How to create a web service proxy? Can we generate #Endpoints? - java

I'm working on a web-service-proxy with auditing (later on with caching = creating own responses) and I need to generate #Endpoints (such that will just forward i.e. call a remote web service or dummy atleast). Marshaling/unmarshaling seems neccessary for the proxy will add "something" to the request...
We are to use spring-ws and JAXB. Got all XSDs and static WSDLs of the proxied web service.
Any hints around? Anyone doing something similar? How are you doing it?
Is there a simple way how to achieve this using spring or spring-integration?
Thanks in advance..

This should be possible using both Spring WS and Spring Integration:
With Spring WS, you can create a proxy class for your remote WS, wrapping around a org.springframework.ws.client.core.WebServiceTemplate to talk to the WS - which has API's to take care of marshalling the request to xml and unmarshalling the response.
With Spring Integration, you can use an outbound Webservices gateway , but you will need to front it with a messaging gateway, which will act as your proxy, along these lines:
<int:gateway id="wsproxy" service-interface="..ProxyInterface" default-request-channel="requestChannel" default-reply-channel="replyChannel"/>
<int-ws:outbound-gateway id="wsGateway" request-channel="requestChannel" uri="http://serviceURL" marshaller="someMarshaller" unmarshaller="someUnmarshaller"/>
However, I would recommend the first approach of using the WebserviceTemplate, as you do not have a very complex integration need here.

Today I can tell how we proceeded without spring-integration. We found two different ways how to generate #Endpoint class.
1) Using XSLT and Freemarker we generated the endpoint class source in pre-compile phase. XSLT transformation walked thru all WSDL files to create one summary file which was then used to generate the source.
2) Using Javassist we copied the template class, then generated methods regarding content of JAXB2Marshaller instance and finally instantiated object using FactoryBean, all at server start-up.
Problem here we met was set of XSD files written in form that caused the root objects were generated without #XmlRootAnnotation. Javassist version we had internally works with Java 1.4 (no generics) so we used global customization file for XJC and forced #XmlRootAnnotation on root objects.
Both solutions have their pros and cons but both are simpler then using ESB.

Related

Workflow mechanism for exception and error handling scenarios in Spring Boot or Spring

I am working on design where the requirement is as follows
The application would be built using spring boot
As part of the requirement we would have to build some orchestration where we would end up calling multiple SOAP and REST services and we would perform aggregation, transformation etc.
When an exception/error occurs during the orchestration, we need to capture and persist the state and retry it from the same point where the error occurred.
For example, Lets say there is a Java method in which we have multiple calls to external components say 1 soap call and 2 rest calls i.e.
String doOrchestration(InputObject obj){
Line 1: Object obj = soap call[ input is XML format];
Line 2: Object obj1 = rest1 call [the input is obj in JSON format]
Line 3: Object obj3 = rest2 call[the input is obj1 in JOSN format]
//do something
return str
}
The error occurred on Line 2. We need to capture/persist the state and continue the execution from the Line 2 later.
Is there any workflow library, orchestration patterns and/or framework that we can integrate with spring/Spring-boot
Thanks,
well, one tecnology that i use to handle this kind of problems is apache camel, whith camel you can set routes,for instance in your requirement, you can build the main route who will orchest other routes such as yours endpoints, if one endpoint has an exception you can call the route who will persist that and call again the route of the endpoint, or something like that.
http://camel.apache.org/getting-started.html
edit: camel has a lot of potencial transforming messages such as json, xml, objects.
i have a very simple project on github with spring boot and camel if you want to check it.
https://github.com/chill-hub/spring_boot_camel_base_archetype
The Apache Camel version spring like is spring-integration at
https://spring.io/projects/spring-integration
Apache Camel and Spring Integration implements enterprise integration pattern called EIP. Please look at https://www.enterpriseintegrationpatterns.com/ first.
It is basically design patterns for workflow and orchestration !
You have an integration (starter) with spring boot made by spring named spring-boot-starter-integration.
You should probably look at Java Spring Config dsl reference at https://github.com/spring-projects/spring-integration-java-dsl/wiki/spring-integration-java-dsl-reference
which will show you a nice overview, with the more modern approach (xml, and annotation starts to disapear).
With what you need to do you will probably need https://docs.spring.io/spring-integration/reference/html/ws.html which is the web extension for spring integration.
Be careful it is a very elegant solution but with lot of abstraction and can be difficult at the beginning. Keep in mind EIP defines building block and vocabulary to build workflows, Apache Camel and Spring Integration are frameworks that implements these building blocks and offer a threading model abstraction (also queue persistant abstraction), and both have several extensions to adapt easily these building blocks to real word (web, ldap, databases, ...)
Both frameworks are good with pros and cons, but you will probably prefer spring integration in a spring ecosysteme team, same conventions than other spring modules !
Again theses framework are really elegant but abstraction has always a cost!
Disclaimer : I was a trainer for spring integration course - Official

Restlet Client using JAX-RS annotated resources

I am writing a restlet client that will invoke some Resteasy coded rest services (cannot change the server code, hence cannot use the Restlet way of annotating resources).
Resource Interface is using JAX-RS annotations and have more than one #POST method (one of the biggest problems of Restlet when dealing with this).
I was trying to do my implementaion this way:
IAppLoginResource resource = JaxRsClientResource.createJaxRsClient("http://localhost:9090/rest", IAppLoginResource.class);
final GetLoginAppInfoResponse response = resource.getLoginAppInfo( getLoginAppInfoRequest );
The problem is that the request by default is GET, I didn't find a way to specify the request method like when using ClientResource (which I can't use because I need to deal with JaxbRepresentation and Jaxb problems).
Any sample/snippet of code that implement a Restlet client using JAX-RS annotated resources?
Any ideas?
Thanks,
I've entered an issue for this topic:
https://github.com/restlet/restlet-framework-java/issues/1081
I've tested a sample application based on your code, and it works properly using the current 2.3 branch (future 2.3.3). I wonder if the fix for this issue https://github.com/restlet/restlet-framework-java/issues/1072 helps.
Regarding the documentation, I 'll complete the current page (http://restlet.com/technical-resources/restlet-framework/guide/2.3/extensions/jaxrs), cf this issue: https://github.com/restlet/restlet-framework-java/issues/1084.
You can also have a look at the org.restlet.test project, especially in this package https://github.com/restlet/restlet-framework-java/tree/2.3/modules/org.restlet.test/src/org/restlet/test/ext/jaxrs.

Web Service Auto Generated Files

When I create a new Web service using RSA 7.5 IDE and Web Sphere 7.0 server from a Web Application, then I can see a few auto-generated files created by this process, namely:
1) For the service, a SEI file is created
2) For the models, ser, deser and helper files are created.
But I cant understand what are the use of all these SEI, ser, deser and helper files.
Any valid explanation on this will be much appreciated.
BOUNTY EDIT:
Bounty-Edit:
Since I did not get any response I would like to ask this question again - offering a bounty to encourage an in-depth answer. I would love to know how and when are these files used internally?
Regards,
Service Endpoint Interface (SEI):
SEI is the Java interface corresponding to the Web service port type
being implemented. It is defined by the JAX-RPC, which specifies the
language mapping from WSDL 1.1 to Java. Ref
Or
A service endpoint interface (SEI) is a Java interface that
declares the methods that a client can invoke on the service. Ref
These ser,dser,helper are helpers to convert an XML document into a java object and vice versa (WebServices). Ref
Files generated in the server project: (WebSphere Application Server 6.1 Ref)
According to the settings made during the run of the wizard, the following files in the WeatherJavaBeanWeb project have been created:
Service endpoint interface (SEI): itso.bean.WeatherJavaBean_SEI.java is the interface defining the methods exposed in the Web service.
WSDL file: /WebContent/WEB-INF/wsdl/WeatherJavaBean.wsdl describes the Web service.
Deployment descriptor: webservices.xml, ibm-webservices-ext.xml and ibm-webservices-bnd.xml. These files describe the Web service according to the Web services for J2EE style (JSR 109). The JAX-RPC mapping is described in the WeatherJavaBean_mapping.xml file.
Data mapping files: The helper beans in the itso.objects package perform the data conversion from XML to Java objects and back.
A servlet is defined in the Web deployment descriptor to invoke the JavaBean.
Hope this information help you.
Those files are related to the WebSphere mapping between Java, WSDL, and XML. They are automatically generated, and should not need to be edited. You should pretend they are not there (except if they are not there you may have trouble deploying...).
SEI - Service Endpoint Interface
ser - Serialize
deser - Deserialize
helper - ?
Here are some psuedo-helpful links, that may provide some more insight into your question:
IBM Technotes
WebSphere v6.1 Handbook (check Chapter 15 -> Creating a Web Service --> Generated Files)
All these files are basically generated for webservice.
A web service ia basically a port between 2 running applications independant of the framework or language.
Leta say if you are using java from one side of web service then for complete compilation the java end would need some class files that have those methids which you wish to call on the service.
For this a stub is generated. This stub is basically an interface(SEI).
Also websphere needs additional files for implementing the webservices functionality, thus tge helper files.
This is basically the summary of it.

Can I use a SimpleJaxWsServiceExporter with a javax.servlet.Filter?

I would like to set up a webservice endpoint using Spring's SimpleJaxWsServiceExporter for ease of use, but I also need to protect the webservice using a subclass of Jespa's HttpSecurityFilter
I suspect this does not work out of the box as SimpleJaxWsServiceExporter is using a separate HTTP server to the host webapp containing the filter - how should I accomplish this?
I have a class annotated with #WebService and in my applicationContext.xml
<bean class="org.springframework.remoting.jaxws.SimpleJaxWsServiceExporter"
p:baseAddress="http://localhost:9581/"/>
I found a couple of alternative ways to host the endpoint within the same HTTP server (behind the filter)
Either using JAX-WS WSSpringServlet and registering my #WebService beans via the wss:binding xml tag under the http://jax-ws.dev.java.net/spring/servlet namespace, or my preferred option, as JAX-WS Spring integration has Maven dependencies on Spring 2, using CXF.

Developing Web services applications from existing WSDL files

I have done this on Websphere (re: title of this topic) using wsdl2java for generating wsdl to java mapping xml file.
My endpoint is a generic stateless EJB. The code in EJB is generated by traversing the each wsdl and getting the wsdl operation and stuck it in the generated remote EJB interface.
Each EJB method impl is generic and handles all the services the same.
Used instructions on this doc to do this on WAS: http://publib.boulder.ibm.com/infocenter/wasinfo/v7r0/index.jsp?topic=/com.ibm.websphere.base.doc/info/aes/ae/twbs_devwbsjaxrpcwsdl.html
Now, I am asking you all for help if anyone has done something similar in Sun AS 9.1.
Starting from existing WSDL (and xsd) files. Knowing the sole EJB service endpoint implementation for each services are the same, and generating an EAR file (webservices.xml, ejb-jar.xml, etc).
Have struggled with wscompile and alike, but not getting anyware in the same fashion I did for WebSphere.
Thanks for help.
You want to create a WS client which runs under Sun AS? I don't know Sun AS in detail and I don't know the WS libraries it supplies. But you may want to use a public WS library:
Apache Axis 2
Apache CXF
For every library there is documentation which describes how to create a project from WSDL.
You could even use Eclipse to create a project from WSDL for you: File -> New -> Other... -> Web Services -> WSDL. Make sure you have the "WST Web Services" Plugins installed.
I've never used it myself, but I just recently read about the wsdlLocation() attribute of the WebService annotation, which is supposed to map the service to a preexisting WSDL document (not sure if you're even using EJB3, though).

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