I've some confusions about ReST clients and need a bit of help.
For ReST, does the service provider give WSDL document or not? If not, how does the client will know what kind of JSON data to expect? When I invoke the rest client, I will recieve the JSON/XML response in a string format which I'll need to convert it into a Java object(or Javascript, if using on client side) to do any meaningful tasks with the response. So it seems like I, as a client developer, need to know the WSDL or the Schema definition so that I can build a java object similar to the JSON response I'm expecting. But if you go by this answer, generating a client class based on the service definition flies directly in the face of ReST fullness. If that is the case, how do I go about creating my client code?
WADL/Web Application Description Language is not a standard but is gaining popularity for REST APIs contract definition.
The Web Application Description Language (WADL) is a machine-readable
XML description of HTTP-based web applications (typically REST web
services).1 WADL models the resources provided by a service and the
relationships between them.1 WADL is intended to simplify the reuse
of web services that are based on the existing HTTP architecture of
the Web.1[2] It is platform and language independent and aims to
promote reuse of applications beyond the basic use in a web
browser.
For documentation:
https://github.com/wordnik/swagger-core/tree/master/modules/swagger-jaxrs
For client code:
https://github.com/wordnik/swagger-ui
You integrate the library and annotate your resources and online documentation is generated on the fly.
You also need a client for which you can integrate the ui.
The dynamically generated REST client looks something like this:
http://petstore.swagger.wordnik.com/
Related
We have currently implemented SOAP endpoints with CXF (Spring Boot). In accordance with the contract-first approach, we provide a WSDL, generate Java objects, and services from it (cxf-codegen-plugin) and finally implement the service interface.
This is all very nice and simple, but we only need the SOAP XML or the corresponding DOM tree. Not only is the conversion to Java objects unnecessary, we also have to convert them back to XML and lose some information from the original XML.
As far as I understand is SAAJ (SOAP with Attachments API for Java) exactly right here, or am I missing something? At most all resources about SAAJ are quite old and "low level". I cannot find good resources for that kind of approach.
In addition, we want to implement new services as microservices soon and are currently reviewing Quarkus and Apache Camel. However, I cannot find a (simple) way to create corresponding endpoints from the WSDLs, via which we then receive the SOAP message as plain XML / DOM tree.
In jax-ws, message-level access can be accomplished on the server side using web service Provider-based endpoints, and on the client side using Dispatch clients.
A web service Provider-based endpoint offers a dynamic alternative to the Java service endpoint interface (SEI)-based endpoint. Unlike the SEI-based endpoint that abstracts the details of converting between Java objects and their XML representation, the Provider interface enables you to access the content directly at the XML message level—without the JAXB binding. web service Provider-based endpoints can be implemented synchronously or asynchronously using the javax.xml.ws.Provider or com.sun.xml.ws.api.server.AsyncProvider interfaces, respectively.
See https://cxf.apache.org/docs/provider-services.html for details
I am learning web services in Java. I would like to know the uses for the following 4 classes with the help of a very simple use case - WebServiceFeature, AddressingFeature, MTOMFeature, RespectBindingFeature.
Suppose, I am publishing a web service which will list all States in the United States. How would I utilize these 4 classes?
Java API for XML-Based Web Services (JAX-WS) Version 2.1 introduced the concept of features as a way to programmatically control specific functions and behaviors.
WebServiceFeature as per Java Doc
A WebServiceFeature is used to represent a feature that can be enabled or disabled for a web service.
The JAX-WS specification will define some standard features and JAX-WS implementors are free to define additional features if necessary. Vendor specific features may not be portable so caution should be used when using them.
AddressingFeature as per Java Doc
AddressingFeature represents the use of WS-Addressing with either the SOAP 1.1/HTTP or SOAP 1.2/HTTP binding. Using this feature with any other binding is undefined.
This feature can be used during the creation of SEI proxy, and Dispatch instances on the client side and Endpoint instances on the server side. This feature cannot be used for Service instance creation on the client side.
MTOMFeature as per Java Doc
This feature represents the use of MTOM with a web service.
Also
JAX-WS supports the use of SOAP Message Transmission Optimized Mechanism (MTOM) for sending binary attachment data. By enabling MTOM, you can send and receive binary data optimally without incurring the cost of data encoding needed to embed the binary data in an XML document.
RespectBindingFeature as per Java Doc
This feature clarifies the use of the wsdl:binding in a JAX-WS runtime. This feature can be used during the creation of SEI proxy, and Dispatch instances on the client side and Endpoint instances on the server side. This feature cannot be used for Service instance creation on the client side.
This feature is only useful with web services that have an associated WSDL.
Use Cases - unfortunately, see the Java Docs - I only say unfortunately as with me developing web services for several years now - I've never needed to use "WebServiceFeature,AddressingFeature, MTOMFeature, RespectBindingFeature" - they're for niche use cases which I dont believe most developers need to deal with. The most beneficial one I see would be the MTOMFeature but if you simply want a web service that lists all of the United States - you wouldn't likely need anything that elaborate.
Some Use Case Findings
MTOM: Using JAX-WS, you can send binary attachments such as images or files along with web services requests. With your example of States - you could have a web service that request that sets/updates each a picture of the states state bird and a base64 encoded audio file of the state song - the picture and song could be MTOM attachments.
AddressingFeature: This looks like it's just used when either the web service or web service client need to use WS-Addressing. I'd imagine trying to integrate with a third party web service that requires the use of WS-Addressing in which case your client you write would need to specify it's use
RespectBindingFeature: You can use the RespectBindingFeature to control whether a JAX-WS implementation is required to respect the contents of a Web Services Description Language (WSDL) binding that is associated with an endpoint. By implementing the feature, RespectBindingFeature, you have specified to enforce adherence of the contents of a WSDL binding that is associated with an endpoint for your JAX-WS application. The actual enforcement of the use of the WSDL document specifications, when they are provided, at run time has not been well defined in versions of the JAX-WS specification previous to Version 2.1.
WebServiceFeature: this is the parent class for the other features. The use case I imagine would only be the facts that the sub-classes inherit from it.
I have started working on web application using jquery touch. My web services is written in soap and I want to call from my application. Can you suggest me how should I move ahead.
Is it possible to call from ajax?
While many people thinks that managing the complexity of SOAP in a JavaScript environment would be counter-productive, it could nevertheless be done, in particular if you are familiar with SOAP web-services and want to avoid the need to learn another middle-layer framework; a library that I would suggest is Apache-CXF support for JavaScript.
The CXF JavaScript client library is indeed a code generator which (with some limitations), in its easiest form, wsdl2js, gets a wsdl file and generates JavaScript
contructors - for an service
methods - for any service operation, and
objects - for any web service complex element/type
which can be directly called in your scripting. Other available tools generate the javascript code starting with the Java code server-side implementation (java2js), or on-the-fly (dynamic javascript).
Pros:
leverage a component of a widely used library for web-services implementation (CXF)
avoid another layer in the middle
easy to use (run the tools against the wsdl, load the generated sources)
Downsides:
client knows nothings about WS urls and ports; you need the URL at which the ws ranswers and thats'it
as a code generator, the JavaScript client generator is parallel to JAXB or JAX-WS. It defines a mapping from an abstract model of a web service to JavaScript objects. Unlike JAXB and JAX-WS, there is no committee that has standardized a 'JavaScript binding.' The CXF binding may not be to everyone's tastes.
Soap 1.1 only
No Authentication support
Using soap from the browser is technically possible, but a very bad idea. You'll spend all your time fighting to get the soap protocol to work correctly and you'll miss all the benefits of soap.
A much better approach would be to build a back end for your new web application using the framework of your choice, eg. J2EE, .Net or any other. All those platforms have nice soap libraries that will do the work for you. Then you will either generate the html pages on server (old school web site) or use a static page and expose the data as a JSON rest API (modern single page app).
In summary: soap is good for communicating between servers, terrible for communication with the browser.
I am doing a project using Java and BPEL. I successfully created webservices in Java and integrated them using BPEL. All i generated a single output WSDL file. Now, I have to use this output WSDL file in my application using SOAP communication. How can i do that? Is there any help out side for such scenarios? Walkthroughs are really appreciated..
Depending on the architecture of your application (Standard Java, Spring-based, ...) there might or not be a documented procedure to consume a SOAP-based webservice.
On the other hand, you're always free to pick a webservice development framework to handle that. For instance, you could pick either CXF or AXIS2 (I believe these are the two most popular frameworks for Java WebServices). Each of these frameworks provides a tool called "wsdl2java" that helps you generate client-side/server-side/both Java classes. Then, you can easily add those classes and the requireds libraries to your application.
Having used CXF in the past, It even does provide several way to consume a webservice
Generating the client-side classes
Using CXF dynamic client factory : basically, you'll retrieve an endpoint proxy from a factory object.
Hope that'll help
I start with SoapUI (or downloadable from sourceforge), that will let you consume the WSDL and fire off requests against your server. Typically I'm hitting someone else's webservice, and trying to figure out what the data looks like before I start wiring my code together, but in your case its just a verification that the services would be/are working.
Then, as #KHY said, you can automatically convert the wsdl into java with a wsdl2java and start coding (look under the Related list on the right panel of this SO screen)
If it is a Java application, then the easiest way to consume a service is using JAX-WS. It's really easy to create a Web service client from WSDL.
See this link
Once you deploy the BPEL project on server, then refer the WSDL with http://server:port/application/YourBPELProjectService?WSDL in the consuming application. You will need to write different client code based on the BPEL type - Synchronous, Asynchronous etc.
I am developing a web service in java and Metro that requires a lot of information to be passed. For example, something like xml describing all the attributes of a customer.
I am wondering if there is some standard way in which to pass the data in a document. Currently I have been passing the data as a string parameter named 'customerXML'.
Any suggestions appreciated. FYI I have defined another restful ws using RestEasy which works great using input/output streams, but am looking for a way to leverage soap-based web services to expose similar functionality.
JAX WS is perfect for this requirement, It works on SOAP
My hypothesis is that there isn't a standard way to pass xml documents to a soap-based web service without coding the entire SOAP message yourself. Hence I do not think there is an easy way to do so and one reason why RESTful web services are gaining acceptance. The best way to do it using SOAP based web services is to pass the document as a string parameter and validate/parse within your server code.