There are a bunch of questions regarding global error handlers and such but none of those address what I need.
Is there any way to add a behavior that will attach to every endpoint or service through .config?
*Specifically what I want to do is add a logger that will capture and log every SOAP request/response. But I would prefer that behavior to be automatically added to every service I have instead of having to manually add it to each.
I looked into behavior extensions and thought that would be the solution but no, you have to add the behavior to every service.*
You may be able to use the <commonBehaviors> section of your machine.config file to define a behavior which would be applied to all services in your machine. Notice that updating the machine.config is really like using a bazooka to solve your problem (and in many scenarios the group policy may forbid you from doing that), so it may not work for all scenarios. You'll also need to make sure that the behavior extension is registered (also in machine.config), and that whatever application you're using with WCF has access to the assembly referenced in the extension (possibly via GAC).
Another alternative would be to use a common library for creating the service hosts (either directly for self-hosted services or via a service host factory for webhosted services), and use that library (which would in turn add the inspector).
Its always good to have a message inspector to get rid of this kind of problem. Message Inspector is an implementation of WCF extension which works nicely to track every incoming request(s) and outgoing response(s) for your service, even if its fails in Message Validation it has an option to trap and work accordingly. More precisely the message inspector can configure using configuration files without making changes in your existing service.
More details about your Message inspector and its implementation can be found Here
Hope this helps !!
Happy Coding :)
Related
We are trying to build a Nservicebus service that can communicated with form and wpf based clients using WCF. I have read that you can inherit from WcfService.
like:
public class ThirdPartyWebSvc : WcfService<ThirdPartyCmd, ThirdPartyCmdResponse>
And then you simple create a endpoint in the app.config and you done like described here. but the problem is that i have to create a endpoint for every command.
I would like to have a single endpoint that excepts any command and returns its response.
public class ThirdPartyWebSvc : WcfService<ICommand, IMessage>
Can someone point me in the right direction? Using Nservicebus for client communication can't be done for us and i don't want to build a proxy like server unless thats the only way to do it.
Thanks
So from what I can gather, you want to expose a WCF service operation which consumers can call to polymorphically pass one of a number of possible commands to, and then have the service route that command to the correct NServiceBus endpoint which then handles the command.
Firstly, in order to achieve this you should forget about using the NserviceBus.WcfService base class, because to use this you must closely follow the guidance in the article you linked in your post.
Instead, you could:
design your service operation contract to accept polymorphic requests by using the ServiceKnownType attribute on your operation definition, adding all possible command types,
host the service using a regular System.ServiceModel.ServiceHost(), and then configure an NserviceBus.IBus in the startup of your hosted WCF service, and
define your UnicastBusConfig config section in your service config file by adding all the command types along with the recipient queue addresses
However, you now have the following drawbacks:
Because of the requirement to be able to pass in implementations of ICommand into the service, you will need to recompile your operation contract each time you need to add a new command type.
You will need to manage a large quantity of routing information in the config file, and if any of the recipient endpoints change, you will need to change your service config.
If your service has availability problems then no more messages to any of your NSB endpoints.
You will need to write code to handle what to do if you do not receive a response message from the NSB endpoints in a timely manner, and this logic may depend on the type of command sent.
I hope you are beginning to see how centralizing this functionality is not a great idea.
All the above problems would go away if you could get your clients to send commands to the bus in the standard way, but without msmq how can you do that?
Well, for a start you could look at using one of the other supported transports.
If none of these work for you and you have to use WCF hosted services, then you must follow the guidance in the linked article. This guidance is there to steer you in the correct direction - multiple WCF services sounds like a pain, until you try to centralize them into a single service - then the pain gets bigger, not less.
I have a WCF service application (actually, it uses WCF Web API preview 5) that intercepts each request and extracts several header values passed from the client. The idea is that the 'interceptor' will extract these values and setup a ClientContext object that is then globally available within the application for the duration of the request. The server is stateless, so the context is per-call.
My problem is that the application uses IoC (Unity) for dependency injection so there is no use of singleton's, etc. Any class that needs to use the context receives it via DI.
So, how do I 'dynamically' create a new context object for each request and make sure that it is used by the container for the duration of that request? I also need to be sure that it is completely thread-safe in that each request is truly using the correct instance.
UPDATE
So I realize as I look into the suggestions below that part of my problem is encapsulation. The idea is that the interface used for the context (IClientContext) contains only read-only properties so that the rest of the application code doesn't have the ability to make changes. (And in a team development environment, if the code allows it, someone will inevitably do it.)
As a result, in my message handler that intercepts the request, I can get an instance of the type implementing the interface from the container but I can't make use of it. I still want to only expose a read-only interface to all other code but need a way to set the property values. Any ideas?
I'm considering implementing two interfaces, one that provides read-only access and one that allows me to initialize the instance. Or casting the resolved object to a type that allows me to set the values. Unfortunately, this isn't fool-proof either but unless someone has a better idea, it might be the best I can do.
Read Andrew Oakley's Blog on WCF specific lifetime managers. He creates a UnityOperationContextLifetimeManager:
we came up with the idea to build a Unity lifetime manager tied to
WCF's OperationContext. That way, our container objects would live
only for the lifetime of the request...
Configure your context class with that lifetime manager and then just resolve it. It should give you an "operation singleton".
Sounds like you need a Unity LifetimeManager. See this SO question or this MSDN article.
If I have a web serice and a client consuming tis webservice, and then I change the service location, orI add another parameter, what is the usual way to change the client?
Do you necesarily need to update the client/ Was UDDI helping in this kind of situation?
You should definitely read Service Versioning - it has the information you need.
But the answer to your question is: maybe.
There are two types of changes: breaking and non-breaking. Unfortunately, sometimes it's not obvious what is a breaking or non-breaking change since it could depend on what the client is doing (and you may not have knowledge of how your service is being used).
In terms of changing the service location this is usually a breaking change. However, as you mention, if the client is using UDDI then they should be able to retrieve the new endpoint location and that change would not be a breaking change.
If you add another parameter then that might be a breaking change (or it might not). If the parameter is optional and the client is using lax versioning (e.g. WCF, .asmx) then the change should not be a breaking one. But it might be that the client is expecting a very specific format or they are doing some schema validation etc. and the optional parameter might cause a failure.
It depends on the nature of change you apply in the service definition. If you add something optional that only new clients can consume but the old clients can ommit, you have introduced a backward compatible change so the clients shouldn't be updated unless they decide to use this new feature. Any change that affects the way the existing clients use the service will require a client update as it represents a breaking change.
In the case of WCF, if you use the latest version 4.0, it introduces a new protocol implementation WS-Discovery, which can help clients to find the service url and the right version they can use. Using this approach, you can for instance, deploy a new version in a different url and the client applications can discover it automatically.
Regards
Pablo.
Hey without fully understanding your problem, and from what i can get from your questino it sounds like you need to update your web reference on the client.
If you have updated your references, not changed the location:
So Load up your client solution, then find your References (not dll references) but Web/Service References, and then right-click and select "update web references"
If you have changed the location, you can change the endpoint if you go to properties, but I would just delete the existing one and create a new one using the new location.
Hope it helps.
For more info check out http://msdn.microsoft.com/en-us/library/bb628652.aspx
I have a universal service hosted on IIS7 that accepts a Message and returns Message ( with Action="*"). This service still publishes meta for the clients.
This metadata is explicitly specified using LocationUrl property in ServiceMetadataBehavior.
We have a requirement that the metadata can change during lifetime of the service, so in essence metadata has a lifetime.
I tried adding IWsdlExportExtension to the service endpoint behavior, but the ExportEndpoint method only gets called once (when the service is loaded first time). Is there a way for me to invalidate the loaded metadata so that anytime there is a call for wsdl using HttpGet, the behavior gets called ?
What you are asking for (changing the published service definition at runtime) is not possible - you need to remove the requirement which specifies that the metadata can change over time.
Once you've published a service, the only reason the service specification should change is because the service has been upgraded.
You should look closer at the business requirement which is making this technical requirement necessary, and try to find another way to satisfy it (perhaps post in programmers.stackexchange). Perhaps you can have multiple services available, and switch between the services over time - but this is a bit of a stab in the dark without knowing the business requirement.
No there is no way. Moreover if you needed you are up to your fully custom solution because this is out of scope of web services. Changing metadata means changing the service itself = its internal logic which always result in restarting the hosting process and publishing new metadata.
Right now we have around 5 service reference added to our projects in a single solution.
I am force to add service reference even for projects having indirect dependencies calling service methods. Is there a way to get around for this situation.
For every single change in the service method, I have to update every single service reference to effect those changes. It is very time consuming too.
I am just wondering, is there any way i cam manage these things globally by making single service reference for the whole solution.
help appreciated.....:)
You should be able to use the svcutil.exe command line utility to generate a single service file (.cs file for example) from multiple service URL's. The nice thing about this is that you can share clinet-side DTO's and message types accross services if they have the same schema.
SvcUtil Reference: http://msdn.microsoft.com/en-us/library/aa347733.aspx
In regards to the requirement of adding the service reference to projects with indirect dependencies. You should probably not consume the service reference and related types directly from your service client. To improve maintainability and adaptability, you should wrap your service reference(s) in a facade. The facade would map between local types and service reference types, and give you much more agility in terms of responding to service changes. You would then only need to have the service references in a single location (preferably an independent project) along with the facade. The facade, which should change infrequently, will buffer you from the issues you are currently having with your service references.
You won't be able to get a single reference if you have multiple service, unfortunately.I stand corrected - see jrista's answer.
What you could do is create and update the service references automatically: instead of adding them manually in Visual Studio using Add Service Reference check out the svcutil.exe command line tool which will basically do the same thing.
Since it's a command line tool, you can have it run as e.g. part of your continuous build and update the necessary proxy client files every time you build the app.
Check out these additional links for tutorials and explanations about the details of using svcutil.exe:
http://msdn.microsoft.com/en-us/library/ms734712.aspx
http://asadsiddiqi.wordpress.com/2008/10/25/how-to-generate-wcf-client-proxy-class-using-svcutilexe/
http://www.xvpj.net/2008/03/08/wcf-step-by-step-tutorial/
Marc