Github user ottobackwards commented on a diff in the pull request: https://github.com/apache/nifi/pull/2711#discussion_r190273915 --- Diff: nifi-nar-bundles/nifi-standard-bundle/nifi-standard-processors/src/main/java/org/apache/nifi/processors/standard/AttributesToCSV.java --- @@ -0,0 +1,272 @@ +/* + * 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; + +import org.apache.commons.lang3.StringEscapeUtils; +import org.apache.commons.lang3.StringUtils; +import org.apache.nifi.annotation.behavior.EventDriven; +import org.apache.nifi.annotation.behavior.SideEffectFree; +import org.apache.nifi.annotation.behavior.SupportsBatching; +import org.apache.nifi.annotation.behavior.InputRequirement; +import org.apache.nifi.annotation.behavior.WritesAttribute; +import org.apache.nifi.annotation.documentation.CapabilityDescription; +import org.apache.nifi.annotation.documentation.Tags; +import org.apache.nifi.annotation.lifecycle.OnScheduled; +import org.apache.nifi.components.PropertyDescriptor; +import org.apache.nifi.expression.ExpressionLanguageScope; +import org.apache.nifi.flowfile.FlowFile; +import org.apache.nifi.flowfile.attributes.CoreAttributes; +import org.apache.nifi.processor.AbstractProcessor; +import org.apache.nifi.processor.ProcessContext; +import org.apache.nifi.processor.ProcessorInitializationContext; +import org.apache.nifi.processor.ProcessSession; +import org.apache.nifi.processor.Relationship; +import org.apache.nifi.processor.exception.ProcessException; +import org.apache.nifi.processor.util.StandardValidators; + +import java.util.Arrays; +import java.util.HashMap; +import java.util.List; +import java.util.ArrayList; +import java.util.Set; +import java.util.HashSet; +import java.util.Map; +import java.util.Collections; +import java.util.stream.Collectors; + +@EventDriven +@SideEffectFree +@SupportsBatching +@Tags({"csv", "attributes", "flowfile"}) +@InputRequirement(InputRequirement.Requirement.INPUT_REQUIRED) +@CapabilityDescription("Generates a CSV representation of the input FlowFile Attributes. The resulting CSV " + + "can be written to either a newly generated attribute named 'CSVAttributes' or written to the FlowFile as content. " + + "If the attribute value contains a comma, newline or double quote, then the attribute value will be " + + "escaped with double quotes. Any double quote characters in the attribute value are escaped with " + + "another double quote. If the attribute value does not contain a comma, newline or double quote, then the " + + "attribute value is returned unchanged.") +@WritesAttribute(attribute = "CSVAttributes", description = "CSV representation of Attributes") +public class AttributesToCSV extends AbstractProcessor { + + private static final String OUTPUT_NEW_ATTRIBUTE = "flowfile-attribute"; + private static final String OUTPUT_OVERWRITE_CONTENT = "flowfile-content"; + private static final String OUTPUT_ATTRIBUTE_NAME = "CSVAttributes"; + private static final String OUTPUT_SEPARATOR = ","; + private static final String OUTPUT_MIME_TYPE = "text/csv"; + + + public static final PropertyDescriptor ATTRIBUTES_LIST = new PropertyDescriptor.Builder() + .name("attribute-list") + .displayName("Attribute List") + .description("Comma separated list of attributes to be included in the resulting CSV. If this value " + + "is left empty then all existing Attributes will be included. This list of attributes is " + + "case sensitive and does not support attribute names that contain commas. If an attribute specified in the list is not found it will be emitted " + --- End diff -- why not use http://commons.apache.org/proper/commons-lang/javadocs/api-release/org/apache/commons/lang3/StringEscapeUtils.html as you do with values for the attributes and headers?
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