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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 )

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Meteor object available in Console, but throws 'cannot read property findOne of undefined

I'm new to Meteor and I've been stuck on this problem for hours. I've created a collection in a file 'sessions.js' at imports/lib/sessions.js import { Meteor } from 'meteor/meteor'; import { Mongo } from 'meteor/mongo'; Sessions = new…
NvdB31
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Arduino publish/subscribe to PubNub

I am trying to create an IoT based smart house system. It contains of my android application which sends and receives messages from/to PubNub (subscribes and publishes on certain channels) and Arduino UNO board with some LEDs and movement sensor…
Rytis
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ActiveMQ - Combining Publish-Subscribe and peer-to-peer

Is there a way to implement a topology with ActiveMQ, where P is a publisher, s_a is a subscriber of service A and s_b1 and s_b2 are subscribers of service B. The latter are set in a cluster for load balancing (so s_b1 or s_b2 gets a message but not…
user49204
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What is the ZeroMQ PUB/SUB internal behaviour?

I'm trying to get my head around to the behaviour of zmq with PUB/SUB. Q1: I can't find a real reason why with the PUSH/PULL sockets combo I can create a queue that actually queue in memory messages that it can't get delivered (the consumer is not…
0x41ndrea
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Meteor.publish on server doesn't show new documents on client

The problem is the next code on server: Meteor.publish(null , function() { let events = []; Groups.find({participants: this.userId}).forEach(function(item) { events.push(item.latestEvent); }); return Events.find({_id: {$in:…
olrg-rdk
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Near real-time pub/sub solution sending emails&http requests

I am trying to architecture the best solution for being able to send email/http requests when something happens within my web api domain. For example, when some entity change i want to send email/http notifications to potential subscribers. There…
dee zg
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Rebus subscriber-publisher system. Process message only by single subscriber

I have system with one publisher several subscribers. But some messages should be processed only by single subscriber. In my case publisher sends message about changing data in database, all subscribers has access to the same database, but I don't…
zabulus
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Should Meteor publication functions be named?

I'm trying to get a better understanding of how the publication / subscription model works. Specifically I'm referring to this step in the tutorial. if (Meteor.isServer) { Meteor.publish('tasks', function tasksPublication() { return…
evan54
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Preventing PyPubSub "Dead Listener" error

I'm using the package PyPubSub in a Python project so I can subscribe methods to channels and publish on those channels while the program runs. As part of a stress test, I set the program to run over and over for multiple hours. (Each run takes…
kepler_kingsnake
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How can I directly link producers and consumers in a pub sub system, without subjects, in RxJS?

Edit I think the implementation of this question is reasonably complex, and have not been able to figure it out for 3 months now. I have re-phrased it in another question here: RxJS5 - How can I cache the last value of a aggregate stream, without…
brokenalarms
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Rabbitmq Subscribe to multiple services but consume it in a round robin fashion

I've got a working solution to my problem but wonder if there is a cleaner way of doing this. My architecture is composed of several services, emitting messages through a Rabbitmq broker. Some workers consume those messages and do background…
user5655560
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Spring session enabled application does not receive session events from redis cluster

We are using spring-session to store user sessions in redis cluster. We want to receive session-created and session-destroyed events. However it seems, redis cluster does not publish events properly. We receive session events if we use standalone…
Sanket Meghani
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Setting state PubSub ReactJS and Rails

I have setup a PubSub events system but for some reason am receiving a Cannot read property 'items' of undefined when trying to set the state of my component again having successfully received. It seems I don't have access to this but am unsure…
Tom Pinchen
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After using $.publish to load a select, want to select particular option in Struts 2 select tag

I am using $.publish to populate the dropdown (Struts 2 select tag) after that, I want the dropdown to be auto-selected to a value. I tried the following: $.publish("reloadAttributeList"); //$('#selectedAttribute…
Preethi Jha
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Publish onto Mosquitto broker running on laptop

I have followed the steps outlined in the following link to install and run the Mosquitto broker on my laptop. https://sivatechworld.wordpress.com/2015/06/11/step-by-step-installing-and-configuring-mosquitto-with-windows-7/ I have tested the…
Chetan Chavan
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