messaging

问题 Does RabbitMQ call the callback function for a consumer when it has some message for it, or does the consumer have to poll the RabbitMQ client? So on the consumer side, if there is a PHP script, can RabbitMQ call it and pass the message/parameters to it. e.g. if rating is submitted on shard 1 and the aggregateRating table is on shard 2, then would RabbitMQ consumer on shard 2 trigger the script say aggRating.php and pass the parameters that were inserted in shard 1? 回答1: What you want is

问题 I have built the following model to handle user's message exchange: create_table "messages", :force => true do |t| t.integer "source_id" t.integer "destination_id" t.string "object" t.string "body" t.datetime "created_at" t.datetime "updated_at" end These are its associations: class Message < ActiveRecord::Base belongs_to :sender, :class_name=>'User', :foreign_key=>'source_id' belongs_to :reciever, :class_name=>'User', :foreign_key=>'destination_id' end And these other are the associations on

问题 I just read RabbitMQ's Java API docs, and found it very informative and straight-forward. The example for how to set up a simple Channel for publishing/consuming is very easy to follow and understand. But it's a very simple/basic example, and it left me with an important question: How can I set up 1+ Channels to publish/consume to and from multiple queues? Let's say I have a RabbitMQ server with 3 queues on it: logging , security_events and customer_orders . So we'd either need a single

问题 Note that I'd like multiple message listeners to handle successive messages from the topic concurrently. In addition I'd like each message listener to operate transactionally so that a processing failure in a given message listener would result in that listener's message remaining on the topic. The spring DefaultMessageListenerContainer seems to support concurrency for JMS queues only. Do I need to instantiate multiple DefaultMessageListenerContainers? If time flows down the vertical axis:

问题 Im just wondering whether there is a way to call a method where i build the name of the method on the fly with a string. e.g. I have a method called loaddata -(void)loadData; to call this i would normally call it like [self loadData]; But i want to be able to call it dynamically with a string e.g. NSString *methodName = [[NSString alloc] initWithString:@"loadData"]; [self methodName]; This is a stupid example but i hope you get my point. I am using it for databinding classes that I am setting

问题 I am working on a multimedia application. I am capturing one image through the camera and want to send that image with a text to some other number. But I am not getting how to send the image via the MMS. 回答1: MMS is just a htttp-post request. You should perform the request using extra network feature : final ConnectivityManager connMgr = (ConnectivityManager)context.getSystemService(Context.CONNECTIVITY_SERVICE); final int result = connMgr.startUsingNetworkFeature( ConnectivityManager.TYPE

问题 I am working on a multimedia application. I am capturing one image through the camera and want to send that image with a text to some other number. But I am not getting how to send the image via the MMS. 回答1: MMS is just a htttp-post request. You should perform the request using extra network feature : final ConnectivityManager connMgr = (ConnectivityManager)context.getSystemService(Context.CONNECTIVITY_SERVICE); final int result = connMgr.startUsingNetworkFeature( ConnectivityManager.TYPE

问题 One of the new features of MQTT 5 is the shared subscriptions feature, which allows client-side load balancing between multiple workers, so that multiple workers can be responsible for handling messages, but every message is only ever sent to a single server. By default, this works with a round-robin approach, but I am in the need of a slightly more advanced scenario: What I want is some kind of routing, so that one of the messages' properties gets used as some kind of routing key. I.e., I

问题 I am finding out that even when my NSB process does not handle messages for say DTOXXX, it is still sending an auto-subscribe message to the publisher queue for DTOXXX. This is not the desired behavior. I want the process to publish and subscribe to messages for DTOYYY, but any communication using DTOXXX is strictly send only. If that wasn't clear enough I have 2 assemblies that contains my DTO. I Want to establish a pub/sub bus, but only for assemblies in YYY.dll. As for the DTOs in the

问题 Source: https://kafka.apache.org/intro "By having a notion of parallelism—the partition—within the topics, Kafka is able to provide both ordering guarantees and load balancing over a pool of consumer processes. This is achieved by assigning the partitions in the topic to the consumers in the consumer group so that each partition is consumed by exactly one consumer in the group. By doing this we ensure that the consumer is the only reader of that partition and consumes the data in order. "