Github user markap14 commented on a diff in the pull request:
https://github.com/apache/incubator-nifi/pull/28#discussion_r25540061
--- Diff:
nifi/nifi-nar-bundles/nifi-standard-bundle/nifi-standard-processors/src/main/java/org/apache/nifi/processors/standard/util/JsonUtils.java
---
@@ -0,0 +1,127 @@
+/*
+ * 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.processors.standard.util;
+
+import com.jayway.jsonpath.Configuration;
+import com.jayway.jsonpath.DocumentContext;
+import com.jayway.jsonpath.InvalidPathException;
+import com.jayway.jsonpath.JsonPath;
+import com.jayway.jsonpath.spi.json.JsonProvider;
+import net.minidev.json.JSONValue;
+import org.apache.nifi.components.ValidationContext;
+import org.apache.nifi.components.ValidationResult;
+import org.apache.nifi.components.Validator;
+import org.apache.nifi.flowfile.FlowFile;
+import org.apache.nifi.processor.ProcessSession;
+import org.apache.nifi.processor.io.InputStreamCallback;
+import org.apache.nifi.stream.io.BufferedInputStream;
+import org.apache.nifi.util.BooleanHolder;
+import org.apache.nifi.util.ObjectHolder;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.InputStreamReader;
+import java.util.List;
+import java.util.Map;
+
+/**
+ * Provides utilities for interacting with JSON elements and JsonPath
expressions and results
+ *
+ * @see <a href="http://json.org";>http://json.org</a>
+ * @see <a
href="https://github.com/jayway/JsonPath";>https://github.com/jayway/JsonPath</a>
+ */
+public class JsonUtils {
+
+ static final JsonProvider JSON_PROVIDER =
Configuration.defaultConfiguration().jsonProvider();
+
+ public static final Validator JSON_PATH_VALIDATOR = new Validator() {
+ @Override
+ public ValidationResult validate(final String subject, final
String input, final ValidationContext context) {
+ String error = null;
+ try {
+ JsonPath compile = JsonPath.compile(input);
+ } catch (InvalidPathException ipe) {
+ error = ipe.toString();
+ }
+ return new ValidationResult.Builder().valid(error ==
null).explanation(error).build();
+ }
+ };
+
+ public static DocumentContext
validateAndEstablishJsonContext(ProcessSession processSession, FlowFile
flowFile) {
+
+ final BooleanHolder validJsonHolder = new BooleanHolder(false);
+ processSession.read(flowFile, new InputStreamCallback() {
+ @Override
+ public void process(InputStream in) throws IOException {
+ validJsonHolder.set(JsonUtils.isValidJson(in));
+ }
+ });
+
+ // Parse the document once into an associated context to support
multiple path evaluations if specified
+ final ObjectHolder<DocumentContext> contextHolder = new
ObjectHolder<>(null);
+
+ if (validJsonHolder.get()) {
+ processSession.read(flowFile, new InputStreamCallback() {
--- End diff --
Do we need to read the content to validate it above and then read it again
here? Can we just assume that it's valid unless an Exception is thrown?
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