We have a really old application hanging around. It is on the block to be re-written. But since it is very complex the rewrite keeps getting put off.
Now I need to know if there is a way to get a Delphi 5 application to call a WCF web service?
I know WCF was not even a glimmer in its inventor's eye when Delphi 5 was released... but can it be done? If so, how?
You can communicate to WCF web services using SOAP over HTTP. Delphi 5 does support SOAP to some extent, but in my experience its early implementation isn't especially compatible with .NET 2.0 (or higher) WSDL. You might wish to try importing the WSDL and see what Delphi makes of it - but I wouldn't get your hopes up.
If that doesn't work, underneath it all it's just a bunch of web requests, so it's theoretically possible to do what you're asking using your own marshalling routines (on top of Indy HTTP, for example). The question is - how easy will it be to marshall your requests + the responses into data structures that you can manipulate in Delphi 5?
An alternative strategy that you might consider would be writing a proxy/wrapper in a suitable language (i.e. something .NET) and expose a more Delphi-5-friendly interface.
Delphi 5 doesn't support calling web-services out of the box, as that feature was introduced with Delphi 6.
The Delphi support for web-services got updated around the Delphi 2005/2006 era to be compatible with newer SOAP versions (used for instance in .NET 2.0 and higher).
RemObjects have an alternative implementation for web-services in Delphi (and a lot more communication stuff), but they don't support Delphi 5.
Delphi 5 can perform HTTP requests and use XML, so you could build your own stuff based on that. It'd take at least days, if not weeks to do that in a generic way, but a specific solution that works only for one web-service call could be doable in a shorter time frame.
WCF web services are just web services, right? Given that your WCF service is using http for transport you should be able to treat it like any other web service. Really even in regards to whether it's a SOAP, REST or other formatted message passing is meaningless. If Delphi 5 can call a web service, it should be able to call a WCF service.
If you own the web service the story obviously gets even better.
Related
I would like to use a technology that is used for communication between services and several thousands of clients. I came to know of WCF and read a little about it. While it looks attractive and has no interoperability issues, i would like to know about other leading technologies which can give me the same features as WCF ? Are there any open source technologies out there ? Also, which is the most widely used technology? I just want this information before i commit myself to WCF.
EDIT: By alternative to WCF, i mean to say that i am looking for a framework that will help me to implement a webservice in linux or any other platform. For example, the wcf simplifies the process of creating a webservice by the use of hard coded .NET applications. Similarly, i need a tool in linux. I came across mono,but found out that it is not complete and not very reliable.
I also provide an Open Source WCF alternative in ServiceStack A modern, code-first, DTO-driven, WCF replacement web services framework encouraging code and remote best-practices for creating DRY, high-perfomance, scalable REST web services.
There's no XML config, or code-gen and your one clean C# web service is enabled all JSON, XML, SOAP, JSV, CSV, HTML endpoints are enabled out-of-the-box. It includes generic sync/async service clients providing a fast, typed, client/server communication gateway end-to-end.
I don't think there is any .net framework with comparable features. But the core protocols of WCF such as WSDL/SOAP are not Microsoft specific so it's not as if you're tying yourself into a particular protocol, you're just choosing an implementation.
To put it another way if you choose to migrate away from .net in the future then I would say the WCF migration would be one of the easiest parts. But if you stay with .net WCF is almost certainly going to be the best implementation available given the investment Microsoft has in it (Azure is built on WCF for example).
i'm about to begin a WP7 project. i currently have a WCF REST service deployed on my LIVE servers, and my Android and iPhone clients are happily consuming this. how do i get my WP7 to communicate with my REST service? The server side is working fine and well, and there is no issue there.
what i thought i would be able to do was simply add my client library (compiled in SL) with all the interfaces, datacontracts etc, create a ChannelFactory, ensure the web behavior was on in the client and yay! away we go. this doesn't seem to be the case however. certainly i can't use the interface created because of the WebGetAttribute reference :S
what is the reccomended way? i would prefer to consume my service in the same way as the other services do for consistency, so i don't want to make new (and more verbose communication) bindings and simply expose the same service over a different endpoint. similarly using WebClient / WebHttpRequest just seems a bit backward: certainly we don't have to parse the response for the other types of bindings available, why would we for this?
any suggestions? basically i want to write as little code as possible to connect the client and the server (ideally as much as normal WCF communication would take) and would prefer to communicate with a channel, since there'd be no parsing or deserializing the JSON response on my behalf.
surely this is possible? most people working on mobile applications have chosen a REST service to communicate with, seems a bit odd that microsoft's mobile solution wouldn't neatly integrate with its own server side solution! i really hope i'm just stupid and have missed something quite glaring.
I believe at this point RESTSharp is your best option.
Another REST Client library: Spring.Rest
I have a web service that is used by many different clients using many different languages.
I want to switch it to wcf to take advantage of the many different endpoints.
However what has been stopping me is that I am afraid that the clients will have to use a special sdk to connect (if they are using java or php or some other language) that is different then the sdk they use to connect to the existing web service.
Is this true? Or is connecting to WCF the exact same as it is for web services in other languages.
The project I am currently working on has multiple WCF configurations, some are using the default SOAP implementation, and some are using a POX (plain-old-xml) style message.
So the short answer is 'yes' you can configure WCF in such a way to work with just about anything.
However, be warned that as soon as you step outside the default little box that WCF has set up for you, it gets pretty complicated. You end up with a lot of custom message parsing and security handling if you go to a POX message format. Its easier if you stick with SOAP though.
As for needing a 'special SDK' you won't. You can communicate with WCF with simple HTTP POST messages if needed.
I have clients that are using VB.NET apps (using SOAP) and Java apps (using POX) to hit my WCF services.
A basicHttpBinding endpoint in WCF is exactly a standard SOAP endpoint, and your Java or PHP clients will not have to change in any way.
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
A .net desktop application will send information to a central server, there will be potentially thousands and thousands of deskop apps sending info to my server(s).
The data will be small in size.
Would .net web services be good for this scenerio or would WCF be better suited?
What are the pros/cons?
I'd go with a WCF REST-based service, because you'll be able to transmit pure data without the overhead of the SOAP header (and other envelope nonsense) that comes with the SOAP-based classic .asmx web service.
the possibilities for throttling, concurrency, etc. are far more developed within wcf.
its a little bit more work in the beginning, but i guess that it's better suited for scenarios where you need to have full control over your bindings.
WCF is a more robust approach to SOA. Microsoft is committed to making it the primary framework for building the next wave of Microsoft business applications. The functionality available already, early in its lifecycle, is superior to plain old web services. It's only going to get better. By going with WCF early, you will be able to ride the wave and take advantage of future new functionality.
In some cases depends on the type and amount of data to send.
WCF will give you more options to tweak your calls.
On the other hand, I can't think of advantages of implementing asp.net web services over WCF. In WCF you could also implement plain 'old' web services
ASMX is like remoting, it's still around because it shipped with 1.0, but you shouldn't use it anymore if you are starting a new project. WCF will give you many more features and better tooling support.