/* * OAIServer.java * Copyright (C) 2002 New Zealand Digital Library, http://www.nzdl.org * * 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., 675 Mass Ave, Cambridge, MA 02139, USA. */ package org.greenstone.gsdl3; import java.io.IOException; import java.io.PrintWriter; import java.util.HashSet; import java.util.Iterator; import java.util.Map; import javax.servlet.ServletConfig; import javax.servlet.ServletException; import javax.servlet.UnavailableException; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import org.apache.log4j.Logger; import org.greenstone.gsdl3.comms.Communicator; //import org.greenstone.gsdl3.comms.SOAPCommunicator; import org.greenstone.gsdl3.core.OAIMessageRouter; import org.greenstone.gsdl3.core.OAIReceptionist; import org.greenstone.gsdl3.util.HttpHeaderUtil; import org.greenstone.gsdl3.util.GSConstants; import org.greenstone.gsdl3.util.GSParams; import org.greenstone.gsdl3.util.GSXML; import org.greenstone.gsdl3.util.OAIResumptionToken; import org.greenstone.gsdl3.util.OAIXML; import org.greenstone.gsdl3.util.XMLConverter; import org.w3c.dom.Document; import org.w3c.dom.Element; import org.w3c.dom.Node; /** a servlet to serve the OAI metadata harvesting - we are using servlets instead * of cgi * the init method is called only once - the first time the servlet classes * are loaded. Each time a request comes in to the servlet, the session() * method is called in a new thread (calls doGet/doPut etc) * takes the verb= type args and builds a simple request to send to * the oai receptionist, which returns a result in xml, conforming to the OAI-PMH * protocol. * @see Receptionist */ /** * OAI server configuration instructions * * */ public class OAIServer extends BaseGreenstoneServlet { /** the receptionist to send messages to */ protected OAIReceptionist recept = null; /** * the default language - is specified by setting a servlet param, otherwise * DEFAULT_LANG is used */ protected String default_lang = null; /** * The default default - used if a default lang is not specified in the * servlet params */ protected final String DEFAULT_LANG = "en"; /** A HashSet which contains all the legal verbs. */ protected HashSet verb_set = null; /** * A HashSet which contains all the legal oai keys in the key/value argument * pair. */ protected HashSet param_set = null; /** * The name of the site with which we will finally be dealing, whether it is * a local site or a remote site through a communicator. */ protected String site = ""; // can be overriddden in OAIConfig.xml // do we output the stylesheet processing instruction? protected boolean use_oai_stylesheet = true; protected String oai_stylesheet = "interfaces/oai/oai2.xsl"; // there is no getQueryString() method in the HttpServletRequest returned from doPost, // since that is actually of type apache RequestFacade, and doesn't define such a method protected String queryString = null; static Logger logger = Logger.getLogger(org.greenstone.gsdl3.OAIServer.class.getName()); /** * initialise the servlet */ public void init(ServletConfig config) throws ServletException { // always call super.init, i.e., HttpServlet.; super.init(config); this.default_lang = config.getInitParameter(GSConstants.DEFAULT_LANG); String servlet_url_name=config.getInitParameter("servlet_url"); initVerbs(); initParams(); String site_name = config.getInitParameter(GSConstants.SITE_NAME); String library_name = config.getInitParameter(GSConstants.LIBRARY_NAME); String remote_site_name = null; String remote_site_type = null; String remote_site_address = null; if (site_name == null) { // no local site, try for communicator (remote site) remote_site_name = config.getInitParameter("remote_site_name"); remote_site_type = config.getInitParameter("remote_site_type"); remote_site_address = config.getInitParameter("remote_site_address"); if (remote_site_name == null || remote_site_type == null || remote_site_address == null) { logger.error("initialisation paramters not all set!"); logger.error("if site_name is not set, then you must have remote_site_name, remote_site_type and remote_site_address set"); throw new UnavailableException("OAIServer: incorrect servlet parameters"); } } if (this.default_lang == null) { // choose english this.default_lang = DEFAULT_LANG; } // Read in OAIConfig-xxx.xml (residing web/WEB-INF/classes/) and //use it to configure the receptionist. And pass it to MR Element oai_config = OAIXML.getOAIConfigXML(servlet_url_name); if (oai_config == null) { logger.error("Fail to parse oai config file OAIConfig-"+servlet_url_name+".xml"); throw new UnavailableException("OAIServer: Couldn't parse OAIConfig-"+servlet_url_name+".xml"); } // the receptionist -the servlet will talk to this this.recept = new OAIReceptionist(); // the receptionist uses a OAIMessageRouter or Communicator to send its requests to. We either create a OAIMessageRouter here for the designated site (if site_name set), or we create a Communicator for a remote site. The is given to the Receptionist, and the servlet never talks to it again directly. if (site_name != null) { if (library_name == null) { logger.error("servlet init-param library_name is not present. Defaulting to 'library'"); library_name = "library"; } //this site_name could consist of comma separated more than one site name. String mr_name = (String) config.getInitParameter("messagerouter_class"); OAIMessageRouter message_router = null; if (mr_name == null) { // just use the normal MR ********* message_router = new OAIMessageRouter(); } else { // try the specified one try { message_router = (OAIMessageRouter) Class.forName("org.greenstone.gsdl3.core." + mr_name).getDeclaredConstructor().newInstance(); } catch (Exception e) { // cant use this new one, so use normal one logger.error("OAIServlet configure exception when trying to use a new OAIMessageRouter " + mr_name, e); message_router = new OAIMessageRouter(); } } message_router.setSiteName(site_name); message_router.setLibraryName(library_name); // lots of work is done in this step; see OAIMessageRouter.java message_router.setOAIConfig(oai_config); if (!message_router.configure()) { throw new UnavailableException("OAIServer: Couldn't configure OAIMessageRouter"); } this.recept.setSiteName(site_name); this.recept.setMessageRouter(message_router); } else { // talking to a remote site, create a communicator Communicator communicator = null; // we need to create the XML to configure the communicator Document site_doc = XMLConverter.newDOM(); Element site_elem = site_doc.createElement(GSXML.SITE_ELEM); site_elem.setAttribute(GSXML.TYPE_ATT, remote_site_type); site_elem.setAttribute(GSXML.NAME_ATT, remote_site_name); site_elem.setAttribute(GSXML.ADDRESS_ATT, remote_site_address); if (remote_site_type.equals(GSXML.COMM_TYPE_SOAP_JAVA)) { try { //communicator = new SOAPCommunicator(); communicator = (Communicator) Class.forName("org.greenstone.gsdl3.comms.SOAPCommunicator").getDeclaredConstructor().newInstance(); } catch (Exception e) { logger.error("OAIServlet.init Error: Couldn't instatiate SOAPCommunicator"); throw new UnavailableException("OAIServer: No SOAPCommunicator available"); } } else { logger.error("OAIServlet.init Error: invalid Communicator type: " + remote_site_type); throw new UnavailableException("OAIServer: invalid communicator type"); } if (!communicator.configure(site_elem)) { logger.error("OAIServlet.init Error: Couldn't configure communicator"); throw new UnavailableException("OAIServer: Couldn't configure communicator"); } this.recept.setSiteName(remote_site_name); this.recept.setMessageRouter(communicator); } // pass it to the receptionist if (!this.recept.configure(oai_config)) { logger.error("Couldn't configure receptionist"); throw new UnavailableException("OAIServer: Couldn't configure receptionist"); } // also, we have something we want to get from here - useOAIStylesheet this.configure(oai_config); }//end of init() private void configure(Element oai_config) { Element use_stylesheet_elem = (Element) GSXML.getChildByTagName(oai_config, OAIXML.USE_STYLESHEET); if (use_stylesheet_elem != null) { String value = GSXML.getNodeText(use_stylesheet_elem); if (value.equals("no")) { this.use_oai_stylesheet = false; } } if (this.use_oai_stylesheet) { // now see if there is a custom stylesheet specified Element stylesheet_elem = (Element) GSXML.getChildByTagName(oai_config, OAIXML.STYLESHEET); if (stylesheet_elem != null) { String value = GSXML.getNodeText(stylesheet_elem); if (!value.equals("")) { oai_stylesheet = value; } } } } private void initVerbs() { verb_set = new HashSet(); verb_set.add(OAIXML.GET_RECORD); verb_set.add(OAIXML.LIST_RECORDS); verb_set.add(OAIXML.LIST_IDENTIFIERS); verb_set.add(OAIXML.LIST_SETS); verb_set.add(OAIXML.LIST_METADATA_FORMATS); verb_set.add(OAIXML.IDENTIFY); } private void initParams() { param_set = new HashSet(); param_set.add(OAIXML.METADATA_PREFIX); param_set.add(OAIXML.FROM); param_set.add(OAIXML.UNTIL); param_set.add(OAIXML.SET); param_set.add(OAIXML.RESUMPTION_TOKEN); param_set.add(OAIXML.IDENTIFIER); } private void logUsageInfo(HttpServletRequest request) { String usageInfo = ""; String query = (queryString == null) ? request.getQueryString() : queryString; //logged info = general-info + session-info usageInfo = request.getContextPath() + " " + //session id request.getServletPath() + " " + //servlet "[" + query + "]" + " " + //the query string "[" + usageInfo.trim() + "]" + " " + // params stored in a session request.getRemoteAddr() + " " + //remote address request.getHeader("user-agent") + " "; //the remote brower info logger.info(usageInfo); } /** * return true if the url is in the form of baseURL?verb=..., */ private boolean validate(String query, String verb) { //Here in OAIServer, only the verbs are validated. All the validation for individual verb // is taken in their doXXX() methods. if (query == null || !query.startsWith(OAIXML.VERB + "=")) { return false; } if (!verb_set.contains(verb)) { return false; } return true; } private String getVerb(String query) { if (query == null) return ""; int verb_start_index = query.indexOf("=") + 1;// first occurence of '=' int verb_end_index = query.indexOf("&"); if (verb_end_index == -1) { return query.substring(verb_start_index); } return query.substring(verb_start_index, verb_end_index); } public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { logUsageInfo(request); // oai always requires the content type be text/xml request.setCharacterEncoding("UTF-8"); response.setContentType("text/xml;charset=UTF-8"); PrintWriter out = response.getWriter(); // String lang = request.getParameter(GSParams.LANGUAGE); if (lang == null || lang.equals("")) { // use the default lang = this.default_lang; } // The following is a direct replacement for using: // 'request.getRequestURL().toString()' // to get the requestedURL. The former way of doing this works // correctly for a localhost setup, but breaks down when trying // to do this when Greenstone3 is configured through a reverse-proxy // (esp. if the Greenstone3 context has been changed) String baseURL = HttpHeaderUtil.externalRequestedURL(request); // this should be everything up to eg oaiserver //logger.error("requested URL = "+baseURL); // if called by doPost (if this was originally a POST request), var queryString would have been set String query = (queryString == null) ? request.getQueryString() : queryString; queryString = null; // reset member variable, else no doGet will work as long as the server remains running if (query!=null && query.equals("reset")) { logger.info("reset was called*******************"); out.println(""); out.println(this.recept.process("")); return; } String[] pairs = (query == null) ? null : query.split("&");//split into key/value pairs // besides "reset", the only other non-verb (non-OAI) requests allowed would be: (de)activate="collName" if(pairs != null && pairs.length == 1) { String command = pairs[0]; int index = command.indexOf('='); if(index != -1) { String collName = command.substring(index+1); command = command.substring(0, index); if(command.equals(GSXML.SYSTEM_TYPE_ACTIVATE)) { logger.info("activating OAI collection " + collName + " was called*******************"); out.println(""); out.println(this.recept.process("")); return; } else if(command.equals(GSXML.SYSTEM_TYPE_DEACTIVATE)) { logger.info("deactivating OAI collection " + collName + " was called*******************"); out.println(""); out.println(this.recept.process("")); return; } } // any other format for activate/deactivate command in query is wrong, continue processing and fail with "badVerb" message: } String verb = getVerb(query); Document response_doc = XMLConverter.newDOM(); Element xml_response = OAIXML.createBasicResponse(response_doc, baseURL, verb, pairs); Element verb_elem = null; if (validate(query, verb) == false) { if (verb_set.contains(verb) == false) { logger.error(OAIXML.BAD_VERB + ": " + query); verb_elem = OAIXML.createErrorElement(response_doc, OAIXML.BAD_VERB, OAIXML.ILLEGAL_OAI_VERB); } else { //must be something else other than bad verbs caused an error, so bad argument logger.error(OAIXML.BAD_ARGUMENT + ": " + query); verb_elem = OAIXML.createErrorElement(response_doc, OAIXML.BAD_ARGUMENT, ""); } xml_response.appendChild(verb_elem); out.println(""); if (this.use_oai_stylesheet) { out.println("\n"); } out.println(XMLConverter.getPrettyString(xml_response)); return; }//end of if(validate // The query is valid, we can now // compose the request message to the receptionist Document request_doc = XMLConverter.newDOM(); Element xml_message = request_doc.createElement(GSXML.MESSAGE_ELEM); Element xml_request = request_doc.createElement(GSXML.REQUEST_ELEM); // The type attribute is set to be 'oaiService' from OAIServer to OAIReceptionist. //xml_request.setAttribute(GSXML.TYPE_ATT, OAIXML.OAI_SERVICE); xml_request.setAttribute(GSXML.LANG_ATT, lang); xml_request.setAttribute(GSXML.TO_ATT, verb); xml_request.setAttribute(GSXML.BASE_URL, baseURL); addParams(xml_request, pairs); //xml_request.setAttribute(GSXML.OUTPUT_ATT, output);???? xml_message.appendChild(xml_request); Node xml_result = this.recept.process(xml_message); if (xml_result == null) { logger.info("xml_result is null"); verb_elem = OAIXML.createErrorElement(response_doc, "Internal error", ""); xml_response.appendChild(verb_elem); } else { /** * All response elements are in the form (with a corresponding verb * name): ... .. this * is optional! */ Node res = GSXML.getChildByTagName(xml_result, GSXML.RESPONSE_ELEM); if (res == null) { logger.info("response element in xml_result is null"); verb_elem = OAIXML.createErrorElement(response_doc, "Internal error", ""); } else { verb_elem = GSXML.getFirstElementChild(res); } if ( verb_elem.getTagName().equals(OAIXML.ERROR)) { xml_response.appendChild(response_doc.importNode(verb_elem, true)); } else if (OAIXML.oai_version.equals(OAIXML.OAI_VERSION2)) { xml_response.appendChild(response_doc.importNode(verb_elem, true)); } else { GSXML.copyAllChildren(xml_response, verb_elem); } } out.println(""); if (this.use_oai_stylesheet) { out.println("\n"); } out.println(XMLConverter.getPrettyString(xml_response)); return; } /** append parameter elements to the request sent to the receptionist */ public void addParams(Element request, String[] pairs) { Document doc = request.getOwnerDocument(); // no params apart from the verb if (pairs == null || pairs.length < 2) return; /** * the request xml is composed in the form: * (No paramList element in between). */ for (int i = 1; i < pairs.length; i++) { //the first pair in pairs is the verb=xxx int index = pairs[i].indexOf("="); if (index != -1) { //just a double check Element param = GSXML.createParameter(doc, pairs[i].substring(0, index), OAIXML.oaiDecode(pairs[i].substring(index + 1))); request.appendChild(param); } } } // For OAI version 2.0, validation tests indicated that POST needs to be supported. Some // modification was required in order to ensure that the request is passed intact to doGet() public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { // the post method returns a wrapper of type RequestFacade by apache and there // is no getQueryString() method defined for it. Therefore, need to work this out // manually before calling doGet(request, response) so that doGet can work as before. queryString = ""; Iterator parameter_entries = request.getParameterMap().entrySet().iterator(); while (parameter_entries.hasNext()) { Map.Entry param_entry = (Map.Entry) parameter_entries.next(); String[] paramVals = (String[]) param_entry.getValue(); if (paramVals != null) { if (paramVals.length > 0) { logger.error("POST request received: " + param_entry.getKey() + " - " + paramVals[0]); queryString = queryString + "&" + param_entry.getKey() + "=" + paramVals[0]; } } } if (queryString.length() > 0) { queryString = queryString.substring(1); //queryString = OAIXML.oaiEncode(queryString); } if (queryString.equals("")) { queryString = null; } doGet(request, response); } public void destroy() { recept.cleanUp(); } }