/**
* Copyright (C) 2012-2017 52°North Initiative for Geospatial Open Source
* Software GmbH
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 as published
* by the Free Software Foundation.
*
* If the program is linked with libraries which are licensed under one of
* the following licenses, the combination of the program with the linked
* library is not considered a "derivative work" of the program:
*
* - Apache License, version 2.0
* - Apache Software License, version 1.0
* - GNU Lesser General Public License, version 3
* - Mozilla Public License, versions 1.0, 1.1 and 2.0
* - Common Development and Distribution License (CDDL), version 1.0
*
* Therefore the distribution of the program linked with libraries licensed
* under the aforementioned licenses, is permitted by the copyright holders
* if the distribution is compliant with both the GNU General Public
* License version 2 and the aforementioned licenses.
*
* 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.
*/
package org.n52.sos.binding;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.Collections;
import java.util.Set;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.xml.transform.OutputKeys;
import javax.xml.transform.Transformer;
import javax.xml.transform.TransformerException;
import javax.xml.transform.TransformerFactory;
import javax.xml.transform.sax.SAXSource;
import javax.xml.transform.stream.StreamResult;
import org.apache.xmlbeans.XmlObject;
import org.n52.sos.coding.OperationKey;
import org.n52.sos.decode.Decoder;
import org.n52.sos.exception.HTTPException;
import org.n52.sos.exception.ows.NoApplicableCodeException;
import org.n52.sos.ogc.ows.OwsExceptionReport;
import org.n52.sos.request.AbstractServiceRequest;
import org.n52.sos.response.AbstractServiceResponse;
import org.n52.sos.util.CodingHelper;
import org.n52.sos.util.XmlHelper;
import org.n52.sos.util.http.MediaType;
import org.n52.sos.util.http.MediaTypes;
import org.n52.sos.utils.EXIUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.xml.sax.InputSource;
import org.xml.sax.XMLReader;
import com.siemens.ct.exi.EXIFactory;
import com.siemens.ct.exi.api.sax.EXISource;
import com.siemens.ct.exi.exceptions.EXIException;
/**
* Binding implementation for EXI - Efficient XML Interchange See See <a
* href="http://www.w3.org/TR/exi/">http://www.w3.org/TR/exi/</a>
*
* @author Carsten Hollmann <c.hollmann@52north.org>
* @since 4.2.0
*
*/
public class EXIBinding extends SimpleBinding {
private static final EXIUtils EXI_UTILS = EXIUtils.getInstance();
private static final String URL_PATTERN = "/exi";
private static final Set<String> CONFORMANCE_CLASSES = Collections
.singleton("http://www.opengis.net/spec/SOS/2.0/conf/exi");
private static final Logger LOGGER = LoggerFactory.getLogger(EXIBinding.class);
@Override
public Set<String> getConformanceClasses() {
return CONFORMANCE_CLASSES;
}
@Override
protected MediaType getDefaultContentType() {
return MediaTypes.APPLICATION_EXI;
}
@Override
public String getUrlPattern() {
return URL_PATTERN;
}
@Override
public Set<MediaType> getSupportedEncodings() {
return Collections.singleton(MediaTypes.APPLICATION_EXI);
}
@Override
protected boolean isUseHttpResponseCodes() {
return true;
}
@Override
public boolean checkOperationHttpPostSupported(OperationKey k) throws HTTPException {
return hasDecoder(k, MediaTypes.TEXT_XML) || hasDecoder(k, MediaTypes.APPLICATION_XML);
}
@Override
public void doPostOperation(HttpServletRequest req, HttpServletResponse res) throws HTTPException, IOException {
AbstractServiceRequest<?> sosRequest = null;
try {
sosRequest = parseRequest(req);
AbstractServiceResponse sosResponse = getServiceOperator(sosRequest).receiveRequest(sosRequest);
writeResponse(req, res, sosResponse);
} catch (OwsExceptionReport oer) {
oer.setVersion(sosRequest != null ? sosRequest.getVersion() : null);
writeOwsExceptionReport(req, res, oer);
}
}
/**
* Parse and decode the incoming EXI encoded {@link InputStream}
*
* @param request
* {@link HttpServletRequest} with EXI encoded
* {@link InputStream}
* @return {@link AbstractServiceRequest} from EXI encoded
* {@link InputStream}
* @throws OwsExceptionReport
* If an error occurs during parsing
*/
protected AbstractServiceRequest<?> parseRequest(HttpServletRequest request) throws OwsExceptionReport {
XmlObject doc = decode(request);
if (LOGGER.isDebugEnabled()) {
LOGGER.debug("EXI-REQUEST: {}", doc.xmlText());
}
Decoder<AbstractServiceRequest<?>, XmlObject> decoder = getDecoder(CodingHelper.getDecoderKey(doc));
return decoder.decode(doc).setRequestContext(getRequestContext(request));
}
/**
* Parse the incoming EXI encoded {@link InputStream} transform to
* {@link XmlObject}
*
* @param request
* {@link HttpServletRequest} with EXI encoded
* {@link InputStream}
* @return {@link XmlObject} created from the EXI encoded
* {@link InputStream}
* @throws OwsExceptionReport
* If an error occurs during parsing
*/
protected XmlObject decode(HttpServletRequest request) throws OwsExceptionReport {
try (ByteArrayOutputStream os = new ByteArrayOutputStream()) {
EXIFactory ef = EXI_UTILS.newEXIFactory();
TransformerFactory tf = TransformerFactory.newInstance();
Transformer transformer = tf.newTransformer();
if (ef.isFragment()) {
transformer.setOutputProperty(OutputKeys.OMIT_XML_DECLARATION,"yes");
}
transformer.setOutputProperty(OutputKeys.METHOD, "xml");
transformer.setOutputProperty(OutputKeys.ENCODING, "UTF-8");
// decode EXI encoded InputStream
EXISource exiSource = new EXISource(ef);
XMLReader exiReader = exiSource.getXMLReader();
InputSource inputSource = new InputSource(request.getInputStream());
inputSource.setEncoding(request.getCharacterEncoding());
SAXSource saxSource = new SAXSource(inputSource);
saxSource.setXMLReader(exiReader);
transformer.transform(saxSource, new StreamResult(os));
// create XmlObject from OutputStream
return XmlHelper.parseXmlString(os.toString());
} catch (IOException ioe) {
throw new NoApplicableCodeException().causedBy(ioe).withMessage(
"Error while reading request! Message: %s", ioe.getMessage());
} catch (TransformerException te) {
throw new NoApplicableCodeException().causedBy(te).withMessage(
"Error while transforming request! Message: %s", te.getMessage());
} catch (EXIException exie) {
throw new NoApplicableCodeException().causedBy(exie).withMessage(
"Error while reading request! Message: %s", exie.getMessage());
}
}
}