Connecting two WebSocket servers to eachother - websocket

I have two WebSocket servers that can communicate wonderfully with a client. They are on two separate machines, implemented in Java and running inside WildFly8 webservers. What I need them to do now is communicate with each other. That means: client sends message to server 1, server 1 sends message to server 2, receives the reply and sends it back to client.
The servers run on different apps in OpenShift and I need them to use websockets. Or some other type of communication, but I haven't managed to find anything that actually works so far (RMI or normal socket connections won't work).
What I basically tried to do is use the same code from the client within the onMessage method of the first server. Something like this:
#OnMessage
public void message(Session session, String msg){
...
WebSocketContainer container = ContainerProvider.getWebSocketContainer();
Session NewSession = container.connectToServer(Client.class, URI.create(URL));
NewSession.getBasicRemote().sendText("Routed :" + input);
...
}
However, the server does not connect to the other server and I don't know why.
Any suggestions?
Thank you!

Put connectToServer inside a try {} catch, you might get an error. Log it.
I'm struggling to do exactly the same things (2 websocket servers, Wildfly 8), and I get a permission denied error. See my post here:
https://stackoverflow.com/questions/30966757/java-server-to-server-communication-with-websockets-permission-denied

Related

Oracle JDBC intermittent connection reset SQLRecoverableException [duplicate]

I am getting the following error trying to read from a socket. I'm doing a readInt() on that InputStream, and I am getting this error. Perusing the documentation this suggests that the client part of the connection closed the connection. In this scenario, I am the server.
I have access to the client log files and it is not closing the connection, and in fact its log files suggest I am closing the connection. So does anybody have an idea why this is happening? What else to check for? Does this arise when there are local resources that are perhaps reaching thresholds?
I do note that I have the following line:
socket.setSoTimeout(10000);
just prior to the readInt(). There is a reason for this (long story), but just curious, are there circumstances under which this might lead to the indicated error? I have the server running in my IDE, and I happened to leave my IDE stuck on a breakpoint, and I then noticed the exact same errors begin appearing in my own logs in my IDE.
Anyway, just mentioning it, hopefully not a red herring. :-(
There are several possible causes.
The other end has deliberately reset the connection, in a way which I will not document here. It is rare, and generally incorrect, for application software to do this, but it is not unknown for commercial software.
More commonly, it is caused by writing to a connection that the other end has already closed normally. In other words an application protocol error.
It can also be caused by closing a socket when there is unread data in the socket receive buffer.
In Windows, 'software caused connection abort', which is not the same as 'connection reset', is caused by network problems sending from your end. There's a Microsoft knowledge base article about this.
Connection reset simply means that a TCP RST was received. This happens when your peer receives data that it can't process, and there can be various reasons for that.
The simplest is when you close the socket, and then write more data on the output stream. By closing the socket, you told your peer that you are done talking, and it can forget about your connection. When you send more data on that stream anyway, the peer rejects it with an RST to let you know it isn't listening.
In other cases, an intervening firewall or even the remote host itself might "forget" about your TCP connection. This could happen if you don't send any data for a long time (2 hours is a common time-out), or because the peer was rebooted and lost its information about active connections. Sending data on one of these defunct connections will cause a RST too.
Update in response to additional information:
Take a close look at your handling of the SocketTimeoutException. This exception is raised if the configured timeout is exceeded while blocked on a socket operation. The state of the socket itself is not changed when this exception is thrown, but if your exception handler closes the socket, and then tries to write to it, you'll be in a connection reset condition. setSoTimeout() is meant to give you a clean way to break out of a read() operation that might otherwise block forever, without doing dirty things like closing the socket from another thread.
Whenever I have had odd issues like this, I usually sit down with a tool like WireShark and look at the raw data being passed back and forth. You might be surprised where things are being disconnected, and you are only being notified when you try and read.
You should inspect full trace very carefully,
I've a server socket application and fixed a java.net.SocketException: Connection reset case.
In my case it happens while reading from a clientSocket Socket object which is closed its connection because of some reason. (Network lost,firewall or application crash or intended close)
Actually I was re-establishing connection when I got an error while reading from this Socket object.
Socket clientSocket = ServerSocket.accept();
is = new BufferedReader(new InputStreamReader(clientSocket.getInputStream()));
int readed = is.read(); // WHERE ERROR STARTS !!!
The interesting thing is for my JAVA Socket if a client connects to my ServerSocket and close its connection without sending anything is.read() is being called repeatedly.It seems because of being in an infinite while loop for reading from this socket you try to read from a closed connection.
If you use something like below for read operation;
while(true)
{
Receive();
}
Then you get a stackTrace something like below on and on
java.net.SocketException: Socket is closed
at java.net.ServerSocket.accept(ServerSocket.java:494)
What I did is just closing ServerSocket and renewing my connection and waiting for further incoming client connections
String Receive() throws Exception
{
try {
int readed = is.read();
....
}catch(Exception e)
{
tryReConnect();
logit(); //etc
}
//...
}
This reestablises my connection for unknown client socket losts
private void tryReConnect()
{
try
{
ServerSocket.close();
//empty my old lost connection and let it get by garbage col. immediately
clientSocket=null;
System.gc();
//Wait a new client Socket connection and address this to my local variable
clientSocket= ServerSocket.accept(); // Waiting for another Connection
System.out.println("Connection established...");
}catch (Exception e) {
String message="ReConnect not successful "+e.getMessage();
logit();//etc...
}
}
I couldn't find another way because as you see from below image you can't understand whether connection is lost or not without a try and catch ,because everything seems right . I got this snapshot while I was getting Connection reset continuously.
Embarrassing to say it, but when I had this problem, it was simply a mistake that I was closing the connection before I read all the data. In cases with small strings being returned, it worked, but that was probably due to the whole response was buffered, before I closed it.
In cases of longer amounts of text being returned, the exception was thrown, since more then a buffer was coming back.
You might check for this oversight. Remember opening a URL is like a file, be sure to close it (release the connection) once it has been fully read.
I had the same error. I found the solution for problem now. The problem was client program was finishing before server read the streams.
I had this problem with a SOA system written in Java. I was running both the client and the server on different physical machines and they worked fine for a long time, then those nasty connection resets appeared in the client log and there wasn't anything strange in the server log. Restarting both client and server didn't solve the problem. Finally we discovered that the heap on the server side was rather full so we increased the memory available to the JVM: problem solved! Note that there was no OutOfMemoryError in the log: memory was just scarce, not exhausted.
Check your server's Java version. Happened to me because my Weblogic 10.3.6 was on JDK 1.7.0_75 which was on TLSv1. The rest endpoint I was trying to consume was shutting down anything below TLSv1.2.
By default Weblogic was trying to negotiate the strongest shared protocol. See details here: Issues with setting https.protocols System Property for HTTPS connections.
I added verbose SSL logging to identify the supported TLS. This indicated TLSv1 was being used for the handshake.
-Djavax.net.debug=ssl:handshake:verbose:keymanager:trustmanager -Djava.security.debug=access:stack
I resolved this by pushing the feature out to our JDK8-compatible product, JDK8 defaults to TLSv1.2. For those restricted to JDK7, I also successfully tested a workaround for Java 7 by upgrading to TLSv1.2. I used this answer: How to enable TLS 1.2 in Java 7
I also had this problem with a Java program trying to send a command on a server via SSH. The problem was with the machine executing the Java code. It didn't have the permission to connect to the remote server. The write() method was doing alright, but the read() method was throwing a java.net.SocketException: Connection reset. I fixed this problem with adding the client SSH key to the remote server known keys.
In my case was DNS problem .
I put in host file the resolved IP and everything works fine.
Of course it is not a permanent solution put this give me time to fix the DNS problem.
In my experience, I often encounter the following situations;
If you work in a corporate company, contact the network and security team. Because in requests made to external services, it may be necessary to give permission for the relevant endpoint.
Another issue is that the SSL certificate may have expired on the server where your application is running.
I've seen this problem. In my case, there was an error caused by reusing the same ClientRequest object in an specific Java class. That project was using Jboss Resteasy.
Initially only one method was using/invoking the object ClientRequest (placed as global variable in the class) to do a request in an specific URL.
After that, another method was created to get data with another URL, reusing the same ClientRequest object, though.
The solution: in the same class was created another ClientRequest object and exclusively to not be reused.
In my case it was problem with TSL version. I was using Retrofit with OkHttp client and after update ALB on server side I should have to delete my config with connectionSpecs:
OkHttpClient.Builder clientBuilder = new OkHttpClient.Builder();
List<ConnectionSpec> connectionSpecs = new ArrayList<>();
connectionSpecs.add(ConnectionSpec.COMPATIBLE_TLS);
// clientBuilder.connectionSpecs(connectionSpecs);
So try to remove or add this config to use different TSL configurations.
I used to get the 'NotifyUtil::java.net.SocketException: Connection reset at java.net.SocketInputStream.read(SocketInputStream.java:...' message in the Apache Console of my Netbeans7.4 setup.
I tried many solutions to get away from it, what worked for me is enabling the TLS on Tomcat.
Here is how to:
Create a keystore file to store the server's private key and
self-signed certificate by executing the following command:
Windows:
"%JAVA_HOME%\bin\keytool" -genkey -alias tomcat -keyalg RSA
Unix:
$JAVA_HOME/bin/keytool -genkey -alias tomcat -keyalg RSA
and specify a password value of "changeit".
As per https://tomcat.apache.org/tomcat-7.0-doc/ssl-howto.html
(This will create a .keystore file in your localuser dir)
Then edit server.xml (uncomment and edit relevant lines) file (%CATALINA_HOME%apache-tomcat-7.0.41.0_base\conf\server.xml) to enable SSL and TLS protocol:
<Connector port="8443" protocol="HTTP/1.1" SSLEnabled="true"
maxThreads="150" scheme="https" secure="true"
clientAuth="false" sslProtocol="TLS" keystorePass="changeit" />
I hope this helps

How to deploy and interact with a rust websocket?

I'm a beginner in Rust and WebSockets and I'm trying to deploy on Heroku a little chat backend I wrote (everything works on localhost). The build went well and I can see the app is running, and I'm now trying to connect to the WebSocket from a local HTML/Javascript frontend, but it is not working.
Here is my code creating the WebSocket on my rust server on Heroku (using the tungstenite WebSocket crate):
async fn main() -> Result<(), IoError> {
let port = env::var("PORT").unwrap_or_else(|_| "8080".to_string());
let addr = format!("0.0.0.0:{}", port);
// Create the event loop and TCP listener we'll accept connections on.
let try_socket = TcpListener::bind(&addr).await;
let listener = try_socket.expect("Failed to bind");
println!("Listening on: {}", addr);
and here is the code in my Javascript file that tries to connect to that WebSocket:
var ws = new WebSocket("wss://https://myappname.herokuapp.com/");
My web client gets the following error in the console:
WebSocket connection to 'wss://https//rocky-wave-51234.herokuapp.com/' failed
I searched to find the answer to my issue but unfortunately didn't find a fix so far. I've found hints that I might have to create an HTTP server first in my backend and then upgrade it to a WebSocket, but I can't find a resource on how to do that and don't even know if this is in fact the answer to my problem. Help would be greatly appreciated, thanks!
I think your mistake is the URL you use:
"wss://https://myappname.herokuapp.com/"
A URL usually starts with <protocol>://. The relevant protocols here are:
http - unencrypted hypertext
https - encrypted hypertext
ws - unencrypted websocket
wss - encrypted websocket
So if your URL is an encrypted websocket, it should start only with wss://, a connection cannot have multiple protocols at once:
"wss://myappname.herokuapp.com/"

Is there a way to invoke the gevent-socketio BaseNamespace.emit server side

Is there a way to invoke the gevent-socketio BaseNamespace.emit on the server side since it uses environ['socketio'] to get the socket from the request.environ. How I can generate new virtual socket or emualate somehow the environ['socketio'] on the server so I can use it to invoke the gevent-socketio BaseNamespace class (for emitting a message for example).
The idea behind this is that the server itself would be able to broadcast messages on a fixed period.
Thanks

Fault Tolerance JMS URL in Java

I am doing a JMS connection using Java. The command I am using to establish connection is
QueueConnectionFactory factory =
new com.tibco.tibjms.TibjmsQueueConnectionFactory(JMSserverUrl);
Where JMSServerUrl is the varible which stores my JMS URL.
Now the problem is that I need to add the fault tolerance URL i.e two different URL's. So can any one tell me how can I specify two URLs together in the above code sample such that if first URL is not accessible it should try connecting to the other URL.
Put all URLs in a single string with a comma between them.
new TibjmsQueueConnectionFactory("ssl://host01:20302,ssl://host02:20302");
Caution, I am a Tibco EMS newbie, but this seems to work, as evidenced by the error I can get ...
javax.jms.JMSSecurityException: Failed to connect to any server at:
ssl://host01:20302,ssl://host02:20302
[Error: Can not initialize SSL client: no trusted certificates are set:
url that returned this exception = SSL://host01:20302 ]
The .NET documentation for tibco(I know your using java) suggests that you can provide a comma delimited list of server URL's for messaging connections. Bear in mind that I don't have any real tibco experience, but this is a common way to handle initial connection fault tolerance(i.e. prior to establishing a connection and receiving information about the cluster, after which failover is typically handled by the connection). It may be worth a try. Another solution that I have seen to this problem is creating a virtual IP and handling fault tolerance at the Network Level.

How to use notificationconf?

I have read THIS tutorial about creating Push nodes and posting/subscribing to notifications.
The only problem I have met is that it seems that notificationconf unable to create that node...
My first question: are nodename (parameter of notificationconf tool) and notificationName (NSString which I use from app) the same things?
Second:
notificationconf createnode push.example.com BFMyTestPushhNotification beefon
Enter password: // password from Open Directory for user beefon - it is Admin of the 10.6 server
2010-01-24 13:24:58.916 notificationconf[15221:903] created XMPP session
2010-01-24 13:24:58.931 notificationconf[15221:903] Connecting to push.example.com:5222 with user com.apple.notificationuser#push.example.com/TestPubsub, security = 2 ...
2010-01-24 13:24:59.130 notificationconf[15221:903] sessionCallback (event 1)
2010-01-24 13:24:59.130 notificationconf[15221:903] Session stopped (event 1)
What I do wrong?
And posting notification from app does nothing...
Thanks for any help!
I've been trying to use Snow Leopard Server's Push Notification service with a custom application based on XMPP Publish–Subscribe. I struggled to create a node but finally figured it out.
Track down the password for the service account com.apple.notificationuser. You can find it, for example, in /private/etc/dovecot/notify/notify.plist.
Connect to your push notification server with JID com.apple.notificationuser#your-chat-server-hostname.com and that password.
Create nodes the normal way. In XMPPFramework it's like this:
XMPPJID *serviceJID =
[XMPPJID jidWithString:#"pubsub.your-chat-server-hostname.com"];
XMPPPubSub *xmppPubSub = [[XMPPPubSub alloc] initWithServiceJID:serviceJID];
[xmppPubSub createNode:#"pubsub.your-chat-server-hostname.com`
withOptions:nil];
The server creates the node. It responds with an iq, but not the one the spec requires. It does send a compliant error if the node already exists.
<iq xmlns="jabber:client"
to="com.apple.notificationuser#your-chat-server-hostname.com/..."
from="pubsub.your-chat-server-hostname.com"
id="...:create_node" type="result"/>
Connect using that same user to publish your updates.
I was never able to get notificationconf to work.
Notifications are easy to use on the same node, but harder across a network. Especially, I don't think too many people are actually using it, as Google search results are scarce :) Now, regarding your questions:
For 1: yes, you need to have matching nodename and notificationName. The man page says so (although not crystal-clear):
createnode hostname nodename username
Creates a node on the server to send notifications using. Before
a client can subscribe to notifications with a given name, the
server must be configured with a node with a matching name.
So, first you have to create the node, then you can listen to notifications of a given name. Otherwise, you don't get the notifications.
For 2: I get this error when there is no XMMP daemon running (i.e. port 5222 is closed). Is that port open for you? (check the output of nmap -p 5222 push.example.com).

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