What does a Web service really mean ? I am not looking for a theoretical explanation, I am looking for something practical.
I was thinking that anything I can call from an external client is a Web service, so a basic PHP which returns JSON data could be a Web service.
But then I started reading about Web services in W3Schools.org and I got confused. If the PHP URL which returns JSON data is a web service, why would I need to do SOAP, WDSL etc ... to create a Web service. Isn't it extra work?
Also, if SOAP is the way data is sent back and forth, what about other transport types?
What differentiates a RESTful Web service from a SOAP based web service?
When you are talking about a webservice people generally misunderstand what it means, a webservice is simply a way to interact between a and b that abstracts the use of local technology standards. A WSDL defines the way in which the SOAP message is being sent over the channel. REST uses JSON over HTTP, WSDL uses SOAP over HTTP.
The advantage of a webservice is, say you develop one piece of code in .net and you wish to use JAVA to consume this code. You can interact directly with the abstracted layer and are unaware of what technology was used to develop the code.
SOA is a set of design paradigms and standards that tell you how to develop your services, in SOA each service is meant to comply with the principles listed below. WSDL is generally linked with but not essential for a SOA solution. If you wish to learn about SOA google "Thomas Erl SOA".
Priciples of SOA
Standardized service contract
Service loose coupling
Service abstraction
Service reusability
Service autonomy
Service statelessness
Service discoverability
Service composability
This Q&A Restful vs Other Web Services brings a lot of light to what is a webserver, and differences from SOAP and REST. Id recommend to read all the answers (many of them are very good).
Related
Right now I'm working in WebApi (trainee developer), and have good knowledge in webapi . But , I don't know anything about WebServices.
My Questions are :
1.What is WebServices?
2.What is the Use of WebServices?
3.Instead of WebServices why we are using WebApi.
4.Where we can use WebServices?
5.At a time We Can use both Webservices and WebApis?
Exposing the Existing Function on the network
A web service is a unit of managed code that can be remotely invoked using HTTP. That is, it can be activated using HTTP requests. Web services allow you to expose the functionality of your existing code over the network. Once it is exposed on the network, other applications can use the functionality of your program.
Interoperability
Web services allow various applications to talk to each other and share data and services among themselves. Other applications can also use the web services. For example, a VB or .NET application can talk to Java web services and vice versa. Web services are used to make the application platform and technology independent.
Standardized Protocol
Web services use standardized industry standard protocol for the communication. All the four layers (Service Transport, XML Messaging, Service Description, and Service Discovery layers) use well-defined protocols in the web services protocol stack. This standardization of protocol stack gives the business many advantages such as a wide range of choices, reduction in the cost due to competition, and increase in the quality.
Low Cost Communication
Web services use SOAP over HTTP protocol, so you can use your existing low-cost internet for implementing web services. This solution is much less costly compared to proprietary solutions like EDI/B2B. Besides SOAP over HTTP, web services can also be implemented on other reliable transport mechanisms like FTP
For Example in Asp.Net Core : https://dzone.com/articles/step-by-step-aspnet-core-restful-web-service-devel
So I have currently been assigned to read about Web Services. I was going through the differences between REST, XML-RPC and SOAP and came across this particular link :
REST vs XML-RPC vs SOAP
It mentions this following, in terms of authentication and authorization
As for authentication and authorization, SOAP places the burden in the hands of the application developer. The REST methodology instead takes into account the fact that Web servers already have support for these tasks. Through the use of industry-standard certificates and a common identity management system, such as an LDAP server, developers can make the network layer do all the heavy lifting.
I was not able to understand this particular reference. Can some one explain how this happens in detail?
A web service is method or mechanism to communicate between different applications using open standard such as XML, WSDL, and SOAP. Using web service different device or program communicates over network
Type of WebService
SOAP Web Service
RESTFul Web Service
more information you can check :http://entityclass.in/rest/home.htm
I am new to web services. I am studying it through various sites. Got confused for below query.
Why do we need client to test SOAP web services, but not for REST?
Thank You :)
Cheers!!!
Nitin
The short answer is "you don't mandatory need client to work with SOAP web services, and you may wish to use a client for ReST service".
Having a SOAP client makes things much simpler. In case of SOAP web service there's thing called WSDL, where your client can get all the information about this service - classes, operations, etc... all together called service contract. Based on this knowledge, a decent client will present you with user-friendly UI to make SOAP calls and display output. But, again, if you're skilled (and crazy) enough, you can do it even through telnet command.
The ReST is more general term. Actually SOAP web services can be referred to as ReST level 0 services. Since ReST is more general, by definition there are more general rules. For example, there's no common rule where to get service contract. On the other hand, ReST services nowadays are written the way that they can be simply consumed from e.g. JavaScript. This means that you can use tools like Postman or DHC Chrome extensions to make requests and see results - and they will work as a client to your ReST service.
Webservices like REST, SOAP which provides services which is made available for web application, as we know it can receives values as JSON, string, XML etc either by POST or GET and in the same way it can return data as JSON, string, XML etc.
The same thing can be done via servlet, as servlet can receive data as string, JSON etc either by POST or GET and in the same way it can return data as JSON, string, XML etc.
We need libraries based upon the web service we use, such as SOAP or REST, servlet libraries are almost in-built int it.
So whats the difference between Servlet and Web Services? Which one is more faster?
Can anyone please tell me some solution for this.
This is the kind of discussion that can lead to a lot of flame wars on semantics, but I would say web services are simply a method of communication utilizing standards to allow different technologies to be interoperable. Like an English-speaker translating between a French- and German-speaker.
Meanwhile, the way to implement web service endpoints (the places that serve responses to your requests) in a Java web server is with servlets. So servlets are simply a technology for implementing web service communication (in the JVM).
When you look at JAX-WS and JAX-RS, the frameworks that implement these standards are simply creating abstractions on top of Java's HttpServlet (typically) to make SOAP and REST web services easier to build by taking care of a lot of the low-level details.
Hope that helps.
where are a lot of difference between servlets and web services, but the main is:
in the web development servlets is the front end object and work in the web container, Web services can have different roles: as backend or as middle layer object.
There are 2 types of web-services as I know. First one is custom xml formatted messages and the second one SOAP standard xml messages. What are the differences between them? Which one is better, what are pros and cons of each of that two approaches?
By "ordinary" I assume you mean RESTful services. This discussion would be a long one, so I'll try to give you some key points:
RESTful services are the most used flavor of Web Services. They are closely linked to the functionality and principles of HTTP and can be accessed as simple as a GET request (other operations are POST, DELETE and PUT). The core concept is the "resource" which is identified by an URI. Common formats for REST are XML and JSON. It's a pretty straightforward and easy to use technology, which is what makes it so widely available.
SOAP web services are based on XML, most of them adhering to the RPC-style of app design (calling remote methods on a server and getting a response), and use 3 main pillars:
WSDL - Web Service Description Language - used to describe a service in terms of available operations, parameters, etc.
SOAP - Simple Object Access Protocol - used to construct interaction messages between the entities involved (client, server).
UDDI - Universal Description, Discovery and Integration - used to classify and publish available web services to a repository and enable discovery by potential users.
SOAP Web Services tend to have high overhead and generally have very verbose messages, but may be good if you need to implement more complex functionality and interaction in your application.
Strictly speaking only the Soap services are webservices. They are based on the WS-* Specs standardisized by W3C and Oasis. Sometimes a also reffered as Webservice are so called POX-Endpoint (Plain old XML) or REST Endpoint, which allows you to simply get a raw XML via HTTP GET.
SOAP Services carry their schema in form of a wsdl endpoint (usualy append ?wsdl to the service endpoint), so there a lots of tools to create proxy objects and hide the complexity of the webservice call. With POX Services you need to know which schema to use from e.g. the documentation.
SOAP Services carry the payload inside the SOAP Envelope (an XML Schema with header and body with the payload in the body). Having a header independent from the payload allows to reroute the content, sign and encrypt, authenticate etc. without knowing the content. But you pay by additional overhead in the message itself.
POX on the other hand leaves all that to the webserver and relies usualy on HTTP for authentification and compression. Encription and signing had to be done by your system. It is low overhead but also low discoverability.
Whats works best for you depends a lot on your scenario. If you work in a .Net or Java World, you often find it simplest to create a proxy and use that to work with the webservices as remote objects. You get a well build infrastructure and a comfortable programming experience. If youre environment does not support the proxy generation or if it had to be called from anything, POX might the very much more lightweight way to go.
"Web Service" refers to a more abstract and general concept. We can say that anything that can be served on web is a Web Service. SOAP Web Services or RESTful services are special kind of Web Services which has wide acceptance and has their own standards. While SOAP services are built on a new XML based standard, RESTful approach makes use of existing HTTP methods, hence more widely accepted (to my experience).