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[CONF] Apache Camel > Jetty

confluence Mon, 19 Apr 2010 13:58:49 -0700

Jetty

Page edited by David Valeri

Jetty Component

Supports non blocking Request Reply producer in Camel 2.1 onwards

The jetty component provides HTTP-based endpoints for consuming HTTP requests. That is, the Jetty component behaves as a simple Web server.

In Camel 2.1 the jetty component also provides non blocking Request Reply for producing HTTP requests. That is it can also acts as HTTP client sending to a remote HTTP server and use non blocking in this process. See more at ToAsync and the HTTP Async Example.

URI format

jetty:http://hostname[:port][/resourceUri][?options]


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

Options



 Name 
 Default Value 
 Description 


 sessionSupport 
 false 
 Specifies whether to enable the session manager on the server side of Jetty. 


 httpClient.XXX 
 null 
 Camel 1.6.0/2.0: Configuration of Jetty's HttpClient. For example, setting httpClient.idleTimeout=30000 sets the idle timeout to 30 seconds. 


 httpBindingRef 
 null 
 Camel 1.6.0/2.0: Reference to an org.apache.camel.component.http.HttpBinding in the Registry. HttpBinding can be used to customize how a response should be written. 


 matchOnUriPrefix 
 false 
 Camel 2.0: Whether or not the CamelServlet should try to find a target consumer by matching the URI prefix if no exact match is found. 


 handlers 
 null 
 Camel 1.6.1/2.0: Specifies a comma-delimited set of org.mortbay.jetty.Handler instances in your Registry (such as your Spring ApplicationContext). These handlers are added to the Jetty servlet context (for example, to add security). 


 chunked 
 true 
 From Camel 2.2: If this option is false Jetty servlet will disable the HTTP streaming and set the content-length header on the response 


 enableJmx 
 false 
 From Camel 2.3: If this option is true, Jetty JMX support will be enabled for this endpoint. See Jetty JMX support for more details. 



Message Headers

Camel uses the same message headers as the HTTP component.

>From Camel 2.2, it also uses (Exchange.HTTP_CHUNKED,CamelHttpChunked) header to turn on or turn off the chuched encoding on the camel-jetty consumer.

Camel also populates all request.parameter and request.headers. For example, given a client request with the URL, http://myserver/myserver?orderid=123, the exchange will contain a header named orderid with the value 123. This feature was introduced in Camel 1.5.

From Camel 1.6.3 and Camel 2.2.0, you can get the request.parameter from the message header not only from Get Method, but also other HTTP method.

Usage

The Jetty component only supports consumer endpoints. Therefore a Jetty endpoint URI should be used only as the input for a Camel route (in a from() DSL call). To issue HTTP requests against other HTTP endpoints, use the HTTP Component

Sample

In this sample we define a route that exposes a HTTP service at http://localhost:8080/myapp/myservice:

from("jetty:http://localhost:9080/myapp/myservice").process(new MyBookService());



Usage of localhost
When you specify localhost in a URL, Camel exposes the endpoint only on the local TCP/IP network interface, so it cannot be accessed from outside the machine it operates on.

If you need to expose a Jetty endpoint on a specific network interface, the numerical IP address of this interface should be used as the host. If you need to expose a Jetty endpoint on all network interfaces, the 0.0.0.0 address should be used.

Our business logic is implemented in the MyBookService class, which accesses the HTTP request contents and then returns a response.

Note: The assert call appears in this example, because the code is part of an unit test.

public class MyBookService implements Processor {
    public void process(Exchange exchange) throws Exception {
        // just get the body as a string
        String body = exchange.getIn().getBody(String.class);

        // we have access to the HttpServletRequest here and we can grab it if we need it
        HttpServletRequest req = exchange.getIn().getBody(HttpServletRequest.class);
        assertNotNull(req);

        // for unit testing
        assertEquals("bookid=123", body);

        // send a html response
        exchange.getOut().setBody("<html><body>Book 123 is Camel in Action</body></html>");
    }
}



The following sample shows a content-based route that routes all requests containing the URI parameter, one, to the endpoint, mock:one, and all others to mock:other.

from("jetty:" + serverUri)
    .choice()
    .when().simple("in.header.one").to("mock:one")
    .otherwise()
    .to("mock:other");


So if a client sends the HTTP request, http://serverUri?>, the Jetty component will copy the HTTP request parameter, one to the exchange's in.header. We can then use the simple language to route exchanges that contain this header to a specific endpoint and all others to another. If we used a language more powerful than Simple--such as EL or OGNL--we could also test for the parameter value and do routing based on the header value as well.

Session Support

The session support option, sessionSupport, can be used to enable a HttpSession object and access the session object while processing the exchange. For example, the following route enables sessions:


<route><from uri="jetty:http://0.0.0.0/myapp/myservice/?sessionSupport=true"/><processRef ref="myCode"/><route>



The myCode Processor can be instantiated by a Spring bean element:


<bean id="myCode"class="com.mycompany.MyCodeProcessor"/>



Where the processor implementation can access the HttpSession as follows:


publicvoid process(Exchange exchange)throwsException { HttpSession session = ((HttpExchange)exchange).getRequest().getSession(); ... }


SSL Support (HTTPS)

Jetty provides SSL support out of the box. To enable Jetty to run in SSL mode, simply format the URI with the https:// prefix---for example:


<from uri="jetty:https://0.0.0.0/myapp/myservice/"/>



Jetty also needs to know where to load your keystore from and what passwords to use in order to load the correct SSL certificate. Set the following JVM System Properties:

until Camel 2.2

	jetty.ssl.keystore specifies the location of the Java keystore file, which contains the Jetty server's own X.509 certificate in a key entry. A key entry stores the X.509 certificate (effectively, the public key) and also its associated private key.
	jetty.ssl.password the store password, which is required to access the keystore file (this is the same password that is supplied to the keystore command's -storepass option).
	jetty.ssl.keypassword the key password, which is used to access the certificate's key entry in the keystore (this is the same password that is supplied to the keystore command's -keypass option).



from Camel 2.3 onwards

	org.eclipse.jetty.ssl.keystore specifies the location of the Java keystore file, which contains the Jetty server's own X.509 certificate in a key entry. A key entry stores the X.509 certificate (effectively, the public key) and also its associated private key.
	org.eclipse.jetty.ssl.password the store password, which is required to access the keystore file (this is the same password that is supplied to the keystore command's -storepass option).
	org.eclipse.jetty.ssl.keypassword the key password, which is used to access the certificate's key entry in the keystore (this is the same password that is supplied to the keystore command's -keypass option).



For details of how to configure SSL on a Jetty endpoint, read the following documentation at the Jetty Site: http://docs.codehaus.org/display/JETTY/How+to+configure+SSL

Some SSL properties aren't exposed directly by Camel, however Camel does expose the underlying SslSocketConnector, which will allow you to set properties like needClientAuth for mutual authentication requiring a client certificate or wantClientAuth for mutual authentication where a client doesn't need a certificate but can have one. There's a slight difference between Camel 1.6.x and 2.x:

Camel 1.x

<bean id="jetty"class="org.apache.camel.component.jetty.JettyHttpComponent"> <property name="sslSocketConnector"> <bean class="org.mortbay.jetty.security.SslSocketConnector"> <property name="password"value="..."/> <property name="keyPassword"value="..."/> <property name="keystore"value="..."/> <property name="wantClientAuth"value="..."/> <property name="truststore"value="..."/> </bean> </property> </bean>



until Camel 2.2

<bean id="jetty"class="org.apache.camel.component.jetty.JettyHttpComponent"> <property name="sslSocketConnectors"> <map> <entry key="8043"> <bean class="org.mortbay.jetty.security.SslSocketConnector"> <property name="password"value="..."/> <property name="keyPassword"value="..."/> <property name="keystore"value="..."/> <property name="needClientAuth"value="..."/> <property name="truststore"value="..."/> </bean> </entry> </map> </property> </bean>




from Camel 2.3 onwards

<bean id="jetty"class="org.apache.camel.component.jetty.JettyHttpComponent"> <property name="sslSocketConnectors"> <map> <entry key="8043"> <bean class="org.eclipse.jetty.server.ssl.SslSocketConnector"> <property name="password"value="..."/> <property name="keyPassword"value="..."/> <property name="keystore"value="..."/> <property name="needClientAuth"value="..."/> <property name="truststore"value="..."/> </bean> </entry> </map> </property> </bean>



The value you use as keys in the above map is the port you configure Jetty to listen on.

Default behavior for returning HTTP status codes

The default behavior of HTTP status codes is defined by the org.apache.camel.component.http.DefaultHttpBinding class, which handles how a response is written and also sets the HTTP status code.

If the exchange was processed successfully, the 200 HTTP status code is returned.

If the exchange failed with an exception, the 500 HTTP status code is returned, and the stacktrace is returned in the body. If you want to specify which HTTP status code to return, set the code in the HttpProducer.HTTP_RESPONSE_CODE header of the OUT message.

Customizing HttpBinding

Available as of Camel 1.5.1/2.0

By default, Camel uses the org.apache.camel.component.http.DefaultHttpBinding to handle how a response is written. If you like, you can customize this behavior either by implementing your own HttpBinding class or by extending DefaultHttpBinding and overriding the appropriate methods.

The following example shows how to customize the DefaultHttpBinding in order to change how exceptions are returned:

public class MyHttpBinding extends DefaultHttpBinding {

    @Override
    public void doWriteExceptionResponse(Throwable exception, HttpServletResponse response) throws IOException {
        // we override the doWriteExceptionResponse as we only want to alter the binding how exceptions is
        // written back to the client. 

        // we just return HTTP 200 so the client thinks its okay
        response.setStatus(200);
        // and we return this fixed text
        response.getWriter().write("Something went wrong but we dont care");
    }
}



We can then create an instance of our binding and register it in the Spring registry as follows:

<bean id="mybinding"class="com.mycompany.MyHttpBinding"/>



And then we can reference this binding when we define the route:

<route><from uri="jetty:http://0.0.0.0:8080/myapp/myservice?httpBindingRef=mybinding"/><to uri="bean:doSomething"/></route>



Jetty handlers and security configuration

Available as of Camel 1.6.1/2.0: You can configure a list of Jetty handlers on the endpoint, which can be useful for enabling advanced Jetty security features. These handlers are configured in Spring XML as follows:

<-- Jetty Security handling --><bean id="userRealm"class="org.mortbay.jetty.plus.jaas.JAASUserRealm"><property name="name"value="tracker-users"/><property name="loginModuleName"value="ldaploginmodule"/></bean><bean id="constraint"class="org.mortbay.jetty.security.Constraint"><property name="name"value="BASIC"/><property name="roles"value="tracker-users"/><property name="authenticate"value="true"/></bean><bean id="constraintMapping"class="org.mortbay.jetty.security.ConstraintMapping"><property name="constraint"ref="constraint"/><property name="pathSpec"value="/*"/></bean><bean id="securityHandler"class="org.mortbay.jetty.security.SecurityHandler"><property name="userRealm"ref="userRealm"/><property name="constraintMappings"ref="constraintMapping"/></bean>



And from Camel 2.3 onwards you can configure a list of Jetty handlers as follows:

<-- Jetty Security handling --><bean id="constraint"class="org.eclipse.jetty.http.security.Constraint"><property name="name"value="BASIC"/><property name="roles"value="tracker-users"/><property name="authenticate"value="true"/></bean><bean id="constraintMapping"class="org.eclipse.jetty.security.ConstraintMapping"><property name="constraint"ref="constraint"/><property name="pathSpec"value="/*"/></bean><bean id="securityHandler"class="org.eclipse.jetty.security.ConstraintSecurityHandler"><property name="authenticator"><bean class="org.eclipse.jetty.security.authentication.BasicAuthenticator"/></property><property name="constraintMappings"><list><ref bean="constraintMapping"/></list></property></bean>



You can then define the endpoint as:

from("jetty:http://0.0.0.0:9080/myservice?handlers=securityHandler")



If you need more handlers, set the handlers option equal to a comma-separated list of bean IDs.

How to return a custom HTTP 500 reply message

You may want to return a custom reply message when something goes wrong, instead of the default reply message Camel Jetty replies with.

You could use a custom HttpBinding to be in control of the message mapping, but often it may be easier to use Camel's Exception Clause to construct the custom reply message. For example as show here, where we return Dude something went wrong with HTTP error code 500:

from("jetty://http://localhost:8234/myserver")
    // use onException to catch all exceptions and return a custom reply message
    .onException(Exception.class)
        .handled(true)
        // create a custom failure response
        .transform(constant("Dude something went wrong"))
        // we must remember to set error code 500 as handled(true)
        // otherwise would let Camel thing its a OK response (200)
        .setHeader(Exchange.HTTP_RESPONSE_CODE, constant(500))
    .end()
    // now just force an exception immediately
    .throwException(new IllegalArgumentException("I cannot do this"));



Multi-part Form support

From Camel 2.3.0, camel-jetty support to multipart form post out of box. The submitted form-data are mapped into the message header. Camel-jetty creates an attachment for each uploaded file. The file name is mapped to the name of the attachment. The content type is set as the content type of the attachment file name. You can find the example here.

from("jetty://http://localhost:9080/test").process(new Processor() {

    public void process(Exchange exchange) throws Exception {
        Message in = exchange.getIn();
        assertEquals("Get a wrong attachement size", 1, in.getAttachments().size());
        // The file name is attachment id
        DataHandler data = "" class="code-quote">"NOTICE.txt");
        assertNotNull("Should get the DataHandle NOTICE.txt", data);
        assertEquals("Get a wrong content type", "text/plain", data.getContentType());
        // The other form date can be get from the message header
        exchange.getOut().setBody(in.getHeader("comment"));
    }

});



Jetty JMX support

From Camel 2.3.0, camel-jetty supports the enabling of Jetty's JMX capabilities at the component and endpoint level with the endpoint configuration taking priority.  Note that JMX must be enabled within the Camel context in order to enable JMX support in this component as the component provides Jetty with a reference to the MBeanServer registered with the Camel context.  Because the camel-jetty component caches and reuses Jetty resources for a given protocol/host/port pairing, this configuration option will only be evaluated during the creation of the first endpoint to use a protocol/host/port pairing.  For example, given two routes created from the following XML fragments, JMX support would remain enabled for all endpoints listening on "https://0.0.0.0".


<from uri="jetty:https://0.0.0.0/myapp/myservice1/?enableJmx=true"/>




<from uri="jetty:https://0.0.0.0/myapp/myservice2/?enableJmx=false"/>



The camel-jetty component also provides for direct configuration of the Jetty MBeanContainer.  Jetty creates MBean names dynamically.  If you are running another instance of Jetty outside of the Camel context and sharing the same MBeanServer between the instances, you can provide both instances with a reference to the same MBeanContainer in order to avoid name collisions when registering Jetty MBeans.


See Also

	Configuring Camel
	Component
	Endpoint
	Getting Started



	HTTP

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