
    protected String getStructureInfo(String doc_id, String info_type){
    return "";  
    }
}