Working on a new chat project, We want to use RabbitMQ to transfer our message.
So can RabbitMQ save all the message in queue or some other place, when an new people(consumer) comes, the RabbitMQ can flush the saved message to the new people?
If you use a persistent queue, rabbitmq can store the messages (the messages are stored in the same mnesia-db path).
So suppose that each user has a own queue, when the user gets on line can download the messages.
Anyway I don’t think it is a good idea use rmq to push messages for chat. There are others appropriate technologies, like MQTT, XMPP.
I suggest to read this post:
using rabbitmq in android for chat
Please read the tutorial to understand what RabbitMQ is.
RabbitMQ is a message broker: it accepts and forwards messages. You can think about it as a post office: when you put the mail that you want posting in a post box, you can be sure that Mr. or Ms. Mailperson will eventually deliver the mail to your recipient. In this analogy, RabbitMQ is a post box, a post office and a postman.
Related
I read the official document of Rabbitmq, it is not really clear for me what was that?
its something like Consumer Ack but with a difference that the Publisher Confirm is send by rabbitmq server to Publisher client when the server get the message from publisher client?
Can someone explain more about it?
thanks in advance.
its something like Consumer Ack but with a difference that the
Publisher Confirm is send by rabbitmq server to Publisher client when
the server get the message from publisher client?
Yes. When you enable publisher confirms, and your publisher receives acknowledgement that the message is published, you can be certain of it.
Without publisher confirms, you can lose messages in several cases. One example: your application could publish the data to the TCP buffer, but then crash, or the server itself could crash. Another example: a network device could fail mid-delivery. Another example: RabbitMQ itself could crash after receiving the TCP data containing your message.
NOTE: the RabbitMQ team monitors the rabbitmq-users mailing list and only sometimes answers questions on StackOverflow.
How can manual retry work in RabbitMQ after a message has been put onto dead letter queue?
Does RabbitMQ provide an user interface through which you can do this? I assume here that RabbitMQ console does not provide you this capability.
The Rabbit MQ management interface would let you do this crudely, you can go into the deadletter queue, 'get' the message then copy the content. Go to the queue you want to retry the message on and 'publish' it directly to that queue.
Alternatively, you can enable the shovel plugin which allows you to move messages from one queue to another. The RabbitMQ Management plugin directly contains instructions on how to do this.
You can write a consumer / producer using a number of various client libraries. For python a popular library is pika (https://pypi.python.org/pypi/pika).
The script can consume all the messages in a queue, then publish them to another queue.
I've got a webservice that accepts messages that can be sent to a RabbitMQ cluster using whatever queue they define. This is so front-end devs can send messages via javascript.
I want to make the webservice more robust so that when we have network trouble, the webservice can still accept messages and then handle them when the network is back up. After some initial reading, it seems that the Shovel plugin should handle this nicely.
What I was thinking was to install a local instance of RabbitMQ on the webservice box with shovel turned on. I can then send all messages through the local RabbitMQ instance and have it push all messages to the cluster and deal with the network problems.
My problem is after looking at the documentation it seems that I have to configure every queue I want to forward to in the shovel config file. If that's the case I'm not sure this will work since we allow clients to define a queue through the webservice on the fly.
I would like to have the webservice take the messages, hand them off to the local rmq instance and have it pass the messages off to the cluster using the same queues/exachanges/etc.
Has anyone tried this or can explain how the shovel plugin works?
Have you considered sending messages to an exchange instead of a queue. Send all messages to one exchange possibly a topic exchange if you need that kind of flexibility. Then have the consumer handle the different messages or different queues from the exchange. Sending to one exchange would make configuring the shovel considerably easier.
We are using MSMQ right now with WCF activation feature, it enables us not to pull queue to read messages. It like push message to application.
As we are looking at porting from MSMQ to RabbitMQ going through what we need from message queue.
I can't anything regarding RabbitMQ .net client support for receiving message notification from subscribed queue?
Is there anything in RabbitMQ with .net which can do push notification to subscriber like MSMQ?
Or we need service running which constantly checks for message?
In AMQP (and RabbitMQ), there are two ways to retrieve messages: basic.get and basic.consume.
Basic.get is used to poll the server for a message. If one exists, it is returned to the client. If not, a get-empty is returned (the .NET method returns null).
Basic.consume sets the consumer for the queue. The broker pushes messages to the consumer as they arrive. You can either derive DefaultBasicConsumer, which gives you your own custom consumer, or you can use the Subscription Message Pattern, which gives you a blocking nextDelivery().
For more information, check out the API guide linked above and the .NET Client Userguide. Also, a great place to ask RabbitMQ-related questions is the rabbitmq-discuss mailing list.
I think you are after something like the EventingBasicConsumer. See also this question/answer
That is a feature provided by WAS (Windows Activation Service). Right now WAS has listener adapters for net.pipe, net.msmq and net.tcp (and its port sharing service). I guess you would need a specific AMQP listener adapter.
This may help http://msdn.microsoft.com/en-us/library/ms789006.aspx
Is it possible to configure a message bridge for GlassFish? The message is currently posted to a topic, and customer requirement is to "redirect" this message from a topic to a queue. (both are on the same GlassFish server). By redirect, I mean, the message will be posted on the topic and then copied to the queue. I cannot find much documentation about this, I have read about Open MQ, JMS broker and JMS bridge, but this does not seem to fit this requirement.
I understand, that I can implement a topic subscriber and then post a message to queue. But I would like to know, if it is possible to do this just by configuration or do I have to implement a bridge?
Thanks for your help, I do appreciate it.
Vladi
You'll need to implement a bridge... or change the submitter to submit to both the queue and the topic.