content: 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;
    }
  
  }
  