I need some direction related to this topic; maybe I am missing the obvious.
I dont see a contrast between WCF bound to HTTP and strongly typed web service. Why would this be any different?? I agree there are some development nuances especially related to XmlSerializer in ASMX vs WCF and a plethora of Microsoft jargons. Short of these; i only see parallels
DataContract=WSDL Type
ServiceContract=WSDL (aka service definition)
OperationContract=WebMethod
Operationally, I understand the binding can be numerous with WCF instead of getting locked down to HTTP, which can involve heavy construct and tear down. But for loose coupling it will all be web services.
Are there other operational differences??
Can someone show me the light and put me out of my misery?? :))
Well, if you reduce your discussion to only HTTP, then there's still a slew of advantages that WCF has over ASMX:
more and better security settings (ability to use either transport or message security)
much more flexibility - a lot more can be configured and tweaked in WCF, either in configuration files or code
ASMX web services can only exist inside IIS - IIS is a must-have requirement; you can self-host your WCF services in a console app or Windows NT Service
the clear focus on using Service and Data Contracts in WCF makes for a much cleaner interface and a much better separation of concern (better code, in the end)
support for things like reliable messaging and transaction support (even over HTTP)
In short: even though the differences might be smaller when you restrain WCF to just HTTP, I still think it's superior and if you have the choice to start something new today, by all means, use WCF instead of ASMX!
Rick Strahl puts it very nicely in his blog post:
I would argue that using WCF for any new services is probably a good idea even if you stick with pure HTTP and SOAP because by creating your service with WCF you can decide later on to publish this same service using WAS and also provide the more high performance TCP/IP transport. Or you might be asked to provide some of the advanced features of WS- protocols like transactions, attachments, session management, encryption etc. By using WCF you are building your service with a view to the future so you can easily move up to other protocols-some of which may not even exist today. Certainly new technologies will come along in the future and WCF protects you somewhat through its abstraction layer and common API.*
Marc
Another point for the consumers of the ASMX web service, which ever platforms will consume the web service will have to implement a SOAP stack. If you're goal is for wide reaching consumption, WCF is preferable and will allow you to expose the WS in more universal ways.
The other big distinction between the two technologies is that Microsoft now considers both ASMX web services and XML Serializer to be "legacy technology", and is no longer fixing bugs in them.
Related
I've very new at WCF, and I'm creating a prototype application to learn, which might turn into a commercial application. I understand the very basics of WCF, and I have my application WCF functional, at a basic level.
What are some tips experienced WCF users can give regarding pitfalls and steps I can take to make the app rock solid, at least regarding the WCF layer?
Couple of points to ponder:
make sure to implement rock-solid exception handling on your server side - implement the IErrorHandler interface on each service, define proper fault contracts
make sure to enable WCF tracing on the server side - those message logs are eminently useful when diagnosing problems!
make sure to think about versioning - make sure to use namespaces for both your service contracts and data contracts that will allow you to distinguish later version from the older ones (by means of the contract namespace)
think hard about your production hosting - IIS seems like a logical choice, but it's typically plagued by too many issues and problems that you don't have if you self-host. It's a bit more work yourself to create all those hosts - but it pays off with increased stability and better control on your side
Use security for your web service, particularly those bindings that support digital certificates.
Ensure your web service is interoperable with other web service frameworks, so that potential clients do not necessary need to be created using .NET and WCF.
Allow for endpoints (methods) to be retired in case they become obsolete. This allows clients of your web service to be informed of these retired endpoints so that they can be updated accordingly. Your retired endpoint could inform callers of what endpoint they should be using instead.
i am new to WCF but i learn this recently and thought to share with you.
if you are hosting your services on IIS then its best practice to make this a new account that you can control the direct privileges too, since NT AUTHORITY\NETWORK SERVICE
uses the default and can have a bit higher level of permissions. You can change this under the Application Pool in IIS that your website hosting WCF is running as.
my2cents
at my workplace we are about to start a big project. My boss (a programmer, this is a startup) wishes to use ASMX webservices for this purpose. I do not want to start off a new program using deprecated technology and would like to show him this. I dislike WCF at this moment because it has such an extreme learning curve, but I'd rather learn it than use an unsupported technology.
The problem I'm having is that I can not find any practical list of cons and downfalls when compared to WCF so that I can convince my boss to not use them. And saying "it's not as powerful" is not an adequate explanation. What exactly can it not do that we may need it to do for a webservice that is not meant to be shared externally? (as in, we don't support third-parties using our webservices unless they are using one of our clients. )
In short:
ASMX is
limited to only HTTP as its transport
limited to only being hosted in IIS (no other alternative)
limited to very simple security
limited to SOAP 1.1
WCF is
more flexible in transports: you can use HTTP, NetTCP, MSMQ, many more
can be hosted in IIS, WAS, or self-hosted in a Windows Service, in a console app, in a Winforms or WPF app
has much more security options
supports a plethora of WS-* standards
can interoperate with SOAP 1.1 and SOAP 1.2
In short: WCF is ASMX done right - much more flexible, much more powerful, much more in every respect.
Here's another quite useful comparison of WCF and ASMX: Comparing ASMX and WCF
and last but not least, WCF is also better in terms of performance, as this quite extensive MSDN article quite nicely shows (including performance numbers and graphs): A Performance Comparison of Windows Communication Foundation (WCF) with Existing Distributed Communication Technologies
I've never understood why some people think that WCF is difficult to learn. Try this: create a new WCF Service Project in Visual Studio. Now look at the code. Compare that with the same code you get from creating a new ASMX project. It's not very different.
I have three words for you: WCF. WCF. WCF.
Here are another three about why you should choose WCF: Power. Versatility. Configurability.
ASMX is great if you want to get a quick and dirty web service up and running, although to be honest it only takes maybe a few minutes more to do a WCF one.
The WS-* are really hard to implement with asmx: transactions, reliable messaging, security... etc etc.
And later the bindings: you can change the communication just by configuration, the asmx is just http.
WF exposing services and AppFabric works over wcf.
I would not have doubts, today wcf is the best option for starting a project that needs services.
I am learning wcf but I have trouble understanding the benefits. Is there ever a time I would want to use traditional web services?
I read another thread with these benefits:
Opt in model for members using a certain attribute
Better security
No need to worry about binding (can't understand how this is true)
No need to worry about the xml
I read Programming WCF Services however this was an advanced book a bit like CLR via C#. I am now reading Learning WCF Services and will read Essential WCF (is recommended).
What would happen if I use a normal class to try to talk to a web/service reference? I know this sounds really naive, it's just my lack of experience in web services.
I am coding some WCF services so I am getting exposed to the specifics. They are interacting with a SOAP web service provided by my web host so I can get stats on my site. Is there anything wrong in this approach?
Thanks
WCF is a unified programming model for developing connected systems. What this means is that you use a single framework to develop service-oriented solutions. WCF allows you to keep your service implementation relatively unaware and care free of what's going on under the covers as far as how your service is consumed by clients and communication is handled. This allows you to take your service implementation and expose it in various ways by configuring it differently without touching your service implementation. This is the unified part. Without WCF, you have to get familiar with a framework specific for a particular communication technology such as ASP.NET asmx web service, .NET remoting, MSMQ etc and usually those frameworks impose on your service implementation and creep in such as using WebMethod attribute or having to derive from MarshallByRefObject object etc and you just can not take your service implementation and easily expose it over another communication stack. If I have a service that adds two numbers, why can it not be exposed over http or tcp easily without having to worry about low level details? This is the question in your post regarding binding. Binding allows you take a service and configure it so that it can be exposed over different transports and protocols using different encodings without ever touching your service implementation.
Is there ever a time I would want to use traditional web service?
Web service uses well defined, accepted, and used standards such as HTTP and SOAP. So if you want your service to be consumed by wide range of clients, then you would want to expose your service as a web service. WCF comes with pre-configured bindings out of the box that allows your service to be exposed as a web service easily: basicHttpBinding and wsHttpBinding. You may also want to consider RESTful services which is an architectural style that fits more natural with the HTTP model. WCF supports RESTful services as well
What would happen if I use a normal
class to try to talk to a web/service
reference? I know this sounds really
naive, it's just my lack of experience
in web services.
WCF service can expose the wsdl for a service just like ASP.NET asmx web service does. You can generate a client side proxy by simply adding a service reference to your client project. There is also a command line tool called svcutil that also generates the client side code that allows you to easily communicate with the service. The client side service class basically mirrors the service interface. You create an instance of the client side proxy for the service and then simply call methods on it just like any other .NET object. Under the covers, your method call will get converted to a message and sent over the wire to the server. On the server side, that message will get dispatched to the appropriate service method.
I hope this helps a bit.There are lots of online content such as videos on MSDN and channel 9 that you check out. The more you pound on it and expose yourself to it, the clearer WCF will get I am sure. Also, WCF is THE framework Microsoft recommends to develop connected system in .NET. The other technologies ASP.NET asmx, WSE, and .NET Remoting will most likely still be available going forward but may not be supported and developed further.
There are a number of existing approaches to building distributed applications. These include Web services, .NET Remoting, Message Queuing and COM Services. Windows Communication Foundation unifies these into a single framework for building and consuming services.
Here is a link from MSDN Why Use Windows Communication Foundation?
WCF is really the "new" standard and new generation of web service - and even more generally, communications - protocols and libraries for the .NET world.
Whenever you feel the need to have two systems talk to one another - think WCF. Whether that'll be behind the corporate firewall in your company LAN, whether it's across the internet, by means of a direct call or a delayed message queueing system - WCF is your answer. Mehmet has written a really nice summary of how WCF is the unification of a great many communication standards that existed in the Microsoft world before WCF.
I would think with the "Learning WCF" book, you should be a lot better off than with Programming WCF - that's quite advanced stuff already!
One of the mainstays of WCF is the architecture that you always talk to your service through a proxy - whether that service runs on the same machine using NetNamedPipe binding or halfway around the world in Down Under on a server - no difference, you always go through a proxy. That then also allows WCF to be so extensible - thanks to the proxy always being between the client (your application) and the service, it offers excellent ways of extending the behavior and the inner workings of WCF to your liking and needs.
WCF basically builds on SOAP communications - so interfacing and using existing SOAP services should be no problem at all. With the WCF REST Starter Kit and in the upcoming .NET 4.0 release cycle, WCF will also extend its reach into the REST style web communications, if that's ever going to be a requirement of yours.
All this really shows one of the biggest strenghts of WCF: it's a unified and extremely flexible and extensible communication framework, that can handle just about anything you throw at it. That alone is more than enough reason to learn WCF (which can be dauting at first, I agree!), and you won't regret the effort you put into this endeavor.
Marc
Have you a specific application you are writing for, or just getting your feet wet?
Google protocol buffers, is a very good choice of communications. John Skeet & Marc Gravell have both done C# implementations. See here
Recently I made the switch from using asmx web services to using wcf services, the transition is nearly finished, but I know I'm in for a lot of error checking and testing to make sure everything ported as expected.
My question is - so far I can only think of 1 good benefit to using wcf, and that is you get an easy way to implement a singleton web service.
Besides that I have to tell you, configuring a WCF Application seems way overly complicated, and I'll forever miss how easy it was to test asmx web services.
What other benefits are there to using WCF over ASMX web services?
more protocol options; ASMX is IIS and HTTP only - WCF gives you HTTP, NetTcp, MSMQ, IPC - you name it
you can write your service once, and expose it on multiple endpoints
self-hosting: you can host your WCF service in a console app, a Winforms app, a WPF app, or let it be handled by IIS/WAS - but you don't have to
a lot more options like reliable sessions, lot more security options
you don't have to deal with as much "plumbing goo" in WCF as you do in ASMX - you can concentrate on your business problem, and let the config and attributes handle all the gooey stuff you don't want to deal with
to name just a few.....
Search Google or Bing for "WCF vs ASMX" and I'm sure you'll find plenty more article, blog posts and comparisons.
ASMX has passed its time - WCF is the present and the future. It can do a lot more - therefore it's a bit more to learn.
But if you check out the right sources, like these two Dotnet Rocks TV shows (Keith Elder Demystifies WCF and Miguel Castro on Extreme WCF), I'm sure you'll get a quick and hopefully painless start into WCF!
Marc
WCF allows you detach service from the physical layout and protocols. For example, you can write one service and deploy it as either REST or SOAP, or whatever that may happen in the future. ASMX is great, but it's pretty much hardcoded to SOAP. Also the idea is that you can plug-in existing features like throttling just by changing preferences, which I haven't seen much benefit of.
I'm looking to understand when to use a WCF services instead of just using webclient or httpwebrequest. I guess I'm also looking to understand the difference between the design patterns that would be appropriate for both.
Are you talking about when to create a WCF service yourself (over web service), or when to consume an existing web service using WCF instead of .NET 2.0 ASMX clients?
As for creating a WCF service yourself:
Gives you a lot more options in terms of hosting (in an app, Windows Service, IIS, WAS)
Gives you a lot more security options
Gives you a lot more protocol options (besides just HTTP, you can also use WS-*, TCP, Named Pipes, MSMQ and more)
Allows you to write your service once, and expose it on multiple end-points with different protocols at the same time
As for using WCF to talk to an existing HTTP (ASMX) web service - I don't see a whole lot of massive benefits, except WCF uses more configuration over code, and it can be good to standardize on one way of doing things, if you already use other WCF services, anyway.
Marc
I'm currently using WCF for most of the things that I would use WebClient or HttpWebRequest/HttpWebResponse in the past. While there definitely is overhead for learing how to make calls to web methods using WCF, the extensibility of WCF and the abstraction it provides makes it a MUCH better candidate for these types of calls.
I've already used it to make calls to Akismet and RPX pretty easily.
To get started, I'd look at the section of the MSDN documentation titled "WCF Web Programming Object Model", located at:
http://msdn.microsoft.com/en-us/library/bb412204.aspx