source: MDService2/trunk/MDService2/src/eu/clarin/cmdi/mdservice/action/GenericProxyAction.java

package eu.clarin.cmdi.mdservice.action;

import java.io.BufferedInputStream;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.MalformedURLException;
import java.net.URISyntaxException;
import java.net.URL;
import java.util.HashMap;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpSession;
import javax.xml.transform.TransformerException;

import net.sf.json.JSON;
import net.sf.json.JSONArray;
import net.sf.json.JSONObject;
import net.sf.json.JSONSerializer;
//import net.sf.saxon.Controller;
//import net.sf.saxon.event.MessageEmitter;


import org.apache.struts2.interceptor.ServletRequestAware;
import com.opensymphony.xwork2.ActionSupport;
import eu.clarin.cmdi.mdservice.model.Diagnostics;
import eu.clarin.cmdi.mdservice.model.WorkspaceProfile;

/**
 * main Struts2 controller (ie implemenets the struts' execute()-method), all other Actions are derived from.   
 * Defines the methods used for retrieving the data 
 * and provides basic implementation where possible.
 *  
 * @author vronk
 */
public class GenericProxyAction extends ActionSupport 
implements ServletRequestAware 
{

        private static final long serialVersionUID = 1L;
        
        
        private Diagnostics diagnostics;
        /** 
         * Properties to be filled by Struts with according request-parameters
         */     
        private String actionkey;
        private String q;
        private String squery;
        private String cache = Cache.USE;
        private String collection;
        private String columns;
        private String startItem;
        private String maximumItems;
        private String sort;
        private String lang="en";
        private int maxdepth;   
        private String format;
        private String options;
        private String actionContentType;
        private String userMsg;
        private String repository;
        //private Map<String,Object> session;
        private HttpServletRequest request; 
        private long duration = 0;
        private InputStream resultStream;
        private InputStream sourceStream;
        protected URL base_url ;
                
         public GenericProxyAction(){
                 super();
                 initialize();
         }
         
         public void setRepositoryByIndex(int id){
                
                                net.sf.json.JSONArray json = WorkspaceProfile.getRepositories();
                                if (json.size() > 0){
                                        repository = json.getJSONObject(id).getString("name");
                                }
                        
         }
         
         protected void  initialize(){
                 //repository = 1;
                 setRepositoryByIndex(0);                               
         }
         
         
         public Diagnostics getDiagnostics(){
                 return this.diagnostics;
         }
         
         public void setDiagnostics(Diagnostics diagnostics){
                 this.diagnostics = diagnostics;
         }
         public Diagnostics Diagnostics(){
                 if (diagnostics == null){
                         diagnostics  = new Diagnostics();
                 }
                 return this.diagnostics;
         }
        public String getQ() {
                return q;
        }

        public void setQ(String pq) {
                if (pq == null) pq="";
                /*
                if (q != null){
                        if (q.trim().length() == 0){
                                q = null;
                        }
                }
                */
                this.q = pq;
        }

        public String getSquery() {
                return squery;
        }

        public void setSquery(String psquery) {
                if (psquery==null) psquery="";
                this.squery = psquery;
        }
        
        public String getCache() {
                return cache;
        }

        public void setCache(String cache) {
                this.cache = cache;
        }

        public String getCollection() {
                return collection;
        }

        public void setCollection(String collection) {
                this.collection = collection;
        }
        
        //TODO defaults
        public String getColumns() {
                String cols = columns;
                /*if (columns == null){
                        cols = "Id,Name,Title";
                }
                */
                return cols;
        }

        public void setColumns(String columns) {
                this.columns = columns;
        }
        
        public int getMaxdepth() {
                return maxdepth;
        }

        public void setMaxdepth(int maxdepth) {
                this.maxdepth = maxdepth;
        }

        public String getFormat() {
                return format;
        }

        public void setFormat(String format) {
                this.format = format;
        }

        public String getOptions() {
                return options;
        }

        public void setOptions(String options) {
                this.options = options;
        }

        /**
         * is used in struts.xml to dynamically set the mime-type of the result, depending on the format-parameter
         * @return
         */
        public String getActionContentType() {
                if (format.toLowerCase().startsWith("html")) {
                        this.actionContentType = "text/html";           
                        //this.actionContentType = "application/xhtml+xml";
                } else {
                        this.actionContentType = "text/xml";
                }
                
                return actionContentType;
        }

        public void setActionContentType(String actionContentType) {
                this.actionContentType = actionContentType;
        }
        

        public void setRepository(String repository) {
                this.repository = repository;
        }
        
        public String getRepository() {
                //default repository = 1 (set on init)
                return repository;
        }
        public String getActionkey() {
                return actionkey;
        }

        public void setActionkey(String actionKey) {
                actionkey = actionKey;
        }

        
        public String getStartItem() {
                return startItem;
        }

        public void setStartItem(String startItem) {
                this.startItem = startItem;
        }

        public String getMaximumItems() {
                return maximumItems;
        }

        public void setMaximumItems(String maximumItems) {
                this.maximumItems = maximumItems;
        }
        

        public String getSort() {
                return sort;
        }

        public void setSort(String sort) {
                this.sort = sort;
        }

        public String getLang() {
                return lang;
        }

        public void setLang(String lang) {
                this.lang = lang;
        }

        public String getFullFormat() {         
                return actionkey + "2" + format;
        }

        /**
         * internal identification of the target-proxy
         * base for finding the right base_url in the properties
         * subclass has to override with its specific proxykey
         * @return the key identifying this type of proxy
         */
        public String getProxyKey() {
                return "";
        }
        
        /**
         * TODO: check what this does, where it is used?
         * @return
         */
        public String getUserMsg() {
                return userMsg;
        }

        public void setUserMsg(String userMsg) {
                this.userMsg = this.userMsg + "\n" + userMsg;
        }
        
        /**
         * TODO: check what this does, where it is used?
         * @return
         */
        @Override
        public void setServletRequest(HttpServletRequest arg0) {
                request = arg0;
        }

        public HttpServletRequest getServletRequest() {
                return request;
        }

        /**
         * The stream holding the resulting data to be sent back to the user as response
         * @return
         */
        public InputStream getResultStream() {
                return resultStream;
    }
        public void setResultStream(InputStream _resultStream){
                resultStream = _resultStream;
        }
        public void setSourceStream(InputStream _sourceStream){
                sourceStream = _sourceStream;
        }
        
        /*
        public InputStream getSourceStream() throws IOException {
                return getTargetRequest().openStream();
    }
*/
        
        
        /**
         * Reads URI from the configuration (mdservice.properties) based on the proxy-key
         * @return the base-URI of the target repository or registry
         */
        public String getBaseURI() {            
                String uri =Admin.getConfig().getProperty(getProxyKey() + ".uri");              
                return uri;
        }

        /**
         * Provides the base-URL specific to given target repository or registry 
         * @return
         * @throws MalformedURLException
         */     
        public URL getBaseURL() throws MalformedURLException {          
                if (base_url == null) {
                        base_url = new URL(getBaseURI());//Admin.getConfig().getProperty(getProxyKey() + ".uri"));
                }
                return base_url;
        }
        
        /**
         * Constructs the actual URL to be send to the target repository/registry
         * It has to be overridden by the subclasses 
         * as every target service has a different request-pattern.  
         * @return URL of the target request 
         * @throws IOException
         */
        public URL getTargetRequest() throws IOException {
                URL targetURL = getBaseURL();                      
        return targetURL;
        }
        
        /**
         * Constructs an unambiguous key for the request (encoding all the parameters).
         * This is used as identifier for caching 
         * @return key unambiguously encoding the request
         */
        
         public String getRequestKey() {
                        String key="";
                        if (getActionkey()!=null) {
                                key += getActionkey() + "//-" ;
                        }else {
                                key +="//-" ;
                        }
                        if (getQ()!=null) {
                                key += getQ() + "//-" ;
                        } else {
                                key +="//-" ;
                        }
                        if (getCollection()!=null) {
                                key += getCollection() + "//-";
                        } else {
                                key +="//-" ;
                        }
                        if (getSquery()!=null) {
                                key += getSquery() + "//-" ;
                        } else {
                                key +="//-" ;
                        }
                        if (getStartItem()!=null) {
                                key += getStartItem() + "//-";
                        }
                                else{
                                        key +="//-" ;
                        }
                        if (getMaximumItems()!=null) {
                                key += getMaximumItems() + "//-";
                        }
                        else{
                                key +="//-" ;
                        }
                        
                        key += getRepository()  + "//-";
                        key += getMaxdepth()  + "//-";
                        
                        if (getLang()!=null) {
                                key += getLang() + "//-";
                        }else{
                                key +="//-" ;
                        }                       
                         
                return key;
        }
         
         
        public InputStream getSourceStream() throws IOException, NoStylesheetException {                
                return getTargetRequest().openStream();
 
        }
        
        
        
                public String addDurationKey(){
                String req_key = getRequestKey();
        
                Double duration_d;

            duration_d = (double)duration; 
            duration_d = duration_d/1000.0;
                req_key += duration_d + "//-";
                return req_key;
        }
        
        public HashMap<String,String> createTransformerParams(){
                
                HashMap<String,String> hm = new HashMap<String,String>();
                
            if (getFullFormat() != null){
                        hm.put("format", getFullFormat());
            }
                if (getColumns() != null){
                        hm.put("cols", getColumns());
                } else {
                        hm.put("cols", "");
                }
                if (getStartItem() != null){
                        hm.put("startItem", getStartItem());
                }
                if (getMaximumItems() != null){
                        hm.put("maximumItems", getMaximumItems());      
                }
                if (getLang() != null){
                        hm.put("lang", getLang());
                }
                if (getQ() != null){
                        hm.put("q", getQ());
                }
                //if (getRepository() != null){
                hm.put("repository_name", String.valueOf(getRepository()));
                hm.put("repository_type", WorkspaceProfile.getRepositoryType(this.getRepository()));
                //}
        
                return hm;
                
        }
        
        /**
         * This is the work-horse function.
         * It does two things: 
         * a) check if the source data is already in cache (based on cache-key that is constructed from the request parameters)
         * b) if format-parameter provided, invokes the transformation. 
         * at the end the data to be returned as result is contained in the resultStream
         * If format is xml, then the data from sourceStream is passed further as resultStream. 
         *    
         * @throws Exception  This is handled by struts (is mapped to some result in struts.xml based on the Exception-Class)
         */
        
        public void prepare() throws Exception {                
                
                String req_key = getRequestKey();
                Admin.notifyUser("request_key: " +  req_key); 
                Admin.notifyUser(getProxyKey() + ".targetURL: " + getTargetRequest() + " .format:" + getFullFormat());
                
                // Caching
                String xcid;
        
                // Admin.notifyUser("GPA.prepareSourceStream");
                
                if (getCache().equals(Cache.SKIP)) {
                        
                        sourceStream = getSourceStream();
                        
                } else { 
                        if (getCache().equals(Cache.USE)) {
                                        sourceStream = Cache.getCache().getFromCache(req_key);
                        }
                        if (sourceStream == null) { // either not in cache or cache_flag=refresh
                                //sourceStream = getTargetRequest().openStream();
                                long startMillis = System.currentTimeMillis();
                                sourceStream = getSourceStream();
                                duration = System.currentTimeMillis() - startMillis;
                                req_key = addDurationKey();
                                
                                long now = System.currentTimeMillis();
                                xcid = Cache.getCache().putInCache(req_key,sourceStream);                       
                                //Admin.notifyUser("putting in cache: " + req_key);                     
                                sourceStream = Cache.getCache().getFromCache(req_key);
                        } /* else {
                                Admin.notifyUser("reading from cache: " + req_key);
                        } */
                }
                        
                if (format.equals("xml")) {                     
                        resultStream = sourceStream;    
                }else {
                        MDTransformer transformer = new MDTransformer();
                        // set URL as srcFile (for MDTransformer to pass to xsl-scripts)
                        // TODO: WHY??
                        transformer.setSrcFile(getTargetRequest());
                        transformer.setParams(createTransformerParams());
                        // here the transformation is invoked
                        resultStream = transformer.transformXML(sourceStream);
                }
                        
                Admin.notifyUser(getProxyKey() + " success:" + (resultStream!=null));
        }

        /**
         * default Action method that gets called by Struts. Everything interesting happens in prepare()
         */
        public String execute() throws Exception {
//              HttpServletRequest request = ServletActionContext.getRequest();

                
                //Admin.notifyUser("session-attrs:");
        //Admin.notifyUser(getServletRequest().getRemoteUser() );
        //Admin.notifyUser(String.valueOf(getSession()));
        
        long now = System.currentTimeMillis();

                prepare();
                long duration = (System.currentTimeMillis() - now);
                //duration

                if (resultStream == null) {
                        return ERROR;   
                } else {
                        return SUCCESS;
                }               
        }


}