WCF communication with several clients without IIS

Question

we're working on a peer to peer comm software that would allow a number of grocery stores to sync their inventory with what we call "headquarters". To so this, we're thinking WCF+WPF, and no IIS and web services. My experience with WCF is basically zero, so my question is whether a TCP comm solution using WCF would work. The data that's being transferred is quite limited, about 2MB for a compressed plain text file (so we're sending binary data!), and this is done once per day only. So bandwidth/load shouldn't be an issue here. The idea at this point is to have a WCF "server" running at HQ. Stores make themselves known to that server and then send files back and forth (simliliar to a chat application). What I'm not sure of: does every store need to have a WCF "server" (or endpoint)? How would the server (=HQ) send a file to one of the clients (=stores)? Every store can send a file to any other store, and the HQ, and every store can also "request" a file from any other store/HQ.

Two limitations: None of the machines/computers involved can run Windows server for budget reasons, and as stated before IIS is a no-go.

Answer 1

If you are only sending files back and forth, I might question whether or not WCF even makes any sense. Have you considered just using a file transfer protocol, like scp or sftp?

Every machine will have to accept connections and have a file drop location setup, and then yuor application will have to monitor that location for new files. I love WCF in general, but a file transfer protocol is going to have a leg up if that is all you want to do.

Answer 2

You don't need to host WCF in IIS, but is there any particular reason you don't want to do that?

You can host WCF in a ServiceHost, but then you need to build, maintain and deploy a lot of server/service features that IIS provides for free, such as application process recycling, activation-based hosting, etc.

In any case, it almost sounds like you need peer to peer networking. You can do that with WCF using the NetPeerTcpBinding .

Answer 3

If you direct all of your traffic via the server then there's no reason why you couldn't achieve this with WCF. The server would host WCF services in IIS with the stores having a client that was able to upload and request files. With this method, stores would not be able to directly transfer fiels to each other, but they would have to do it via the main server, which would suit your needs if you don't have the budget for the other scenario.

If all transfers are made once per day, the requests for files would be made with each client requesting what files they require, followed by each client uploading any files that are required by the server or any other client. The final step would be the server distributing the required files to each client. Obviously, this is a simplified view of it, the actual process may require some more thinking.

Answer 4

If you have an opportunity to redesign your application, I suggest you do. You can throw strings around in WCF but if you can create a data contract you can keep all your communication strongly typed.

If you have access to windows server 2008 then the new IIS can host your WCF even if it isn't using tcp. Otherwise you just need to write an application that opens a service host, which you would usually wrap into a windows service. But as @MArk Seemann pointed out, you get lots of freebies by running your service in IIS.

Don't have any experience with the PeerTcpBinding but I can tell you that the NetTcpBinding is nice and fast plus it comes with all sorts of goodies like encryption and authentication if you want it.