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Questions tagged [publish-subscribe]

Publish/subscribe is a messaging pattern where senders (publishers) of messages do not program the messages to be sent directly to specific receivers (subscribers). Rather, published messages are characterized into channels, without knowledge of what, if any, subscribers there may be.

Publish/subscribe is a messaging pattern where senders (publishers) of messages do not program the messages to be sent directly to specific receivers (subscribers). Rather, published messages are characterized into channels, without knowledge of what, if any, subscribers there may be. Subscribers express interest in one or more channels, and only receive messages that are of interest, without knowledge of what, if any, publishers there are.

Among technologies known to implement the Publish/Subscribe pattern you can find :
( in a purely alphabetical order )

2940 questions
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RSS: refresh rate?

I'm writing a little application for my own use which will consume a publicly published RSS feed. As far as I can tell, there's no subscribe/post mechanism in the protocol; I need to have my application HTTP-GET the RSS feed periodically. If that's…
bukzor
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Faye or Redis Pubsub

I thought I understood this technology, but maybe I don't. What's the difference between the two? Why would you choose one over the other? Usecase: ~Realtime updates.
user558957
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Swift Combine - delaying a publisher

TL;DR I want to delay a publication, but can't figure out how to, er, combine the parts In Brief I have a Publisher let generator = PassthroughSubject() and want somehow to use the modifier .delay(for: 2, scheduler: RunLoop.main) so…
Andrew Duncan
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Error in shutting down the Google Pub sub publisher

I have started the publisher of google pub sub using the coding[1].After finishing the publisher I shut down the publisher as[2].But when I run I'm getting an error[3]saying that the publisher is not properly shutdown. I'm using pubsub 1.61.0…
Ayodhya
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RabbitMQ reordering messages

RabbitMQ ticks all the boxes for the project I am planning, save one. I would have different workers listening on a queue and it is important that they process the newest messages (i.e., latest sequence number) first (LIFO). My application is such…
dgorissen
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How to Subscribe on Multiple topic using PAHO-MQTT on python

I am trying to subscribe on three different topics using single subscriber client. But with the below mentioned code I am able to get data from only one server. Please suggest ant modification in my code that can be implemented to get the desired…
Abhay Singh
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Update Rails view with Faye from Database change (after_commit callback) on model

I am very puzzled and this is my first Faye or Pub/Sub implementation so please forgive me if this is a basic questions. I have not found answers anywhere else. Any help is appreciated. How can I call and update a Rails view page from a model…
Yuri
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Google Cloud Pub/Sub Retry Count

We are moving from an unstable messaging queue service to Google's Pub Sub in NodeJS. It seems to work well but we would like to include error handling. We would like to limit the number of retries for a particular message, say 10 times in our test…
T.Okahara
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Does the number of consumer groups impact Kafka performance

While trying to get a deep understanding of the Kafka distribution model, one sentence here from StackOverflow got me buzzing, and I can't get a confirmation nor deny. So, the more subscriber groups you have, the lower the performance is, as kafka…
Aleksandar Stojadinovic
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How do I create a publisher/subscriber model in Angular?

I've been playing with Angular and have been trying to find a way to use a pub/sub mechanism across the whole component tree. It seems that EventEmitter is only emitting an event that can be subscribed to one level up - but not more. Similarly, it…
Lior
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Notify of changes between controllers that may or may not exist

If you have two area's on a page, i.e
And lets say the LeftController can live and exist without the RightController. But should the RightController exist…
Phill
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Auto-expire orphaned Subscription (Azure ServiceBus Messaging SubscriptionClient)

The scenario I have in mind is this: Service Bus is used for instance-to-instance communication, so a Subscription is unique per service instance. The end result is that if an instance does not shut down gracefully, its subscription does not get…
Andrei
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Best Publish/Subscribe "Middleware"

I'm in the market for a good open source network based Pub/Sub (observer pattern) library. I haven't found any I like: JMS - tied to Java, treats message contents as dumb binary blobs NDDS - $$, use of IDL CORBA/ICE - Pub/Sub is built on-top of…
David
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Best practices for pubnub on android

I'm using pubnub as a publish/subscribe channel between an android app and a server. Currently I'm thinking of how I will implement this. I'm using the provided library for android (https://github.com/pubnub/pubnub-api/tree/master/android) but I…
Quentin
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What is the proper way to handle Redis connection in Tornado ? (Async - Pub/Sub)

I am using Redis along with my Tornado application with asyc client Brukva, when I looked at the sample apps at Brukva site they are making new connection on "init" method in websocket class MessagesCatcher(tornado.websocket.WebSocketHandler): …
Burak Dede
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