I have gone through the blog NServiceBus and wcf ServiceHost where it talks about having a WCF service acting as publisher and publishing the events.
In my service implementation class I inherited IWantToRunAtStartup interface and defined Start and Stop methods. But getting null exception on trying to IBus property as it is not getting injected. Can someone provide pointers on resolving this.
Thanks in advance.
Related
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.
Thank you in advance for any advice. I have a Windows service that is hosting a WCF service through net.tcp and this is working great. I have also created a WCF service application. I am trying to add the net.tcp service reference to the service application. Then I add it to the GAC that goes ok but if I try to RegAsm the WCF service application to allow it to be called from Server.CreateObject I get the error:
Warning: Type library exporter encountered a type that derives from a
generic class and is not marked as
[ClassInterface(ClassInterfaceType.None)]. Class interfaces cannot be
exposed for such types. Consider marking the type with
[ClassInterface(ClassInterfaceType.None)] and exposing an explicit
interface as the default interface to COM using the
ComDefaultInterface attribute.
It does not work. I have tried to call it through a class library but this does not work either as the end point is not set correctly.
Any advice?
Ok Fixed this. Was a Permissions Error the iusr account did not have access to the web.config file from the WCF Service Application. So It works now. Now another problem has arised. I need to be able to call the WCF Service Application from asp classic but it does not use a web.config.
Where is the best place to put code for when a WCF service is just started up? Similar to Page_Load in a web application.
The service implementation constructor would be the obvious place but it also depends on your hosting model
1) run once code: IIS hosting = global.asax; self-hosting = Main / OnStart
2) run once per service instance: constructor of service class
3) Something more exotic: implement IInstanceProvider
In the class constructor of the service implementation.
Honestly the best place is the constructor and/or static constructor for your service class (for static members). There is no other WCF specific lifecycle event that will notify your service implementation when it's being created by the service host.
Now, if you're talking about the creation of services generically, that would mean you're willing to hook into the WCF runtime and there you can do things like get in the middle of the instance creation with a custom IInstanceProvider implementation.
If I have a client/server type of application built using both Prism and WCF, and I would like on the serverside to have the wcf service to be instatiated per call BUT I would like to use dependency injection (using the UnityContainer in Prism). How could I possibly do this? Should I have a single instance service it would be no problem, but are there any hooks in WCF to allow for a delegate to be called whenever a service is supposed to be instantiated and have this instance returned?
Any ideas?
Cheers!
It is possible! WCF provides a plugin to the WCF responsibility chain called an IInstanceProvider. This allows for you to replace the construction with your own.
Someone has implemented this as a service behavior and is available here:
http://code.msdn.microsoft.com/WCFResources/Release/ProjectReleases.aspx?ReleaseId=1252
I want to know what happens when I create an instance of a ServiceHost class?
What it does ?
The ServiceHost (whether instantiated by yourself directly, or whether you delegate that job to IIS/WAS) is the runtime environment for your WCF class - which is just a simple .NET class after all (which needs to run somewhere).
The ServiceHost basically provides all the "plumbing" around your WCF service - creating the endpoints and the listeners on those endpoints to listen for messages and catch those as they come in; it provides the whole channel stack from the transport level through all the layers of WCF up through deserializers on to the dispatcher which then decides which class and which method on that class to call, and so on.
In WCF, in your service class, you write only the actual busienss logic of your service - the ServiceHost and all its classes around it handle all the nitty-gritty details of the receiving of messages and sending back of responses etc.
Marc
Typically the ServiceHost class is used to host your WCF services in a standalone app (such as a console app), if you are not using IIS or Windows Activation Service (WAS).
In simple terms it will deal with the COMs (listening for messages for a particular service).
You can also derive from ServiceHost to add customization if required, in combination with a specialization of ServiceHostFactory.
See MSDN example.
HTH
Phil'
It creates channels that are responsible for things like reliable transfer and security. It listens for incoming messages and calls your operation methods.