Goal is, create an HTML page which can send and receive updates from server.
I created HTML page and made connection with Apache ActiveMQ via STOMP over websocket and wrote Java code at server side which will send updates to those queue. This works fine, but ideally HTML page will be used by many users, so I want each to have their separate queue( dynamically generated) and listen and send on their respective queue only. HTML client would be able to register queue but thing which I don't know is how my server side code will get notified, do we have any callback func for this? Tried with DestinationSource class which does tell how many queue's exist but not clear how to get access to that queue
Am I going on wrong path for solving this? Any help/link/info on this will be appreciated
You might want to look into ActiveMQ Advisory Message's which can fire events for various things such as Destination creation and destruction, no consumer, message expiration etc.
The ActiveMQ site has documentation on this.
Related
I'm working on an node js application, called ngdf-diversion-client, that is running in AWS and is connecting to a Solace instance, that is also running in AWS.
I see that through the ngdf-diversion-client config file its receiving messages over the ngdf/diversions queue, and I can see that in the SolAdmin.
This image here shows the application ngdf-diversion-client listed in the SolAdmin tool:
This image shows ngdf-diversion-client being the owner (and in my case the recipient of data) on the ngdf/diversions queue:
But I cannot see who sends data to ngdf-diversion-client on the ngdf/diversions queue.
Does anyone know how I can see that information in Solace or SolAdmin?
I know with ActiveMQ when you select a Queue or Topic from the web console, you can see who are the consumers and producers so it was pretty easy seeing who sent and who received data over a queue or topic.
But with Solace/SolAdmin I don't see that.
With Solace, publishers and subscribers are decoupled by design so there is no way to see which publishers have sent messages to a specific queue. If it is required that the publisher of a message is identifiable then you could implement an identifier in the message as it is published in the application.
I want to know how do I retrieve the messages already present on the Solace Queue. I am able to send and receive the messages I created from my machine but can't receive any messages that are already present in the queue. I want to retrieve the messages and store it in a text file.
I am sending my messages by integrating Solace APIs in Gradle and writing code in Java. Can anyone guide me regarding the same?
There's an exact tutorial for this.
If you had downloaded the Solace Java JAR via the Maven links, you might have missed the entire suite, which contains all the dependent JARs distributed by Solace, API reference docs, as well as a bunch of samples. The latter is in addition to what you may find on http://dev.solace.com/get-started/java-tutorials/. Get the entire ZIP file, as well as the Release Notes, from http://dev.solace.com/downloads/.
There are multiple possibilities why you cannot receive messages from a queue:
Queue name is misspelt.
Queue permissions are wrong.
Queue is shut down on the egress.
Message spool is not active on the router.
Client profile is set not to receive Guaranteed Messages.
Number of egress flows has exceeded the router / message-vpn limit.
Bind count on the queue has exceeded.
The egress flow is not active.
Client is not connected to the router.
...
Examining the error / exception will give you information why you cannot receive messages.
I am streaming a tty's stdout and stderr to RabbitMQ (logs to be exact). These logs can be viewed on a website and while the content is streamed to RabbitMQ they are consumed by the webserver and forwarded to the client using WebSockets. Logs are immediately persisted after sending it to RabbitMQ.
When the user accesses the website the persisted logs are rendered and the consecutive parts are streamed using WebSockets. The problem is that there is a race condition as the persisted logs might be missing chunks of the log that occurred between rendering the site and receiving the first chunk via WebSocket.
My idea was to keep all chunks in the queue and send those via the WebSocket after connecting. Additionally I would add a worker to listen to some kind of a "finished" event which then takes everything in the queue and persists it at once.
The problem is that I don't know if this is possible using RabbitMQ or how. Any ideas or other solutions?
I don't think it really matters but my stack is using Ruby Sinatra and the Bunny RabbitMQ client.
While I agree with your general idea about picking up where you left off, after loading the intial page, what you're trying to do isn't something that should be done from RabbitMQ.
There are a lot of potential problems that this would cause, which I've outlined in a blog post, previously.
Instead of trying to do this w/ RMQ, I would do this from a database layer.
As you push things into the database, you have an ID - hopefully one that is sequential. If not, add a sequence to the entries.
When you load the page for the user, send the current ID that they are at down to the browser.
After the page finishes loading and you're setting up the websocket connection, send the user's current spot in the list of messages via the websocket. then the websocket connection can use that id to say "give me all the messages after this id, and start streaming them"
Again, this is not done via RabbitMQ (see my article on why this is a bad idea), but via your database and sequential IDs.
I have a project that is related to job postings. Consultants or employers register on my website and then start posting jobs. I want to make push notifications for all users. When a consultant or employer posts a job, all online users must get notified that an employer has posted this job without any page refreshes on jquery setInterval or timeout.
I am using Spring framework. I have searched for the solution but found nothing. I want to know whether Spring provided WebSockets in their latest version. Is this possible to do with WebSockets?
I want a proper resource so that I can implement it on my website.
There are two ways to satisfy your need;
First is polling in which you repeatedly send requests from client to the server. On server side you somehow need have a kind of message queue for each client to deliver the incidents on a request. There also is a different type of polling in which you send a request from client and never end the request on the server-side thus you have a kind of pipe between two ends. This is called long polling.
Disadvantage of polling is that you have to send requests to the server forever from the client and in many cases server sends empty messages as there is no events happened.
The real application of pushing messages is recently avaliable with websockets (thanks to html5). However this requires the application server to be capable of websocket functionality. afaik jetty and tomcat has this ability. Spring 4 has websocket here you can find the tutorial; http://syntx.io/using-websockets-in-java-using-spring-4/
You can find a related stackoverflow post here
So our team has recently implemented torquebox into our jruby on rails applications. The purpose of this was to be able to receive queue/topic messages from an outside source which is streaming live data.
We have setup our queues/topics and they are receiving the messages without an issue. The next step we want to take is to get these messages on the browser.
So we started to look into leveraging the power of stomp. But we have come across some issues with this. It seems from the documentation that the purpose of using stomp + websockets is to receive messages from the client-side and push those messages to other clients. But we want to receive messages on our queues, and then push these messages to the client-side using websockets. Is this possible? Or would we have to implement a different technology such as Pusher or socket.io to get the queue/topic messages to the browser?
Thanks.
I think stomplets is good solution for this task. In rails application you should use ruby base stomp client, in browser javascript base stomp client. In rails just send data, and in browser just receive.
More detail how do it you can find in torquebox documentation
http://torquebox.org/documentation/2.0.0/stomp.html
It is indeed possible to push messages straight from the server to clients. It took me quite a bit of digging to find it as it is not listed in the documentation directly. Their blog lists it in their example of how to build a chat client using websockets.
http://torquebox.org/news/2011/08/23/stomp-chat-demo-part3/
Basically you use the inject method to choose which channel you're publishing to, and then use the publish method on the returned object to actually send the message. This code excerpt from the article should get you pointed in the right direction.
inject( '/topics/chat' ).publish( message,
:properties=>{
:recipient=>username,
:sender=>'system'
} )
It looks like :properties is the same thing as message headers. I'll be giving this a go over the next couple of days to see how well this works in Rails.