Github user apiri commented on a diff in the pull request:
https://github.com/apache/nifi-minifi/pull/99#discussion_r152324349
--- Diff:
minifi-nar-bundles/minifi-framework-bundle/minifi-framework/minifi-runtime/src/main/java/org/apache/nifi/minifi/FlowParser.java
---
@@ -0,0 +1,154 @@
+/*
+ * 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.nifi.minifi;
+
+import org.apache.commons.io.IOUtils;
+import org.apache.nifi.util.LoggingXmlParserErrorHandler;
+import org.apache.nifi.util.file.FileUtils;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.w3c.dom.Document;
+import org.w3c.dom.Element;
+import org.w3c.dom.Node;
+import org.w3c.dom.NodeList;
+import org.xml.sax.SAXException;
+
+import javax.xml.parsers.DocumentBuilder;
+import javax.xml.parsers.DocumentBuilderFactory;
+import javax.xml.parsers.ParserConfigurationException;
+import javax.xml.transform.Result;
+import javax.xml.transform.Source;
+import javax.xml.transform.TransformerException;
+import javax.xml.transform.TransformerFactory;
+import javax.xml.transform.dom.DOMSource;
+import javax.xml.transform.stream.StreamResult;
+import java.io.ByteArrayInputStream;
+import java.io.ByteArrayOutputStream;
+import java.io.File;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.OutputStream;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.StandardOpenOption;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.zip.GZIPInputStream;
+import java.util.zip.GZIPOutputStream;
+
+/**
+ * Parses a flow from its xml.gz format into an XML {@link Document}.
This class is primarily toward utilities for assisting
+ * with the handling of component bundles.
+ * <p>
+ * Provides auxiliary methods to aid in evaluating and manipulating the
flow.
+ */
+public class FlowParser {
+
+ private static final Logger logger =
LoggerFactory.getLogger(FlowParser.class);
+
+ /**
+ * Generates a {@link Document} from the flow configuration file
provided
+ */
+ public Document parse(final File flowConfigurationFile) {
+ if (flowConfigurationFile == null) {
+ logger.debug("Flow Configuration file was null");
+ return null;
+ }
+
+ // if the flow doesn't exist or is 0 bytes, then return null
+ final Path flowPath = flowConfigurationFile.toPath();
+ try {
+ if (!Files.exists(flowPath) || Files.size(flowPath) == 0) {
+ logger.warn("Flow Configuration does not exist or was
empty");
+ return null;
+ }
+ } catch (IOException e) {
+ logger.error("An error occurred determining the size of the
Flow Configuration file");
+ return null;
+ }
+
+ // otherwise create the appropriate input streams to read the file
+ try (final InputStream in = Files.newInputStream(flowPath,
StandardOpenOption.READ);
+ final InputStream gzipIn = new GZIPInputStream(in)) {
+
+ final byte[] flowBytes = IOUtils.toByteArray(gzipIn);
+ if (flowBytes == null || flowBytes.length == 0) {
+ logger.warn("Could not extract root group id because Flow
Configuration File was empty");
+ return null;
+ }
+
+ final DocumentBuilderFactory docFactory =
DocumentBuilderFactory.newInstance();
+ docFactory.setNamespaceAware(true);
+
--- End diff --
Added and verified it still worked. I'm not sure the vector directly
applies to the case of how this code would be used but there seems to be no
side effects so I see no harm in including it.
---
