org.apache.nifi.processors.standard.PostHTTP.java Source code

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/*
 * 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 java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.MalformedURLException;
import java.security.KeyManagementException;
import java.security.KeyStore;
import java.security.KeyStoreException;
import java.security.NoSuchAlgorithmException;
import java.security.UnrecoverableKeyException;
import java.security.cert.Certificate;
import java.security.cert.CertificateException;
import java.security.cert.X509Certificate;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.UUID;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentMap;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicReference;
import java.util.regex.Pattern;
import javax.net.ssl.SSLContext;
import javax.net.ssl.SSLPeerUnverifiedException;
import javax.net.ssl.SSLSession;
import javax.servlet.http.HttpServletResponse;
import org.apache.commons.io.IOUtils;
import org.apache.http.Header;
import org.apache.http.HttpException;
import org.apache.http.HttpHost;
import org.apache.http.HttpResponse;
import org.apache.http.HttpResponseInterceptor;
import org.apache.http.auth.AuthScope;
import org.apache.http.auth.UsernamePasswordCredentials;
import org.apache.http.client.CredentialsProvider;
import org.apache.http.client.HttpClient;
import org.apache.http.client.config.RequestConfig;
import org.apache.http.client.methods.CloseableHttpResponse;
import org.apache.http.client.methods.HttpDelete;
import org.apache.http.client.methods.HttpHead;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.config.Registry;
import org.apache.http.config.RegistryBuilder;
import org.apache.http.conn.HttpClientConnectionManager;
import org.apache.http.conn.ManagedHttpClientConnection;
import org.apache.http.conn.socket.ConnectionSocketFactory;
import org.apache.http.conn.socket.PlainConnectionSocketFactory;
import org.apache.http.conn.ssl.SSLConnectionSocketFactory;
import org.apache.http.conn.ssl.SSLContextBuilder;
import org.apache.http.conn.ssl.SSLContexts;
import org.apache.http.conn.ssl.TrustSelfSignedStrategy;
import org.apache.http.entity.ContentProducer;
import org.apache.http.entity.EntityTemplate;
import org.apache.http.impl.client.BasicCredentialsProvider;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClientBuilder;
import org.apache.http.impl.conn.PoolingHttpClientConnectionManager;
import org.apache.http.protocol.HttpContext;
import org.apache.http.protocol.HttpCoreContext;
import org.apache.http.util.EntityUtils;
import org.apache.http.util.VersionInfo;
import org.apache.nifi.annotation.behavior.InputRequirement;
import org.apache.nifi.annotation.behavior.InputRequirement.Requirement;
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.annotation.lifecycle.OnScheduled;
import org.apache.nifi.annotation.lifecycle.OnStopped;
import org.apache.nifi.components.PropertyDescriptor;
import org.apache.nifi.components.ValidationContext;
import org.apache.nifi.components.ValidationResult;
import org.apache.nifi.flowfile.FlowFile;
import org.apache.nifi.flowfile.attributes.CoreAttributes;
import org.apache.nifi.logging.ComponentLog;
import org.apache.nifi.processor.AbstractProcessor;
import org.apache.nifi.processor.DataUnit;
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.InputStreamCallback;
import org.apache.nifi.processor.util.StandardValidators;
import org.apache.nifi.security.util.CertificateUtils;
import org.apache.nifi.security.util.KeyStoreUtils;
import org.apache.nifi.ssl.SSLContextService;
import org.apache.nifi.stream.io.BufferedInputStream;
import org.apache.nifi.stream.io.BufferedOutputStream;
import org.apache.nifi.stream.io.GZIPOutputStream;
import org.apache.nifi.stream.io.LeakyBucketStreamThrottler;
import org.apache.nifi.stream.io.StreamThrottler;
import org.apache.nifi.stream.io.StreamUtils;
import org.apache.nifi.util.FlowFilePackager;
import org.apache.nifi.util.FlowFilePackagerV1;
import org.apache.nifi.util.FlowFilePackagerV2;
import org.apache.nifi.util.FlowFilePackagerV3;
import org.apache.nifi.util.FormatUtils;
import org.apache.nifi.util.StopWatch;
import org.apache.nifi.util.StringUtils;
import com.sun.jersey.api.client.ClientResponse.Status;

@SupportsBatching
@InputRequirement(Requirement.INPUT_REQUIRED)
@Tags({ "http", "https", "remote", "copy", "archive" })
@CapabilityDescription("Performs an HTTP Post with the content of the FlowFile")
public class PostHTTP extends AbstractProcessor {

    public static final String CONTENT_TYPE_HEADER = "Content-Type";
    public static final String ACCEPT = "Accept";
    public static final String ACCEPT_ENCODING = "Accept-Encoding";
    public static final String APPLICATION_FLOW_FILE_V1 = "application/flowfile";
    public static final String APPLICATION_FLOW_FILE_V2 = "application/flowfile-v2";
    public static final String APPLICATION_FLOW_FILE_V3 = "application/flowfile-v3";
    public static final String DEFAULT_CONTENT_TYPE = "application/octet-stream";
    public static final String FLOWFILE_CONFIRMATION_HEADER = "x-prefer-acknowledge-uri";
    public static final String LOCATION_HEADER_NAME = "Location";
    public static final String LOCATION_URI_INTENT_NAME = "x-location-uri-intent";
    public static final String LOCATION_URI_INTENT_VALUE = "flowfile-hold";
    public static final String GZIPPED_HEADER = "flowfile-gzipped";
    public static final String CONTENT_ENCODING_HEADER = "Content-Encoding";
    public static final String CONTENT_ENCODING_GZIP_VALUE = "gzip";

    public static final String PROTOCOL_VERSION_HEADER = "x-nifi-transfer-protocol-version";
    public static final String TRANSACTION_ID_HEADER = "x-nifi-transaction-id";
    public static final String PROTOCOL_VERSION = "3";

    public static final PropertyDescriptor URL = new PropertyDescriptor.Builder().name("URL").description(
            "The URL to POST to. The first part of the URL must be static. However, the path of the URL may be defined using the Attribute Expression Language. "
                    + "For example, https://${hostname} is not valid, but https://1.1.1.1:8080/files/${nf.file.name} is valid.")
            .required(true)
            .addValidator(StandardValidators.createRegexMatchingValidator(Pattern.compile("https?\\://.*")))
            .addValidator(StandardValidators.URL_VALIDATOR).expressionLanguageSupported(true).build();
    public static final PropertyDescriptor SEND_AS_FLOWFILE = new PropertyDescriptor.Builder()
            .name("Send as FlowFile")
            .description(
                    "If true, will package the FlowFile's contents and attributes together and send the FlowFile Package; otherwise, will send only the FlowFile's content")
            .required(true).allowableValues("true", "false").defaultValue("false").build();
    public static final PropertyDescriptor CONNECTION_TIMEOUT = new PropertyDescriptor.Builder()
            .name("Connection Timeout")
            .description("How long to wait when attempting to connect to the remote server before giving up")
            .required(true).defaultValue("30 sec").addValidator(StandardValidators.TIME_PERIOD_VALIDATOR).build();
    public static final PropertyDescriptor DATA_TIMEOUT = new PropertyDescriptor.Builder().name("Data Timeout")
            .description(
                    "How long to wait between receiving segments of data from the remote server before giving up and discarding the partial file")
            .required(true).defaultValue("30 sec").addValidator(StandardValidators.TIME_PERIOD_VALIDATOR).build();
    public static final PropertyDescriptor USERNAME = new PropertyDescriptor.Builder().name("Username")
            .description("Username required to access the URL").required(false)
            .addValidator(StandardValidators.NON_EMPTY_VALIDATOR).build();
    public static final PropertyDescriptor PASSWORD = new PropertyDescriptor.Builder().name("Password")
            .description("Password required to access the URL").required(false).sensitive(true)
            .addValidator(StandardValidators.NON_EMPTY_VALIDATOR).build();
    public static final PropertyDescriptor USER_AGENT = new PropertyDescriptor.Builder().name("User Agent")
            .description("What to report as the User Agent when we connect to the remote server").required(false)
            .addValidator(StandardValidators.NON_EMPTY_VALIDATOR).defaultValue(VersionInfo
                    .getUserAgent("Apache-HttpClient", "org.apache.http.client", HttpClientBuilder.class))
            .build();
    public static final PropertyDescriptor COMPRESSION_LEVEL = new PropertyDescriptor.Builder()
            .name("Compression Level")
            .description(
                    "Determines the GZIP Compression Level to use when sending the file; the value must be in the range of 0-9. A value of 0 indicates that the file will not be GZIP'ed")
            .required(true).addValidator(StandardValidators.createLongValidator(0, 9, true)).defaultValue("0")
            .build();
    public static final PropertyDescriptor ATTRIBUTES_AS_HEADERS_REGEX = new PropertyDescriptor.Builder()
            .name("Attributes to Send as HTTP Headers (Regex)")
            .description(
                    "Specifies the Regular Expression that determines the names of FlowFile attributes that should be sent as HTTP Headers")
            .addValidator(StandardValidators.REGULAR_EXPRESSION_VALIDATOR).required(false).build();
    public static final PropertyDescriptor MAX_DATA_RATE = new PropertyDescriptor.Builder()
            .name("Max Data to Post per Second")
            .description(
                    "The maximum amount of data to send per second; this allows the bandwidth to be throttled to a specified data rate; if not specified, the data rate is not throttled")
            .required(false).addValidator(StandardValidators.DATA_SIZE_VALIDATOR).build();
    public static final PropertyDescriptor MAX_BATCH_SIZE = new PropertyDescriptor.Builder().name("Max Batch Size")
            .description(
                    "If the Send as FlowFile property is true, specifies the max data size for a batch of FlowFiles to send in a single "
                            + "HTTP POST. If not specified, each FlowFile will be sent separately. If the Send as FlowFile property is false, this "
                            + "property is ignored")
            .required(false).addValidator(StandardValidators.DATA_SIZE_VALIDATOR).defaultValue("100 MB").build();
    public static final PropertyDescriptor CHUNKED_ENCODING = new PropertyDescriptor.Builder()
            .name("Use Chunked Encoding")
            .description(
                    "Specifies whether or not to use Chunked Encoding to send the data. This property is ignored in the event the contents are compressed "
                            + "or sent as FlowFiles.")
            .allowableValues("true", "false").build();
    public static final PropertyDescriptor SSL_CONTEXT_SERVICE = new PropertyDescriptor.Builder()
            .name("SSL Context Service")
            .description("The Controller Service to use in order to obtain an SSL Context").required(false)
            .identifiesControllerService(SSLContextService.class).build();
    public static final PropertyDescriptor PROXY_HOST = new PropertyDescriptor.Builder().name("Proxy Host")
            .description("The fully qualified hostname or IP address of the proxy server").required(false)
            .addValidator(StandardValidators.NON_EMPTY_VALIDATOR).build();
    public static final PropertyDescriptor PROXY_PORT = new PropertyDescriptor.Builder().name("Proxy Port")
            .description("The port of the proxy server").required(false)
            .addValidator(StandardValidators.PORT_VALIDATOR).build();
    public static final PropertyDescriptor CONTENT_TYPE = new PropertyDescriptor.Builder().name("Content-Type")
            .description("The Content-Type to specify for the content of the FlowFile being POSTed if "
                    + SEND_AS_FLOWFILE.getName() + " is false. "
                    + "In the case of an empty value after evaluating an expression language expression, Content-Type defaults to "
                    + DEFAULT_CONTENT_TYPE)
            .required(true).expressionLanguageSupported(true)
            .defaultValue("${" + CoreAttributes.MIME_TYPE.key() + "}")
            .addValidator(StandardValidators.NON_EMPTY_VALIDATOR).build();

    public static final Relationship REL_SUCCESS = new Relationship.Builder().name("success")
            .description("Files that are successfully send will be transferred to success").build();
    public static final Relationship REL_FAILURE = new Relationship.Builder().name("failure")
            .description("Files that fail to send will transferred to failure").build();

    private Set<Relationship> relationships;
    private List<PropertyDescriptor> properties;

    private final AtomicReference<DestinationAccepts> acceptsRef = new AtomicReference<>();
    private final AtomicReference<StreamThrottler> throttlerRef = new AtomicReference<>();
    private final ConcurrentMap<String, Config> configMap = new ConcurrentHashMap<>();

    @Override
    protected void init(final ProcessorInitializationContext context) {
        final Set<Relationship> relationships = new HashSet<>();
        relationships.add(REL_SUCCESS);
        relationships.add(REL_FAILURE);
        this.relationships = Collections.unmodifiableSet(relationships);

        final List<PropertyDescriptor> properties = new ArrayList<>();
        properties.add(URL);
        properties.add(MAX_BATCH_SIZE);
        properties.add(MAX_DATA_RATE);
        properties.add(SSL_CONTEXT_SERVICE);
        properties.add(USERNAME);
        properties.add(PASSWORD);
        properties.add(SEND_AS_FLOWFILE);
        properties.add(CHUNKED_ENCODING);
        properties.add(COMPRESSION_LEVEL);
        properties.add(CONNECTION_TIMEOUT);
        properties.add(DATA_TIMEOUT);
        properties.add(ATTRIBUTES_AS_HEADERS_REGEX);
        properties.add(USER_AGENT);
        properties.add(PROXY_HOST);
        properties.add(PROXY_PORT);
        properties.add(CONTENT_TYPE);
        this.properties = Collections.unmodifiableList(properties);
    }

    @Override
    public Set<Relationship> getRelationships() {
        return relationships;
    }

    @Override
    protected List<PropertyDescriptor> getSupportedPropertyDescriptors() {
        return properties;
    }

    @Override
    protected Collection<ValidationResult> customValidate(final ValidationContext context) {
        final Collection<ValidationResult> results = new ArrayList<>();

        if (context.getProperty(URL).getValue().startsWith("https")
                && context.getProperty(SSL_CONTEXT_SERVICE).getValue() == null) {
            results.add(new ValidationResult.Builder()
                    .explanation("URL is set to HTTPS protocol but no SSLContext has been specified").valid(false)
                    .subject("SSL Context").build());
        }

        if (context.getProperty(PROXY_HOST).isSet() && !context.getProperty(PROXY_PORT).isSet()) {
            results.add(
                    new ValidationResult.Builder().explanation("Proxy Host was set but no Proxy Port was specified")
                            .valid(false).subject("Proxy server configuration").build());
        }

        boolean sendAsFlowFile = context.getProperty(SEND_AS_FLOWFILE).asBoolean();
        int compressionLevel = context.getProperty(COMPRESSION_LEVEL).asInteger();
        boolean chunkedSet = context.getProperty(CHUNKED_ENCODING).isSet();

        if (compressionLevel == 0 && !sendAsFlowFile && !chunkedSet) {
            results.add(new ValidationResult.Builder().valid(false).subject(CHUNKED_ENCODING.getName())
                    .explanation("if compression level is 0 and not sending as a FlowFile, then the \'"
                            + CHUNKED_ENCODING.getName() + "\' property must be set")
                    .build());
        }

        return results;
    }

    @OnStopped
    public void onStopped() {
        this.acceptsRef.set(null);

        for (final Map.Entry<String, Config> entry : configMap.entrySet()) {
            final Config config = entry.getValue();
            config.getConnectionManager().shutdown();
        }

        configMap.clear();

        final StreamThrottler throttler = throttlerRef.getAndSet(null);
        if (throttler != null) {
            try {
                throttler.close();
            } catch (IOException e) {
                getLogger().error("Failed to close StreamThrottler", e);
            }
        }
    }

    @OnScheduled
    public void onScheduled(final ProcessContext context) {
        final Double bytesPerSecond = context.getProperty(MAX_DATA_RATE).asDataSize(DataUnit.B);
        this.throttlerRef
                .set(bytesPerSecond == null ? null : new LeakyBucketStreamThrottler(bytesPerSecond.intValue()));
    }

    private String getBaseUrl(final String url) {
        final int index = url.indexOf("/", 9);
        if (index < 0) {
            return url;
        }

        return url.substring(0, index);
    }

    private Config getConfig(final String url, final ProcessContext context) {
        final String baseUrl = getBaseUrl(url);
        Config config = configMap.get(baseUrl);
        if (config != null) {
            return config;
        }

        final PoolingHttpClientConnectionManager conMan;
        final SSLContextService sslContextService = context.getProperty(SSL_CONTEXT_SERVICE)
                .asControllerService(SSLContextService.class);
        if (sslContextService == null) {
            conMan = new PoolingHttpClientConnectionManager();
        } else {
            final SSLContext sslContext;
            try {
                sslContext = createSSLContext(sslContextService);
                getLogger().info("PostHTTP supports protocol: " + sslContext.getProtocol());
            } catch (final Exception e) {
                throw new ProcessException(e);
            }

            final SSLConnectionSocketFactory sslsf = new SSLConnectionSocketFactory(sslContext);
            // Also use a plain socket factory for regular http connections (especially proxies)
            final Registry<ConnectionSocketFactory> socketFactoryRegistry = RegistryBuilder
                    .<ConnectionSocketFactory>create().register("https", sslsf)
                    .register("http", PlainConnectionSocketFactory.getSocketFactory()).build();

            conMan = new PoolingHttpClientConnectionManager(socketFactoryRegistry);
        }

        conMan.setDefaultMaxPerRoute(context.getMaxConcurrentTasks());
        conMan.setMaxTotal(context.getMaxConcurrentTasks());
        config = new Config(conMan);
        final Config existingConfig = configMap.putIfAbsent(baseUrl, config);

        return existingConfig == null ? config : existingConfig;
    }

    private SSLContext createSSLContext(final SSLContextService service) throws KeyStoreException, IOException,
            NoSuchAlgorithmException, CertificateException, KeyManagementException, UnrecoverableKeyException {
        SSLContextBuilder builder = SSLContexts.custom();
        final String trustFilename = service.getTrustStoreFile();
        if (trustFilename != null) {
            final KeyStore truststore = KeyStoreUtils.getTrustStore(service.getTrustStoreType());
            try (final InputStream in = new FileInputStream(new File(service.getTrustStoreFile()))) {
                truststore.load(in, service.getTrustStorePassword().toCharArray());
            }
            builder = builder.loadTrustMaterial(truststore, new TrustSelfSignedStrategy());
        }

        final String keyFilename = service.getKeyStoreFile();
        if (keyFilename != null) {
            final KeyStore keystore = KeyStoreUtils.getKeyStore(service.getKeyStoreType());
            try (final InputStream in = new FileInputStream(new File(service.getKeyStoreFile()))) {
                keystore.load(in, service.getKeyStorePassword().toCharArray());
            }
            builder = builder.loadKeyMaterial(keystore, service.getKeyStorePassword().toCharArray());
        }

        builder = builder.useProtocol(service.getSslAlgorithm());

        final SSLContext sslContext = builder.build();
        return sslContext;
    }

    @Override
    public void onTrigger(final ProcessContext context, final ProcessSession session) {
        final boolean sendAsFlowFile = context.getProperty(SEND_AS_FLOWFILE).asBoolean();
        final int compressionLevel = context.getProperty(COMPRESSION_LEVEL).asInteger();
        final String userAgent = context.getProperty(USER_AGENT).getValue();

        final RequestConfig.Builder requestConfigBuilder = RequestConfig.custom();
        requestConfigBuilder.setConnectionRequestTimeout(
                context.getProperty(DATA_TIMEOUT).asTimePeriod(TimeUnit.MILLISECONDS).intValue());
        requestConfigBuilder.setConnectTimeout(
                context.getProperty(CONNECTION_TIMEOUT).asTimePeriod(TimeUnit.MILLISECONDS).intValue());
        requestConfigBuilder.setRedirectsEnabled(false);
        requestConfigBuilder
                .setSocketTimeout(context.getProperty(DATA_TIMEOUT).asTimePeriod(TimeUnit.MILLISECONDS).intValue());
        final RequestConfig requestConfig = requestConfigBuilder.build();

        final StreamThrottler throttler = throttlerRef.get();
        final ComponentLog logger = getLogger();

        final Double maxBatchBytes = context.getProperty(MAX_BATCH_SIZE).asDataSize(DataUnit.B);
        String lastUrl = null;
        long bytesToSend = 0L;

        final List<FlowFile> toSend = new ArrayList<>();
        DestinationAccepts destinationAccepts = null;
        CloseableHttpClient client = null;
        final String transactionId = UUID.randomUUID().toString();

        final AtomicReference<String> dnHolder = new AtomicReference<>("none");
        while (true) {
            FlowFile flowFile = session.get();
            if (flowFile == null) {
                break;
            }

            final String url = context.getProperty(URL).evaluateAttributeExpressions(flowFile).getValue();
            try {
                new java.net.URL(url);
            } catch (final MalformedURLException e) {
                logger.error(
                        "After substituting attribute values for {}, URL is {}; this is not a valid URL, so routing to failure",
                        new Object[] { flowFile, url });
                flowFile = session.penalize(flowFile);
                session.transfer(flowFile, REL_FAILURE);
                continue;
            }

            // If this FlowFile doesn't have the same url, throw it back on the queue and stop grabbing FlowFiles
            if (lastUrl != null && !lastUrl.equals(url)) {
                session.transfer(flowFile);
                break;
            }

            lastUrl = url;
            toSend.add(flowFile);

            if (client == null || destinationAccepts == null) {
                final Config config = getConfig(url, context);
                final HttpClientConnectionManager conMan = config.getConnectionManager();

                final HttpClientBuilder clientBuilder = HttpClientBuilder.create();
                clientBuilder.setConnectionManager(conMan);
                clientBuilder.setUserAgent(userAgent);
                clientBuilder.addInterceptorFirst(new HttpResponseInterceptor() {
                    @Override
                    public void process(final HttpResponse response, final HttpContext httpContext)
                            throws HttpException, IOException {
                        final HttpCoreContext coreContext = HttpCoreContext.adapt(httpContext);
                        final ManagedHttpClientConnection conn = coreContext
                                .getConnection(ManagedHttpClientConnection.class);
                        if (!conn.isOpen()) {
                            return;
                        }

                        final SSLSession sslSession = conn.getSSLSession();

                        if (sslSession != null) {
                            final Certificate[] certChain = sslSession.getPeerCertificates();
                            if (certChain == null || certChain.length == 0) {
                                throw new SSLPeerUnverifiedException("No certificates found");
                            }

                            try {
                                final X509Certificate cert = CertificateUtils
                                        .convertAbstractX509Certificate(certChain[0]);
                                dnHolder.set(cert.getSubjectDN().getName().trim());
                            } catch (CertificateException e) {
                                final String msg = "Could not extract subject DN from SSL session peer certificate";
                                logger.warn(msg);
                                throw new SSLPeerUnverifiedException(msg);
                            }
                        }
                    }
                });

                clientBuilder.disableAutomaticRetries();
                clientBuilder.disableContentCompression();

                final String username = context.getProperty(USERNAME).getValue();
                final String password = context.getProperty(PASSWORD).getValue();
                // set the credentials if appropriate
                if (username != null) {
                    final CredentialsProvider credentialsProvider = new BasicCredentialsProvider();
                    if (password == null) {
                        credentialsProvider.setCredentials(AuthScope.ANY,
                                new UsernamePasswordCredentials(username));
                    } else {
                        credentialsProvider.setCredentials(AuthScope.ANY,
                                new UsernamePasswordCredentials(username, password));
                    }
                    clientBuilder.setDefaultCredentialsProvider(credentialsProvider);
                }

                // Set the proxy if specified
                if (context.getProperty(PROXY_HOST).isSet() && context.getProperty(PROXY_PORT).isSet()) {
                    final String host = context.getProperty(PROXY_HOST).getValue();
                    final int port = context.getProperty(PROXY_PORT).asInteger();
                    clientBuilder.setProxy(new HttpHost(host, port));
                }

                client = clientBuilder.build();

                // determine whether or not destination accepts flowfile/gzip
                destinationAccepts = config.getDestinationAccepts();
                if (destinationAccepts == null) {
                    try {
                        destinationAccepts = getDestinationAcceptance(sendAsFlowFile, client, url, getLogger(),
                                transactionId);
                        config.setDestinationAccepts(destinationAccepts);
                    } catch (final IOException e) {
                        flowFile = session.penalize(flowFile);
                        session.transfer(flowFile, REL_FAILURE);
                        logger.error(
                                "Unable to communicate with destination {} to determine whether or not it can accept "
                                        + "flowfiles/gzip; routing {} to failure due to {}",
                                new Object[] { url, flowFile, e });
                        context.yield();
                        return;
                    }
                }
            }

            bytesToSend += flowFile.getSize();
            if (bytesToSend > maxBatchBytes.longValue()) {
                break;
            }

            // if we are not sending as flowfile, or if the destination doesn't accept V3 or V2 (streaming) format,
            // then only use a single FlowFile
            if (!sendAsFlowFile
                    || !destinationAccepts.isFlowFileV3Accepted() && !destinationAccepts.isFlowFileV2Accepted()) {
                break;
            }
        }

        if (toSend.isEmpty()) {
            return;
        }

        final String url = lastUrl;
        final HttpPost post = new HttpPost(url);
        final List<FlowFile> flowFileList = toSend;
        final DestinationAccepts accepts = destinationAccepts;
        final boolean isDestinationLegacyNiFi = accepts.getProtocolVersion() == null;

        final EntityTemplate entity = new EntityTemplate(new ContentProducer() {
            @Override
            public void writeTo(final OutputStream rawOut) throws IOException {
                final OutputStream throttled = throttler == null ? rawOut
                        : throttler.newThrottledOutputStream(rawOut);
                OutputStream wrappedOut = new BufferedOutputStream(throttled);
                if (compressionLevel > 0 && accepts.isGzipAccepted()) {
                    wrappedOut = new GZIPOutputStream(wrappedOut, compressionLevel);
                }

                try (final OutputStream out = wrappedOut) {
                    for (final FlowFile flowFile : flowFileList) {
                        session.read(flowFile, new InputStreamCallback() {
                            @Override
                            public void process(final InputStream rawIn) throws IOException {
                                try (final InputStream in = new BufferedInputStream(rawIn)) {

                                    FlowFilePackager packager = null;
                                    if (!sendAsFlowFile) {
                                        packager = null;
                                    } else if (accepts.isFlowFileV3Accepted()) {
                                        packager = new FlowFilePackagerV3();
                                    } else if (accepts.isFlowFileV2Accepted()) {
                                        packager = new FlowFilePackagerV2();
                                    } else if (accepts.isFlowFileV1Accepted()) {
                                        packager = new FlowFilePackagerV1();
                                    }

                                    // if none of the above conditions is met, we should never get here, because
                                    // we will have already verified that at least 1 of the FlowFile packaging
                                    // formats is acceptable if sending as FlowFile.
                                    if (packager == null) {
                                        StreamUtils.copy(in, out);
                                    } else {
                                        final Map<String, String> flowFileAttributes;
                                        if (isDestinationLegacyNiFi) {
                                            // Old versions of NiFi expect nf.file.name and nf.file.path to indicate filename & path;
                                            // in order to maintain backward compatibility, we copy the filename & path to those attribute keys.
                                            flowFileAttributes = new HashMap<>(flowFile.getAttributes());
                                            flowFileAttributes.put("nf.file.name",
                                                    flowFile.getAttribute(CoreAttributes.FILENAME.key()));
                                            flowFileAttributes.put("nf.file.path",
                                                    flowFile.getAttribute(CoreAttributes.PATH.key()));
                                        } else {
                                            flowFileAttributes = flowFile.getAttributes();
                                        }

                                        packager.packageFlowFile(in, out, flowFileAttributes, flowFile.getSize());
                                    }
                                }
                            }
                        });
                    }

                    out.flush();
                }
            }
        }) {

            @Override
            public long getContentLength() {
                if (compressionLevel == 0 && !sendAsFlowFile
                        && !context.getProperty(CHUNKED_ENCODING).asBoolean()) {
                    return toSend.get(0).getSize();
                } else {
                    return -1;
                }
            }
        };

        if (context.getProperty(CHUNKED_ENCODING).isSet()) {
            entity.setChunked(context.getProperty(CHUNKED_ENCODING).asBoolean());
        }
        post.setEntity(entity);
        post.setConfig(requestConfig);

        final String contentType;
        if (sendAsFlowFile) {
            if (accepts.isFlowFileV3Accepted()) {
                contentType = APPLICATION_FLOW_FILE_V3;
            } else if (accepts.isFlowFileV2Accepted()) {
                contentType = APPLICATION_FLOW_FILE_V2;
            } else if (accepts.isFlowFileV1Accepted()) {
                contentType = APPLICATION_FLOW_FILE_V1;
            } else {
                logger.error(
                        "Cannot send data to {} because the destination does not accept FlowFiles and this processor is "
                                + "configured to deliver FlowFiles; rolling back session",
                        new Object[] { url });
                session.rollback();
                context.yield();
                IOUtils.closeQuietly(client);
                return;
            }
        } else {
            final String contentTypeValue = context.getProperty(CONTENT_TYPE)
                    .evaluateAttributeExpressions(toSend.get(0)).getValue();
            contentType = StringUtils.isBlank(contentTypeValue) ? DEFAULT_CONTENT_TYPE : contentTypeValue;
        }

        final String attributeHeaderRegex = context.getProperty(ATTRIBUTES_AS_HEADERS_REGEX).getValue();
        if (attributeHeaderRegex != null && !sendAsFlowFile && flowFileList.size() == 1) {
            final Pattern pattern = Pattern.compile(attributeHeaderRegex);

            final Map<String, String> attributes = flowFileList.get(0).getAttributes();
            for (final Map.Entry<String, String> entry : attributes.entrySet()) {
                final String key = entry.getKey();
                if (pattern.matcher(key).matches()) {
                    post.setHeader(entry.getKey(), entry.getValue());
                }
            }
        }

        post.setHeader(CONTENT_TYPE_HEADER, contentType);
        post.setHeader(FLOWFILE_CONFIRMATION_HEADER, "true");
        post.setHeader(PROTOCOL_VERSION_HEADER, PROTOCOL_VERSION);
        post.setHeader(TRANSACTION_ID_HEADER, transactionId);
        if (compressionLevel > 0 && accepts.isGzipAccepted()) {
            if (sendAsFlowFile) {
                post.setHeader(GZIPPED_HEADER, "true");
            } else {
                post.setHeader(CONTENT_ENCODING_HEADER, CONTENT_ENCODING_GZIP_VALUE);
            }
        }

        // Do the actual POST
        final String flowFileDescription = toSend.size() <= 10 ? toSend.toString() : toSend.size() + " FlowFiles";

        final String uploadDataRate;
        final long uploadMillis;
        CloseableHttpResponse response = null;
        try {
            final StopWatch stopWatch = new StopWatch(true);
            response = client.execute(post);

            // consume input stream entirely, ignoring its contents. If we
            // don't do this, the Connection will not be returned to the pool
            EntityUtils.consume(response.getEntity());
            stopWatch.stop();
            uploadDataRate = stopWatch.calculateDataRate(bytesToSend);
            uploadMillis = stopWatch.getDuration(TimeUnit.MILLISECONDS);
        } catch (final IOException e) {
            logger.error("Failed to Post {} due to {}; transferring to failure",
                    new Object[] { flowFileDescription, e });
            context.yield();
            for (FlowFile flowFile : toSend) {
                flowFile = session.penalize(flowFile);
                session.transfer(flowFile, REL_FAILURE);
            }
            return;
        } finally {
            if (response != null) {
                try {
                    response.close();
                } catch (final IOException e) {
                    getLogger().warn("Failed to close HTTP Response due to {}", new Object[] { e });
                }
            }
        }

        // If we get a 'SEE OTHER' status code and an HTTP header that indicates that the intent
        // of the Location URI is a flowfile hold, we will store this holdUri. This prevents us
        // from posting to some other webservice and then attempting to delete some resource to which
        // we are redirected
        final int responseCode = response.getStatusLine().getStatusCode();
        final String responseReason = response.getStatusLine().getReasonPhrase();
        String holdUri = null;
        if (responseCode == HttpServletResponse.SC_SEE_OTHER) {
            final Header locationUriHeader = response.getFirstHeader(LOCATION_URI_INTENT_NAME);
            if (locationUriHeader != null) {
                if (LOCATION_URI_INTENT_VALUE.equals(locationUriHeader.getValue())) {
                    final Header holdUriHeader = response.getFirstHeader(LOCATION_HEADER_NAME);
                    if (holdUriHeader != null) {
                        holdUri = holdUriHeader.getValue();
                    }
                }
            }

            if (holdUri == null) {
                for (FlowFile flowFile : toSend) {
                    flowFile = session.penalize(flowFile);
                    logger.error(
                            "Failed to Post {} to {}: sent content and received status code {}:{} but no Hold URI",
                            new Object[] { flowFile, url, responseCode, responseReason });
                    session.transfer(flowFile, REL_FAILURE);
                }
                return;
            }
        }

        if (holdUri == null) {
            if (responseCode == HttpServletResponse.SC_SERVICE_UNAVAILABLE) {
                for (FlowFile flowFile : toSend) {
                    flowFile = session.penalize(flowFile);
                    logger.error(
                            "Failed to Post {} to {}: response code was {}:{}; will yield processing, "
                                    + "since the destination is temporarily unavailable",
                            new Object[] { flowFile, url, responseCode, responseReason });
                    session.transfer(flowFile, REL_FAILURE);
                }
                context.yield();
                return;
            }

            if (responseCode >= 300) {
                for (FlowFile flowFile : toSend) {
                    flowFile = session.penalize(flowFile);
                    logger.error("Failed to Post {} to {}: response code was {}:{}",
                            new Object[] { flowFile, url, responseCode, responseReason });
                    session.transfer(flowFile, REL_FAILURE);
                }
                return;
            }

            logger.info("Successfully Posted {} to {} in {} at a rate of {}", new Object[] { flowFileDescription,
                    url, FormatUtils.formatMinutesSeconds(uploadMillis, TimeUnit.MILLISECONDS), uploadDataRate });

            for (final FlowFile flowFile : toSend) {
                session.getProvenanceReporter().send(flowFile, url, "Remote DN=" + dnHolder.get(), uploadMillis,
                        true);
                session.transfer(flowFile, REL_SUCCESS);
            }
            return;
        }

        //
        // the response indicated a Hold URI; delete the Hold.
        //
        // determine the full URI of the Flow File's Hold; Unfortunately, the responses that are returned have
        // changed over the past, so we have to take into account a few different possibilities.
        String fullHoldUri = holdUri;
        if (holdUri.startsWith("/contentListener")) {
            // If the Hold URI that we get starts with /contentListener, it may not really be /contentListener,
            // as this really indicates that it should be whatever we posted to -- if posting directly to the
            // ListenHTTP component, it will be /contentListener, but if posting to a proxy/load balancer, we may
            // be posting to some other URL.
            fullHoldUri = url + holdUri.substring(16);
        } else if (holdUri.startsWith("/")) {
            // URL indicates the full path but not hostname or port; use the same hostname & port that we posted
            // to but use the full path indicated by the response.
            int firstSlash = url.indexOf("/", 8);
            if (firstSlash < 0) {
                firstSlash = url.length();
            }
            final String beforeSlash = url.substring(0, firstSlash);
            fullHoldUri = beforeSlash + holdUri;
        } else if (!holdUri.startsWith("http")) {
            // Absolute URL
            fullHoldUri = url + (url.endsWith("/") ? "" : "/") + holdUri;
        }

        final HttpDelete delete = new HttpDelete(fullHoldUri);
        delete.setHeader(TRANSACTION_ID_HEADER, transactionId);

        while (true) {
            try {
                final HttpResponse holdResponse = client.execute(delete);
                EntityUtils.consume(holdResponse.getEntity());
                final int holdStatusCode = holdResponse.getStatusLine().getStatusCode();
                final String holdReason = holdResponse.getStatusLine().getReasonPhrase();
                if (holdStatusCode >= 300) {
                    logger.error(
                            "Failed to delete Hold that destination placed on {}: got response code {}:{}; routing to failure",
                            new Object[] { flowFileDescription, holdStatusCode, holdReason });

                    for (FlowFile flowFile : toSend) {
                        flowFile = session.penalize(flowFile);
                        session.transfer(flowFile, REL_FAILURE);
                    }
                    return;
                }

                logger.info("Successfully Posted {} to {} in {} milliseconds at a rate of {}",
                        new Object[] { flowFileDescription, url, uploadMillis, uploadDataRate });

                for (final FlowFile flowFile : toSend) {
                    session.getProvenanceReporter().send(flowFile, url);
                    session.transfer(flowFile, REL_SUCCESS);
                }
                return;
            } catch (final IOException e) {
                logger.warn("Failed to delete Hold that destination placed on {} due to {}",
                        new Object[] { flowFileDescription, e });
            }

            if (!isScheduled()) {
                context.yield();
                logger.warn(
                        "Failed to delete Hold that destination placed on {}; Processor has been stopped so routing FlowFile(s) to failure",
                        new Object[] { flowFileDescription });
                for (FlowFile flowFile : toSend) {
                    flowFile = session.penalize(flowFile);
                    session.transfer(flowFile, REL_FAILURE);
                }
                return;
            }
        }
    }

    private DestinationAccepts getDestinationAcceptance(final boolean sendAsFlowFile, final HttpClient client,
            final String uri, final ComponentLog logger, final String transactionId) throws IOException {
        final HttpHead head = new HttpHead(uri);
        if (sendAsFlowFile) {
            head.addHeader(TRANSACTION_ID_HEADER, transactionId);
        }
        final HttpResponse response = client.execute(head);

        // we assume that the destination can support FlowFile v1 always when the processor is also configured to send as a FlowFile
        // otherwise, we do not bother to make any determinations concerning this compatibility
        final boolean acceptsFlowFileV1 = sendAsFlowFile;
        boolean acceptsFlowFileV2 = false;
        boolean acceptsFlowFileV3 = false;
        boolean acceptsGzip = false;
        Integer protocolVersion = null;

        final int statusCode = response.getStatusLine().getStatusCode();
        if (statusCode == Status.METHOD_NOT_ALLOWED.getStatusCode()) {
            return new DestinationAccepts(acceptsFlowFileV3, acceptsFlowFileV2, acceptsFlowFileV1, false, null);
        } else if (statusCode == Status.OK.getStatusCode()) {
            Header[] headers = response.getHeaders(ACCEPT);
            // If configured to send as a flowfile, determine the capabilities of the endpoint
            if (sendAsFlowFile) {
                if (headers != null) {
                    for (final Header header : headers) {
                        for (final String accepted : header.getValue().split(",")) {
                            final String trimmed = accepted.trim();
                            if (trimmed.equals(APPLICATION_FLOW_FILE_V3)) {
                                acceptsFlowFileV3 = true;
                            } else if (trimmed.equals(APPLICATION_FLOW_FILE_V2)) {
                                acceptsFlowFileV2 = true;
                            }
                        }
                    }
                }

                final Header destinationVersion = response.getFirstHeader(PROTOCOL_VERSION_HEADER);
                if (destinationVersion != null) {
                    try {
                        protocolVersion = Integer.valueOf(destinationVersion.getValue());
                    } catch (final NumberFormatException e) {
                        // nothing to do here really.... it's an invalid value, so treat the same as if not specified
                    }
                }

                if (acceptsFlowFileV3) {
                    logger.debug("Connection to URI " + uri + " will be using Content Type "
                            + APPLICATION_FLOW_FILE_V3 + " if sending data as FlowFile");
                } else if (acceptsFlowFileV2) {
                    logger.debug("Connection to URI " + uri + " will be using Content Type "
                            + APPLICATION_FLOW_FILE_V2 + " if sending data as FlowFile");
                } else if (acceptsFlowFileV1) {
                    logger.debug("Connection to URI " + uri + " will be using Content Type "
                            + APPLICATION_FLOW_FILE_V1 + " if sending data as FlowFile");
                }
            }

            headers = response.getHeaders(ACCEPT_ENCODING);
            if (headers != null) {
                for (final Header header : headers) {
                    for (final String accepted : header.getValue().split(",")) {
                        if (accepted.equalsIgnoreCase("gzip")) {
                            acceptsGzip = true;
                        }
                    }
                }
            }

            if (acceptsGzip) {
                logger.debug("Connection to URI " + uri + " indicates that inline GZIP compression is supported");
            } else {
                logger.debug(
                        "Connection to URI " + uri + " indicates that it does NOT support inline GZIP compression");
            }

            return new DestinationAccepts(acceptsFlowFileV3, acceptsFlowFileV2, acceptsFlowFileV1, acceptsGzip,
                    protocolVersion);
        } else {
            logger.warn(
                    "Unable to communicate with destination; when attempting to perform an HTTP HEAD, got unexpected response code of "
                            + statusCode + ": " + response.getStatusLine().getReasonPhrase());
            return new DestinationAccepts(false, false, false, false, null);
        }
    }

    private static class DestinationAccepts {

        private final boolean flowFileV1;
        private final boolean flowFileV2;
        private final boolean flowFileV3;
        private final boolean gzip;
        private final Integer protocolVersion;

        public DestinationAccepts(final boolean flowFileV3, final boolean flowFileV2, final boolean flowFileV1,
                final boolean gzip, final Integer protocolVersion) {
            this.flowFileV3 = flowFileV3;
            this.flowFileV2 = flowFileV2;
            this.flowFileV1 = flowFileV1;
            this.gzip = gzip;
            this.protocolVersion = protocolVersion;
        }

        public boolean isFlowFileV3Accepted() {
            return flowFileV3;
        }

        public boolean isFlowFileV2Accepted() {
            return flowFileV2;
        }

        public boolean isFlowFileV1Accepted() {
            return flowFileV1;
        }

        public boolean isGzipAccepted() {
            return gzip;
        }

        public Integer getProtocolVersion() {
            return protocolVersion;
        }
    }

    private static class Config {

        private volatile DestinationAccepts destinationAccepts;
        private final HttpClientConnectionManager conMan;

        public Config(final HttpClientConnectionManager conMan) {
            this.conMan = conMan;
        }

        public DestinationAccepts getDestinationAccepts() {
            return this.destinationAccepts;
        }

        public void setDestinationAccepts(final DestinationAccepts destinationAccepts) {
            this.destinationAccepts = destinationAccepts;
        }

        public HttpClientConnectionManager getConnectionManager() {
            return conMan;
        }
    }
}