Message Format in WebService - web-services

What is meant by Message Format in WebService
I have been told that Message Format can be of two styles (RPC / Document )
Please tell me what is meant by Message Format and how it is actually related to the Web services ??

Message Exchanging Formats means the way in which the client XML structure should look like so that the provider can understand the document. there are 4 MEF's:
RPC-Encoded
RPC-literal
document-encoded (This combination is not recommended by WS-I BP 1.0 & 2.0)
document-literal
RPC-encoded is the default MEF for the JAX-RPC API and document-literal is the default MEF for the JAX-WS API

does RPC/Literal and Freedom of Choice help? or Which style of WSDL should I use?

Related

Support both SOAP 1.1 and 1.2 by same JAX-WS service

I have a JAX-WS #WebServiceProvider and would like to support both SOAP 1.1 and 1.2 protocols. I handle creation of response SOAPMessage of proper version manually. I have WSDL describing bindings for both, 1.1 and 1.2 protocol.
But the service endpoint is only able to support either version at a time.
I would appreciate either a solution or a pointer to a piece of doc where it's stated that it's impossible.
P.S. i'm using WebSphere 7 app server, which is bundled with JAX-WS 2.0 (which is Axis2 based)
I experienced the same problem. The main issue for me is that it is not possible to compile the class with both #BindingType(value = SOAPBinding.SOAP12HTTP_BINDING) and #BindingType(value = SOAPBinding.SOAP11HTTP_BINDING). Have a look to this http://www-01.ibm.com/support/docview.wss?uid=swg1PK96819, and this http://www-01.ibm.com/support/docview.wss?uid=swg1PK83482, it should be possible to set #BindingType(SOAPBinding.SOAP_HTTP_BINDING) to have the both SOAP version to be delivered. Unfortunaltely, i did not compile also with the Websphere runtime environment, what i don't understand.
I recently dealt with a service deployment issue related to trying to simultaneously enable both SOAP 1.1 and 1.2 for a service (on WebSphere v7.0). Unfortunately, I don't think that your question gives enough information to provide a specific solution.
It IS possible to support both bindings at the same time, but there are some considerations. I think the main thing is that the server has to be able to listen on separate endpoints (URLs) for each binding. As near as I can tell, this requires appropriate entries in your web.xml and/or your webservices.xml configuraiton files.
For an annotation based service, these configuration entries are theoretically optional; but when you try to enable multiple bindings for a given service without the "optional" configuration entries, the WAS Axis2 extension fails with various possible exceptions.
If you could provide more detail about your wsdl, and the relevant portions of web.xml and webservices.xml (if any), as well as any error messages reported in the WAS log(s) during deployment and application startup, then I could probably give a better answer.

Send/Receive a SOAP request using SPRING JAVA

I am new to Spring web services. I am going to create an xml request, and send it as a SOAP request to a web service and receive the response.I read different documents but still confused as I could not find a working sample yet.
I know that I should use WebServiceTemplate and WebServiceMessageSender, SaajSoapmessageFactory (please let me know if I am wrong) but not sure how to use them.
Do I need WSDL? if yes why?
If you have any sample code please send me to get clear on it.
Thanks
If you want to send SOAP requests, you would like to be a SOAP client. Seems like you want to use spring-ws project. Check out their great documentation on the client side. The same documentation will guide you through the process of creating a server. There are plenty of examples and ready-made configuration snippets waiting for you.
Spring-WS is built on top of XML Schema description of your message, so you will need WSDL to generate e.g. JAXB models of your requests and responses.
AFAIK, for "web services" , the WSDL file is the machine blueprint of the "ports" as they are called However! ports in WSDL "means" java language(or any other programming language used with a routine or sub or procedure or function) method and has a specific naming scheme associate the .wsdl xml file(template of the service). Each WSDL port(language method) has specifications of return value and data specifications for how to feed it arguments and their type values.

How non-SOAP web service clients knows about the structure of the response?

How non-SOAP (REST WS, HTTP WS) web service clients knows about the structure of the response?
I mean, is there a formal way?
No.
The "provider" of the service needs to provide some form of documentation for that service - what parameters are possible, what the response will look like.
This is one of the major drawbacks of non-SOAP services...
There are a few initiatives like WADL (Web Application Description Language) - but those are far from widely accepted and thus not really a valid alternative to WSDL.
Microsoft has also extended REST to include metadata used in WCF REST and the WCF Data Services to allow .NET client-side proxies that "know" about the REST calls and the parameters - but again, that's not really an industry standard that everyone follows.

What are WSDL, SOAP and REST?

What is WSDL? How is it related to SOAP? Where does REST fit in all of that?
A WSDL is an XML document that describes a web service. It actually stands for Web Services Description Language.
SOAP is an XML-based protocol that lets you exchange info over a particular protocol (can be HTTP or SMTP, for example) between applications. It stands for Simple Object Access Protocol and uses XML for its messaging format to relay the information.
REST is an architectural style of networked systems and stands for Representational State Transfer. It's not a standard itself, but does use standards such as HTTP, URL, XML, etc.
Example: In a simple terms if you have a web service of calculator.
WSDL: WSDL tells about the functions that you can implement or exposed to the client. For example: add, delete, subtract and so on.
SOAP: Where as using SOAP you actually perform actions like doDelete(), doSubtract(), doAdd(). So SOAP and WSDL are apples and oranges. We should not compare them. They both have their own different functionality.
Why we use SOAP and WSDL: For platform independent data exchange.
EDIT: In a normal day to day life example:
WSDL: When we go to a restaurant we see the Menu Items, those are the WSDL's.
Proxy Classes: Now after seeing the Menu Items we make up our Mind (Process our mind on what to order): So, basically we make Proxy classes based on WSDL Document.
SOAP: Then when we actually order the food based on the Menu's: Meaning we use proxy classes to call upon the service methods which is done using SOAP. :)
Every time someone mentions SOAP/WSDL, I think of objects and classes defined in xml...
"You use SOAP just the same way that you would any PHP class. However, in this case the class does not exist in the local applications file system, but at a remote site accessed over http."
...
"If we think of using a SOAP service as just another PHP class then the WSDL document is a list of all the available class methods and properties. "
http://www.doublehops.com/2009/07/07/quick-tutorial-on-getting-started-with-soap-in-php/comment-page-1/
..and whenever someone talks about REST I think of HTTP's commands (request methods) like POST, GET and DELETE
SOAP -> SOAP(Simple object access protocal) is the application level protocal created for machine to machine interaction. Protocol defines standard rules. All the parties who are using the particular protocol should adhere to the protocol rules. Like TCP, It unwinds at transport layer, The SOAP protocol will be understood by Application layer( any application which supports SOAP - Axis2, .Net).
WSDL -> SOAP message consist of SoapEnevelope->SoapHeader and SoapBody. It doesn't define what would be message format? what are all the transports(HTTP,JMS) it supports? without this info, It is hard for any client who wants to consume the particular web service to construct the SOAP message. Even if they do, they won't be sure, it'll work all the time. WSDL is the rescue. WSDL (Web Service description Language) defines the operations, message formats and transport details for the SOAP message.
REST -> REST(Representational state transfer) is based on the Transport. Unlike SOAP which targets the actions, REST concerns more on the resources. REST locates the resources by using URL (example -http://{serverAddress}/employees/employeeNumber/12345) and it depends on the transport protocol( with HTTP - GET,POST, PUT, DELETE,...) for the actions to be performed on the resources. The REST service locates the resource based on the URL and perform the action based on the transport action verb. It is more of architectural style and conventions based.
You're not going to "simply" understand something complex.
WSDL is an XML-based language for describing a web service. It describes the messages, operations, and network transport information used by the service. These web services usually use SOAP, but may use other protocols.
A WSDL is readable by a program, and so may be used to generate all, or part of the client code necessary to call the web service. This is what it means to call SOAP-based web services "self-describing".
REST is not related to WSDL at all.
SOAP stands for Simple (sic) Object Access Protocol. It was intended to be a way to do Remote Procedure Calls to remote objects by sending XML over HTTP.
WSDL is Web Service Description Language. A request ending in '.wsdl' to an endpoint will result in an XML message describing request and response that a use can expect. It descibes the contract between service & client.
REST uses HTTP to send messages to services.
SOAP is a spec, REST is a style.
Wikipedia says "The Web Services Description Language is an XML-based language that provides a model for describing Web services". Put another way, WSDL is to a web service, as javadoc is to a java library.
The really sweet thing about WSDL, though, is that software can generate a client and server using WSDL.
Some clear explanations (for SOAP and WSDL) can be found here as well.
Difference between a SOAP message and a WSDL?
REST is light-weight in terms of encoding, much more useful for light weight devices i.e. non strict APIs.
REST is format independent. XML, HTML, JSON all options are available.
REST provides abilities for on 2 point message transfer (not surprising since REST stands for REpresentational State Transfer) where WSDL/SOAP interaction is multiple point message interaction.
REST does not require a new extension for XML messages, where in WSDL/SOAP this is the case.
WSDL/SOAP uses multiple transport protocols, REST relies on only HTTP. Therefore WSDL/SOAP can be used like a RESTful way, however simple requests can be overly complicated/heavy weighted.
A simple analogy: REST is like a motoboy delivers your food easy and quick. XML extended WSDL/SOAP more like UPS delivery, more structured and serious stuff but comes with a cost.
A WSDL document describes a webservice. It specifies the location of the service and the methods of the service using these major elements:
data types using in webservice
data elements for each operation
describe the operations that can be performed and the messages envolved
SOAP (Simple Object Access Protocol) is a messaging protocol that allows programs that run on disparate operating systems to communicate using http and xml.

How to handle rpc/literal webservice with JAXB2 and Spring-WS

We need to access a legacy webservice that uses the RPC/literal webservice style and also to provide webservice endpoints for it. If you use webservices of document/literal style with Spring WebserviceTemplates / WebserviceEndpoints, you can use JAXB2 to generate / marshal / unmarshal the webservice requests. But how do you do this with RPC/literal style? The org.jvnet.jaxb2.maven2:maven-jaxb2-plugin does not seem to be able to generate Java classes for the requests / responses.
With rpc/literal you will be stuck in the dark ages of Axis 1.4
Spring-WS or Jax-WS won't help you here as the concentrate on WS-I Basic Profile compliant document/literal services.