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wcfappfabricfilesystemwatcher

WCF, FileSystemWatcher and Architecture

I'm new to WCF and need some assistance with architecture for the following solution:

I want to create a WCF Service that hosts a FileSystemWatcher. This service must watch a series of folders on the machine and when a file is placed in a folder or is renamed I need this WCF service to 'Publish' an event.

Another WCF service must then 'Subscribe' to this event and do some processing.

The basic idea is that there is one service to monitor a predetermined set of directories, whilst an appropriate service gets notified that there are files available for processing.

So my questions are :- 1. Regarding the FileSystemWatcher WCF Service, I want to host it in AppFabric but am not sure exactly how this is going to work. I.E. When this service is deployed to the server I want the appropriate FileSystemWatcher object to be called and stay 'on' and monitor folders indefinately. Can WCF do this in this manner or is this a better candidate for a Windows Service 2. Can one WCF service publish events and another WCF service subscribe to these events and how? All WCF services hosted inside AppFabric?

Solution

    1. WCF is a communication framework that can be used to expose or consume SOAP/REST services. A Windows Service is one way of hosting such applications. WAS/IIS and self-hosting are other methods. A Windows Service provides greater control of service startup/shutdown, which seems relevant to your scenario.Windows Server AppFabric improves some of the control over applications lifecycle hosted in WAS/IIS, but it is still a fundamentally different hosting choice to a Windows Service.

    2. As far as I know WCF has no inbuilt event publishing capability (I assume you're referring to the publish/subscribe pattern). However, you can implement such a pattern using WCF duplex channels. There is no restriction on an application concurrently acting as 'server' and 'client'.