Restlet Component
The Restlet component provides Restlet based endpoints for consuming and producing RESTful resources.
URI format
restlet:restletUrl[?options]
Format of restletUrl:
protocol://hostname[:port][/resourcePattern]
Restlet promotes decoupling of protocol and application concerns. The reference implementation of Restlet Engine supports a number of protocols. However, we have tested the HTTP protocol only. The default port is port 80. We do not automatically switch default port based on the protocol yet.
Options
Name |
Default Value |
Description |
|---|---|---|
headerFilterStrategy=#refName (2.x or later) |
An instance of RestletHeaderFilterStrategy object |
Use the # notation (headerFilterStrategy=#refName) to reference a header filter strategy in the Camel Registry. The strategy will be plugged into the Restlet Binding if it is HeaderFilterStrategyAware. |
restletBindingRef (1.x). For 2.x or later, use restletBinding=#refName |
An instance of DefaultRestletBinding object |
The name to lookup the RestletBinding object in the Camel Registry. |
restletMethod |
GET |
The method to be used in the request for producer. For consumer, the Restlet Endpoint only consumes requests made by restletMethod. The string value is converted to org.restlet.data.Method by the Method.valueOf(String) method. |
restletMethods (2.x or later) |
none |
This option is only valid for consumer. Specify one or more methods separated by commas (e.g. restletMethods=post,put) to be serviced by a Restlet endpoint. If both "restletMethod" and "restletMethods" options are specified, the value of restletMethod is ignored. |
restletRealmRef (1.x). For 2.x or later use restletRealm=#refName |
null |
The name to lookup the Realm Map in the Camel Registry. |
uriPatterns=#refName (2.x or later) |
none |
This option is only valid for consumer. Specify one ore more uri templates to be serviced by a Restlet endpoint using the # notation to reference a List (of String) in Camel Registry. |
Message Headers
Camel 1.x
Name |
Type |
Description |
|---|---|---|
org.apache.camel.restlet.auth.login |
String |
Login name for basic authentication. It is set on the IN message by application and get filtered before Restlet Request header by Camel. |
org.apache.camel.restlet.auth.password |
String |
Password name for basic authentication. It is set on the IN message by application and get filtered before Restlet Request header by Camel. |
org.apache.camel.restlet.mediaType |
String |
It can be set on the OUT message by application/processor. The value is the content-type of the response message. If this header is not set, content-type will be set based on the object type of the out message body. |
org.apache.camel.restlet.queryString |
String |
The query string of the request URI. It is set on the IN message by DefaultRestletBinding when the Restlet Component receives a request. |
org.apache.camel.restlet.responseCode |
String or Integer |
It can be set on the OUT message by application/processor. The value is the response code of the response message. If this header is not set, response code will be set by Restlet runtime engine. |
org.restlet.* |
|
Attributes of a Restlet message that get propagated to Camel IN headers. |
Camel 2.0
Name |
Type |
Description |
|---|---|---|
CamelContentType |
String |
It can be set on the OUT message by application/processor. The value is the content-type of the response message. If this header is not set, content-type will be set based on the object type of the out message body. |
CamelHttpMethod |
String |
The HTTP request method. This is et in the IN message header. |
CamelHttpQuery |
String |
The query string of the request URI. It is set on the IN message by DefaultRestletBinding when the Restlet Component receives a request. |
CamelHttpRsponseCode |
String or Integer |
It can be set on the OUT message by application/processor. The value is the response code of the response message. If this header is not set, response code will be set by Restlet runtime engine. |
CamelHttpUri |
String |
The HTTP request URI. This is set in the IN message header. |
CamelRestletLogin |
String |
Login name for basic authentication. It is set on the IN message by application and get filtered before Restlet Request header by Camel. |
CamelRestletPassword |
String |
Password name for basic authentication. It is set on the IN message by application and get filtered before Restlet Request header by Camel. |
org.restlet.* |
|
Attributes of a Restlet message that get propagated to Camel IN headers. |
Message Body
Camel will store the Restlet response from the external server on the OUT body. All headers from the IN message will be copied to the OUT message so headers is preserved during routing.
Samples
Restlet Endpoint with Authentication
This sample starts a Restlet consumer endpoint that listens POST requests on http://localhost:8080. The route looks like follow. The consumer invokes a processor that creates a response to echo the request body and the value of header "id".
The restletRealmRef (in 2.x, use the # notation. i.e. restletRealm=#refName)in URI query is an option to lookup a Realm Map in the registry. If this option is specified, the Restlet consumer will use the information to authenticate user logins. Only authenticated requests can access the resources. In this sample, we create a Spring application context that serves as a registry. The bean ID of the Realm Map should match the restletRealmRef.
The sample starts a direct endpoint that sends requests to the server on http://localhost:8080 (i.e. our Restlet consumer endpoint).
That is all we need. We are ready to send a request and try out the Restlet component. The sample client sends a request to "direct:start-auth" endpoint with the following headers. Notice that org.apache.camel.restlet.auth.login and org.apache.camel.restlet.auth.password will not be propagated as Restlet header.
- CamelRestletLogin (internally used by Camel)
- CamelRestletPassword (internally used by Camel)
- id ("application" header)
The sample client will get a response:
received [<order foo='1'/>] as an order id = 89531
Single Restlet endpoint to service multiple methods and URI templates (2.0 or later)
It is possible to create a single route to service multiple HTTP methods using the restletMethods option. This snippet also shows how to retrieve the request method from the header.
In addition to service multiple methods, the next snippet shows how to create an endpoint to support multiple URI templates by using the uriPatterns option. The request URI is available in the header of the IN message as well.
The uriPatterns=#uriTemplates option references to the List bean (of String) defined in the Spring configuration.