/**
* This file is part of Graylog2.
*
* Graylog2 is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* Graylog2 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.
*
* You should have received a copy of the GNU General Public License
* along with Graylog2. If not, see <http://www.gnu.org/licenses/>.
*/
package org.graylog2.rest.resources.search.responses;
import au.com.bytecode.opencsv.CSVWriter;
import org.graylog2.indexer.results.ResultMessage;
import org.graylog2.indexer.results.ScrollResult;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import javax.ws.rs.Produces;
import javax.ws.rs.WebApplicationException;
import javax.ws.rs.core.MediaType;
import javax.ws.rs.core.MultivaluedMap;
import javax.ws.rs.ext.MessageBodyWriter;
import javax.ws.rs.ext.Provider;
import java.io.IOException;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.lang.annotation.Annotation;
import java.lang.reflect.Type;
import java.nio.charset.StandardCharsets;
import java.util.List;
@Provider
@Produces("text/csv")
public class ScrollChunkWriter implements MessageBodyWriter<ScrollResult.ScrollChunk> {
private static final Logger LOG = LoggerFactory.getLogger(ScrollChunkWriter.class);
public static final MediaType TEXT_CSV = new MediaType("text", "csv");
@Override
public boolean isWriteable(Class<?> type, Type genericType, Annotation[] annotations, MediaType mediaType) {
return ScrollResult.ScrollChunk.class.equals(type) && TEXT_CSV.isCompatible(mediaType);
}
@Override
public long getSize(ScrollResult.ScrollChunk scrollChunk,
Class<?> type,
Type genericType,
Annotation[] annotations,
MediaType mediaType) {
return -1;
}
@Override
public void writeTo(ScrollResult.ScrollChunk scrollChunk,
Class<?> type,
Type genericType,
Annotation[] annotations,
MediaType mediaType,
MultivaluedMap<String, Object> httpHeaders,
OutputStream entityStream) throws IOException, WebApplicationException {
if (LOG.isDebugEnabled()) {
LOG.debug("[{}] Writing chunk {}", Thread.currentThread().getId(), scrollChunk.getChunkNumber());
}
final CSVWriter csvWriter = new CSVWriter(new OutputStreamWriter(entityStream, StandardCharsets.UTF_8));
final List<String> fields = scrollChunk.getFields();
final int numberOfFields = fields.size();
if (scrollChunk.isFirstChunk()) {
// write field headers only on first chunk
csvWriter.writeNext(fields.toArray(new String[numberOfFields]));
}
// write result set in same order as the header row
final String[] fieldValues = new String[numberOfFields];
for (ResultMessage message : scrollChunk.getMessages()) {
int idx = 0;
// first collect all values from the current message
for (String fieldName : fields) {
final Object val = message.getMessage().get(fieldName);
if (val == null) {
fieldValues[idx] = null;
} else {
String stringVal = val.toString();
fieldValues[idx] = stringVal
.replaceAll("\n", "\\\\n")
.replaceAll("\r", "\\\\r");
}
idx++;
}
// write the complete line, some fields might not be present in the message, so there might be null values
csvWriter.writeNext(fieldValues);
}
if (csvWriter.checkError()) {
LOG.error("Encountered unspecified error when writing message result as CSV, result is likely malformed.");
}
csvWriter.close();
}
}