[CONF] Apache CXF 2.0 Documentation: JavaScript (page edited)

Fri, 11 May 2007 11:44:32 -0700

Page Edited : CXF20DOC : _javascript_

_javascript_ has been edited by Ken Geis (May 11, 2007).

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Content:

Using Dynamic Languages to Implement Services

Overview

_javascript_, also known by its formal name ECMAScript, is one of the many dynamic languages that are growing in prevalence in development environments. It provides a quick and lightweight means of creating functionality that can be run on a number of platforms. Another strength of _javascript_ is that applications can be quickly rewritten.

CXF provides support for developing services using _javascript_ and ECMAScript for XML(E4X). The pattern used to develop these services are similar to JAX-WS Provider implementations that handle their requests and responses (either SOAP messages or SOAP payloads) as DOM documents.

Implementing a Service in _javascript_

Writing a service in _javascript_is a two step process:

  1. Define the JAX-WS style metadata.
  2. Implement the services business logic.

Defining the Metadata

Normal Java providers typically use Java annotations to specify JAX-WS metadata. Since _javascript_ does not support annotations, you use ordinary _javascript_ variables to specify metadata for _javascript_ implementations. CXF treats any _javascript_ variable in your code whose name equals or begins with WebServiceProvider as a JAX-WS metadata variable.

Properties of the variable are expected to specify the same metadata that the JAX-WS WebServiceProvider annotation specifies, including:

  • wsdlLocation specifies a URL for the WSDL defining the service.
  • serviceName specifies the name of the service.
  • portName specifies the service's port/interface name.
  • targetNamespace specifies the target namespace of the service.

The _javascript_ WebServiceProvider can also specify the following optional properties:

  • ServiceMode indicates whether the specified service handles SOAP payload documents or full SOAP message documents. This property mimics the JAX-WS ServiceMode annotation. The default value is PAYLOAD.
  • BindingMode indicates the service binding ID URL. The default is the SOAP 1.1/HTTP binding.
  • EndpointAddress indicates the URL consumer applications use to communicate with this service. The property is optional but has no default.

Example 1 shows a metadata description for a _javascript_ service implementation.

Example 1:_javascript_ Metadata
var WebServiceProvider1 = {
    'wsdlLocation': 'file:./wsdl/hello_world.wsdl',
    'serviceName': 'SOAPService1',
    'portName': 'SoapPort1',
    'targetNamespace': 'http://apache.org/hello_world_soap_http',
};



Implementing the Service Logic



You implement the service's logic using the required invoke property of the WebServiceProvider variable. This variable is a function that accepts one input argument, a javax.xml.transform.dom.DOMSource node, and returns a document of the same type. The invoke function can manipulate either the input or output documents using the regular Java DOMSource class interface just as a Java application would.



Example 2 shows an invoke property for a simple _javascript_ service implementation.



Example 2:_javascript_ Service Implementation


WebServiceProvider.invoke = function(document) {
    var ns4 = "http://apache.org/hello_world_soap_http/types";
    var list = document.getElementsByTagNameNS(ns4, "requestType");
    var name = list.item(0).getFirstChild().getNodeValue();
    var newDoc = document.getImplementation().createDocument(ns4, "ns4:greetMeResponse", null);
    var el = newDoc.createElementNS(ns4, "ns4:responseType");
    var txt = newDoc.createTextNode("Hi " + name);
    el.insertBefore(txt, null);
    newDoc.getDocumentElement().insertBefore(el, null);
    return newDoc;
}




Implementing a Service in ECMAScript for XML(E4X)



Writing a CXF service using E4X is very similar to writing a service using _javascript_. You define the JAX-WS metadata using the same WebServiceProvider variable in _javascript_. You also implement the service's logic in the WebServiceProvider variable's invoke property.



The only difference between the two approaches is the type of document the implementation manipulates. When working with E4X, the implementation receives requests as an E4X XML document and returns a document of the same type. These documents are manipulated using built-in E4X XML features.



Example 3 shows an invoke property for a simple E4X service implementation.



Example 3:E4X Service Implementation


var SOAP_ENV = new Namespace('SOAP-ENV',
                             'http://schemas.xmlsoap.org/soap/envelope/');
var xs = new Namespace('xs', 'http://www.w3.org/2001/XMLSchema');
var xsi = new Namespace('xsi', 'http://www.w3.org/2001/XMLSchema-instance');
var ns = new Namespace('ns', 'http://apache.org/hello_world_soap_http/types');

WebServiceProvider1.invoke = function(req) {
    default xml namespace = ns;
    var name = (req..requestType)[0];
    default xml namespace = SOAP_ENV;
    var resp = <SOAP-ENV:Envelope xmlns:SOAP-ENV={SOAP_ENV} xmlns:xs={xs} xmlns:xsi={xsi}/>;
    resp.Body = <Body/>;
    resp.Body.ns::greetMeResponse = <ns:greetMeResponse xmlns:ns={ns}/>;
    resp.Body.ns::greetMeResponse.ns::responseType = 'Hi ' + name;
    return resp;
}




Deploying Scripted Services



CXF provides a lightweight container that allows you to deploy your _javascript_ and E4X services and take advantage of CXF's pluggable transport infrastructure.


Note


Script based services can only work with SOAP messages. So, while they are multi-transport, they can only use the SOAP binding.


You deploy services into the container using the following command:




java org.apache.cxf.js.rhino.ServerApp [ -a addressURL ] [ -b baseAddressURL ] file.js [ file2.js file3.jsx ... ]




The org.apache.cxf.js.rhino.ServerApp class, shorted to ServerApp below, takes one or more _javascript_ files, suffixed with a .js, or E4X files, suffixed with a .jsx, and loads them into the CXF runtime. If ServerApp locates JAX-WS metadata in the files it creates and registers a JAX-WS Provider<DOMSource> object for each service. The Provider<DOMSource> object delegates the processing of requests to the implementation stored in the associated file. ServerApp can also take the name of a directory containing _javascript_ and E4X files. It will load all of the scripts that contain JAX-WS metadata, load them, and publish a service endpoint for each one.



ServerApp has three optional arguments:





Argument
Description




 -a addressURL 
 Specifies the address at which ServerApp publishes the service endpoint implementation found in the script file following the URL. 




 -b baseAddressURL 
 Specifies the base address used by ServerApp when publishing the service endpoints defined by the script files. The full address for the service endpoints is formed by appending the service's port name to the base address. 




 -v 
 Specifies that {ServerApp is to run in verbose mode.






The optional arguments take precedence over any addressing information provided in {{EndpointAddress}}properties that appear in the JAX-WS metadata.



For example, if you deployed a _javascript_ service using the command shown in Example 4, your service would be deployed at http://cxf.apache.org/goodness.



Example 4:Deploying a Service at a Specified Address


java org.apache.cxf.js.rhino.ServerApp -a http://cxf.apache.org/goodness hello_world.jsx





To deploy a number of services using a common base URL you could use the command shown in Example 5. If the service defined by hello_world.jsx had port name of helloWorld, ServerApp would publish it at http://cxf.apache.org/helloWorld. If the service defined by goodbye_moon.js had a port name of blue, ServerApp would publish at http://cxf.apache.org/blue.



Example 5:Deploying a Group of Services to a Base Address


java org.apache.cxf.js.rhino.ServerApp -b http://cxf.apache.org hello_world.jsx goodbye_moon.js





You can also combine the arguments as shown in Example 6 and your service would be deployed at http://cxf.apache.org/goodness. ServerApp would publish three service endpoints:

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