Chapter 123. Paho

Paho Component
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Paho component provides connector for the MQTT messaging protocol using the Eclipse Paho library. Paho is one of the most popular MQTT libraries, so if you would like to integrate it with your Java project - Camel Paho connector is a way to go.

URI format
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paho:queueName[?options]

paho:queueName[?options]

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For example the following snippet reads messages from the MQTT broker installed on the same host as the Camel router:

from("paho:some/queue").
  to("mock:test");

from("paho:some/queue").
  to("mock:test");

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While the snippet below sends message to the MQTT broker:

from("direct:test").
  to("paho:some/target/queue");

from("direct:test").
  to("paho:some/target/queue");

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You can append query options to the URI in the following format: ?option=value&option=value&... . For example this is how to read messages from the remote MQTT broker:

from("paho:some/queue?brokerUrl=tcp://iot.eclipse.org:1883").
  to("mock:test");

from("paho:some/queue?brokerUrl=tcp://iot.eclipse.org:1883").
  to("mock:test");

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Adding the component to the project
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Maven users will need to add the following dependency to their pom.xml for this component:

<dependency>
    <groupId>org.apache.camel</groupId>
    <artifactId>camel-paho</artifactId>
    <version>x.y.z</version>
    <!-- use the same version as your Camel core version -->
</dependency>

<dependency>
    <groupId>org.apache.camel</groupId>
    <artifactId>camel-paho</artifactId>
    <version>x.y.z</version>
    <!-- use the same version as your Camel core version -->
</dependency>

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Keep in mind that Paho artifacts are not hosted in the Maven Central, so you need to add Eclipse Paho repository to your POM xml file:

<repositories>
  <repository>
    <id>eclipse-paho</id>
    <url>https://repo.eclipse.org/content/repositories/paho-releases</url>
    <snapshots>
      <enabled>false</enabled>
    </snapshots>
  </repository>
</repositories>

<repositories>
  <repository>
    <id>eclipse-paho</id>
    <url>https://repo.eclipse.org/content/repositories/paho-releases</url>
    <snapshots>
      <enabled>false</enabled>
    </snapshots>
  </repository>
</repositories>

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Default payload type
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By default Camel Paho component operates on the binary payloads extracted out of (or put into) the MQTT message:

// Receive payload
byte[] payload = (byte[]) consumerTemplate.receiveBody("paho:topic");
 
// Send payload
byte[] payload = "message".getBytes();
producerTemplate.sendBody("paho:topic", payload);

// Receive payload
byte[] payload = (byte[]) consumerTemplate.receiveBody("paho:topic");
 
// Send payload
byte[] payload = "message".getBytes();
producerTemplate.sendBody("paho:topic", payload);

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But of course Camel build-in type conversion API can perform the automatic data type transformations for you. In the example below Camel automatically converts binary payload into String (and conversely):

// Receive payload
String payload = consumerTemplate.receiveBody("paho:topic", String.class);
 
// Send payload
String payload = "message";
producerTemplate.sendBody("paho:topic", payload);

// Receive payload
String payload = consumerTemplate.receiveBody("paho:topic", String.class);
 
// Send payload
String payload = "message";
producerTemplate.sendBody("paho:topic", payload);

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URI Options
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Expand

Option	Default	Description
`clientId`	`camel-<timestamp>`	MQTT client identifier.
`brokerUrl`	`tcp://localhost:1883`	The URL of the MQTT broker.
`persistence`	`memory`	Client persistence to be used - `memory` or `file`.
`filePersistenceDirectory`	current directory	(Camel 2.16.1 and 2.17) Base directory used by file persistence. Takes no effect if non-file persistence is used.
`qos`	2	Client quality of service level (`0`-`2`).
`connectOptions`	none	The reference to the org.eclipse.paho.client.mqttv3.`MqttConnectOptions` instance located in the Camel registry. Referenced `MqttConnectOptions` instance will be used by the endpoint to initialize the connection. For example `connectOptions=#myConnectOptions` notation can be used to reference Spring bean named `my`ConnectOptions. If there is only a single instance of the `MqttConnectOptions` in the registry, it will be automatically picked up by the endpoint.

For example the convention-over-configuration approach used in Camel is really handy for the most of the situations, but sometimes you would like to have more fine-grained control over the MQTT client connection. To cover such situations just add the bean of type org.eclipse.paho.client.mqttv3.MqttConnectOptions to your Camel registry. For Spring applications that would means adding bean to your application context. The snippet below uses password-based authentication to connect to the MQTT broker:

@Bean
MqttConnectOptions connectOptions() {
  MqttConnectOptions connectOptions = new MqttConnectOptions();
  connectOptions.setUserName("henry");
  connectOptions.setPassword("secret".toCharArray());
  return connectOptions;
}

@Bean
MqttConnectOptions connectOptions() {
  MqttConnectOptions connectOptions = new MqttConnectOptions();
  connectOptions.setUserName("henry");
  connectOptions.setPassword("secret".toCharArray());
  return connectOptions;
}

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Headers
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The following headers are recognized by the Paho component:

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Header	Java constant	Endpoint type	Value type	Description
`PahoOriginalMessage`	`PahoConstants.HEADER_ORIGINAL_MESSAGE`	Consumer	`org.eclipse.paho.client.mqttv3.MqttMessage`	The original Paho message instance received by the client. Deprecated: from Camel 2.17 onwards the original MqttMessage is not stored as a header but on the `org.apache.camel.component.paho.PahoMessage` message that has a getter `getMqttMessage`.
`CamelMqttTopic`	PahoConstants.MQTT_TOPIC	Consumer	String	Camel 2.17: The topic

이 콘텐츠는 선택한 언어로 제공되지 않습니다.

Paho Component
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URI format
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Adding the component to the project
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Default payload type
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URI Options
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Headers
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이 콘텐츠는 선택한 언어로 제공되지 않습니다.

Chapter 123. Paho

Paho Component링크 복사링크가 클립보드에 복사되었습니다!

URI format링크 복사링크가 클립보드에 복사되었습니다!

Adding the component to the project링크 복사링크가 클립보드에 복사되었습니다!

Default payload type링크 복사링크가 클립보드에 복사되었습니다!

URI Options링크 복사링크가 클립보드에 복사되었습니다!

Headers링크 복사링크가 클립보드에 복사되었습니다!

자세한 정보

평가판, 구매 및 판매

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Paho Component
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URI format
링크 복사

Adding the component to the project
링크 복사

Default payload type
링크 복사

URI Options
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Headers
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