Mustache Component

Since Camel 2.12

Only producer is supported

The Mustache component allows for processing a message using a Mustache template. This can be ideal when using Templating to generate responses for requests.

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

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

URI format

mustache:templateName[?options]

Where templateName is the classpath-local URI of the template to invoke; or the complete URL of the remote template (eg: file://folder/myfile.mustache).

You can append query options to the URI in the following format, ?option=value&option=value&…​

Options

The Mustache component supports 4 options, which are listed below.

Name Description Default Type

mustacheFactory (advanced)

To use a custom MustacheFactory

MustacheFactory

basicPropertyBinding (advanced)

Whether the component should use basic property binding (Camel 2.x) or the newer property binding with additional capabilities

false

boolean

lazyStartProducer (producer)

Whether the producer should be started lazy (on the first message). By starting lazy you can use this to allow CamelContext and routes to startup in situations where a producer may otherwise fail during starting and cause the route to fail being started. By deferring this startup to be lazy then the startup failure can be handled during routing messages via Camel’s routing error handlers. Beware that when the first message is processed then creating and starting the producer may take a little time and prolong the total processing time of the processing.

false

boolean

bridgeErrorHandler (consumer)

Allows for bridging the consumer to the Camel routing Error Handler, which mean any exceptions occurred while the consumer is trying to pickup incoming messages, or the likes, will now be processed as a message and handled by the routing Error Handler. By default the consumer will use the org.apache.camel.spi.ExceptionHandler to deal with exceptions, that will be logged at WARN or ERROR level and ignored.

false

boolean

The Mustache endpoint is configured using URI syntax:

mustache:resourceUri

with the following path and query parameters:

Path Parameters (1 parameters):

Name Description Default Type

resourceUri

Required Path to the resource. You can prefix with: classpath, file, http, ref, or bean. classpath, file and http loads the resource using these protocols (classpath is default). ref will lookup the resource in the registry. bean will call a method on a bean to be used as the resource. For bean you can specify the method name after dot, eg bean:myBean.myMethod.

String

Query Parameters (7 parameters):

Name Description Default Type

contentCache (producer)

Sets whether to use resource content cache or not

false

boolean

encoding (producer)

Character encoding of the resource content.

String

endDelimiter (producer)

Characters used to mark template code end.

}}

String

lazyStartProducer (producer)

Whether the producer should be started lazy (on the first message). By starting lazy you can use this to allow CamelContext and routes to startup in situations where a producer may otherwise fail during starting and cause the route to fail being started. By deferring this startup to be lazy then the startup failure can be handled during routing messages via Camel’s routing error handlers. Beware that when the first message is processed then creating and starting the producer may take a little time and prolong the total processing time of the processing.

false

boolean

startDelimiter (producer)

Characters used to mark template code beginning.

{{

String

basicPropertyBinding (advanced)

Whether the endpoint should use basic property binding (Camel 2.x) or the newer property binding with additional capabilities

false

boolean

synchronous (advanced)

Sets whether synchronous processing should be strictly used, or Camel is allowed to use asynchronous processing (if supported).

false

boolean

Spring Boot Auto-Configuration

When using Spring Boot make sure to use the following Maven dependency to have support for auto configuration:

<dependency>
  <groupId>org.apache.camel.springboot</groupId>
  <artifactId>camel-mustache-starter</artifactId>
  <version>x.x.x</version>
  <!-- use the same version as your Camel core version -->
</dependency>

The component supports 5 options, which are listed below.

Name Description Default Type

camel.component.mustache.basic-property-binding

Whether the component should use basic property binding (Camel 2.x) or the newer property binding with additional capabilities

false

Boolean

camel.component.mustache.bridge-error-handler

Allows for bridging the consumer to the Camel routing Error Handler, which mean any exceptions occurred while the consumer is trying to pickup incoming messages, or the likes, will now be processed as a message and handled by the routing Error Handler. By default the consumer will use the org.apache.camel.spi.ExceptionHandler to deal with exceptions, that will be logged at WARN or ERROR level and ignored.

false

Boolean

camel.component.mustache.enabled

Whether to enable auto configuration of the mustache component. This is enabled by default.

Boolean

camel.component.mustache.lazy-start-producer

Whether the producer should be started lazy (on the first message). By starting lazy you can use this to allow CamelContext and routes to startup in situations where a producer may otherwise fail during starting and cause the route to fail being started. By deferring this startup to be lazy then the startup failure can be handled during routing messages via Camel’s routing error handlers. Beware that when the first message is processed then creating and starting the producer may take a little time and prolong the total processing time of the processing.

false

Boolean

camel.component.mustache.mustache-factory

To use a custom MustacheFactory. The option is a com.github.mustachejava.MustacheFactory type.

String

Mustache Context

Camel will provide exchange information in the Mustache context (just a Map). The Exchange is transferred as:

key value

exchange

The Exchange itself.

exchange.properties

The Exchange properties.

headers

The headers of the In message.

camelContext

The Camel Context.

request

The In message.

body

The In message body.

response

The Out message (only for InOut message exchange pattern).

Dynamic templates

Camel provides two headers by which you can define a different resource location for a template or the template content itself. If any of these headers is set then Camel uses this over the endpoint configured resource. This allows you to provide a dynamic template at runtime.

Header Type Description Support Version

MustacheConstants.MUSTACHE_RESOURCE_URI

String

A URI for the template resource to use instead of the endpoint configured.

MustacheConstants.MUSTACHE_TEMPLATE

String

The template to use instead of the endpoint configured.

Samples

For example you could use something like:

from("activemq:My.Queue").
to("mustache:com/acme/MyResponse.mustache");

To use a Mustache template to formulate a response for a message for InOut message exchanges (where there is a JMSReplyTo header).

If you want to use InOnly and consume the message and send it to another destination you could use:

from("activemq:My.Queue").
to("mustache:com/acme/MyResponse.mustache").
to("activemq:Another.Queue");

It’s possible to specify what template the component should use dynamically via a header, so for example:

from("direct:in").
setHeader(MustacheConstants.MUSTACHE_RESOURCE_URI).constant("path/to/my/template.mustache").
to("mustache:dummy");

The Email Sample

In this sample we want to use Mustache templating for an order confirmation email. The email template is laid out in Mustache as:

Dear {{headers.lastName}}, {{headers.firstName}}

Thanks for the order of {{headers.item}}.

Regards Camel Riders Bookstore
{{body}}