Chapter 232. Mustache Component
Available as of Camel version 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>
232.1. 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&…
232.2. Options
The Mustache component supports 4 options, which are listed below.
| Name | Description | Default | Type |
|---|---|---|---|
| allowContextMapAll (producer) | Sets whether the context map should allow access to all details. By default only the message body and headers can be accessed. This option can be enabled for full access to the current Exchange and CamelContext. Doing so imposes a potential security risk as this opens access to the full power of CamelContext API. | false | boolean |
| allowTemplateFromHeader (producer) | Whether to allow to use resource template from header or not (default false). Enabling this option has security ramifications. For example, if the header contains untrusted or user derived content, this can ultimately impact on the confidentility and integrity of your end application, so use this option with caution. | false | boolean |
| mustacheFactory (advanced) | To use a custom MustacheFactory | MustacheFactory | |
| resolveProperty Placeholders (advanced) | Whether the component should resolve property placeholders on itself when starting. Only properties which are of String type can use property placeholders. | true | boolean |
The Mustache endpoint is configured using URI syntax:
mustache:resourceUri
with the following path and query parameters:
232.2.1. 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 |
232.2.2. Query Parameters (7 parameters):
| Name | Description | Default | Type |
|---|---|---|---|
| allowContextMapAll (producer) | Sets whether the context map should allow access to all details. By default only the message body and headers can be accessed. This option can be enabled for full access to the current Exchange and CamelContext. Doing so imposes a potential security risk as this opens access to the full power of CamelContext API. | false | boolean |
| allowTemplateFromHeader (producer) | Whether to allow to use resource template from header or not (default false). Enabling this option has security ramifications. For example, if the header contains untrusted or user derived content, this can ultimately impact on the confidentility and integrity of your end application, so use this option with caution. | false | boolean |
| 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 |
| startDelimiter (producer) | Characters used to mark template code beginning. | {{ | String |
| synchronous (advanced) | Sets whether synchronous processing should be strictly used, or Camel is allowed to use asynchronous processing (if supported). | false | boolean |
232.3. Spring Boot Auto-Configuration
The component supports 3 options, which are listed below.
| Name | Description | Default | Type |
|---|---|---|---|
| camel.component.mustache.enabled | Enable mustache component | true | Boolean |
| camel.component.mustache.mustache-factory | To use a custom MustacheFactory. The option is a com.github.mustachejava.MustacheFactory type. | String | |
| camel.component.mustache.resolve-property-placeholders | Whether the component should resolve property placeholders on itself when starting. Only properties which are of String type can use property placeholders. | true | Boolean |
232.4. Mustache Context
Camel will provide exchange information in the Mustache context (just a Map). The Exchange is transferred as:
| key | value |
|---|---|
|
|
The |
|
|
The |
|
| The headers of the In message. |
|
| The Camel Context. |
|
| The In message. |
|
| The In message body. |
|
| The Out message (only for InOut message exchange pattern). |
232.5. 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. |
232.6. 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?allowTemplateFromHeader=true");
Enabling the allowTemplateFromHeader option has security ramifications. For example, if the header contains untrusted or user derived content, this can ultimately impact on the confidentility and integrity of your end application, so use this option with caution.
232.7. 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}}232.8. See Also
- Configuring Camel
- Component
- Endpoint
- Getting Started
