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Is REST a better approach to doing Web Services or is SOAP? Or are they different tools for different problems? Or is it a nuanced issue - that is, is one slightly better in certain arenas than another, etc?
I would especially appreciate information about those concepts and their relation to the PHP-universe and also modern high-end web-applications.
I built one of the first SOAP servers, including code generation and WSDL generation, from the original spec as it was being developed, when I was working at Hewlett-Packard. I do NOT recommend using SOAP for anything.
The acronym "SOAP" is a lie. It is not Simple, it is not Object-oriented, it defines no Access rules. It is, arguably, a Protocol. It is Don Box's worst spec ever, and that's quite a feat, as he's the man who perpetrated "COM".
There is nothing useful in SOAP that can't be done with REST for transport, and JSON, XML, or even plain text for data representation. For transport security, you can use https. For authentication, basic auth. For sessions, there's cookies. The REST version will be simpler, clearer, run faster, and use less bandwidth.
XML-RPC clearly defines the request, response, and error protocols, and there are good libraries for most languages. However, XML is heavier than you need for many tasks.
REST is an architecture, SOAP is a protocol.
That's the first problem.
You can send SOAP envelopes in a REST application.
SOAP itself is actually pretty basic and simple, it's the WSS-* standards on top of it that make it very complex.
If your consumers are other applications and other servers, there's a lot of support for the SOAP protocol today, and the basics of moving data is essentially a mouse-click in modern IDEs.
If your consumers are more likely to be RIAs or Ajax clients, you will probably want something simpler than SOAP, and more native to the client (notably JSON).
JSON packets sent over HTTP is not necessarily a REST architecture, it's just messages to URLs. All perfectly workable, but there are key components to the REST idiom. It is easy to confuse the two however. But just because you're talking HTTP requests does not necessarily mean you have a REST architecture. You can have a REST application with no HTTP at all (mind, this is rare).
So, if you have servers and consumers that are "comfortable" with SOAP, SOAP and WSS stack can serve you well. If you're doing more ad hoc things and want to better interface with web browsers, then some lighter protocol over HTTP can work well also.
REST is a fundamentally different paradigm from SOAP. A good read on REST can be found here: How I explained REST to my wife.
If you don't have time to read it, here's the short version: REST is a bit of a paradigm shift by focusing on "nouns", and restraining the number of "verbs" you can apply to those nouns. The only allowed verbs are "get", "put", "post" and "delete". This differs from SOAP where many different verbs can be applied to many different nouns (i.e. many different functions).
For REST, the four verbs map to the corresponding HTTP requests, while the nouns are identified by URLs. This makes state management much more transparent than in SOAP, where its often unclear what state is on the server and what is on the client.
In practice though most of this falls away, and REST usually just refers to simple HTTP requests that return results in JSON, while SOAP is a more complex API that communicates by passing XML around. Both have their advantages and disadvantages, but I've found that in my experience REST is usually the better choice because you rarely if ever need the full functionality you get from SOAP.
Quick lowdown for 2012 question:
Areas that REST works really well for are:
Limited bandwidth and resources. Remember the return structure is really in any format (developer defined). Plus, any browser can be used because the REST approach uses the standard GET, PUT, POST, and DELETE verbs. Again, remember that REST can also use the XMLHttpRequest object that most modern browsers support today, which adds an extra bonus of AJAX.
Totally stateless operations. If an operation needs to be continued, then REST is not the best approach and SOAP may fit it better. However, if you need stateless CRUD (Create, Read, Update, and Delete) operations, then REST is it.
Caching situations. If the information can be cached because of the totally stateless operation of the REST approach, this is perfect.That covers a lot of solutions in the above three.
So why would I even consider SOAP? Again, SOAP is fairly mature and well-defined and does come with a complete specification. The REST approach is just that, an approach and is wide open for development, so if you have the following then SOAP is a great solution:
Asynchronous processing and invocation. If your application needs a guaranteed level of reliability and security then SOAP 1.2 offers additional standards to ensure this type of operation. Things like WSRM – WS-Reliable Messaging.
Formal contracts. If both sides (provider and consumer) have to agree on the exchange format then SOAP 1.2 gives the rigid specifications for this type of interaction.
Stateful operations. If the application needs contextual information and conversational state management then SOAP 1.2 has the additional specification in the WS* structure to support those things (Security, Transactions, Coordination, etc). Comparatively, the REST approach would make the developers build this custom plumbing.
http://www.infoq.com/articles/rest-soap-when-to-use-each
SOAP currently has the advantage of better tools where they will generate a lot of the boilerplate code for both the service layer as well as generating clients from any given WSDL.
REST is simpler, can be easier to maintain as a result, lies at the heart of Web architecture, allows for better protocol visibility, and has been proven to scale at the size of the WWW itself. Some frameworks out there help you build REST services, like Ruby on Rails, and some even help you with writing clients, like ADO.NET Data Services. But for the most part, tool support is lacking.
SOAP is useful from a tooling perspective because the WSDL is so easily consumed by tools. So, you can get Web Service clients generated for you in your favorite language.
REST plays well with AJAX'y web pages. If you keep your requests simple, you can make service calls directly from your JavaScript, and that comes in very handy. Try to stay away from having any namespaces in your response XML, I've seen browsers choke on those. So, xsi:type is probably not going to work for you, no overly complex XML Schemas.
REST tends to have better performance as well. CPU requirements of the code generating REST responses tend to be lower than what SOAP frameworks exhibit. And, if you have your XML generation ducks lined up on the server side, you can effectively stream XML out to the client. So, imagine you're reading rows of database cursor. As you read a row, you format it as an XML element, and you write that directly out to the service consumer. This way, you don't have to collect all of the database rows in memory before starting to write your XML output - you read and write at the same time. Look into novel templating engines or XSLT to get the streaming to work for REST.
SOAP on the other hand tends to get generated by tool-generated services as a big blob and only then written. This is not an absolute truth, mind you, there are ways to get streaming characteristics out of SOAP, like by using attachments.
My decision making process is as follows: if I want my service to be easily tooled by consumers, and the messages I write will be medium-to-small-ish (10MB or less), and I don't mind burning some extra CPU cycles on the server, I go with SOAP. If I need to serve to AJAX on web browsers, or I need the thing to stream, or my responses are gigantic, I go REST.
Finally, there are lots of great standards built up around SOAP, like WS-Security and getting stateful Web Services, that you can plug in to if you're using the right tools. That kind of stuff really makes a difference, and can help you satisfy some hairy requirements.
I know this is an old question but I have to post my answer - maybe someone will find it useful. I can't believe how many people are recommending REST over SOAP. I can only assume these people are not developers or have never actually implemented a REST service of any reasonable size. Implementing a REST service takes a LOT longer than implementing a SOAP service. And in the end it comes out a lot messier, too. Here are the reasons I would choose SOAP 99% of the time:
1) Implementing a REST service takes infinitely longer than implementing a SOAP service. Tools exist for all modern languages/frameworks/platforms to read in a WSDL and output proxy classes and clients. Implementing a REST service is done by hand and - get this - by reading documentation. Furthermore, while implementing these two services, you have to make "guesses" as to what will come back across the pipe as there is no real schema or reference document.
2) Why write a REST service that returns XML anyway? The only difference is that with REST you don't know the types each element/attribute represents - you are on your own to implement it and hope that one day a string doesn't come across in a field you thought was always an int. SOAP defines the data structure using the WSDL so this is a no-brainer.
3) I've heard the complaint that with SOAP you have the "overhead" of the SOAP Envelope. In this day and age, do we really need to worry about a handful of bytes?
4) I've heard the argument that with REST you can just pop the URL into the browser and see the data. Sure, if your REST service is using simple or no authentication. The Netflix service, for instance, uses OAuth which requires you to sign things and encode things before you can even submit your request.
5) Why do we need a "readable" URL for each resource? If we were using a tool to implement the service, do we really care about the actual URL?
Need I go on?
Most of the applications I write are server-side C# or Java, or desktop applications in WinForms or WPF. These applications tend to need a richer service API than REST can provide. Plus, I don't want to spend any more than a couple minutes creating my web service client. The WSDL processing client generation tools allow me to implement my client and move on to adding business value.
Now, if I were writing a web service explicitly for some javascript ajax calls, it'd probably be in REST; just for the sake knowing the client technology and leveraging JSON. In my opinion, web service APIs used from javascript probably shouldn't be very complex, as that type of complexity seems to be better handled server-side.
With that said, there some SOAP clients for javascript; I know jQuery has one. Thus, SOAP can be leveraged from javascript; just not as nicely as a REST service returning JSON strings. So if I had a web service that I wanted to be complex enough that it was flexible for an arbitrary number of client technologies and uses, I'd go with SOAP.
I'd recommend you go with REST first - if you're using Java look at JAX-RS and the Jersey implementation. REST is much simpler and easy to interop in many languages.
As others have said in this thread, the problem with SOAP is its complexity when the other WS-* specifications come in and there are countless interop issues if you stray into the wrong parts of WSDL, XSDs, SOAP, WS-Addressing etc.
The best way to judge the REST v SOAP debate is look on the internet - pretty much all the big players in the web space, google, amazon, ebay, twitter et al - tend to use and prefer RESTful APIs over the SOAP ones.
The other nice approach to going with REST is that you can reuse lots of code and infratructure between a web application and a REST front end. e.g. rendering HTML versus XML versus JSON of your resources is normally pretty easy with frameworks like JAX-RS and implicit views - plus its easy to work with RESTful resources using a web browser
I'm sure Don Box created SOAP as a joke - 'look you can call RPC methods over the web' and today groans when he realises what a bloated nightmare of web standards it has become :-)
REST is good, simple, implemented everywhere (so more a 'standard' than the standards) fast and easy. Use REST.
I think that both has its own place. In my opinion:
SOAP: A better choice for integration between legacy/critical systems and a web/web-service system, on the foundation layer, where WS-* make sense (security, policy, etc.).
RESTful: A better choice for integration between websites, with public API, on the TOP of layer (VIEW, ie, javascripts taking calls to URIs).
One thing that hasn't been mentioned is that a SOAP envelope can contain headers as well as body parts. This lets you use the full expressiveness of XML to send and receive out of band information. REST, as far as I know, limits you to HTTP Headers and result codes.
(otoh, can you use cookies with a REST service to send "header"-type out of band data?)
Don't overlook XML-RPC. If you're just after a lightweight solution then there's a great deal to be said for a protocol that can be defined in a couple of pages of text and implemented in a minimal amount of code. XML-RPC has been around for years but went out of fashion for a while - but the minimalist appeal seems to be giving it something of a revival of late.
Answering the 2012 refreshed (by the second bounty) question, and reviewing the today's results (other answers).
SOAP, pros and cons
About SOAP 1.2, advantages and drawbacks when comparing with "REST"... Well, since 2007
you can describe REST Web services with WSDL,
and using SOAP protocol... That is, if you work a little harder, all W3C standards of the web services protocol stack can be REST!
It is a good starting point, because we can imagine a scenario in which all the philosophical and methodological discussions are temporarily avoided. We can compare technically "SOAP-REST" with "NON-SOAP-REST" in similar services,
SOAP-REST (="REST-SOAP"): as showed by L.Mandel, WSDL2 can describe a REST webservice, and, if we suppose that exemplified XML can be enveloped in SOAP, all the implementation will be "SOAP-REST".
NON-SOAP-REST: any REST web service that can not be SOAP... That is, "90%" of the well-knowed REST examples. Some not use XML (ex. typical AJAX RESTs use JSON instead), some use another XML strucutures, without the SOAP headers or rules. PS: to avoid informality, we can suppose REST level 2 in the comparisons.
Of course, to compare more conceptually, compare "NON-REST-SOAP" with "NON-SOAP-REST", as different modeling approaches. So, completing this taxonomy of web services:
NON-REST-SOAP: any SOAP web service that can not be REST... That is, "90%" of the well-knowed SOAP examples.
NON-REST-NEITHER-SOAP: yes, the universe of "web services modeling" comprises other things (ex. XML-RPC).
SOAP in the REST condictions
Comparing comparable things: SOAP-REST with NON-SOAP-REST.
PROS
Explaining some terms,
Contractual stability: for all kinds of contracts (as "written agreements"),
By the use of standars: all levels of the W3C stack are mutually compliant. REST, by other hand, is not a W3C or ISO standard, and have no normatized details about service's peripherals. So, as I, #DaveWoldrich(20 votes), #cynicalman(5), #Exitos(0) said before, in a context where are NEED FOR STANDARDS, you need SOAP.
By the use of best practices: the "verbose aspect" of the W3C stack implementations, translates relevant human/legal/juridic agreements.
Robustness: the safety of SOAP structure and headers. With metada communication (with the full expressiveness of XML) and verification you have an "insurance policy" against any changes or noise. SOAP have "transactional reliability (...) deal with communication failures. SOAP has more controls around retry logic and thus can provide more end-to-end reliability and service guarantees", E. Terman.
Sorting pros by popularity,
Better tools (~70 votes): SOAP currently has the advantage of better tools, since 2007 and still 2012, because it is a well-defined and widely accepted standard. See #MarkCidade(27 votes), #DaveWoldrich(20), #JoshM(13), #TravisHeseman(9).
Standars compliance (25 votes): as I, #DaveWoldrich(20 votes), #cynicalman(5), #Exitos(0) said before, in a context where are NEED FOR STANDARDS, you need SOAP.
Robustness: insurance of SOAP headers, #JohnSaunders (8 votes).
CONS
SOAP strucuture is more complex (more than 300 votes): all answers here, and sources about "SOAP vs REST", manifest some degree of dislike with SOAP's redundancy and complexity. This is a natural consequence of the requirements for formal verification (see below), and for robustness (see above). "REST NON-SOAP" (and XML-RPC, the SOAP originator) can be more simple and informal.
The "only XML" restriction is a performance obstacle when using tiny services (~50 votes): see json.org/xml and this question, or this other one. This point is showed by #toluju(41), and others. PS: as JSON is not a IETF standard, but we can consider a de facto standard for web software community.
Modeling services with SOAP
Now, we can add SOAP-NON-REST with NON-SOAP-REST comparisons, and explain when is better to use SOAP:
Need for standards and stable contracts (see "PROS" section). PS: see a typical "B2B need for standards" described by #saille.
Need for tools (see "PROS" section). PS: standards, and the existence of formal verifications (see bellow), are important issues for the tools automation.
Parallel heavy processing (see "Context/Foundations" section below): with bigger and/or slower processes, no matter with a bit more complexity of SOAP, reliability and stability are the best investments.
Need more security: when more than HTTPS is required, and you really need additional features for protection, SOAP is a better choice (see #Bell, 32 votes). "Sending the message along a path more complicated than request/response or over a transport that does not involve HTTP", S. Seely. XML is a core issue, offering standards for XML Encryption, XML Signature, and XML Canonicalization, and, only with SOAP you can to embed these mechanisms into a message by a well-accepted standard as WS-Security.
Need more flexibility (less restrictions): SOAP not need exact correspondence with an URI; not nedd restrict to HTTP; not need to restrict to 4 verbs. As #TravisHeseman (9 votes) says, if you wanted something "flexible for an arbitrary number of client technologies and uses", use SOAP.PS: remember that XML is more universal/expressive than JSON (et al).
Need for formal verifications: important to understand that W3C stack uses formal methods, and REST is more informal. Your WSDL (a formal language) service description is a formal specification of your web services interfaces, and SOAP is a robust protocol that accept all possible WSDL prescriptions.
CONTEXT
Historical
To assess trends is necessary historical perspective. For this subject, a 10 or 15 years perspective...
Before the W3C standardization, there are some anarchy. Was difficult to implement interoperable services with different frameworks, and more difficult, costly, and time consuming to implement something interoperable between companys.
The W3C stack standards has been a light, a north for interoperation of sets of complex web services.
For day-by-day tasks, like to implement AJAX, SOAP is heavy... So, the need for simple approaches need to elect a new theory-framework... And big "Web software players", as Google, Amazon, Yahoo, et al, elected the best alternative, that is the REST approach. Was in this context that REST concept arrived as a "competing framework", and, today (2012's), this alternative is a de facto standard for programmers.
Foundations
In a context of Parallel Computing the web services provides parallel subtasks; and protocols, like SOAP, ensures good synchronization and communication. Not "any task": web services can be classified as
coarse-grained and embarrassing parallelism.
As the task gets bigger, it becomes less significant "complexity debate", and becomes more relevant the robustness of the communication and the solidity of the contracts.
It's nuanced.
If you need to have other systems interface with your services, than a lot of clients will be happier with SOAP, due to the layers of "verification" you have with the contracts, WSDL, and the SOAP standard.
For day-to-day systems calling into systems, I think that SOAP is a lot of unnecessary overhead when a simple HTML call will do.
I am looking at the same, and i think,
they are different tools for different problems.
Simple Object Access Protocol (SOAP) standard an XML language defining a message architecture and message formats, is used by Web services it contain a description of the operations. WSDL is an XML-based language for describing Web services and how to access them. will run on SMTP,HTTP,FTP etc. Requires middleware support, well defined mechanisam to define services like WSDL+XSD, WS-Policy SOAP will return XML based data SOAP provide standards for security and reliability
Representational State Transfer (RESTful) web services. they are second generation Web Services. RESTful web services, communicate via HTTP than SOAP-based services and do not require XML messages or WSDL service-API definitions. for REST no middleware is required only HTTP support is needed.WADL Standard, REST can return XML, plain text, JSON, HTML etc
It is easier for many types of clients to consume RESTful web services while enabling the server side to evolve and scale. Clients can choose to consume some or all aspects of the service and mash it up with other web-based services.
REST uses standard HTTP so it is simplerto creating clients, developing APIs
REST permits many different data formats like XML, plain text, JSON, HTML where as SOAP only permits XML.
REST has better performance and scalability.
Rest and can be cached and SOAP can't
Built-in error handling where SOAP has No error handling
REST is particularly useful PDA and other mobile devices.
REST is services are easy to integrate with existing websites.
SOAP has set of protocols, which provide standards for security and reliability, among other things, and interoperate with other WS conforming clients and servers.
SOAP Web services (such as JAX-WS) are useful in handling asynchronous processing and invocation.
For Complex API's SOAP will be more usefull.
REST is an architecture invented by Roy Fielding and described in his dissertation Architectural Styles and the Design of Network-based Software Architectures. Roy is also the main author of HTTP - the protocol that defines document transfer over the World Wide Web. HTTP is a RESTful protocol. When developers talk about "using REST Web services" it is probably more accurate to say "using HTTP."
SOAP is a XML-based protocol that tunnels inside an HTTP request/response, so even if you use SOAP, you are using REST too. There is some debate over whether SOAP adds any significant functionality to basic HTTP.
Before authoring a Web service, I would recommend studying HTTP. Odds are your requirements can be implemented with functionality already defined in the spec, so other protocols won't be needed.
I am looking at the same issue. Seems to me that actually REST is quick and easy and good for lightweight calls and responses and great for debugging (what could be better than pumping a URL into a browser and seeing the response).
However where REST seems to fall down is to do with the fact that its not a standard (although it is comprised of standards). Most programming libraries have a way of inspecting a WSDL to automatically generate the client code needed to consume a SOAP based services. Thus far consuming REST based web services seems a more adhoc approach of writing an interface to match the calls that are possible. Making a manual http request then parsing the response. This in itself can be dangerous.
The beauty of SOAP is that once a WSDL is issued then business' can structure their logic aorund that set contract any change to the interface will change the wsdl. There isnt any room for manouvre. You can validate all requests against that WSDL. However because a WSDL doesnt properly describe a REST service then you have no defined way of agreeing on the interface for communication.
From a business perspective this does seem to leave the communication open to interpretation and change which seems like a bad idea.
The top 'Answer' in this thread seems to say that SOAP stands for Simple Object-oriented Access Protocol, however looking at wiki the O means Object not Object-oriented. They are different things.
I know this post is very old but thought I should respond with my own findings.
It's a good question... I don't want to lead you astray, so I'm open to other people's answers as much as you are. For me, it really comes down to cost of overhead and what the use of the API is. I prefer consuming web services when creating client software, however I don't like the weight of SOAP. REST, I believe, is lighter weight but I don't enjoy working with it from a client perspective nearly as much.
I'm curious as to what others think.
Listen to this podcast to find out. If you want to know the answer without listening, then OK, its REST. But I really do recommend listening.
My general rule is that if you want a browser web client to directly connect to a service then you should probably use REST. If you want to pass structured data between back-end services then use SOAP.
SOAP can be a real pain to set up sometimes and is often overkill for simple web client and server data exchanges. Unfortunately, most simple programming examples I've seen (and learned from) somewhat reenforce this perception.
That said, SOAP really shines when you start combining multiple SOAP services together as part of a larger process driven by a data workflow (think enterprise software). This is something that many of the SOAP programming examples fail to convey because a simple SOAP operation to do something, like fetch the price of a stock, is generally overcomplicated for what it does by itself unless it is presented in the context of providing a machine readable API detailing specific functions with set data formats for inputs and outputs that is, in turn, scripted by a larger process.
This is sad, in a way, as it really gives SOAP a bad reputation because it is difficult to show the advantages of SOAP without presenting it in the full context of how the final product is used.
SOAP embodies a service-oriented approach to Web services — one in which methods (or verbs) are the primary way you interact with the service. REST takes a resource-oriented approach in which the object (or the noun) takes center stage.
In sense with "PHP-universe" PHP support for any advanced SOAP sucks big time. You will end up using something like http://wso2.com/products/web-services-framework/php/ as soon as you cross the basic needs, even to enable WS-Security or WS-RM no inbuilt support.
SOAP envelope creation I feel is lot messy in PHP, the way it creates namespaces, xsd:nil, xsd:anytype and old styled soap Services which use SOAP Encoding (God knows how's that different) with in SOAP messages.
Avoid all this mess by sticking to REST, REST is nothing really big we have been using it since the start of WWW. We realized only when this http://www.ics.uci.edu/~fielding/pubs/dissertation/top.htm paper came out it shows how can we use HTTP capabilities to implement RESTFul Services. HTTP is inherently REST, that doesn't mean just using HTTP makes your services RESTFul.
SOAP neglects the core capabilities of HTTP and considers HTTP just as an transport protocol, hence it is transport protocol independent in theory (in practical it's not the case have you heard of SOAP Action header? if not google it now!).
With JSON adaption increasing and HTML5 with javascript maturing REST with JSON has become the most common way of dealing with services. JSON Schema has also been defined can be used for enterprise level solutions (still in early stages) along with WADL if needed.
PHP support for REST and JSON is definitely better than existing inbuilt SOAP support it has.
Adding few more BUZZ words here SOA, WOA, ROA
http://blog.dhananjaynene.com/2009/06/rest-soa-woa-or-roa/
http://www.scribd.com/doc/15657444/REST-White-Paper
by the way I do love SOAP especially for the WS-Security spec, this is one good spec and if someone thinking in Enterprise JSON adaption definetly need to come with some thing similar for JSON, like field level encryption etc.
One quick point - transmission protocol and orchestration;
I use SOAP over TCP for speed, reliability and security reasons, including orchestrated machine to machine services (ESB) and to external services. Change the service definition, the orchestration raises an error from the WSDL change and its immediately obvious and can be rebuilt/deployed.
Not sure you can do the same with REST - I await being corrected or course!
With REST, change the service definition - nothing knows about it until it returns 400 (or whatever).
If you are looking for interoperability between different systems and languages, I would definately go for REST. I've had a lot of problems trying to get SOAP working between .NET and Java, for example.
i create a benchmark for find which of them are faster!
i see this result:
for 1000 requests :
REST took 3 second
SOAP took 7 second
for 10,000 requests :
REST took 33 second
SOAP took 69 second
for 1,000,000 requests :
REST took 62 second
SOAP took 114 second
An old question but still relevant today....due to so many developers in the enterprise space still using it.
My work involves designing and developing IoT (Internet of Things) solutions. Which includes developing code for small embedded devices that communicate with the Cloud.
It is clear REST is now widely accepted and useful, and pretty much the defacto standard for the web, even Microsoft has REST support included throughout Azure. If I needed to rely on SOAP I could not do what I need to do, as is just too big, bulky and annoying for small embedded devices.
REST is simple and clean and small. Making it ideal for small embedded devices. I always scream when I am working with a web developer who sends me a WSDLs. As I will have to begin an education campaign about why this just isn't going to work and why they are going to have to learn REST.
1.From my experience. I would say REST gives you option to access the URL which is already built. eg-> a word search in google. That URL could be used as webservice for REST.
In SOAP, you can create your own web service and access it through SOAP client.
REST supports text,JSON,XML format. Hence more versatile for communicating between two applications. While SOAP supports only XML format for message communication.
I read some questions already posted here regarding Soap and Rest
and I didn't find the answer I am looking for.
We have a system which has been built using Soap web services.
The system is not very performant and it is under discussion
to replace all Soap web services for REST web services.
Somebody has argued that Rest has a better performance.
I don't know if this is true. (This was my first question)
Assuming that this is true, is there any disadvantage using
REST instead of Soap? (Are we loosing something?)
Thanks in advance.
Performance is broad topic.
If you mean the load of the server, REST has a bit better performance because it bears minimal overhead on top of HTTP. Usually SOAP brings with it a stack of different (generated) handlers and parsers. Anyway, the performance difference itself is not that big, but RESTful service is more easy to scale up since you don't have any server side sessions.
If you mean the performance of the network (i.e. bandwidth), REST has much better performance. Basically, it's just HTTP. No overhead. So, if your service runs on top of HTTP anyway, you can't get much leaner than REST. Furthermore if you encode your representations in JSON (as opposed to XML), you'll save many more bytes.
In short, I would say 'yes', you'll be more performant with REST. Also, it (in my opinion) will make your interface easier to consume for your clients. So, not only your server becomes leaner but the client too.
However, couple of things to consider (since you asked 'what will you lose?'):
RESTful interfaces tend to be a bit more "chatty", so depending on your domain and how you design your resources, you may end up doing more HTTP requests.
SOAP has a very wide tool support. For example, consultants love it because they can use tools to define the interface and generate the wsdl file and developers love it because they can use another set of tools to generate all the networking code from that wsdl file. Moreover, XML as representation has schemas and validators, which in some cases may be a key issue. (JSON and REST do have similar stuff coming but the tool support is far behind)
SOAP requires an XML message to be parsed and all that <riduculouslylongnamespace:mylongtagname>extra</riduculouslylongnamespace:mylongtagname> stuff to be sent and receieved.
REST usually uses something much more terse and easily parsed like JSON.
However in practice the difference is not that great.
Building a DOM from XMLis usually done a superfast superoptimised piece of code like XERCES in C++ or Java whereas most JSON parsers are in the roll your own or interpreted catagory.
In fast network environment (LAN or Broadband) there is not much difference between sending a one or two K versus 10 to 15 k.
You phrase the question as if REST and SOAP were somehow interchangeable in an existing system. They are not.
When you use SOAP (a technology), you usually have a system that is defined in 'methods', since in effect you are dealing with RPC.
When you use REST (an architectural style, not a technology) then you are creating a system that is defined in terms of 'resources' and not at all in methods. There is no 1:1 mapping between SOAP and REST. The system architecture is fundamentally different.
Or are you merely talking about "RPC via URI", which often gets confused with REST?
I'm definitely not an expert when it comes to SOAP vs REST, but the only performance difference I know of is that SOAP has a lot of overhead when sending/receiving packets since it's XML based, requires a SOAP header, etc. REST uses the URL + querystring to make a request, and thus doesn't send that many kB over the wire.
I'm sure there are other ppl here on SO who can give you better and more detailed answers, but at least I tried ;)
One thing the other answers seem to overlook is REST support for caching and other benefits of HTTP. While SOAP uses HTTP, it does not take advantage HTTP's supporting infrastructure. The SOAP 1.1 binding only defines the use of the POST verb. This was fixed with version 1.2 with the introduction of GET bindings, however this may be an issue if using the older version or not using the appropriate bindings.
Security is another key performance concern. REST applications typically use TLS or other session layer security mechanisms. TLS is much faster than using application level security mechanisms such as WS Security (WS Security also suffers from security flaws).
However, I think that these are mostly minor issues when comparing SOAP and REST based services. You can find work arounds for either SOAP's or REST's performance issues. My personal opinion is that neither SOAP, nor REST (by REST I mean HTTP-based REST services) are appropriate for services requiring high throughput and low-latency. For those types of services, you probably want to go with something like Apache Thrift, 0MQ, or the myriad of other binary RPC protocols.
It all depends. REST doesn't really have a (good) answer for the situation where the request data may become large. I feel this point if sometimes overlooked when hyping REST.
Let's imagine a service that allows you to request informational data for thousands of different items.
The SOAP developer would define a method that would allow you retrieve the information for one or as many items as you like ... in a single call.
The REST developer would be concerned that his URI would become too long so he would define a GET method that would take a single item as parameter. You would then have to call this multiple times, once for each item, in order to get your data. Clean and easy to understand ... but.
In this case there would be a lot more round-trips required for the REST service to accomplish what can be done with a single call on the SOAP service.
Yes, I know there are workarounds for how to handle large request data in the REST scenario. For example you can pack stuff into the body of your request. But then you will have to define carefully (on both the server and the client side) how this is to be interpreted. In these situations you start to feel the pain that REST is not really a standard (like SOAP) but more of a way of doing things.
For situations where only relatively limited amount of data is exchanged REST is a very good choice. At the end of the day this is the majority of use cases.
Just to add a little to wuher's answer.
Http Header bytes when requesting this page using the Chrome web browser: 761
Bytes required for the sample soap message in wikipedia article: 299
My conclusion: It is not the size of bytes on the wire that allows REST to perform well.
It is highly unlikely that simply converting a SOAP service over to REST is going to gain any significant performance benefits. The advantage REST has is that if you follow the constraints then you can take advantage of the mechanisms that HTTP provides for producing scalable systems. Caching and partitioning are the tools in your toolbelt.
In general, a REST based Web service is preferred due to its simplicity, performance, scalability, and support for multiple data formats. SOAP is favored where service requires comprehensive support for security and transactional reliability.
The answer really depends on the functional and non-functional requirements. Asking the questions listed below will help you choose.
REf: http://java-success.blogspot.ca/2012/02/java-web-services-interview-questions.html
Does the service expose data or business logic? (REST is a better choice for exposing data, SOAP WS might be a better choice for logic).
Do the consumers and the service providers require a formal contract? (SOAP has a formal contract via WSDL)
Do we need to support multiple data formats?
Do we need to make AJAX calls? (REST can use the XMLHttpRequest)
Is the call synchronous or asynchronous?
Is the call stateful or stateless? (REST is suited for statless CRUD operations)
What level of security is required? (SOAP WS has better support for security)
What level of transaction support is required? (SOAP WS has better support for transaction management)
Do we have limited band width? (SOAP is more verbose)
What’s best for the developers who will build clients for the service? (REST is easier to implement, test, and maintain)
You don't have to make the choice, modern frameworks allow you to expose data in those formats with a minimum change. Follow your business requirements and load-test the specific implementation to understand the throughput, there is no correct answer to this question without correct load test of a specific system.
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Attended an interesting demo on REST today, however, I couldn't think of a single reason (nor was one presented) why REST is in anyway better or simpler to use and implement than a SOAP based Services stack.
What are some of the reasons Why anyone in the "real world" use REST instead of the SOAP based Services?
Less overhead (no SOAP envelope to wrap every call in)
Less duplication (HTTP already represents operations like DELETE, PUT, GET, etc. that have to otherwise be represented in a SOAP envelope).
More standardized - HTTP operations are well understood and operate consistently. Some SOAP implementations can get finicky.
More human readable and testable (harder to test SOAP with just a browser).
Don't need to use XML (well you kind of don't have to for SOAP either but it hardly makes sense since you're already doing parsing of the envelope).
Libraries have made SOAP (kind of) easy. But you are abstracting away a lot of redundancy underneath as I have noted. yes in theory SOAP can go over other transports so as to avoid riding atop a layer doing similar things, but in reality just about all SOAP work you'll ever do is over HTTP.
RESTful services are much simpler to consume than SOAP based (regular) services. The reason for this is that REST is based on normal HTTP requests which enables intent to be inferred from the type of request being made (GET = retrive, POST = write, DELETE = remove, etc...) and is completely stateless. On the other hand you could argue that it is less flexible as it does away with the concept of a message envelope that contains request context.
In my experience SOAP has been preferred for services within the enterprise and REST has been preferred for services that are exposed as public APIs.
With tools like WCF in the .NET framework it is very trivial to implement a service as REST or SOAP.
Some relevant reading:
Amazon Web Services Blog: REST vs SOAP
Dare Obasanjo writes often about REST
I'll assume that when you say "web services" you mean SOAP and the WS-* set of standards. (Otherwise, I could argue that REST services are "web services".)
The canonical argument is that REST services are a closer match to the design of the web - that is, the design of HTTP and associated infrastructure. Thus, using a REST service will be more compatible with existing web tools and techniques.
Of course, once you drill into specifics, you find out that both approaches have strengths in different scenarios. Is it those specifics that you're interested in?
The overhead isn't that important as good architecture.
REST isn't a protocol it is an architecture that encourage good scalable design.
It is often chosen because too much freedom in RPC can easily lead to a poor design.
The other reason is predictable cost of RESTful protocols over HTTP because it can leverage existing technologies (mainly proxies).
RPC initial cost is quite low but it tend to increase significantly with load intensification.
REST is implementation-agnostic and much more transparent, and this makes it great for public APIs, especially for big websites like Flickr, Amazon or Digg that are using their APIs as marketing tools and really want people to consume their data. They don't want to be hand-holding 1000s of novice developers who are trying to debug their scripting language of choice's buggy SOAP library.
Versus SOAP and WSDL, which are better for internal applications, where you have drop-in libraries and known clueful people on both ends. (And you maybe don't have to care about things like Internet-scale load-balancing, HTTP caching etc.) Then you get APIs that are self-documented, preserve types etc. with zero work.
Got to read Roy Fielding's most excellent dissertation on the topic. He makes an excellent case and was definitely WAY ahead of his time when he wrote it (2000).
Steve Vinoski's blog and his latest articles are definitely worth perusing. He's a former CORBA guru, who wrote probably the best book on the subject with Michi Henning, "Advanced CORBA® Programming with C++". However, he has since seen the error of his client/server ways, and now swears by REST.
REST allows your non-mutating operations (that generally use the GET verb) to be cached. That is, cached by the client and/or cached by proxies. This can be a huge win!
REST is basically just a way to implement web services. It is just a way to use HTTP correctly to query the web services you are trying to hit.
http://www.xfront.com/REST-Web-Services.html
http://en.wikipedia.org/wiki/Representational_State_Transfer
It is super simple and slim. You could do it with browser via http verb: GET.
I haven't find a browser can manually do generic http POST request easily
Here's one data point: Amazon offers its APIs in both REST and SOAP formats and 85% of the usage is REST.
REST is easier to implement, easier to understand and higher performance.