Pi4J – ADC MCP3008 – SPI – Sensor Reader Example


import com.pi4j.io.spi.SpiChannel;
import com.pi4j.io.spi.SpiDevice;
import com.pi4j.io.spi.SpiFactory;

import java.nio.ByteBuffer;
import java.io.IOException;

public class SpiMCP3008 {

    public static SpiDevice spi = null;
    public static byte INIT_CMD = (byte) 0xD0; // 11010000

    public static void main(String args[]) throws InterruptedException, IOException {
        System.out.println("<--Pi4J--> SPI test program using MCP3008 AtoD Chip");

        spi = SpiFactory.getInstance(SpiChannel.CS0,
                                     SpiDevice.DEFAULT_SPI_SPEED, // default spi speed 1 MHz
                                     SpiDevice.DEFAULT_SPI_MODE); // default spi mode 0

        while(true) {
            read(0); // Read channel 1
			read(1); // Read channel 2
            Thread.sleep(100);
        }
    }

    public static void read(int channel) throws IOException {
        // 10-bit ADC MCP3008
        byte packet[] = new byte[3];
        packet[0] = 0x01;  // INIT_CMD;  // address byte
        packet[1] = (byte) ((0x08 + channel) << 4);  // singleEnded + channel
        packet[2] = 0x00;
           
        byte[] result = spi.write(packet);
        System.out.println( ((result[1] & 0x03 ) << 8) | (result[2] & 0xff) );
    }
}
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AWS DynamoDB map object to Base64 encoded gzipped JSON in Java


Annotation in a DynamoDBTable class:
    @DynamoDBAttribute
    @DynamoDBMarshalling(marshallerClass=PojoMarshaller.class)
    private Pojo pojo;

public static class PojoMarshaller extends GzipJsonMarshaller<Pojo> { }

-------------------------------------------------------------------------------------------------------------

import com.amazonaws.services.dynamodbv2.datamodeling.DynamoDBMarshaller;
import com.fasterxml.jackson.databind.*;
import org.apache.commons.codec.binary.Base64;
import org.apache.commons.io.IOUtils;

import java.io.*;
import java.io.IOException;
import java.nio.ByteBuffer;
import java.util.zip.*;

import static com.amazonaws.util.Throwables.failure;

public class GzipJsonMarshaller<T extends Object> implements DynamoDBMarshaller<T> {

    private static final ObjectMapper mapper = new ObjectMapper();
    private static final ObjectWriter writer = mapper.writer();

    @Override
    public String marshall(T obj) {
        try {
            String plainJsonString = writer.writeValueAsString(obj);
            byte[] binaryBytes = compressString(plainJsonString).array();
            String base64BinaryString = Base64.encodeBase64String(binaryBytes);
            return base64BinaryString;
        } catch (Exception e) {
            throw failure(e, "Unable to marshall the instance of " + obj.getClass() + "into a string");
        }
    }

    @Override
    public T unmarshall(Class<T> clazz, String base64BinaryString) {
        try {
            byte[] binaryBytes = Base64.decodeBase64(base64BinaryString);
            String plainJsonString = uncompressString(ByteBuffer.wrap(binaryBytes));
            return mapper.readValue(plainJsonString, clazz);
        } catch (Exception e) {
            throw failure(e, "Unable to unmarshall the string " + base64BinaryString + "into " + clazz);
        }
    }

    public static ByteBuffer compressString(String input) throws IOException {
        ByteArrayOutputStream byteArrayOutput = new ByteArrayOutputStream();
        GZIPOutputStream gzipOutput = new GZIPOutputStream(byteArrayOutput);
        gzipOutput.write(input.getBytes("UTF-8"));
        gzipOutput.finish();
        byte[] compressedBytes = byteArrayOutput.toByteArray();
        ByteBuffer buffer = ByteBuffer.wrap(compressedBytes);
        return buffer;
    }

    public static String uncompressString(ByteBuffer input) throws IOException {
        byte[] bytes = input.array();
        ByteArrayInputStream byteArrayInput = new ByteArrayInputStream(bytes);
        GZIPInputStream gzipInput = new GZIPInputStream(byteArrayInput);
        ByteArrayOutputStream byteArrayOutput = new ByteArrayOutputStream();
        IOUtils.copy(gzipInput, byteArrayOutput);
        return new String(byteArrayOutput.toByteArray(), "UTF-8");
    }

}


Convert Mongo DBObject to POJO with Jongo


import org.jongo.ResultHandler;
import org.jongo.bson.Bson;
import org.jongo.bson.BsonDocument;
import org.jongo.marshall.Unmarshaller;
import org.jongo.marshall.jackson.JacksonEngine;
import org.jongo.marshall.jackson.configuration.Mapping;

...

    public Pojo getPojo(DBObject dbObject) {
        JacksonEngine engine = new JacksonEngine(new Mapping.Builder().build());
        ResultHandler<Pojo> handler = new UnmarshallingResultHandler<>(engine, Pojo.class); 
        Pojo pojo = handler.map(dbObject);
        return pojo;
    }

    public static class UnmarshallingResultHandler<T> implements ResultHandler<T> {
        private final Unmarshaller unmarshaller;
        private final Class<T> clazz;
        public UnmarshallingResultHandler(Unmarshaller unmarshaller, Class<T> clazz) {
            this.unmarshaller = unmarshaller;
            this.clazz = clazz;
        }
        public T map(DBObject result) {
            BsonDocument bsonDocument = Bson.createDocument(result);
            return unmarshaller.unmarshall(bsonDocument, clazz);
        }
    }

How to convert Unicode URL to ASCII in Java

URLs can be quite complex when you add Internationalized Domain Names (IDNs) and Unicode characters to to the path. Often you’ll want to view and store these in ASCII, so proper conversion can become important. After much searching, I couldn’t find a great way to convert an entire Unicode URL to ASCII. Most examples just convert the domain to punycode, but forget about the port, path, and query string. Most examples don’t cover the case when the provided URL doesn’t have a scheme on the front. I tried to incorporate all of those URL components. I wanted a flexible conversion so I came up with some working code that probably has flaws, but it works for most URL formats you will encounter and a large variety that I tested it with.

Here’s a good list of domains to test this with. You can add ports, unicode paths, unicode params, and encoded paths characters to these for additional testing.
https://blogs.msdn.microsoft.com/shawnste/2006/09/14/idn-test-urls/

package com.company.utils;

import java.net.*;

public class UnicodeUtil {
    public static String convertUnicodeURLToAscii(String url) throws URISyntaxException {
        if(url != null) {
            url = url.trim();
            // Handle international domains by detecting non-ascii and converting them to punycode
            boolean isAscii = CharMatcher.ASCII.matchesAllOf(url);
            if(!isAscii) {
                URI uri = new URI(url);
                boolean includeScheme = true;

                // URI needs a scheme to work properly with authority parsing
                if(uri.getScheme() == null) {
                    uri = new URI("http://" + url);
                    includeScheme = false;
                }

                String scheme = uri.getScheme() != null ? uri.getScheme() + "://" : null;
                String authority = uri.getRawAuthority() != null ? uri.getRawAuthority() : ""; // includes domain and port
                String path = uri.getRawPath() != null ? uri.getRawPath() : "";
                String queryString = uri.getRawQuery() != null ? "?" + uri.getRawQuery() : "";

                // Must convert domain to punycode separately from the path
                url = (includeScheme ? scheme : "") + IDN.toASCII(authority) + path + queryString;

                // Convert path from unicode to ascii encoding
                url = new URI(url).toASCIIString();
            }
        }
        return url;
    }
}

Image Proxy using Jersey and HttpClient

Here’s the Jersey Endpoint:

    @GET
    @Path("imageproxy")
    @Produces("image/png")
    public Response imageproxy(@QueryParam("url") String url) {
        byte[] result = null;
        try {
             result = ImageHelper.getUrlBinary(url);
        } catch(Exception ex) {
            logger.error("Error proxying image", ex);
        }
        if(result != null) {
            return Response.ok(new ByteArrayInputStream(result)).build();
        } else {
            return Response.noContent().build();
        }
    }

Here’s the HttpClient code:

import org.apache.commons.io.IOUtils;
import org.apache.http.HttpResponse;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.log4j.Logger;
import java.net.URI;

public class ImageHelper {
    private static Logger logger = Logger.getLogger(ImageHelper.class);
    public static byte[] getUrlBinary(String url) {
        byte[] result = null;
        try {
            URI uri = new URI(url);
            HttpClient client = new DefaultHttpClient();
            HttpGet httpGet = new HttpGet(uri);
            HttpResponse response = client.execute(httpGet);
            result = IOUtils.toByteArray(response.getEntity().getContent());
        } catch(Exception ex) {
            logger.error("Error getting binary from: " + url, ex);
        }
        return result;
    }
}

Java – TAXII – Collection Management Endpoint

As a followup to my last post, here’s a partial implementation of the collection management endpoint for a TAXII server. I added error handling via the TAXII status message response too.

    @POST
    @Path("collection")
    @Consumes (MediaType.APPLICATION_XML)
    @Produces (MediaType.APPLICATION_XML)
    public Response collection(@Context HttpServletRequest request, String x) {
        CollectionInformationRequest collectionRequest = null;
        SubscriptionManagementRequest subscriptionRequest = null;
        try {
            //printHeaders(request);

            System.out.println("---------- Request:");
            Object requestObject = getRequestObject(x);
            if(requestObject instanceof CollectionInformationRequest) {
                collectionRequest = (CollectionInformationRequest) requestObject;
            } else if(requestObject instanceof SubscriptionManagementRequest) {
                subscriptionRequest = (SubscriptionManagementRequest) requestObject;
            } else {
                throw new Exception("Unsupported request type");
            }
            
            System.out.println("---------- Response:");
            if(collectionRequest != null) {
                System.out.println(toXml(collectionRequest));

                List collections = new ArrayList();
                collections.add(factory.createCollectionRecordType()
                        .withAvailable(true)
                        .withCollectionType(CollectionTypeEnum.DATA_FEED)
                        .withCollectionName("default")
                        .withDescription("Default data set description")
                        .withPollingServices(factory.createServiceContactInfoType()
                                .withAddress("/poll")
                                .withMessageBindings(Versions.VID_TAXII_XML_11)
                                .withProtocolBinding(Versions.VID_TAXII_HTTP_10)
                        )
                        .withSubscriptionServices(factory.createServiceContactInfoType()
                                .withAddress("/collection")
                                .withMessageBindings(Versions.VID_TAXII_XML_11)
                                .withProtocolBinding(Versions.VID_TAXII_HTTP_10)
                        )
                        .withContentBindings(factory.createContentBindingIDType().withBindingId(ContentBindings.CB_STIX_XML_111))
                );

                CollectionInformationResponse collectionResponse = factory.createCollectionInformationResponse()
                        .withInResponseTo(collectionRequest.getMessageId())
                        .withMessageId(MessageHelper.generateMessageId())
                        .withCollections(collections);

                String responseString = toXml(collectionResponse);
                System.out.println(taxiiXml.marshalToString(collectionResponse, true));

                return generateResponse(responseString, request);
            } else {
                System.out.println(toXml(subscriptionRequest));
                
                String subscriptionId = subscriptionRequest.getSubscriptionID(); // Should be null on a subscribe
                CollectionActionEnum action = subscriptionRequest.getAction();
                PushParameterType pushLocation = subscriptionRequest.getPushParameters();
                
                // Gather type, query, content bindings so we know what kind of delivery they want
                // Store/update their subscription based on the desired action.  
                // Pause/Resume are tricky because you need to pick up where they paused and send what they missed
                
                SubscriptionManagementRequest subscriptionResponse = factory.createSubscriptionManagementRequest()
                        .withMessageId(MessageHelper.generateMessageId())
                        .withSubscriptionID(subscriptionId)
                        .withCollectionName(subscriptionRequest.getCollectionName())
                        .withAction(subscriptionRequest.getAction());
                
                String responseString = toXml(subscriptionResponse);
                return generateResponse(responseString, request);
            }
        } catch(Exception ex) {
            return handleError(ex, request, collectionRequest);
        }
    }

    private Response handleError(Exception ex, HttpServletRequest httpRequest, RequestMessageType taxiiRequest) {
        ex.printStackTrace();
        try {
            StatusMessage status = factory.createStatusMessage()
                    .withMessage("Error: " + ex.getMessage())
                    .withInResponseTo(taxiiRequest != null ? taxiiRequest.getMessageId() : null)
                    .withMessageId(MessageHelper.generateMessageId())
                    .withStatusType(StatusTypeEnum.FAILURE.value());
            String responseString = toXml(status);
            return generateResponse(responseString, httpRequest);
        } catch(Exception e) {
            e.printStackTrace();
            return Response.status(Response.Status.INTERNAL_SERVER_ERROR).build(); 
        }
    }

Java TAXII Server Implementation

TAXII is a protocol standard for sharing security threat information between systems.  TAXII operates over HTTP/HTTPS and uses a specific XML schema for the message payloads.  Typically STIX is used as the main content of the messages.  TAXII is slowly being adopted by various organizations, particularly the banking industry.  The folks backing TAXII have provided YETI, a basic Python/Django TAXII server implementation and a Python client as well.  They also have a Java client which provides all the JAXB XML mappings for the specification.  In most enterprise environments, Python will not be ideal.  I decided to take the TAXII Java Client code and produce a simple Java Jersey (JAX-RS) TAXII server implementation of the DISCOVERY and POLL endpoints only. There are lots of println’s to show what is going on.  I built the java-taxii  and stix-binding code into a jars and loaded them into a local Maven repo to have available.

Dependencies: com.sun.jersey:jersey-bundle:1.17, javax.servlet:servlet-api:2.4, org.mitre.stix:stix-bindings:1.0 and org.mitre.taxii:java-taxii-all:1.0

Avalanche/SoltraEdge is a nice implementation of TAXII with a great UI, but licensing of the community edition is very limited in terms of usage and customization/modification.  It is developed in Python/Django as well and is most likely a spin-off from YETI.  Their website is incomplete, so it is hard to know what their commercial offerings are.  If you already have your security threat data stored somewhere, you’ll want to be able to customize your own TAXII interface in front of this data store.  Even YETI assumes you want to store incoming data in its own SQLITE database and serve it up from there.

The protocol is well documented, so it is easy to understand what each field is for so you can abide by the specifications.  The INBOX and COLLECTION_MANAGEMENT endpoints are more complex than the POLL and DISCOVERY endpoints, but can be done in a similar fashion.

Follow-up post with a sample/starter collection management endpoint: Java Taxii Collection Management Endpoint

import java.io.*;
import java.math.BigInteger;
import java.net.URI;
import java.util.*;
import javax.servlet.http.HttpServletRequest;
import javax.ws.rs.*;
import javax.ws.rs.core.*;
import javax.xml.bind.*;
import javax.xml.datatype.*;
import org.mitre.taxii.*;
import org.mitre.taxii.client.HttpClient;
import org.mitre.taxii.messages.TaxiiXml;
import org.mitre.taxii.messages.xml11.*;

@Path("/")
public class TestEndpoints {

    /* Example request headers
            User-Agent: java-taxii.httpclient
            content-type: application/xml
            accept: application/xml
            x-taxii-accept: urn:taxii.mitre.org:message:xml:1.1
            x-taxii-content-type: urn:taxii.mitre.org:message:xml:1.1
            x-taxii-services: urn:taxii.mitre.org:services:1.1
            x-taxii-protocol: urn:taxii.mitre.org:protocol:http:1.0
    */
    
    // Are these thread-safe???
    private ObjectFactory factory = new ObjectFactory();
    private TaxiiXmlFactory txf = new TaxiiXmlFactory();
    private TaxiiXml taxiiXml = txf.createTaxiiXml();
    
    @POST
    @Path("discovery")
    @Produces (MediaType.APPLICATION_XML)
    @Consumes (MediaType.APPLICATION_XML)
    public Response discovery(@Context HttpServletRequest request, String x) {
        try {
            printHeaders(request);

            System.out.println("---------- Request:");
            DiscoveryRequest discoveryRequest = (DiscoveryRequest) getRequestObject(x);
            System.out.println(toXml(discoveryRequest));

            System.out.println("---------- Response:");
            List services = new ArrayList<>();
            services.add(factory.createServiceInstanceType()
                    .withServiceType(ServiceTypeEnum.POLL)
                    .withAddress("/poll")
                    .withAvailable(true)
                    .withProtocolBinding(Versions.VID_TAXII_HTTP_10)
                    .withServiceVersion(Versions.VID_TAXII_SERVICES_11)
                    .withMessageBindings(Versions.VID_TAXII_XML_11)
                    .withMessage("Super awesome data comes from this service")
                    .withContentBindings(factory.createContentBindingIDType().withBindingId(ContentBindings.CB_STIX_XML_111))
            );
            
            DiscoveryResponse discoveryResponse = factory.createDiscoveryResponse()
                    .withInResponseTo(discoveryRequest.getMessageId())
                    .withMessageId(MessageHelper.generateMessageId())
                    .withServiceInstances(services);
            
            String responseString = toXml(discoveryResponse);
            System.out.println(taxiiXml.marshalToString(discoveryResponse, true));
            
            return generateResponse(responseString, request);
        } catch(Exception ex) {
            ex.printStackTrace();
            return Response.status(Response.Status.INTERNAL_SERVER_ERROR).build();
        }
    }
    
    @POST
    @Path("poll")
    @Produces (MediaType.APPLICATION_XML)
    @Consumes (MediaType.APPLICATION_XML)
    public Response poll(@Context HttpServletRequest request, String x) {
        try {
            printHeaders(request);

            System.out.println("---------- Request:");
            PollRequest pollRequest = (PollRequest) getRequestObject(x);
            System.out.println(toXml(pollRequest));
            String type = pollRequest.getPollParameters().getResponseType().equals(ResponseTypeEnum.FULL) ? "FULL" : "COUNT ONLY";
            System.out.println("Response Type: " + type);
            System.out.println("Collection: " + pollRequest.getCollectionName());
            System.out.println("Start Time: " + (pollRequest.getExclusiveBeginTimestamp() != null ? pollRequest.getExclusiveBeginTimestamp().toXMLFormat() : "(none)"));
            System.out.println("End Time: " + (pollRequest.getInclusiveEndTimestamp() != null ? pollRequest.getInclusiveEndTimestamp().toXMLFormat() : "(none)"));

            System.out.println("---------- Response:");
            PollResponse pollResponse = factory.createPollResponse()
                    .withInResponseTo(pollRequest.getMessageId())
                    .withMessageId(MessageHelper.generateMessageId())
                    .withCollectionName(pollRequest.getCollectionName())
                    .withRecordCount(factory.createRecordCountType().withValue(BigInteger.valueOf(9999)).withPartialCount(false)) 
                    .withExclusiveBeginTimestamp(pollRequest.getExclusiveBeginTimestamp())
                    .withInclusiveEndTimestamp(pollRequest.getInclusiveEndTimestamp())
                    .withContentBlocks(
                            factory.createContentBlock()
                                    .withContentBinding(factory.createContentInstanceType().withBindingId(ContentBindings.CB_STIX_XML_111))
                                    .withContent(factory.createAnyMixedContentType().withContent("Content Block Stuff Goes Here, STIX for example"))
                                    .withTimestampLabel(getTimestamp(null))
                                    .withMessage("Here's your data")
                    );
            
            String responseString = toXml(pollResponse);
            System.out.println(taxiiXml.marshalToString(pollResponse, true));
            
            return generateResponse(responseString, request);
        } catch(Exception ex) {
            ex.printStackTrace();
            return Response.status(Response.Status.INTERNAL_SERVER_ERROR).build();
        }
    }
    
    private Response generateResponse(String responseString, HttpServletRequest request) throws Exception {
        return Response.ok(responseString)
                    .header(HttpClient.HEADER_X_TAXII_PROTOCOL, getProtocol(request))
                    .header(HttpClient.HEADER_X_TAXII_CONTENT_TYPE, Versions.VID_TAXII_XML_11)
                    .header(HttpClient.HEADER_X_TAXII_SERVICES, Versions.VID_TAXII_SERVICES_11)
                    .build();
    }
    
    private String getProtocol(HttpServletRequest request) throws Exception {
        String scheme = new URI(request.getRequestURL().toString()).getScheme();
        if(scheme != null && scheme.equalsIgnoreCase("https")) {
            return Versions.VID_TAXII_HTTPS_10;
        } else {
            return Versions.VID_TAXII_HTTP_10;
        }
    }
    
    private void printHeaders(HttpServletRequest request) {
        System.out.println("--------------------------------------------");
        List headerNames = Collections.list(request.getHeaderNames());         
        for(String name : headerNames) {
            System.out.println(name + ": " + request.getHeader(name));
        }
    }

    private String toXml(Object discoveryResponse) throws Exception {
        final Marshaller m = taxiiXml.createMarshaller(false); 
        m.setProperty(Marshaller.JAXB_FRAGMENT, true); // Don't generate xml declaration.
        final StringWriter sw = new StringWriter();
        m.marshal(discoveryResponse, sw);
        return sw.toString();
    }

    private Object getRequestObject(String x) throws Exception {
        Unmarshaller um = taxiiXml.getJaxbContext().createUnmarshaller();
        return um.unmarshal(new StringReader(x));
    }

    private XMLGregorianCalendar getTimestamp(Date dte) throws Exception {
        if(dte == null) {
            dte = new Date();
        }
        GregorianCalendar gc = new GregorianCalendar();
        gc.setTime(dte);
        return DatatypeFactory.newInstance().newXMLGregorianCalendar(gc);
    }