Github user joetrite commented on a diff in the pull request:
https://github.com/apache/nifi/pull/2711#discussion_r193808025
--- Diff:
nifi-nar-bundles/nifi-standard-bundle/nifi-standard-processors/src/main/java/org/apache/nifi/processors/standard/AttributesToCSV.java
---
@@ -0,0 +1,335 @@
+/*
+ * 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.text.StringEscapeUtils;
+import org.apache.commons.lang3.StringUtils;
+import org.apache.nifi.annotation.behavior.WritesAttribute;
+import org.apache.nifi.annotation.behavior.WritesAttributes;
+import org.apache.nifi.annotation.behavior.SideEffectFree;
+import org.apache.nifi.annotation.behavior.SupportsBatching;
+import org.apache.nifi.annotation.behavior.EventDriven;
+import org.apache.nifi.annotation.behavior.InputRequirement;
+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.AllowableValue;
+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.Map;
+import java.util.Set;
+import java.util.HashSet;
+import java.util.List;
+import java.util.LinkedHashMap;
+import java.util.LinkedHashSet;
+import java.util.regex.Pattern;
+import java.util.stream.Collectors;
+import java.util.Collections;
+import java.util.Arrays;
+import java.util.ArrayList;
+
+@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.")
+@WritesAttributes({
+ @WritesAttribute(attribute = "CSVSchema", description = "CSV
representation of the Schema"),
+ @WritesAttribute(attribute = "CSVData", description = "CSV
representation of Attributes")
+})
+
+public class AttributesToCSV extends AbstractProcessor {
+ private static final String DATA_ATTRIBUTE_NAME = "CSVData";
+ private static final String SCHEMA_ATTRIBUTE_NAME = "CSVSchema";
+ private static final String OUTPUT_SEPARATOR = ",";
+ private static final String OUTPUT_MIME_TYPE = "text/csv";
+ private static final String SPLIT_REGEX = OUTPUT_SEPARATOR +
"(?=(?:[^\"]*\"[^\"]*\")*[^\"]*$)";
+
+ static final AllowableValue OUTPUT_OVERWRITE_CONTENT = new
AllowableValue("flowfile-content", "flowfile-content", "The resulting CSV
string will be placed into the content of the flowfile." +
+ "Existing flowfile context will be overwritten. 'CSVData' will
not be written to at all (neither null nor empty string).");
+ static final AllowableValue OUTPUT_NEW_ATTRIBUTE= new
AllowableValue("flowfile-attribute", "flowfile-attribute", "The resulting CSV
string will be placed into a new flowfile" +
+ " attribute named 'CSVData'. The content of the flowfile will
not be changed.");
+
+ 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 supports attribute names that
contain commas. If an attribute specified in the list is not found it will be
emitted " +
+ "to the resulting CSV with an empty string or null
depending on the 'Null Value' property. " +
+ "If a core attribute is specified in this list " +
+ "and the 'Include Core Attributes' property is false,
the core attribute will be included. The attribute list " +
+ "ALWAYS wins.")
+ .required(false)
+ .addValidator(StandardValidators.NON_EMPTY_EL_VALIDATOR)
+
.expressionLanguageSupported(ExpressionLanguageScope.FLOWFILE_ATTRIBUTES)
+ .build();
+
+ public static final PropertyDescriptor ATTRIBUTES_REGEX = new
PropertyDescriptor.Builder()
+ .name("attributes-regex")
+ .displayName("Attributes Regular Expression")
+ .description("Regular expression that will be evaluated
against the flow file attributes to select "
+ + "the matching attributes. This property can be used
in combination with the attributes "
+ + "list property. The final output will contain a
combination of matches found in the ATTRIBUTE_LIST and ATTRIBUTE_REGEX.")
+ .required(false)
+
.expressionLanguageSupported(ExpressionLanguageScope.FLOWFILE_ATTRIBUTES)
+ .addValidator(StandardValidators.createRegexValidator(0,
Integer.MAX_VALUE, true))
+ .addValidator(StandardValidators.NON_EMPTY_EL_VALIDATOR)
+ .build();
+
+ public static final PropertyDescriptor DESTINATION = new
PropertyDescriptor.Builder()
+ .name("destination")
+ .displayName("Destination")
+ .description("Control if CSV value is written as a new
flowfile attribute 'CSVData' " +
+ "or written in the flowfile content.")
+ .required(true)
+ .allowableValues(OUTPUT_NEW_ATTRIBUTE,
OUTPUT_OVERWRITE_CONTENT)
+ .defaultValue(OUTPUT_NEW_ATTRIBUTE.getDisplayName())
--- End diff --
we are writting two attributes, the CSVSchema(attribute names) and the
CSVData(attribute values). it looks like allMatchingAttributes will take care
of the CSVData attribute nicely, but I don't see any option to handle the
schema attribute. I don't see anything like allMatchingAttributeNames, which
would take care of the CSVSchema part.
---
