package org.apache.solr.handler;
/**
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
import org.apache.solr.update.processor.UpdateRequestProcessor;
import org.apache.solr.util.xslt.TransformerProvider;
import org.apache.solr.request.SolrQueryRequest;
import org.apache.solr.response.SolrQueryResponse;
import org.apache.solr.common.SolrException;
import org.apache.solr.common.util.ContentStream;
import org.apache.solr.common.util.ContentStreamBase;
import org.apache.solr.common.util.XMLErrorLogger;
import org.apache.solr.core.SolrConfig;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.apache.commons.io.IOUtils;
import javax.xml.stream.XMLStreamReader;
import javax.xml.stream.XMLStreamException;
import javax.xml.stream.XMLInputFactory;
import javax.xml.transform.Transformer;
import javax.xml.transform.TransformerException;
import javax.xml.transform.dom.DOMSource;
import javax.xml.transform.dom.DOMResult;
import javax.xml.transform.sax.SAXSource;
import org.xml.sax.InputSource;
import java.io.InputStream;
import java.io.IOException;
import java.util.Map;
/**
* Extends the XMLLoader by applying an XSLT transform before the
* XMLLoader actually loads the XML
*
**/
class XsltXMLLoader extends XMLLoader {
public static final String TRANSFORM_PARAM = "tr";
public static final String CONTEXT_TRANSFORMER_KEY = "xsltupdater.transformer";
private final Integer xsltCacheLifetimeSeconds;
public XsltXMLLoader(UpdateRequestProcessor processor, XMLInputFactory inputFactory, Integer xsltCacheLifetimeSeconds) {
super(processor, inputFactory);
this.xsltCacheLifetimeSeconds = xsltCacheLifetimeSeconds;
}
@Override
public void load(SolrQueryRequest req, SolrQueryResponse rsp, ContentStream stream) throws Exception {
final DOMResult result = new DOMResult();
final Transformer t = getTransformer(req);
InputStream is = null;
XMLStreamReader parser = null;
// first step: read XML and build DOM using Transformer (this is no overhead, as XSL always produces
// an internal result DOM tree, we just access it directly as input for StAX):
try {
is = stream.getStream();
final String charset = ContentStreamBase.getCharsetFromContentType(stream.getContentType());
final InputSource isrc = new InputSource(is);
isrc.setEncoding(charset);
final SAXSource source = new SAXSource(isrc);
t.transform(source, result);
} catch(TransformerException te) {
throw new SolrException(SolrException.ErrorCode.BAD_REQUEST, te.getMessage(), te);
} finally {
IOUtils.closeQuietly(is);
}
// second step feed the intermediate DOM tree into StAX parser:
try {
parser = inputFactory.createXMLStreamReader(new DOMSource(result.getNode()));
this.processUpdate(processor, parser);
} catch (XMLStreamException e) {
throw new SolrException(SolrException.ErrorCode.BAD_REQUEST, e.getMessage(), e);
} finally {
if (parser != null) parser.close();
}
}
/** Get Transformer from request context, or from TransformerProvider.
* This allows either getContentType(...) or write(...) to instantiate the Transformer,
* depending on which one is called first, then the other one reuses the same Transformer
*/
protected Transformer getTransformer(SolrQueryRequest request) throws IOException {
final String xslt = request.getParams().get(TRANSFORM_PARAM,null);
if(xslt==null) {
throw new IOException("'" + TRANSFORM_PARAM + "' request parameter is required to use the XSLTResponseWriter");
}
// not the cleanest way to achieve this
SolrConfig solrConfig = request.getCore().getSolrConfig();
// no need to synchronize access to context, right?
// Nothing else happens with it at the same time
final Map<Object,Object> ctx = request.getContext();
Transformer result = (Transformer)ctx.get(CONTEXT_TRANSFORMER_KEY);
if(result==null) {
result = TransformerProvider.instance.getTransformer(solrConfig, xslt,xsltCacheLifetimeSeconds.intValue());
result.setErrorListener(XsltUpdateRequestHandler.xmllog);
ctx.put(CONTEXT_TRANSFORMER_KEY,result);
}
return result;
}
}