We use Spring-integration to send messages from a RabbitMQ to MQSeries. This works fine.
<int-jms:outbound-channel-adapter channel="toJms" .../>
For some consumers we need to force the format of the ibm message or the charset
We allready use a header enricher to force some properties:
<int:header-enricher id="theHeaderEnricher" input-channel="fromRabbit" output-channel="toJms" >
How can we change the mq format and the charset of messages? Format is not a JmsHeaders but a property of the message. Can this be done with xml configuration?
Thanks for your help
Eric
Before sending to the <int-jms:outbound-channel-adapter> you can place a <transformer> in between with POJO method call and there you can do whatever you need with your reformatting.
Unfortunately it is not clear from your question how that formatting looks and what you would like to change from and into.
Therefore my answer is as generic as your question.
Please, see more info about transformer in the Docs: https://docs.spring.io/spring-integration/reference/html/#messaging-transformation-chapter
Related
CLARIFICATION:
Thanks to #JustinBertram comment I realized that this question does not make sense.
STOMP protocol does not support selectors by itself, you have to use brokers such as ActiveMQ that implement it. STOMP supports headers that can be used by brokers for filtering messages by selectors.
In my case, I'm not using any broker, just frontend with Angular + Stomp + SocksJS and backend with Spring Boot, so I can't use selectors.
The documentation of STOMP protocol does not make this clear to me and I got confused. See these references:
the specification:
Stomp brokers may support the selector header which allows you to
specify an SQL 92 selector on the message headers which acts as a
filter for content based routing.
this article:
The subscribe() method takes an optional headers argument to specify
additional headers when subscribing to a destination:
var headers = {ack: 'client', 'selector': "location = 'Europe'"};
client.subscribe("/queue/test", message_callback, headers);
The client specifies that it will handle the message acknowledgement
and is interested to receive only messages matching the selector
location = 'Europe'.
I'm implementing a backend in Spring Boot. For two-way communications with the frontend I'm using stomp over websockets.
I have followed this Spring Boot + Angular example
It works, but one of my requirements is that the backend has to send messages with selectors so that the frontend subscribes to a topic and only receives the filtered data, to avoid performance issues with real time data.
i.e. { 'selector': "location = 'Europe'" }
For that purpose, I'm trying to make the backend send the messages with selectors, but I can't make it work.
I have followed this article to implement the frontend with selectors and it works correctly, the problem is only the backend.
I tried with #SendTo annotation but it seems it doesn't have any params for that as per the article:
#MessageMapping("/hello")
#SendTo("/topic/greetings")
public Greeting greeting(HelloMessage message) throws Exception {
Thread.sleep(1000);
return new Greeting("Hello, " + HtmlUtils.htmlEscape(message.getName()) + "!");
}
Also I tried with the MessagingTemplate, but I don't know how to set the selector properties in the header:
http://assets.spring.io/wp/WebSocketBlogPost.html
MessageSendingOperations<String> messagingTemplate;
messagingTemplate.convertAndSend(destination, quote);
I really appreciate any help, I have read many articles and docs but I don't find anything talking in particular about this with a solution.
Well, it's possible to use the JMS' selectors with Spring (Boot) Websocket and a STOMP client. I found a native way.
The key thing is that the selector is applied to the org.springframework.messaging.Message instance, and it uses Spring's Spel language to apply the condition (it's not the JMS SQL-like).
So using the default SimpMessagingTemplate, in the backend you can send header variables like this:
this.messagingTemplate.convertAndSend(
"/topic/something", //your destination
payload, //any kind of payload (body)
Map.of("id", 1) //header with key/value
);
In the frontend, to enter a selector that will be evaluated by the org.springframework.messaging.simp.broker.DefaultSubscriptionRegistry.filterSubscriptions, you must declare your Stomp/WebSockets headers as:
{"selector": "headers['nativeHeaders']['id'][0] == '999'"}
Yeah, it's horrible but it works.
As the default Message is GenericMessage, the headers are processed in a new key called "nativeHeaders".
The ['key'],[0] and == are Spring's Spel sintaxes.
Go ahead and filter your messages on the backend, not in the frontend, please!
The latest version of the STOMP specification doesn't include any specific statement about selectors and their syntax because it's really up to the broker implementation as to what is supported here. The specification now just states:
STOMP servers MAY support additional server specific headers to customize the delivery semantics of the subscription. Consult your server's documentation for details.
Brokers like ActiveMQ 5.x and ActiveMQ Artemis support the selector STOMP header and the syntax & behavior of the selector is based on JMS selectors.
Selectors in JMS are for selecting messages on consumption and are configured by the consuming client. You can't set the selector when sending the message.
JMS selectors select messages based on the headers or properties of the message, although some implementations go beyond this and allow selecting based on the content of the message itself. Therefore, if you want to have a selector location = 'Europe' on a consumer then you should set a header on the message when it is sent with the name location and the value of Europe.
The convertAndSend method is overloaded and provides a couple of ways to set a header:
Pass a map of key/value pairs to the convertAndSend method.
Implement a MessagePostProcessor and pass that to the convertAndSend method. Inside your post-processor you can invoke the javax.jms.Message#setStringProperty() method.
I want some messageId kind of thing when I am sending to Rabbit Mq Queue as I will get when sending to IBM MQ using jms. I am using spring MQ amqp starter dependency with Spring Boot. Configuration is done only in application.yml (property file). I am using Rabbit template for sending.
rabbitMqTemplate.convertAndSend(EMPTY_STRING,queueName, message, messagePostProcessor);
I have tried messagePostProcessor. Any help is appreciated. I had a look into below content. But didnt understand how to implement. Does it require special configuration (connectionfactory/ container)?
https://www.rabbitmq.com/confirms.html
Unlike JMS, the rabbit client doesn't assign message ids.
However, you can configure the RabbitTemplate's MessageConverter to create an id, which you can then retrieve with a post processor.
See AbstractMessageConverter...
/**
* Flag to indicate that new messages should have unique identifiers added to their properties before sending.
* Default false.
* #param createMessageIds the flag value to set
*/
public void setCreateMessageIds(boolean createMessageIds) {
this.createMessageIds = createMessageIds;
}
For message confirmations, see the reference manual. But that is unrelated to the message id property.
I am using Spring JMS 4.1.2, and I am using org.springframework.messaging.Message as the input payload in the JMS Listener. I am listening to an Active MQ Queue, and I would like to know if it is possible to obtain the JMSXDeliveryCount and JMSDestination using the org.springframework.messaging.Message, or if I have to use the javax.jms.Message class to accomplish this.
Thanks,
Juan
The delivery count property is mapped by default; I just ran a test...
message: GenericMessage [payload=jms test, headers={jms_redelivered=true, JMSXDeliveryCount=2, ...
Standard headers are mapped with a jms_ prefix all; message properties are mapped as-is.
The destination from which the message is received is not currently mapped to the message.
You would need to add a custom JmsHeaderMapper - perhaps a subclass of DefaultJmsHeaderMapper.
I opened a JIRA issue to make this standard.
How can I publish messages with different topics programmatically?
<mqtt:outbound-channel-adapter id="mqttOut"
auto-startup="true"
client-id="foo"
url="tcp://localhost:1883"
client-factory="clientFactory"
default-qos="0"
default-retained="false"
default-topic="bar"
async="true"
async-events="true" />
I tried Spring integration MQTT publish & subscribe to multiple topics, but were not able to configure.
Also tried with MqttPahoMessageHandlerAdapter which has a publish() but protected.
Going with org.eclipse.paho.client.mqttv3.MqttAsyncClient and org.eclipse.paho.client.mqttv3.MqttCallback is very easy. But I would like to stick with spring all the way.
Appreciate if somebody can points me to a correct direction.
Declare a <publish-subscribe-channel id="toMqtt" />; set it as the channel attribute on each outbound channel adapter; the message will be sent to each adapter.
You can do that with Spring Integration anyway! Having a lot of EIP components implementation and Spring power on board (injection, SpEL etc,), plus switching on a bit of imagination, we can reach any end-application requirements even without any Java code.
So, <mqtt:outbound-channel-adapter> allows determine topic at runtime. Instead of default-topic you should supply MqttHeaders.TOPIC MessageHeader.
So, if you have a requirement to send the same message to several topics, you just build a copy of that message for each topic. The <splitter> can help us:
<int:splitter input-channel="enricheMessage" output-channel="sendMessage" apply-sequence="false">
<int-groovy:script>
['topic1', 'topic2', 'topic3'].collect {
org.springframework.integration.support.MessageBuilder.withPayload(payload)
.copyHeaders(headers)
.setHeader(org.springframework.integration.mqtt.support.MqttHeaders.TOPIC, it)
.build()
}
</int-groovy:script>
</int:splitter>
sendMessage can be ExecutorChannel to achieve the parallel publishing.
UPDATE
You can achieve the same iteration and message enrichment logic with similar Java code using ref and method on <splitter>.
Of course, we can do that even with SpEL , but it will look a bit complex with Collection Projection.
I work with Mule. And I have spring bean
<spring:bean id="`MyPropertiesSaver`" name="MyPropertiesSaver" class="MyPropertiesSaver">
<spring:property name="prop_name" value="${PROP_VALUE}"/>
</spring:bean>
Also I work with file in flow
<flow name="Handler" doc:name="Handler">
<file:inbound-endpoint `path="${PROP_VALUE}"` moveToPattern="#[header:originalFilename].txt" responseTimeout="10000" doc:name="File"/>
...
</flow>
So I get PROP_VALUE from system variables. I want to change path of file while programm is running. I change prop_name of class MyPropertiesSaver using MX4J. But path="${PROP_VALUE}" does not change. That's why I want to get prop_name from MyPropertiesSaver. Somthing like this
path="MyPropertiesSaver.prop_name"
How can I do that?
You need to extend the file message receiver to allow to externally set of the fileDir and disconnect-connect when this happens. Then in your connector use a service-override to use that customised message receiver.
Having a Dynamic Endpoint for File Inbound is not possible.
File Inbound should know where to look for when the flow is started.
If your usecase demands a dynamic file location and reading you can try the workaround with Mule Requester module.
Read throubh the following link for more details.
Unable to create dynamic file inbound endpoint in mule
Hope this helps.