Is there a way where I can create a set of wcf services where one service depends upon the request of the previous service?
That is, I create Service1, Service2, Service3.
Service2 should be invoked when the request of Service1 arrives.
Similarly, Service3 should be invoked when the request of Service2 arrives.
The response would then travel back from the Serice3 to Service2 then to Service1.
If this is not feasible, what is the nearest thing that is possible?
Kindly provide links to tutorials if you can.
Thanks
Related
I'm developing a UWP client project which need to consume some services of a WCF server. I uses the "add service reference" tool of Visual Studio to auto generate service clients(proxies). The binding type is NetTcpBinding. Below is some code snippet which create the service client:
NetTcpBinding tcpBinding = new NetTcpBinding();
tcpBinding.Security.Mode = SecurityMode.None;
tcpBinding.Security.Transport.ClientCredentialType = TcpClientCredentialType.None;
tcpBinding.Security.Message.ClientCredentialType = MessageCredentialType.None;
MainServiceClient = new MainServiceClient(tcpBinding, new EndpointAddress("net.tcp://localhost:8773/MyWCF/MainService/tcp"));
The question is do I need to call OpenAsync() method of MainServiceClient? It seems the service client can be auto opened when it is first called. But I read from this article that auto-opened service client would have some performance penalty. The article was written in 2007. I just wonder if this mechanism have changed today, especially in UWP project. Can anyone share more light on this topic? Thanks!
To explain this case, you should know three ways to do WCF instance management. WCF has provided three ways by which you can control WCF service instances:Per call, Per session, Single instance.
When we configure a WCF service as per call, new service instances are created for every method call you make via a WCF proxy client.
Very often we need to maintain state between method calls or for a particular session. For those kinds of scenarios, we will need to configure the service per session. In per session, only one instance of a WCF service object is created for a session interaction.
Often we would like to create one global WCF instance for all WCF clients. To create a single instance of a WCF service, we need to configure the WCF service as Single instance mode.
And there are three ways by which you can handle concurrency for each service instance in WCF :single, multiple, and reentrant.
Single: A single request has access to the WCF service object at a given moment of time. So only one request will be processed at any given moment of time. The other requests have to wait until the request processed by the WCF service is completed.
Multiple: In this scenario, multiple requests can be handled by the WCF service object at any given moment of time. In other words, requests are processed at the same time by spawning multiple threads on the WCF server object. So you have great throughput here but you need to ensure concurrency issues related to WCF server objects.
Reentrant: A single request thread has access to the WCF service object, but the thread can exit the WCF service to call another WCF service or can also call a WCF client through callback and reenter without deadlock.
In "Instance mode = Per Session and Concurrency = Single" combination, one WCF service instance is created for every WCF client session because the WCF instance mode is set to per session. All the method are executed in a sequential manner one by one. In other words, only one thread is available for all method calls for a particular service instance.
For the above scenario, you should always open WCF client proxy explicitly before you are making any calls. Because it will maintain service state between method calls and obtain high performance.
For more detail you could refer to "WCF Concurrency (Single, Multiple, and Reentrant) and Throttling" and "Three ways to do WCF instance management".
I have one Wcf service project and in it many services called Service1, Service2 etc.
However, only Service1 is running. Why is this and how to resolve it?
This is a bit vague description of your problem, but maybe this will help. I did a post on how to host many WCF services in one windows service. If it doesn't help, check that your ABC(address, binding and contract) are set correctly.
I want to create a service which receives a request from the client, adds the request to a database and than calls another WWF service ASYNCRONOUS which does some time consuming job withthe data from the database.
How do I make a service to be asincronous in Windows Workflow service?
I use the second Windows Workflow service as a queue(as it can only be one instance of this service=I set canCreateInstance to false).
To make a Workflow Service behave asynchronously create a One Way contract by using a Receive activity without a correlated SendReply.
When another Workflow (or WCF client proxy) calls this service it will not wait for a reply from the service.
As for your comment about only one instance of a service you are mistaken. There is no way to have a singleton workflow service (as there is with WCF services) and CanCreateInstance has no effect on this behavior.
I'm not experienced WCF programmer, so I do not fully understand all those configs and endpoints.
I have made two WCF services. One is web service hosted in IIS7, and the other is Windows service.
What should i change in which app.config and web.config to make possible to IIS7 service be a client of Windows service. I have generated proxy for Win service imported in Web service, but I have no idea what to do with those app.config files... Can somebody give me general or concrete suggestions?
Thank you very much,
Regards,
A simple general suggestion. You can start with:
Client1 => Service1
Client2 => Service2
Once that working you can take the configuration from Client2 and copy it to Service1. Lastly you look at you Service1 as a client and do the same stuff you did for Client2 - add a service reference to Service2 (or get the proxy through another way if you will). Effectively, now your Service1 is also a Client2.
Client1 => Service1 => Client2 => Service2
WCF hosting doesn't matter here as services are communicating via ABC that is:
A - address (e.g. http://localhost:8080/Service1)
B - binding (e.g. BasicHttpBinding)
C - contract (e.g. IService1 interface)
I have a WCF service hosted as Windows Service with most of its methods currently defined as:
[OperationContract(IsOneWay = true)]
But, now I need to send response back to the calling Web application for these service methods.
Now, because service methods are bit heavy (FYI, they are reporting methods that needs to do mail merge for a no. of records), I am thinking to either queue them or to process asynchronously, so essentially when the request is sent to the service it should save the request to database/queue, returning Request-Id to calling Web application.
In the mean-time, WCF service can just process incompleted requests from the queue or database.
Then either calling Web application can ping WCF service for status of request because it has Request-Id or
WCF service can ping back to calling app when the process corresponding to a Request-Id is completed.
To achieve above, can anyone please guide what changes I need to make to my WCF service (which currently has all one way operation)?
Also, please guide me whether I need to go for Asynch operation or message queuing?
Thank you!
Of course, going Async is simple:
remove the OneWay on the OperationContract in question and regenerate your Service WITH Async methods. There's a reason why Silverlight forces you to use Async operations. They do force you to rethink your UI.