I have been googling for quite some time now but cannot find a definite answer.
I want to consume a wcf service, whose address will be provided at runtime.
The user will enter the address of the wcf service at runtime.
During compilation I have no idea of the service contract or the data contract or the endpoints of the wcf service.
Could someone please let me know how to achieve this requirement ?
This was the original idea behind UDDI. Before making a call, the client would query some central repository and obtain the address, contracts, and bindings of the service endpoint. It would then use this information to assemble and call the channel.
Some ESBs work on this principal - the call to UDDI can also be logged centrally, so an audit is kept of all service calls made within the enterprise.
Microsoft implemented it's own UDDI server which can be integration into SCOM for this purpose.
Related
I added the service to the WCF Test Client app and I get Service Added Successfully, but I don't see any of the operations available.
This WCF service is already being consumed by several javascript charts, so I should be able to see something here.
What am I doing wrong?
By default, WCFTestclient doesn’t support call the Restful service by using a client proxy. WCF creates the Restful style service with WebHttpbinding. thereby the client proxy class generates nothing thought the service WSDL is available.
Besides, we are capable of making a successful call to the service by using a client proxy. please refer to the below link.
WCF: There was no endpoint listening at, that could accept the message
the above client proxy class is generated by adding service reference.
https://learn.microsoft.com/en-us/dotnet/framework/wcf/accessing-services-using-a-wcf-client
Here is a detailed exposition of WCFTestClient from Microsoft document.
https://learn.microsoft.com/en-us/dotnet/framework/wcf/wcf-test-client-wcftestclient-exe?redirectedfrom=MSDN
Feel free to let me know if there is anything I can help with.
as you can see, I am relatively new on SO please don't kill me after posting this question :) I will do my best to describe the dilemma I am currently in.
I am creating something like a "Guardian Service" that is hosted on Windows Azure inside a Worker Role. This service has external ports, that can be accessed via HTTPS to allow clients to call it's service methods.
The WCF service is meant to call other services hosted in other Worker Roles that have only internal ports open, and which can be accessed only through the use of the Guardian Service. That's the main idea. Similar to a proxy or something.
I read already an excellent article from Jim O'Neil, what the caveats are when you try to access internal service points from within other WCF Services hosted in worker Roles:
His blog Troubleshooting Endpoints on a WCF Web Role
This is not the point for this question, and totally clear to me how to do that.
I have no idea at the moment, how I could do this, without implementing every contract from every single service I want to make accessible from within the Guardian Service to the outside world.
There must be a better way to decouple those things.
Any tips are appreciated.
Thank you.
I do not know the exact requirements for your project but I would say that what you are looking for is WCF Routing. I've used it in the past to redirect requests for different versions of Workflow instances.
The way it works is completely transparent to the client connecting to its endpoint. The router implementation must decide where to send the requests to, based on the request data (message headers and body).
In your case, if you are using SOAP and namespaces correctly, you might be able to base your decision on the message soap address and then send the request to the correct endpoint. You could also look at the Action property of the message.
Some links that might be useful:
http://msdn.microsoft.com/en-us/library/ee517423.aspx
http://www.codeproject.com/Articles/227699/RoutingService-on-Azure
Can anyone please explain me how to discover a WCF service if you do not know the type of the service Interface.
I am very new to WCF services and I need to write an application to discover some WCF services hosted in the subnet.
I found that you need to specify the service interface in inorder to create a FindCriteria object.
FindCriteria criteria new FindCriteria(typeof(IService1)
Please explain me how this works generally.
This is not how discovery works. WCF discovery is based on WS-Discovery protocol. The protocol is for discovering service with known contract = discovery finds address of the service with known contract. If you don't know the contract you can't use WCF discovery. This is explained in WCF Discovery overview.
If you don't know the contract you don't know what service you are looking for so how would you like to automatically discover it and how would you like to use it?
You can create an empty findcriteria: new FindCriteria().
This will find all discoverable service endpoints.
If you just want to take a look at the service operations, you can use the wcf test client application usually located in "C:\Program Files\Microsoft Visual Studio 10.0\Common7\IDE\"
All you'll need is the address to the service and you'll be able to try its operations
You can define scopes in the service behavior to "classify" your service and define the scope and scopematch on the findcriteria for partial or full or none match...
I am developing a solution with multiple WCF services which all communicate among themselves, even though they are of different types. The services connect to one another through the ChannelFactory generic interface, and every service is hosted inside a ServiceHost.
My question is if it would be correct to use a callback contract among the servers to communicate with one another and if so how would such a solution look.
Currently I don't like the implementation because every service needs to host a couple of endpoints with different interfaces some for other services and some for other clients.
When I tried to implement the callback contract inside a service class that was hosted inside a ServiceHost it failed.
First of all, whenever you post a question saying, "it failed", you need to tell us in what way it failed. If there was an exception, then you need to post the entire exception, including all InnerException instances, by posting the result of ex.ToString().
To your problem, I'd implement a service contract that represents the part of each service that needs to talk to the other services. There would also be a callback contract associated with this service contract.
That way, it's as though each service operates a miniature service intended only for service-to-service communications. They can then each do their own thing with the information that is passed between the services.
I am learning WCF,one of the benefits of WCF is that you can use WCF even the client and service are not in the same network.Can anyone explain why?
Why using normal asp.net services, .NET remoting or Windows enterprise service client and service have to be in the same network?
Another question is that does the client needs to have a service contract interface and data contract? I assume not ,but how the client understand the type returned from the WCF services?
Edit: Reflecting More comments
A primer on WCF (such as What Is Windows Communication Foundation?) is a good place to start. WCF can use SOAP to implement the contracts way down deep. WCF also uses a variety of communication facilities within windows (and any custom ones you want to create) so talking across machines is built in.
The very essence of contract (IMO) implies that this is present on both sides of the communication. In a pure .net cases I've usually put the contract definitions in separate assemblies and share them. In other places I've used WSDL to be the main contract definition so that the client and service share definitions.
Edit: Answering comments
You can knock up simple examples of communication in WCF easilyy (provided you know the basics of comms on windows including firewalls etc). However doing something custom is not easy but there are many many resources on the web and books to help you get there.
The books i used:
http://www.amazon.com/Programming-WCF-Services-Juval-Lowy/dp/0596526997
http://www.amazon.com/Essential-Windows-Communication-Foundation-WCF/dp/0321440064/ref=pd_bxgy_b_img_c
http://www.amazon.com/Inside-Windows-Communication-Foundation-Developer/dp/0735623066/ref=sr_1_1?ie=UTF8&s=books&qid=1252111759&sr=1-1
Another question on SO with a set of resources is "WCF for the Totally Clueless"
I don't know where you read that a benefit of WCF is that it allows the client and server to be on different networks. They can already be on different networks using .NET Remoting or DCOM (Enterprise Services).
The client does need to know the service contract and any other contracts required in order to use the service. This can be provided through WSDL or the Metadata Exchange Protocol (mex). If using .NET on both sides, then it is possible to share the contract assemblies, but this introduces a coupling between client and service.
Previous Microsoft technologies were designed for some specific needs in particular environment. For example ASMX Web Services were designed to send and receive messages using SOAP over Http only. .NET Remoting specific to Microsoft environment, no interoperability. But WCF is designed to send and receive messages using any format (SOAP as default) over any transport protocol i.e. HTTP, TCP, NamedPipes, MSMQ etc.
And your second question "but how the client understand the type returned from the WCF services?"
Its through proxy, client interacts with proxy which contains all the types etc.
You can find a good concepts and questions here for understanding WCF core concepts.