view flys-client/src/main/java/de/intevation/flys/client/server/FileUploadServiceImpl.java @ 5779:ebec12def170

Datacage: Add a pool of builders to make it multi threadable. XML DOM is not thread safe. Therefore the old implementation only allowed one thread to use the builder at a time. As the complexity of the configuration has increased over time this has become a bottleneck of the whole application because it took quiet some time to build a result. Furthermore the builder code path is visited very frequent. So many concurrent requests were piled up resulting in long waits for the users. To mitigate this problem a round robin pool of builders is used now. Each of the pooled builders has an independent copy of the XML template and can be run in parallel. The number of builders is determined by the system property 'flys.datacage.pool.size'. It defaults to 4.
author Sascha L. Teichmann <teichmann@intevation.de>
date Sun, 21 Apr 2013 12:48:09 +0200
parents 04ccec566689
children
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package de.intevation.flys.client.server;

import de.intevation.artifacts.common.utils.XMLUtils;
import de.intevation.artifacts.common.utils.XMLUtils.ElementCreator;
import de.intevation.artifacts.httpclient.exceptions.ConnectionException;
import de.intevation.artifacts.httpclient.http.HttpClient;
import de.intevation.artifacts.httpclient.http.HttpClientImpl;

import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;

import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.apache.commons.codec.binary.Base64;
import org.apache.commons.fileupload.FileItemIterator;
import org.apache.commons.fileupload.FileItemStream;
import org.apache.commons.fileupload.servlet.ServletFileUpload;
import org.apache.log4j.Logger;
import org.w3c.dom.Document;
import org.w3c.dom.Element;

public class FileUploadServiceImpl
extends      HttpServlet
{
    private static final Logger logger = Logger.getLogger(FileUploadServiceImpl.class);

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) {
        logger.debug("handling post request.");

        String url  = getServletContext().getInitParameter("server-url");

        Document request = createFileXML(req);

        if (request == null) {
            return;
        }
        HttpClient client = new HttpClientImpl(url);

        try {
            Document result = client.callService(url, "fileupload", request);

            PrintWriter respWriter = resp.getWriter();
            respWriter.write("<html><link href='FLYS.css' rel='stylesheet' type='text/css'>");
            respWriter.write("<body><div style='font-face: Arial,Verdana,sans-serif; font-size: 11px'>");

            if (result == null) {
                logger.warn("FileUpload service returned no result.");
                respWriter.write("FileUpload service returned no result");
            }
            else {
                String status = result.getElementsByTagName("status")
                        .item(0).getTextContent();
                respWriter.write(status);
            }

            respWriter.write("</div></body></html>");
            respWriter.flush();

            return;
        }
        catch (ConnectionException ce) {
            logger.error(ce, ce);
        }
        catch (IOException e) {
            logger.error(e, e);
        }
    }


    protected Document createFileXML(HttpServletRequest req) {
           ServletFileUpload upload = new ServletFileUpload();

        try{
            FileItemIterator iter = upload.getItemIterator(req);

            while (iter.hasNext()) {
                FileItemStream item = iter.next();
                InputStream stream = item.openStream();

                // Process the input stream
                ByteArrayOutputStream out = new ByteArrayOutputStream();
                int len;
                byte[] buffer = new byte[stream.available()];
                while ((len = stream.read(buffer, 0, buffer.length)) != -1) {
                    out.write(buffer, 0, len);
                }

                buffer = Base64.encodeBase64(buffer);
                String b64File = new String(buffer);

                Document fileDoc = XMLUtils.newDocument();

                ElementCreator ec = new ElementCreator(fileDoc, null, null);
                Element root = ec.create("upload");
                Element id = ec.create("artifact-uuid");
                id.setTextContent(req.getParameter("uuid"));

                Element data = ec.create("data");
                data.setTextContent(b64File);

                fileDoc.appendChild(root);
                root.appendChild(id);
                root.appendChild(data);

                return fileDoc;
            }
        }
        catch(Exception e){
            logger.debug("Failed to create xml document containing the file.");
            logger.debug(e, e);
        }
        return null;
    }
}

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