/*
* 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.email;
import java.io.IOException;
import java.io.UnsupportedEncodingException;
import java.net.URLEncoder;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashSet;
import java.util.List;
import java.util.Map.Entry;
import java.util.Properties;
import java.util.Set;
import java.util.concurrent.ArrayBlockingQueue;
import java.util.concurrent.BlockingQueue;
import java.util.concurrent.TimeUnit;
import javax.mail.Address;
import javax.mail.Flags;
import javax.mail.Message;
import javax.mail.MessagingException;
import org.apache.nifi.annotation.lifecycle.OnStopped;
import org.apache.nifi.components.PropertyDescriptor;
import org.apache.nifi.flowfile.FlowFile;
import org.apache.nifi.processor.AbstractProcessor;
import org.apache.nifi.processor.ProcessContext;
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 org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.support.StaticListableBeanFactory;
import org.springframework.integration.mail.AbstractMailReceiver;
import org.springframework.util.Assert;
/**
* Base processor for implementing processors to consume messages from Email
* servers using Spring Integration libraries.
*
* @param <T> the type of {@link AbstractMailReceiver}.
*/
abstract class AbstractEmailProcessor<T extends AbstractMailReceiver> extends AbstractProcessor {
public static final PropertyDescriptor HOST = new PropertyDescriptor.Builder()
.name("host")
.displayName("Host Name")
.description("Network address of Email server (e.g., pop.gmail.com, imap.gmail.com . . .)")
.required(true)
.expressionLanguageSupported(true)
.addValidator(StandardValidators.NON_EMPTY_VALIDATOR)
.build();
public static final PropertyDescriptor PORT = new PropertyDescriptor.Builder()
.name("port")
.displayName("Port")
.description("Numeric value identifying Port of Email server (e.g., 993)")
.required(true)
.expressionLanguageSupported(true)
.addValidator(StandardValidators.PORT_VALIDATOR)
.build();
public static final PropertyDescriptor USER = new PropertyDescriptor.Builder()
.name("user")
.displayName("User Name")
.description("User Name used for authentication and authorization with Email server.")
.required(true)
.expressionLanguageSupported(true)
.addValidator(StandardValidators.NON_EMPTY_VALIDATOR)
.build();
public static final PropertyDescriptor PASSWORD = new PropertyDescriptor.Builder()
.name("password")
.displayName("Password")
.description("Password used for authentication and authorization with Email server.")
.required(true)
.expressionLanguageSupported(true)
.addValidator(StandardValidators.NON_EMPTY_VALIDATOR)
.sensitive(true)
.build();
public static final PropertyDescriptor FOLDER = new PropertyDescriptor.Builder()
.name("folder")
.displayName("Folder")
.description("Email folder to retrieve messages from (e.g., INBOX)")
.required(true)
.expressionLanguageSupported(true)
.defaultValue("INBOX")
.addValidator(StandardValidators.NON_EMPTY_VALIDATOR)
.build();
public static final PropertyDescriptor FETCH_SIZE = new PropertyDescriptor.Builder()
.name("fetch.size")
.displayName("Fetch Size")
.description("Specify the maximum number of Messages to fetch per call to Email Server.")
.required(true)
.expressionLanguageSupported(true)
.defaultValue("10")
.addValidator(StandardValidators.POSITIVE_INTEGER_VALIDATOR)
.build();
public static final PropertyDescriptor SHOULD_DELETE_MESSAGES = new PropertyDescriptor.Builder()
.name("delete.messages")
.displayName("Delete Messages")
.description("Specify whether mail messages should be deleted after retrieval.")
.required(true)
.allowableValues("true", "false")
.defaultValue("false")
.addValidator(StandardValidators.BOOLEAN_VALIDATOR)
.build();
static final PropertyDescriptor CONNECTION_TIMEOUT = new PropertyDescriptor.Builder()
.name("connection.timeout")
.displayName("Connection timeout")
.description("The amount of time to wait to connect to Email server")
.required(true)
.addValidator(StandardValidators.TIME_PERIOD_VALIDATOR)
.expressionLanguageSupported(true)
.defaultValue("30 sec")
.build();
static final Relationship REL_SUCCESS = new Relationship.Builder()
.name("success")
.description("All messages that are the are successfully received from Email server and converted to FlowFiles are routed to this relationship")
.build();
final static List<PropertyDescriptor> SHARED_DESCRIPTORS = new ArrayList<>();
final static Set<Relationship> SHARED_RELATIONSHIPS = new HashSet<>();
/*
* Will ensure that list of PropertyDescriptors is build only once, since
* all other lifecycle methods are invoked multiple times.
*/
static {
SHARED_DESCRIPTORS.add(HOST);
SHARED_DESCRIPTORS.add(PORT);
SHARED_DESCRIPTORS.add(USER);
SHARED_DESCRIPTORS.add(PASSWORD);
SHARED_DESCRIPTORS.add(FOLDER);
SHARED_DESCRIPTORS.add(FETCH_SIZE);
SHARED_DESCRIPTORS.add(SHOULD_DELETE_MESSAGES);
SHARED_DESCRIPTORS.add(CONNECTION_TIMEOUT);
SHARED_RELATIONSHIPS.add(REL_SUCCESS);
}
protected final Logger logger = LoggerFactory.getLogger(this.getClass());
protected volatile T messageReceiver;
private volatile BlockingQueue<Message> messageQueue;
private volatile String displayUrl;
private volatile ProcessSession processSession;
private volatile boolean shouldSetDeleteFlag;
@OnStopped
public void stop(ProcessContext processContext) {
this.flushRemainingMessages(processContext);
try {
this.messageReceiver.destroy();
this.messageReceiver = null;
} catch (Exception e) {
this.logger.warn("Failure while closing processor", e);
}
}
/**
*
*/
@Override
public Set<Relationship> getRelationships() {
return SHARED_RELATIONSHIPS;
}
/**
*
*/
@Override
public void onTrigger(ProcessContext context, ProcessSession processSession) throws ProcessException {
this.initializeIfNecessary(context, processSession);
Message emailMessage = this.receiveMessage();
if (emailMessage != null) {
this.transfer(emailMessage, context, processSession);
}
}
/**
*
*/
@Override
protected PropertyDescriptor getSupportedDynamicPropertyDescriptor(final String propertyDescriptorName) {
return new PropertyDescriptor.Builder()
.description("Specifies the value for '" + propertyDescriptorName + "' Java Mail property.")
.name(propertyDescriptorName).addValidator(StandardValidators.NON_EMPTY_VALIDATOR).dynamic(true)
.build();
}
/**
* Delegates to sub-classes to build the target receiver as
* {@link AbstractMailReceiver}
*
* @param context instance of {@link ProcessContext}
* @return new instance of {@link AbstractMailReceiver}
*/
protected abstract T buildMessageReceiver(ProcessContext context);
/**
* Return the target receiver's mail protocol (e.g., imap, pop etc.)
*/
protected abstract String getProtocol(ProcessContext processContext);
/**
* Builds the url used to connect to the email server.
*/
String buildUrl(ProcessContext processContext) {
String host = processContext.getProperty(HOST).evaluateAttributeExpressions().getValue();
String port = processContext.getProperty(PORT).evaluateAttributeExpressions().getValue();
String user = processContext.getProperty(USER).evaluateAttributeExpressions().getValue();
String password = processContext.getProperty(PASSWORD).evaluateAttributeExpressions().getValue();
String folder = processContext.getProperty(FOLDER).evaluateAttributeExpressions().getValue();
StringBuilder urlBuilder = new StringBuilder();
try {
urlBuilder.append(URLEncoder.encode(user, "UTF-8"));
} catch (UnsupportedEncodingException e) {
throw new ProcessException(e);
}
urlBuilder.append(":");
try {
urlBuilder.append(URLEncoder.encode(password, "UTF-8"));
} catch (UnsupportedEncodingException e) {
throw new ProcessException(e);
}
urlBuilder.append("@");
urlBuilder.append(host);
urlBuilder.append(":");
urlBuilder.append(port);
urlBuilder.append("/");
urlBuilder.append(folder);
String protocol = this.getProtocol(processContext);
String finalUrl = protocol + "://" + urlBuilder.toString();
// build display-safe URL
int passwordStartIndex = urlBuilder.indexOf(":") + 1;
int passwordEndIndex = urlBuilder.indexOf("@");
urlBuilder.replace(passwordStartIndex, passwordEndIndex, "[password]");
this.displayUrl = protocol + "://" + urlBuilder.toString();
if (this.logger.isInfoEnabled()) {
this.logger.info("Connecting to Email server at the following URL: " + this.displayUrl);
}
return finalUrl;
}
/**
* Builds and initializes the target message receiver if necessary (if it's
* null). Upon execution of this operation the receiver is fully functional
* and is ready to receive messages.
*/
private synchronized void initializeIfNecessary(ProcessContext context, ProcessSession processSession) {
if (this.messageReceiver == null) {
this.processSession = processSession;
this.messageReceiver = this.buildMessageReceiver(context);
this.shouldSetDeleteFlag = context.getProperty(SHOULD_DELETE_MESSAGES).asBoolean();
int fetchSize = context.getProperty(FETCH_SIZE).evaluateAttributeExpressions().asInteger();
this.messageReceiver.setMaxFetchSize(fetchSize);
this.messageReceiver.setJavaMailProperties(this.buildJavaMailProperties(context));
// need to avoid spring warning messages
this.messageReceiver.setBeanFactory(new StaticListableBeanFactory());
this.messageReceiver.afterPropertiesSet();
this.messageQueue = new ArrayBlockingQueue<>(fetchSize);
}
}
/**
* Extracts dynamic properties which typically represent the Java Mail
* properties from the {@link ProcessContext} returning them as instance of
* {@link Properties}
*/
private Properties buildJavaMailProperties(ProcessContext context) {
Properties javaMailProperties = new Properties();
for (Entry<PropertyDescriptor, String> propertyDescriptorEntry : context.getProperties().entrySet()) {
if (propertyDescriptorEntry.getKey().isDynamic()
&& !propertyDescriptorEntry.getKey().getName().equals("mail.imap.timeout")
&& !propertyDescriptorEntry.getKey().getName().equals("mail.pop3.timeout")) {
javaMailProperties.setProperty(propertyDescriptorEntry.getKey().getName(),
propertyDescriptorEntry.getValue());
}
}
String propertyName = this.getProtocol(context).equals("pop3") ? "mail.pop3.timeout" : "mail.imap.timeout";
final String timeoutInMillis = String.valueOf(context.getProperty(CONNECTION_TIMEOUT).evaluateAttributeExpressions().asTimePeriod(TimeUnit.MILLISECONDS));
javaMailProperties.setProperty(propertyName, timeoutInMillis);
return javaMailProperties;
}
/**
* Fills the internal message queue if such queue is empty. This is due to
* the fact that per single session there may be multiple messages retrieved
* from the email server (see FETCH_SIZE).
*/
private synchronized void fillMessageQueueIfNecessary() {
if (this.messageQueue.isEmpty()) {
Object[] messages;
try {
messages = this.messageReceiver.receive();
} catch (MessagingException e) {
String errorMsg = "Failed to receive messages from Email server: [" + e.getClass().getName()
+ " - " + e.getMessage();
this.getLogger().error(errorMsg);
throw new ProcessException(errorMsg, e);
}
if (messages != null) {
for (Object message : messages) {
Assert.isTrue(message instanceof Message, "Message is not an instance of javax.mail.Message");
this.messageQueue.offer((Message) message);
}
}
}
}
/**
* Disposes the message by converting it to a {@link FlowFile} transferring
* it to the REL_SUCCESS relationship.
*/
private void transfer(Message emailMessage, ProcessContext context, ProcessSession processSession) {
long start = System.nanoTime();
FlowFile flowFile = processSession.create();
flowFile = processSession.append(flowFile, out -> {
try {
emailMessage.writeTo(out);
} catch (MessagingException e) {
throw new IOException(e);
}
});
long executionDuration = TimeUnit.NANOSECONDS.toMillis(System.nanoTime() - start);
String fromAddressesString = "";
try {
Address[] fromAddresses = emailMessage.getFrom();
if (fromAddresses != null) {
fromAddressesString = Arrays.asList(fromAddresses).toString();
}
} catch (MessagingException e) {
this.logger.warn("Failed to retrieve 'From' attribute from Message.");
}
processSession.getProvenanceReporter().receive(flowFile, this.displayUrl, "Received message from " + fromAddressesString, executionDuration);
this.getLogger().info("Successfully received {} from {} in {} millis", new Object[]{flowFile, fromAddressesString, executionDuration});
processSession.transfer(flowFile, REL_SUCCESS);
try {
emailMessage.setFlag(Flags.Flag.DELETED, this.shouldSetDeleteFlag);
} catch (MessagingException e) {
this.logger.warn("Failed to set DELETE Flag on the message", e);
this.getLogger().warn("Failed to set DELETE Flag on the message");
}
}
/**
* Receives message from the internal queue filling up the queue if
* necessary.
*/
private Message receiveMessage() {
Message emailMessage = null;
try {
this.fillMessageQueueIfNecessary();
emailMessage = this.messageQueue.poll(1, TimeUnit.MILLISECONDS);
} catch (InterruptedException e) {
Thread.currentThread().interrupt();
this.logger.debug("Current thread is interrupted");
}
return emailMessage;
}
/**
* Will flush the remaining messages when this processor is stopped. The
* flushed messages are disposed via
* {@link #disposeMessage(Message, ProcessContext, ProcessSession)}
* operation
*/
private void flushRemainingMessages(ProcessContext processContext) {
Message emailMessage;
try {
while ((emailMessage = this.messageQueue.poll(1, TimeUnit.MILLISECONDS)) != null) {
this.transfer(emailMessage, processContext, this.processSession);
this.processSession.commit();
}
} catch (InterruptedException e) {
Thread.currentThread().interrupt();
this.logger.debug("Current thread is interrupted");
}
}
}