I am trying to connect to my gmail inbox to read messages through Java Application. I am using..
jdk1.6.0_13
javamail-1.4.3 libs - (mail.jar, mailapi.jar, imap.jar)
Below is my code : MailReader.java
import java.util.Properties;
import javax.mail.MessagingException;
import javax.mail.Session;
import javax.mail.Store;
public class MailReader
{
public static void main(String[] args)
{
readMail();
}
public static void readMail()
{
Properties props = System.getProperties();
props.setProperty("mail.store.protocol", "imaps");
try
{
Session session = Session.getDefaultInstance(props, null);
Store store = session.getStore("imaps");
store.connect("imap.gmail.com", "myEmailId#gmail.com", "myPwd");
System.out.println("Store Connected..");
//inbox = (Folder) store.getFolder("Inbox");
//inbox.open(Folder.READ_WRITE);
//Further processing of inbox....
}
catch (MessagingException e)
{
e.printStackTrace();
}
}
}
I expect to get store connected, but call to store.connect() never returns and I get below output :
javax.mail.MessagingException: Connection timed out;
nested
exception is:
java.net.ConnectException: Connection timed out
at
com.sun.mail.imap.IMAPStore.protocolConnect(IMAPStore.java:441)
at
javax.mail.Service.connect(Service.java:233)
at
javax.mail.Service.connect(Service.java:134)
at
ReadMail.readMail(ReadMail.java:21)
at ReadMail.main(ReadMail.java:10)
However I am able to SEND email by Java using SMTP, Transport.send() and same gmail account. But cannot read emails.
What can be the solution ?
IMAP work off a different port (143 for non-secure, 993 for secure) to sendmail (25) and I suspect that's blocked. Can you telnet on that port to that server e.g.
telnet imap.gmail.com {port number}
That'll indicate if you have network connectivity.
Related
I have a question regarding configuration of timeouts on a netty TCP server.
Currently we have configured readTimeOut as 120s. Set the connect timout like this:
socketChannel.pipeline().addLast(new ReadTimeoutHandler(120, TimeUnit.SECONDS));
But if the read time exceeds 120s, service doesn't response to front end correctly. If tested from postman, got the "Could not get any response" as response.
Following is the netty config we using:
public class EventLoopNettyCustomizer implements NettyServerCustomizer {
#Override
public HttpServer apply(HttpServer httpServer) {
EventLoopGroup bossGroup = new NioEventLoopGroup(1);
EventLoopGroup workGroup = new NioEventLoopGroup();
return httpServer.tcpConfiguration(tcpServer -> tcpServer
.bootstrap(serverBootstrap -> serverBootstrap
.group(bossGroup, workGroup)
.option(ChannelOption.SO_BACKLOG, 10000)
.option(ChannelOption.CONNECT_TIMEOUT_MILLIS, 30000)
.childHandler(new ChannelInitializer<SocketChannel>() {
#Override
protected void initChannel(SocketChannel socketChannel) throws Exception {
socketChannel.pipeline().addLast(new ReadTimeoutHandler(120, TimeUnit.SECONDS));
socketChannel.pipeline().addLast(new WriteTimeoutHandler(120, TimeUnit.SECONDS));
}
})
.channel(NioServerSocketChannel.class)));
}
}
How can I config the netty so that it is able to return customized response? Including http status and message.
I am doing a POC so here is the quick and dirty code. I use MQTT.fx desktop client to test Pub/Sub to my MQTT Server. Works fine. I can publish/subscribe to my topic. I can publish from another mqtt client and I get the messages. When using this code, I do not receive anything when I publish messages from MQTT.fx or any other publishers. I will receive something if I publish with the mqttClient (if you uncomment the line). I am scratching my head...
Can someone help? Thanks.
class Program
{
private static CancellationTokenSource cts = new CancellationTokenSource(); //TODO create token using the Timeout delay from config
private static async Task Main(string[] args)
{
var factory = new MqttFactory();
var mqttClient = factory.CreateMqttClient();
var options = new MqttClientOptionsBuilder()
.WithClientId("MyClientIDHere")
.WithTcpServer("IPAddressHere", 1883)
//.WithCredentials("Wbo", string.Empty)
//.WithTls()
.WithCleanSession()
.Build();
try
{
mqttClient.UseApplicationMessageReceivedHandler(async e =>
{
Console.WriteLine("### RECEIVED APPLICATION MESSAGE ###");
Console.WriteLine($"+ Topic = {e.ApplicationMessage.Topic}");
Console.WriteLine($"+ Payload = {Encoding.UTF8.GetString(e.ApplicationMessage.Payload)}");
Console.WriteLine($"+ QoS = {e.ApplicationMessage.QualityOfServiceLevel}");
Console.WriteLine($"+ Retain = {e.ApplicationMessage.Retain}");
Console.WriteLine();
});
mqttClient.UseConnectedHandler(async e =>
{
Console.WriteLine("### CONNECTED WITH SERVER ###");
// Subscribe to a topic
await mqttClient.SubscribeAsync(new TopicFilterBuilder().WithTopic("MyClientIDHere/Device_2/Instance_1").Build());
Console.WriteLine("### SUBSCRIBED ###");
});
await mqttClient.ConnectAsync(options, cts.Token);
// UNCOMMENT AND YOU WILL RECEIVE A MESSAGE Task.Run(() => mqttClient.PublishAsync("MyClientIDHere/Device_2/Instance_1","met=Temperature~data=29"));
}
catch (OperationCanceledException)
{
Console.WriteLine("task cancelled");
}
catch (Exception e)
{
Console.WriteLine(e);
}
Console.ReadKey();
}
}
With the latest version of MQTTnet I could not reproduce your issue, it seems to work here. I'm using a mosquitto MQTT server which is located on another server than where I run my program.
Your code looks good. You can improve some, by subscribing to the topics before connecting.
I am trying to test ActiveMQ connection and return a value. it crashes on line:
httpResponse = client.execute(theHttpGet);
It is not my code I am trying to debug it. Can anyone help me to understand why the code is using HttpGet?
public ActivemqBrokerInfo(String serverAddress, int port, String apiUrl, int timeout) {
// Default Activemq location
this.serverAddress = String.format("http://%s:%s/%s", serverAddress, port, apiUrl);
int timeoutInMs = timeout;
HttpClientBuilder builder = HttpClientBuilder.create();
RequestConfig requestConfig = RequestConfig.custom().setConnectTimeout(timeoutInMs).build();
builder.setDefaultRequestConfig(requestConfig);
client = builder.build();
}
public ActivemqBrokerInfo(String serverAddress) {
this(serverAddress, DEFAULT_PORT, DEFAULT_API_URL, DEFAULT_TIMEOUT);
}
#Override
public boolean testConnection() {
HttpGet theHttpGet = new HttpGet(serverAddress);
theHttpGet.addHeader("test-header-name", "test-header-value");
HttpResponse httpResponse = null;
try{
httpResponse = client.execute(theHttpGet);// Code is crashing on this line
} catch (IOException ex){
LOGGER.error("Broker down: ", ex);
}
return httpResponse != null;
}
When ActiveMQ runs is normally starts an embedded web server. This web server is used to host the web admin console as well as the Jolokia endpoint which acts as an HTTP facade in front of the broker's MBeans. In other words, any client can send HTTP requests to specially formed URLs on the broker to get results from the underlying management beans. This is exactly what your bit of code appears to be doing. It appears to be sending an HTTP request to the Jolokia endpoint (i.e. api/jolokia) in order to determine if the broker is alive or not.
Based on the information provided it is impossible to determine why testConnection() is not returning successfully since you've included no information about the configuration or state of the broker.
I recommend you add additional logging to see what may be happening and also catch Exception rather than just IOException.
I am following the solace tutorial for Publish/Subscribe (link: https://dev.solace.com/samples/solace-samples-java/publish-subscribe/). Therefore, there shouldn't be anything "wrong" with the code.
I am trying to get my TopicSubscriber to connect to the cloud. After building my jar I run the following command:
java -cp target/SOM_Enrichment-1.0-SNAPSHOT.jar TopicSubscriber <host:port> <client-username#message-vpn> <password>
(with the appropriate fields filled in)
I get the following error:
TopicSubscriber initializing...
Jul 12, 2018 2:27:56 PM com.solacesystems.jcsmp.protocol.impl.TcpClientChannel call
INFO: Connecting to host 'blocked out' (host 1 of 1, smfclient 2, attempt 1 of 1, this_host_attempt: 1 of 1)
Jul 12, 2018 2:28:17 PM com.solacesystems.jcsmp.protocol.impl.TcpClientChannel call
INFO: Connection attempt failed to host 'blocked out' ConnectException com.solacesystems.jcsmp.JCSMPTransportException: ('blocked out') - Error communicating with the router. cause: java.net.ConnectException: Connection timed out: no further information ((Client name: 'blocked out' Local port: -1 Remote addr: 'blocked out') - )
Jul 12, 2018 2:28:20 PM com.solacesystems.jcsmp.protocol.impl.TcpClientChannel close
INFO: Channel Closed (smfclient 2)
Exception in thread "main" com.solacesystems.jcsmp.JCSMPTransportException" (Client name: 'blocked out' Local port: -1 Remote addr: 'blocked out') - Error communicating with the router.
Below is the TopicSubscriber.java file:
import java.util.concurrent.CountDownLatch;
import com.solacesystems.jcsmp.BytesXMLMessage;
import com.solacesystems.jcsmp.JCSMPException;
import com.solacesystems.jcsmp.JCSMPFactory;
import com.solacesystems.jcsmp.JCSMPProperties;
import com.solacesystems.jcsmp.JCSMPSession;
import com.solacesystems.jcsmp.TextMessage;
import com.solacesystems.jcsmp.Topic;
import com.solacesystems.jcsmp.XMLMessageConsumer;
import com.solacesystems.jcsmp.XMLMessageListener;
public class TopicSubscriber {
public static void main(String... args) throws JCSMPException {
// Check command line arguments
if (args.length != 3 || args[1].split("#").length != 2) {
System.out.println("Usage: TopicSubscriber <host:port> <client-username#message-vpn> <client-password>");
System.out.println();
System.exit(-1);
}
if (args[1].split("#")[0].isEmpty()) {
System.out.println("No client-username entered");
System.out.println();
System.exit(-1);
}
if (args[1].split("#")[1].isEmpty()) {
System.out.println("No message-vpn entered");
System.out.println();
System.exit(-1);
}
System.out.println("TopicSubscriber initializing...");
final JCSMPProperties properties = new JCSMPProperties();
properties.setProperty(JCSMPProperties.HOST, args[0]); // host:port
properties.setProperty(JCSMPProperties.USERNAME, args[1].split("#")[0]); // client-username
properties.setProperty(JCSMPProperties.PASSWORD, args[2]); // client-password
properties.setProperty(JCSMPProperties.VPN_NAME, args[1].split("#")[1]); // message-vpn
final Topic topic = JCSMPFactory.onlyInstance().createTopic("tutorial/topic");
final JCSMPSession session = JCSMPFactory.onlyInstance().createSession(properties);
session.connect();
final CountDownLatch latch = new CountDownLatch(1); // used for
// synchronizing b/w threads
/** Anonymous inner-class for MessageListener
* This demonstrates the async threaded message callback */
final XMLMessageConsumer cons = session.getMessageConsumer(new XMLMessageListener() {
#Override
public void onReceive(BytesXMLMessage msg) {
if (msg instanceof TextMessage) {
System.out.printf("TextMessage received: '%s'%n",
((TextMessage) msg).getText());
} else {
System.out.println("Message received.");
}
System.out.printf("Message Dump:%n%s%n", msg.dump());
latch.countDown(); // unblock main thread
}
#Override
public void onException(JCSMPException e) {
System.out.printf("Consumer received exception: %s%n", e);
latch.countDown(); // unblock main thread
}
});
session.addSubscription(topic);
System.out.println("Connected. Awaiting message...");
cons.start();
// Consume-only session is now hooked up and running!
try {
latch.await(); // block here until message received, and latch will flip
} catch (InterruptedException e) {
System.out.println("I was awoken while waiting");
}
// Close consumer
cons.close();
System.out.println("Exiting.");
session.closeSession();
}
}
Any help would be greatly appreciated.
java.net.ConnectException: Connection timed out
The log entry indicates that network connectivity to the specified DNS name/IP address cannot be established.
Next step includes:
Verifying that you are able to resolve the DNS name to an IP
address.
Verifying that the correct DNS name/IP address/Port is in use - You need the "SMF Host" in the Solace Cloud Connection Details.
Verifying that the IP address/Port is not blocked by an intermediate network device.
I am presently working on program on Android Things for connecting to Google Cloud IoT Core. I used to sample maven code provided by Google and modified it for Gradle(with all the imports and stuff). After doing every kind of check, whenever I am trying to run the program on a Raspberry Pi3 running Android Things it keeps giving this error
W/System.err: java.io.FileNotFoundException: com/example/adityaprakash/test/rsa_private.pem (No such file or directory)
telling me that the private key file that I am supposed to use for the JWT doesn't exist despite the fact it does and I have given the path for the pem file.Here are my java codes
package com.example.adityaprakash.test;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
public class MainActivity extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
//setContentView(R.layout.activity_main);
Log.i("#########","######");
MqttExample mqtt = new MqttExample();
try {
mqtt.Start();
} catch (Exception e) {
e.printStackTrace();
}
}
}
The MqttExample.java
package com.example.adityaprakash.test;
// [END cloudiotcore_mqtt_imports]
import org.eclipse.paho.client.mqttv3.MqttClient;
import org.eclipse.paho.client.mqttv3.MqttConnectOptions;
import org.eclipse.paho.client.mqttv3.MqttMessage;
import org.eclipse.paho.client.mqttv3.persist.MemoryPersistence;
import org.joda.time.DateTime;
import java.io.BufferedReader;
import java.io.FileReader;
import java.security.KeyFactory;
import java.security.spec.PKCS8EncodedKeySpec;
import android.util.Base64;
import io.jsonwebtoken.JwtBuilder;
import io.jsonwebtoken.Jwts;
import io.jsonwebtoken.SignatureAlgorithm;
public class MqttExample {
// [START cloudiotcore_mqtt_createjwt]
/** Create a Cloud IoT Core JWT for the given project id, signed with the given RSA key. */
public static String createJwtRsa(String projectId, String privateKeyFile) throws Exception {
DateTime now = new DateTime();
String strKeyPEM = "";
BufferedReader br = new BufferedReader(new FileReader(privateKeyFile));
String line;
while ((line = br.readLine()) != null) {
strKeyPEM += line + "\n";
}
br.close();
// Create a JWT to authenticate this device. The device will be disconnected after the token
// expires, and will have to reconnect with a new token. The audience field should always be set
// to the GCP project id.
JwtBuilder jwtBuilder =
Jwts.builder()
.setIssuedAt(now.toDate())
.setExpiration(now.plusMinutes(20).toDate())
.setAudience(projectId);
String privateKeyPEM = strKeyPEM;
privateKeyPEM = privateKeyPEM.replace("-----BEGIN PRIVATE KEY-----\n", "");
privateKeyPEM = privateKeyPEM.replace("-----END PRIVATE KEY-----", "");
byte[] encoded = Base64.decode(privateKeyPEM,Base64.DEFAULT);
PKCS8EncodedKeySpec spec = new PKCS8EncodedKeySpec(encoded);
KeyFactory kf = KeyFactory.getInstance("RSA");
return jwtBuilder.signWith(SignatureAlgorithm.RS256, kf.generatePrivate(spec)).compact();
}
/** Parse arguments, configure MQTT, and publish messages. */
public void Start() throws Exception {
// [START cloudiotcore_mqtt_configuremqtt]
MqttExampleOptions options = MqttExampleOptions.values();
if (options == null) {
// Could not parse.
System.exit(1);
}
// Build the connection string for Google's Cloud IoT Core MQTT server. Only SSL
// connections are accepted. For server authentication, the JVM's root certificates
// are used.
final String mqttServerAddress =
String.format("ssl://%s:%s", options.mqttBridgeHostname, options.mqttBridgePort);
// Create our MQTT client. The mqttClientId is a unique string that identifies this device. For
// Google Cloud IoT Core, it must be in the format below.
final String mqttClientId =
String.format(
"projects/%s/locations/%s/registries/%s/devices/%s",
options.projectId, options.cloudRegion, options.registryId, options.deviceId);
MqttConnectOptions connectOptions = new MqttConnectOptions();
// Note that the the Google Cloud IoT Core only supports MQTT 3.1.1, and Paho requires that we
// explictly set this. If you don't set MQTT version, the server will immediately close its
// connection to your device.
connectOptions.setMqttVersion(MqttConnectOptions.MQTT_VERSION_3_1_1);
// With Google Cloud IoT Core, the username field is ignored, however it must be set for the
// Paho client library to send the password field. The password field is used to transmit a JWT
// to authorize the device.
connectOptions.setUserName("unused");
System.out.println(options.algorithm);
if (options.algorithm.equals("RS256")) {
connectOptions.setPassword(
createJwtRsa(options.projectId, options.privateKeyFile).toCharArray());
}else {
throw new IllegalArgumentException(
"Invalid algorithm " + options.algorithm + ". Should be one of 'RS256' or 'ES256'.");
}
// [END cloudiotcore_mqtt_configuremqtt]
// [START cloudiotcore_mqtt_publish]
// Create a client, and connect to the Google MQTT bridge.
MqttClient client = new MqttClient(mqttServerAddress, mqttClientId, new MemoryPersistence());
try {
client.connect(connectOptions);
// Publish to the events or state topic based on the flag.
String subTopic = options.messageType.equals("event") ? "events" : options.messageType;
// The MQTT topic that this device will publish telemetry data to. The MQTT topic name is
// required to be in the format below. Note that this is not the same as the device registry's
// Cloud Pub/Sub topic.
String mqttTopic = String.format("/devices/%s/%s", options.deviceId, subTopic);
// Publish numMessages messages to the MQTT bridge, at a rate of 1 per second.
for (int i = 1; i <= options.numMessages; ++i) {
String payload = String.format("%s/%s-payload number-%d", options.registryId, options.deviceId, i);
System.out.format(
"Publishing %s message %d/%d: '%s'\n",
options.messageType, i, options.numMessages, payload);
// Publish "payload" to the MQTT topic. qos=1 means at least once delivery. Cloud IoT Core
// also supports qos=0 for at most once delivery.
MqttMessage message = new MqttMessage(payload.getBytes());
message.setQos(1);
client.publish(mqttTopic, message);
if (options.messageType.equals("event")) {
// Send telemetry events every second
Thread.sleep(1000);
}
else {
// Note: Update Device state less frequently than with telemetry events
Thread.sleep(5000);
}
}
} finally {
// Disconnect the client and finish the run.
client.disconnect();
}
System.out.println("Finished loop successfully. Goodbye!");
// [END cloudiotcore_mqtt_publish]
}
}
and the MqttExampleOptions.java code:
package com.example.adityaprakash.test;
public class MqttExampleOptions {
String projectId;
String registryId;
String deviceId;
String privateKeyFile;
String algorithm;
String cloudRegion;
int numMessages;
String mqttBridgeHostname;
short mqttBridgePort;
String messageType;
/** Construct an MqttExampleOptions class. */
public static MqttExampleOptions values() {
try {
MqttExampleOptions res = new MqttExampleOptions();
res.projectId = "_";
res.registryId = "_";
res.deviceId = "_";
res.privateKeyFile = "com/example/adityaprakash/test/rsa_private.pem";
res.algorithm = "RS256";
res.cloudRegion = "asia-east1";
res.numMessages = 100;
res.mqttBridgeHostname = "mqtt.googleapis.com";
res.mqttBridgePort = 8883;
res.messageType = "event";
return res;
} catch (Exception e) {
System.err.println(e.getMessage());
return null;
}
}
}
Please can anyone give a solution to this problem.
P.S. I know the code looks totally crappy.I don't have experience with Android programming,so please let it go.
The example you are following is not designed for Android.
res.privateKeyFile = "com/example/adityaprakash/test/rsa_private.pem";
Will not relate to the same directory on the Android file system.
I wrote up an AndroidThings explanation of how to talk to Cloud IoT Core here: http://blog.blundellapps.co.uk/tut-google-cloud-iot-core-mqtt-on-android/
You can setup communication like this (with your pem file going into the /raw directory)
// Setup the communication with your Google IoT Core details
communicator = new IotCoreCommunicator.Builder()
.withContext(this)
.withCloudRegion("your-region") // ex: europe-west1
.withProjectId("your-project-id") // ex: supercoolproject23236
.withRegistryId("your-registry-id") // ex: my-devices
.withDeviceId("a-device-id") // ex: my-test-raspberry-pi
.withPrivateKeyRawFileId(R.raw.rsa_private)
.build();
Source code is here: https://github.com/blundell/CloudIoTCoreMQTTExample
Note that the above is good enough for a secure environment or for testing that the end to end works. However if you wanted to release a production IoT device, you would look at embedding the PEM into the ROM and using private file storage access. https://developer.android.com/training/articles/keystore.html
An example of this can be found here: https://github.com/androidthings/sensorhub-cloud-iot
Specifically this class:
https://github.com/androidthings/sensorhub-cloud-iot/blob/e50bde0100fa81818ebbadb54561b3b68ccb64b8/app/src/main/java/com/example/androidthings/sensorhub/cloud/cloudiot/MqttAuthentication.java
You can then generate and use the PEM on the device:
public Certificate getCertificate() {
KeyStore ks = KeyStore.getInstance("AndroidKeyStore");
ks.load(null);
certificate = ks.getCertificate("Cloud IoT Authentication");
if (certificate == null) {
Log.w(TAG, "No IoT Auth Certificate found, generating new cert");
generateAuthenticationKey();
certificate = ks.getCertificate(keyAlias);
}
Log.i(TAG, "loaded certificate: " + keyAlias);
}
and
private void generateAuthenticationKey() throws GeneralSecurityException {
KeyPairGenerator kpg = KeyPairGenerator.getInstance(KeyProperties.KEY_ALGORITHM_RSA, "AndroidKeyStore");
kpg.initialize(new KeyGenParameterSpec.Builder("Cloud IoT Authentication",KeyProperties.PURPOSE_SIGN)
.setKeySize(2048)
.setCertificateSubject(new X500Principal("CN=unused"))
.setDigests(KeyProperties.DIGEST_SHA256)
.setSignaturePaddings(KeyProperties.SIGNATURE_PADDING_RSA_PKCS1)
.build());
kpg.generateKeyPair();
}
I'm pretty sure you're not doing the file I/O correctly. Your file, "com/example/adityaprakash/test/rsa_private.pem", doesn't correspond to an actual filepath on the device. The location of files on the device may be different than in your project. You will have to determine where on the device your file actually is.
On AndroidThings, it is easier to provide the authentication credentials in an Android Resource. See my fork of the WeatherStation sample to see how this works.
First, copy the private key file (e.g. rsa_private_pkcs8) to app/src/main/res/raw/privatekey.txt
Next, you can load the key used to calculate your JWT as:
Context mContext;
int resIdPk = getResources().getIdentifier("privatekey", "raw", getPackageName());
...
InputStream privateKey = mContext.getResources().openRawResource(resIdPk);
byte[] keyBytes = inputStreamToBytes(privateKey);
PKCS8EncodedKeySpec spec = new PKCS8EncodedKeySpec(keyBytes);
KeyFactory kf = KeyFactory.getInstance("EC");
One final note, it appears that you're referencing a file that is not in pkcs8 format, which will cause issues with Java. Make sure to use a key that is packaged in PKCS8 when opening credentials on Android (Java).