org.atombeat.xquery.functions.util.StreamZipEntryToResponse.java Source code

Introduction

Here is the source code for org.atombeat.xquery.functions.util.StreamZipEntryToResponse.java

Source

/*
 *  eXist Open Source Native XML Database
 *  Copyright (C) 2001-09 Wolfgang M. Meier
 *  wolfgang@exist-db.org
 *  http://exist.sourceforge.net
 *  
 *  This program is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU Lesser 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 Lesser General Public License for more details.
 *  
 *  You should have received a copy of the GNU Lesser General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 *  
 *  $Id: GetData.java 9749 2009-08-09 23:18:12Z ixitar $
 */
package org.atombeat.xquery.functions.util;

import java.io.InputStream;
import java.io.OutputStream;
import java.util.zip.ZipEntry;
import java.util.zip.ZipFile;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.exist.dom.QName;
import org.exist.http.servlets.ResponseWrapper;
import org.exist.xquery.BasicFunction;
import org.exist.xquery.Cardinality;
import org.exist.xquery.FunctionSignature;
import org.exist.xquery.Variable;
import org.exist.xquery.XPathException;
import org.exist.xquery.XQueryContext;
import org.exist.xquery.functions.response.ResponseModule;
import org.exist.xquery.value.FunctionParameterSequenceType;
import org.exist.xquery.value.JavaObjectValue;
import org.exist.xquery.value.Sequence;
import org.exist.xquery.value.SequenceType;
import org.exist.xquery.value.Type;

/**
 */
public class StreamZipEntryToResponse extends BasicFunction {

    protected static final Log logger = LogFactory.getLog(StreamZipEntryToResponse.class);

    public final static FunctionSignature signature = new FunctionSignature(
            new QName("stream-zip-entry-to-response", AtomBeatUtilModule.NAMESPACE_URI, AtomBeatUtilModule.PREFIX),
            "Streams an entry from a zip file to the current servlet response output stream.",
            new SequenceType[] {
                    new FunctionParameterSequenceType("path", Type.STRING, Cardinality.EXACTLY_ONE,
                            "The path of the zip file."),
                    new FunctionParameterSequenceType("entry", Type.STRING, Cardinality.EXACTLY_ONE,
                            "The name of the zip entry."),
                    new FunctionParameterSequenceType("content-type", Type.STRING, Cardinality.EXACTLY_ONE,
                            "The Content-Type HTTP header value.") },
            new SequenceType(Type.ITEM, Cardinality.EMPTY));

    public StreamZipEntryToResponse(XQueryContext context) {
        super(context, signature);
    }

    /* (non-Javadoc)
     * @see org.exist.xquery.BasicFunction#eval(org.exist.xquery.value.Sequence[], org.exist.xquery.value.Sequence)
     */
    public Sequence eval(Sequence[] args, Sequence contextSequence) throws XPathException {

        ResponseModule resModule = (ResponseModule) context.getModule(ResponseModule.NAMESPACE_URI);

        // request object is read from global variable $response
        Variable respVar = resModule.resolveVariable(ResponseModule.RESPONSE_VAR);

        if (respVar == null || respVar.getValue() == null)
            throw new XPathException(this, "No request object found in the current XQuery context.");

        if (respVar.getValue().getItemType() != Type.JAVA_OBJECT)
            throw new XPathException(this, "Variable $response is not bound to an Java object.");

        JavaObjectValue respValue = (JavaObjectValue) respVar.getValue().itemAt(0);

        if (!"org.exist.http.servlets.HttpResponseWrapper".equals(respValue.getObject().getClass().getName()))
            throw new XPathException(this,
                    signature.toString() + " can only be used within the EXistServlet or XQueryServlet");

        ResponseWrapper response = (ResponseWrapper) respValue.getObject();

        String path = args[0].getStringValue();
        logger.debug(path);
        String entry = args[1].getStringValue();
        logger.debug(entry);
        String contentType = args[2].getStringValue();
        logger.debug(contentType);
        response.setContentType(contentType);

        try {

            ZipFile f = new ZipFile(path);
            ZipEntry e = f.getEntry(entry);
            InputStream in = f.getInputStream(e);
            OutputStream out = response.getOutputStream();
            Stream.copy(in, out);
            response.flushBuffer(); // is this necessary?

        } catch (Exception e) {
            e.printStackTrace();
            throw new XPathException(this, "Exception while streaming data from zip file: " + e.getMessage(), e);
        }

        return Sequence.EMPTY_SEQUENCE;
    }

}