Github user ToivoAdams commented on a diff in the pull request: https://github.com/apache/nifi/pull/420#discussion_r62806150 --- Diff: nifi-nar-bundles/nifi-standard-bundle/nifi-standard-processors/src/main/java/org/apache/nifi/processors/standard/FilterCSVColumns.java --- @@ -0,0 +1,258 @@ +/* + * 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 static java.sql.Types.CHAR; +import static java.sql.Types.LONGNVARCHAR; +import static java.sql.Types.LONGVARCHAR; +import static java.sql.Types.NCHAR; +import static java.sql.Types.NVARCHAR; +import static java.sql.Types.VARCHAR; + +import java.io.IOException; +import java.io.InputStream; +import java.io.InputStreamReader; +import java.io.OutputStream; +import java.io.Reader; +import java.nio.charset.StandardCharsets; +import java.sql.Connection; +import java.sql.DriverManager; +import java.sql.ResultSet; +import java.sql.ResultSetMetaData; +import java.sql.SQLException; +import java.sql.Statement; +import java.util.ArrayList; +import java.util.Collections; +import java.util.HashMap; +import java.util.HashSet; +import java.util.List; +import java.util.Properties; +import java.util.Set; +import java.util.concurrent.TimeUnit; + +import org.apache.calcite.adapter.csv.CsvSchemaFactory2; +import org.apache.calcite.jdbc.CalciteConnection; +import org.apache.calcite.schema.Schema; +import org.apache.calcite.schema.SchemaPlus; +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.InputRequirement; +import org.apache.nifi.annotation.behavior.InputRequirement.Requirement; +import org.apache.nifi.annotation.behavior.SideEffectFree; +import org.apache.nifi.annotation.behavior.SupportsBatching; +import org.apache.nifi.annotation.documentation.CapabilityDescription; +import org.apache.nifi.annotation.documentation.Tags; +import org.apache.nifi.components.PropertyDescriptor; +import org.apache.nifi.flowfile.FlowFile; +import org.apache.nifi.logging.ProcessorLog; +import org.apache.nifi.processor.AbstractProcessor; +import org.apache.nifi.processor.ProcessContext; +import org.apache.nifi.processor.ProcessSession; +import org.apache.nifi.processor.ProcessorInitializationContext; +import org.apache.nifi.processor.Relationship; +import org.apache.nifi.processor.exception.ProcessException; +import org.apache.nifi.processor.io.StreamCallback; +import org.apache.nifi.processor.util.StandardValidators; +import org.apache.nifi.stream.io.BufferedInputStream; +import org.apache.nifi.util.StopWatch; + +import com.google.common.collect.ImmutableMap; + +@EventDriven +@SideEffectFree +@SupportsBatching +@Tags({"xml", "xslt", "transform"}) +@InputRequirement(Requirement.INPUT_REQUIRED) +@CapabilityDescription("Filter out specific columns from CSV data. Some other transformations are also supported." + + "Columns can be renamed, simple calculations performed, aggregations, etc." + + "SQL select statement is used to specify how CSV data should be transformed." + + "SQL statement follows standard SQL, some restrictions may apply." + + "Successfully transformed CSV data is routed to the 'success' relationship." + + "If transform fails, the original FlowFile is routed to the 'failure' relationship") +public class FilterCSVColumns extends AbstractProcessor { + + public static final PropertyDescriptor SQL_SELECT = new PropertyDescriptor.Builder() + .name("SQL select statement") + .description("SQL select statement specifies how CSV data should be transformed. " + + "Sql select should select from CSV.A table") + .required(true) + .addValidator(StandardValidators.NON_EMPTY_VALIDATOR) + .build(); + + public static final Relationship REL_SUCCESS = new Relationship.Builder() + .name("success") + .description("The FlowFile with transformed content will be routed to this relationship") + .build(); + public static final Relationship REL_FAILURE = new Relationship.Builder() + .name("failure") + .description("If a FlowFile fails processing for any reason (for example, the SQL statement contains columns not present in CSV), it will be routed to this relationship") + .build(); + + private List<PropertyDescriptor> properties; + private Set<Relationship> relationships; + + @Override + protected void init(final ProcessorInitializationContext context) { + final List<PropertyDescriptor> properties = new ArrayList<>(); + properties.add(SQL_SELECT); + this.properties = Collections.unmodifiableList(properties); + + final Set<Relationship> relationships = new HashSet<>(); + relationships.add(REL_SUCCESS); + relationships.add(REL_FAILURE); + this.relationships = Collections.unmodifiableSet(relationships); + } + + @Override + public Set<Relationship> getRelationships() { + return relationships; + } + + @Override + protected List<PropertyDescriptor> getSupportedPropertyDescriptors() { + return properties; + } + + @Override + public void onTrigger(final ProcessContext context, final ProcessSession session) { + final FlowFile original = session.get(); + if (original == null) { + return; + } + + final ProcessorLog logger = getLogger(); + final StopWatch stopWatch = new StopWatch(true); + + try { + FlowFile transformed = session.write(original, new StreamCallback() { + @Override + public void process(final InputStream rawIn, final OutputStream out) throws IOException { + try (final InputStream in = new BufferedInputStream(rawIn)) { + + String sql = context.getProperty(SQL_SELECT).getValue(); + final ResultSet resultSet = transform(rawIn, sql); + convertToCSV(resultSet, out); + + } catch (final Exception e) { + throw new IOException(e); + } + } + }); + session.transfer(transformed, REL_SUCCESS); + session.getProvenanceReporter().modifyContent(transformed, stopWatch.getElapsed(TimeUnit.MILLISECONDS)); + logger.info("Transformed {}", new Object[]{original}); + } catch (ProcessException e) { + logger.error("Unable to transform {} due to {}", new Object[]{original, e}); + session.transfer(original, REL_FAILURE); + } + } + + static protected ResultSet transform(InputStream rawIn, String sql) throws SQLException { + + Reader readerx = new InputStreamReader(rawIn); + HashMap<String, Reader> inputs = new HashMap<>(); + inputs.put("A", readerx); + + Statement statement = null; + final Properties properties = new Properties(); +// properties.setProperty("caseSensitive", "true"); --- End diff -- Right, I will fix.
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