Chapter 112. Mustache

Mustache

Available as of Camel 2.12
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

Option Default Description
encoding null Character encoding of the resource content.
startDelimiter {{ Characters used to mark template code beginning.
endDelimiter }} Characters used to mark template code end.

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}}