# Scalate

The scalate: component allows you to process a message using a Scalate template, which supports either SSP or Scaml format templates. This can be ideal when using Templating to generate responses for requests.

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

    <dependency>
        <groupId>org.fusesource.scalate</groupId>
        <artifactId>scalate-core_2.10</artifactId>
        <version>1.6.1</version>
    </dependency>

## URI format

    scalate: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.ssp).

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

## Scalate Context

Apache Camel will provide exchange information in the Scalate context (just a `Map`). The `Exchange` is transfered as:

key | value
--- | ---
`exchange` | The `Exchange` itself.
`headers` | The headers of the In message.
`camelContext` | The Camel Context intance.
`request` | The In message.
`in` | The In message.
`body` | The In message body.
`out` | The Out message (only for InOut message exchange pattern).
`response` | The Out message (only for InOut message exchange pattern).

## Hot reloading

The Scalate template resource is, by default, hot reloadable for both file and classpath resources (expanded jar).

## Dynamic templates

Apache 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 Apache Camel uses this over the endpoint configured resource. This allows you to provide a dynamic template at runtime.

Header | Type | Description
--- | --- | ---
CamelScalateResourceUri | String | An URI for the template resource to use instead of the endpoint configured.
CamelScalateTemplate | String | The template to use instead of the endpoint configured.

## Samples

For example you could use something like

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

To use a Scalate template to formulate a response to 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 the following route:

    from("activemq:My.Queue").
      to("scalate:com/acme/MyResponse.scaml").
      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("CamelScalateResourceUri").constant("path/to/my/template.scaml").
      to("scalate:dummy");

It's possible to specify a template directly as a header the component should use dynamically via a header, so for example:

    from("direct:in").
      setHeader("CamelScalateTemplate").constant("<%@ attribute body: Object %>\nHi this is a scalate template that can do templating ${body}").
      to("scalate:dummy");

## The Email Sample

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

    <%@ attribute in: org.apache.camel.scala.RichMessage %>
    Dear ${in("lastName"}, ${in("firstName")}

    Thanks for the order of ${in("item")}.

    Regards Camel Riders Bookstore
    ${in.body}