Freedom9339 commented on code in PR #10013: URL: https://github.com/apache/nifi/pull/10013#discussion_r2276966413
########## nifi-extension-bundles/nifi-parquet-bundle/nifi-parquet-content-viewer/src/main/java/org/apache/parquet/web/controller/ParquetContentViewerController.java: ########## @@ -0,0 +1,142 @@ +/* + * 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. + */ +package org.apache.parquet.web.controller; + +import com.fasterxml.jackson.core.JsonGenerator; +import com.fasterxml.jackson.databind.ObjectMapper; +import com.fasterxml.jackson.databind.SerializationFeature; +import jakarta.servlet.ServletContext; +import jakarta.servlet.http.HttpServlet; +import jakarta.servlet.http.HttpServletRequest; +import jakarta.servlet.http.HttpServletResponse; +import org.apache.avro.generic.GenericRecord; +import org.apache.commons.io.output.ByteArrayOutputStream; +import org.apache.hadoop.conf.Configuration; +import org.apache.nifi.authorization.AccessDeniedException; +import org.apache.nifi.web.ContentAccess; +import org.apache.nifi.web.ContentRequestContext; +import org.apache.nifi.web.DownloadableContent; +import org.apache.nifi.web.HttpServletContentRequestContext; +import org.apache.nifi.web.ResourceNotFoundException; +import org.apache.parquet.avro.AvroParquetReader; +import org.apache.parquet.hadoop.ParquetReader; +import org.apache.parquet.io.InputFile; +import org.apache.nifi.parquet.shared.NifiParquetInputFile; +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; +import java.io.ByteArrayInputStream; +import java.io.IOException; +import java.io.InputStream; +import java.net.HttpURLConnection; + +public class ParquetContentViewerController extends HttpServlet { + private static final Logger logger = LoggerFactory.getLogger(ParquetContentViewerController.class); + private static final long MAX_CONTENT_SIZE = 1024 * 1024 * 2; // 10MB + private static final int BUFFER_SIZE = 8 * 1024; // 8KB + private static final ObjectMapper objectMapper = new ObjectMapper().enable(SerializationFeature.INDENT_OUTPUT); + + static { + objectMapper.getFactory().configure(JsonGenerator.Feature.AUTO_CLOSE_TARGET, false); + } + + @Override + public void doGet(final HttpServletRequest request, final HttpServletResponse response) throws IOException { + final ContentRequestContext requestContext = new HttpServletContentRequestContext(request); + + final ServletContext servletContext = request.getServletContext(); + final ContentAccess contentAccess = (ContentAccess) servletContext.getAttribute("nifi-content-access"); + // get the content + final DownloadableContent downloadableContent; + try { + downloadableContent = contentAccess.getContent(requestContext); + } catch (final ResourceNotFoundException e) { + logger.warn("Content not found", e); + response.sendError(HttpURLConnection.HTTP_NOT_FOUND, "Content not found"); + return; + } catch (final AccessDeniedException e) { + logger.warn("Content access denied", e); + response.sendError(HttpURLConnection.HTTP_FORBIDDEN, "Content access denied"); + return; + } catch (final Exception e) { + logger.warn("Content retrieval failed", e); + response.sendError(HttpURLConnection.HTTP_INTERNAL_ERROR, "Content retrieval failed"); + return; + } + + response.setStatus(HttpServletResponse.SC_OK); + + try { + //Convert InputStream to a seekable InputStream + byte[] data = getInputStreamBytes(downloadableContent.getContent()); + + if (data.length == 0) { + response.sendError(HttpURLConnection.HTTP_INTERNAL_ERROR, "Content size is too large to display."); + return; + } + + Configuration conf = new Configuration(); + + //Allow older deprecated schemas + conf.setBoolean("parquet.avro.readInt96AsFixed", true); + + final InputFile inputFile = new NifiParquetInputFile(new ByteArrayInputStream(data), data.length); + final ParquetReader<GenericRecord> reader = AvroParquetReader.<GenericRecord>builder(inputFile) + .withConf(conf) + .build(); + + //Format and write out each record + GenericRecord record; + boolean firstRecord = true; + response.getOutputStream().write("[\n".getBytes()); + while ((record = reader.read()) != null) { + if (firstRecord) { + firstRecord = false; + } else { + response.getOutputStream().write(",\n".getBytes()); + } + + objectMapper.writerWithDefaultPrettyPrinter().writeValue(response.getOutputStream(), objectMapper.readTree(record.toString())); Review Comment: I see, The best approach I can think of is how I had it implemented in an earlier iteration where we get the JSON string from the parquet reader and use Jackson to prettify it. -- This is an automated message from the Apache Git Service. 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