I have developed two java web services; one is SOAP based and the second one REST. Now I have to ask some clients (they can be either java/non java clients) to use my web services. Now what information do I need to pass to the clients to use my web service?
If SOAP, what should I share to clients to use my web service?
If REST, what should I share to clients to use my web service?
With SOAP, you should share the WSDL document that describes the service. This should be enough, but often isn't; the most common missing things are what type of security is required and what interaction patterns (i.e., how to string the methods together) should be used. Theoretically, WSDL can describe these things. Practically, you never see them in the wild. In fact, you're probably better off doing the interaction patterns by just documenting them properly in a human-readable document.
With REST, the ideal is often regarded as being just sharing the URL to the root page of the service, as the service should be self-describing to an extent whereby clients can find out what to do by just following links. This is the core of the HATEOAS principle. In practice, it is much more complex than that. Many JAX-RS implementations can publish service descriptions via a WADL document, which can help. The typical security models used with REST are more discoverable than with SOAP, but are still rather opaque even so, and interaction patterns remain problematic (prodding random stuff at a service in the hope that it works sucks, whether you're doing SOAP or REST or whatever).
Related
I know RESTful WS is an architecture all together, which is a new way of implementing Web Services over old fashioned JAX-RPC's.
In RESTful, we use #GET, #POST, etc to manage calls/develop resources. Same can be achieved using HTTP programming (both are stateless too).
But what are other core main uses or need for bringing/implementing RESTful? As everything we do in it, can be done using HTTP programming (in which we use same methods)?
The question is comparing different things. HTTP is a protocol, while REST is an architectural style. This is like asking what a house does that a brick doesn't. It doesn't make sense. HTTP can be a building block of a REST application.
REST is not about HTTP or any particular protocol. REST is about applying the successful design decisions of the Web itself to software development. The problem is terminology. 99.9% of the so called REST applications around the internet aren't really RESTful, because REST became a buzzword to refer to any HTTP API that isn't SOAP. Some REST advocates gave up on fighting for the proper usage of the term and now refer to REST applications as Hypermedia.
Like the Web, REST is intended for software development in the scale of decades. REST makes it easier to evolve your application without breaking clients. Think about how today you can still access websites that were created decades ago, and almost everything still works fine. If you're creating software that has long-term objectives in the scale of several years, then maybe REST is adequate for you. If that's not what you really need, then getting REST right is not important. Just use whatever works for you, and at this point I think nobody cares anymore if you call it REST.
The question is not "REST versus HTTP-Programing". REST is a higher concept on how to to create distributed web applications. HTTP is a concrete technology . REST defines some constraints which are considered as good practice.
HTTP is just a technology which is well suited to implement REST-Style services:
Addressability => in HTTP every resource can be addressed through a unique identifier (URI)
multiple Representations => every resource can have multiple representations (JSON, XML) - a HTTP-Request for instance can 'ask' for the right representation (via headers)
Common Interface => Instead of creating an application specific interface (Methodnames in SOAP) HTTP already provides an Interface: GET, PUT, POST, DELETE ...)
Stateless => HTTP-Requests are stateless by design
Hypermedia => The application state (client) is driven by examining the links contained in the representations
HTTP is a transfer protocol.
RESTful is a group of principles.
Basically a RESTful web service is a particular HTTP application that follow the following principles:
client server
stateless
cacheable
layered
I have read lot a whats are difference b/w soap and restful web services. I have got specific doubts for which i did not get answers. Here they are :-
What goes in favor of Restful web services
In nutshell everybody seems to be preferring Restful web services over soap. main reason behind it easy to develop and understand. Also faster mainly because of light weight data exchange format like json. Also in Performance in restful web services is better because less data is traveled over network(Soap involves extra layer of saop message under http request). So far so good.
Accepted answer at how is Restful web services better than SOAP based webservices also says
REST naturally fits for Web/Cloud API's, whilst SOAP fits for
distributed computing scenarios.
I did not get whats the difference between Web and distributed computing scenarios. Web is also case of distributed computing scenarios. Is n't it ? so how come one is better for web while another is for distributed scenarios ? (Q1)
What goes in favor of SOAP :-
Same answer also says that SOAP caters for stateful operations. As per my understanding its not true. If you need to maintain the state you need to maintain thru you code like sending some unique ID in both request/response that relates them Is n't it? (Q2) If thats the case that can be done in restful web services also.
Some says SOAP is better in terms of security. I don't what security soap provides that rest does not? (Q3)
Soap is probably is better in one sense that it has WSDL(that too generated by tools) doc thru which clients can generate their respective stubs. In restful webservices developer has to create the comprehensive doc himself so that client knows about the input request parameters. correct ? (Q4)
Note :- I have referred Q for question(Q1 is Question1)
There are 3 reasons to prefer REST over SOAP
Resources have URLS that identify them. If you want to share the result of some API operation with a friend, then you don't have to instruct them verbally on which API method to call and which parameters to pass. Instead, you can just share with him the URL. (for safe operations only). A great example is restaurant sites that are built in flash. If you just want to share with a friend the menu of the restaurant, you can't do that very easily. You can only tell him which buttons to press when the flash page loads.
With REST you can take advantage of the existing HTTP infrastructure on the internet to do a lot of work, i.e. caching, resource conflict management, and so on. You don't have to reinvent the wheel.
Related to #2, many developers are already used to working with REST architectures. If you use REST you significantly cut down on the learning curve that new devlopers will have to incur when learning how to use your service.
REST is cache-able for GET request. For SOAP, when using HTTP as the transfer mechanism, is sent via HTTP POST requests which are not cache-able.
I am planning to design such an architecture for my website as shown in picture above. I am building a core platform in Java that do the communication with DB and other high processing tasks and modules can hook up with the core by means of defined interfaces.
Modules could be anything like, front-end website, email box, admin consoles etc. and could be built on any technology like PHP, Java, ruby on rails etc.
Now tell me which communication protocol should I use for communication between modules and core. Protocol must be something that majority of languages understand and can be process easily in both way communication.
And if somebody find any flaws with such an architecture then kindly suggest a better one that provide great extensibility and flexibility.
I would use HTTP, exposing a REST API on the Core, such as Thilo suggested.
The complexity lies on the trade-offs between RPC (procedural model) of traditional webservices, and the Resource Model, which fits better when using http requests (verbs GET, POST, PUT and DELETE on URI's, complemented with some headers and a body).
Yet, this makes a soft, easy to maitain and portable ditribution. Every single client module may be built on a whole different technology, which allows you to use "the best tool for the job".
Not to mention HTTP advantages for caching, rewriting, load-balancing, ssl, etc.
So basically this is a SOA-like architekture. JavaEE and EJB (3+) or the Spring frameworks come to mind immediately.
The components (your "modules") are usually coupled via SOAP services with an optional Enterprise Service Bus (ESB) between frontend, backend and the composite services.
Whether this is a good match for your case or simply oversized... noone but you can say...
I am building websites in spring MVC. as there are many spring projects , i wanted know what will be scenario when spring web Services is used for.
i mean what can be done with that. Do i really need it for ecommerce site
Your question is really about "web services". For a layman's explanation of what it is all about, read this Wikipedia article.
There are a number of related acronyms that get bandied about:
SOAP (Simple Object Access Protocol) is a protocol for sending requests to a service and getting back a response. The messages are encoded in XML, and send over HTTP.
WSDL (Web Services Description Language) is a service description language for SOAP-based services. It does things like specify what is in the messages, and how the messages are bound to services.
SOA (Service Oriented Architecture) is essentially a system architecture in which the system consists of lots of SOAP services (and others) described using WSDL.
(The proponents of SOA talk about "design principles", but in my cynical view is that this is just a repackaging / recasting of stuff that people have been doing for 20+ years under other names.)
Do i really need it for ecommerce site
Ask your customers. Ask the people whose systems your system will be interfacing with. Ask the vendors whose components you intend to embed in your system.
If you have to use WS then what extra facility it will give
If you have to use WS (e.g. because your site needs to talk to other services that require WS), then you have to. That is sufficient justification.
If you don't have to use WS, then you need to balance the advantages of using WSDL + SOAP against the advantages of some other approach to implementing your web APIs. An SOA expert will probably say use SOA; an AJAX expert will probably say otherwise. And there are other remote procedure call technologies around ... if you really need that kind of thing.
WSDL + SOAP certainly does have some advantages; e.g.
machine readable specifications for your web APIs,
possibility of validation of messages against XML schemas,
an ecosystem of existing WSDL services,
adoption in some sectors of IT.
But it has downsides also; e.g.
WSDL + SOAP have a significant learning curve compared to some alternatives,
XML is a heavy-weight encoding scheme - relatively expensive to parse,
SOAP only pretends to be type-safe (compared with say CORBA / IIOP),
SOAP is not usually used* in browser-based clients; JSON or plain XML are commonly used for AJAX apps,
many people think SOA is over-hyped and steer clear.
* However, it can be used; read these IBM DeveloperWorks Articles.
My advice (FWIW) if your system is primarily a website, doesn't need to talk to SOAP services, and doesn't need to provide a SOAP service API for others .... don't bother. You can always add SOAP service APIs later if you need to.
Spring Web Services is a product of the Spring community focused on creating document-driven Web services. Spring Web Services aims to facilitate contract-first SOAP service development, allowing for the creation of flexible web services using one of the many ways to manipulate XML payloads.
More here : Spring Web Services
How to use Spring Web Service : Spring WS
If you don't know what Web Services are, you probably don't need them. Web Services are a way (speaking generally here) for one web application to talk to another. You can formulate a request as an xml document and send that xml to a web service, which is listening on a specific URL and port. The Web Service can then perform some action based on this document, and respond back with an XML document. It's commonly used as a means for integration between applications.
If you're building a simple e-commerce site, which does not integrate with other live web products, then likely you don't need Web Services. Spring Web Services is simply an API/library to make reading/writing web services easy.
This question already has answers here:
SOAP vs REST (differences)
(13 answers)
Closed 5 years ago.
For now I have a slight idea about the differences between SOAP and RESTful services.
My question is when I should use SOAP, and when I should use RESTful; which one is "better" when it comes to performance/speed or request handling?
I'm implementing it for the first time in RESTful (Java) and I want know more about it; I've dealt with SOAP before.
This is a follow-up question to this post.
REST is almost always going to be faster. The main advantage of SOAP is that it provides a mechanism for services to describe themselves to clients, and to advertise their existence.
REST is much more lightweight and can be implemented using almost any tool, leading to lower bandwidth and shorter learning curve. However, the clients have to know what to send and what to expect.
In general, When you're publishing an API to the outside world that is either complex or likely to change, SOAP will be more useful. Other than that, REST is usually the better option.
REST vs. SOAP Web Services
I am seeing a lot of new web services are implemented using a REST
style architecture these days rather than a SOAP one. Lets step back a
second and explain what REST is.
What is a REST web service?
The acronym REST stands for representational state transfer, and this
basically means that each unique URL is a representation of some
object. You can get the contents of that object using an HTTP GET, to
delete it, you then might use a POST, PUT, or DELETE to modify the
object (in practice most of the services use a POST for this).
Who's using REST?
All of Yahoo's web services use REST, including Flickr and Delicious.
APIs use it, pubsub, bloglines, Technorati, and both eBay, and Amazon
have web services for both REST and SOAP.
Who's using SOAP?
Google seams to be consistent in implementing their web services to
use SOAP, with the exception of Blogger, which uses XML-RPC. You will
find SOAP web services in lots of enterprise software as well.
REST vs. SOAP
As you may have noticed the companies I mentioned that are using REST
APIs haven't been around for very long, and their APIs came out this
year mostly. So REST is definitely the trendy way to create a web
service, if creating web services could ever be trendy (lets face it
you use soap to wash, and you rest when your tired). The main
advantages of REST web services are:
Lightweight - not a lot of extra XML markup Human Readable Results
Easy to build - no toolkits required. SOAP also has some advantages:
Easy to consume - sometimes Rigid - type checking, adheres to a
contract Development tools For consuming web services, its sometimes a
toss up between which is easier. For instance Google's AdWords web
service is really hard to consume (in ColdFusion anyway), it uses SOAP
headers, and a number of other things that make it kind of difficult.
On the converse, Amazon's REST web service can sometimes be tricky to
parse because it can be highly nested, and the result schema can vary
quite a bit based on what you search for.
Whichever architecture you choose make sure its easy for developers
to access it, and well documented.
Freitag, P. (2005). "REST vs SOAP Web Services". Retrieved from http://www.petefreitag.com/item/431.cfm on June 13, 2010
SOAP
Simple Object Access Protocol (SOAP) is a standard, an XML language, defining a message architecture and message formats. It is used by Web services. It contains a description of the operations.
WSDL is an XML-based language for describing Web services and how to access them. It will run on SMTP, HTTP, FTP, etc. It requires middleware support and well-defined mechanism to define services like WSDL+XSD and WS-Policy.
SOAP will return XML based data
REST
Representational State Transfer (RESTful) web services. They are second-generation Web services.
RESTful web services communicate via HTTP rather than SOAP-based services and do not require XML messages or WSDL service-API definitions. For REST middleware is not required, only HTTP support is needed. It is a WADL standard, REST can return XML, plain text, JSON, HTML, etc.
REST is an architecture.
REST will give human-readable results.
REST is stateless.
REST services are easily cacheable.
SOAP is a protocol. It can run on top of JMS, FTP, and HTTP.
REST has no WSDL (Web Description Language) interface definition.
REST is over HTTP, but SOAP can be over any transport protocols such as HTTP, FTP, SMTP, JMS, etc.
REST stands for representational state transfer whereas SOAP stands for Simple Object Access Protocol.
SOAP defines its own security where as REST inherits security from the underlying transport.
SOAP does not support error handling, but REST has built-in error handling.
REST is lightweight and does not require XML parsing. REST can be consumed by any client, even a web browser with Ajax and JavaScript. REST consumes less bandwidth, it does not require a SOAP header for every message.
REST is useful over any protocol which provide a URI. Ignore point 5 for REST as mentioned below in the picture.
REST vs. SOAP
SOAP:
► SOAP is simple object access protocol that run on TCP/UDP/SMTP.
► SOAP read and write request response messages in XML format.
► SOAP uses interface in order to define the services.
► SOAP is more secure as it has its own security and well defined standards.
► SOAP follows RPC and Document style to define web services.
► SOAP uses SOAP-UI as client tools for testing.
REST
► REST is representational state transfer that uses underlying HTTP protocols.
► REST is stateless.
► REST is an architectural style that is used to describe and define web services.
► REST can read and write request response messages in JSON/XML/Plain HTML.
► REST uses URI for each resource that is used in web service.A resource can be image text method etc.
► REST uses set of verbs, like HTTP's GET, POST, PUT, DELETE.
► REST is easy to develop and easy to manage as compared to SOAP UI.
► REST has light-weight client tools or plugins that can easily be integrated inside a browser.
► REST services are cacheable.
Difference between REST and SOAP:
SOAP Web services:
If your application needs a guaranteed level of reliability and security then SOAP offers additional standards to ensure this type of operation.
If both sides (service provider and service consumer) have to agree on the exchange format then SOAP gives the rigid specifications for this type of interaction.
RestWeb services:
Totally stateless operations: for stateless CRUD (Create, Read, Update, and Delete) operations.
Caching situations: If the information needs to be cached.
SOAP web service always make a POST operation whereas using REST you can choose specific HTTP methods like GET, POST, PUT, and DELETE.
Example: to get an item using SOAP you should create a request XML, but in the case of REST you can just specify the item id in the URL itself.
REST is easier to use for the most part and is more flexible. Unlike SOAP, REST doesn’t have to use XML to provide the response. We can find REST-based Web services that output the data in the Command Separated Value (CSV), JavaScript Object Notation (JSON) and Really Simple Syndication (RSS) formats.
We can obtain the output we need in a form that’s easy to parse within the language we need for our application.REST is more efficient (use smaller message formats), fast and closer to other Web technologies in design philosophy.