如何为 WCF 创建客户端库

Question

I am new to .NET and I'm researching options for implementing a client/server architecture.

I've followed the MSDN tutorial for creating a simple WFC Calculator client and server but I think I want to produce some sort of simple client–side library that a third party could use to call my service.

I've made a class library project to which I added auto generated proxy coded but found that the app.config still needs to be included in the client application rather than the library.

Question

In my target design, I'd prefer to encapsulate most (but not all) of the app.config data inside something that the company producing the client can't touch. app.config includes some information I wouldn't want a third party to modify and some information, such as the address (including port) of the service that I'd want to be configurable at installation time.

Can anyone point me at further reading, samples or tutorials that would help me progress my research? (I realise I may not even be trying to do something sensible!)

Background: What I'm really trying to do

I need to design a service that can be called from a .NET 3.5 client. I don't yet know what technology will be used for the service (eg it could be written in Java not .NET) or the protocols that will be used for the communication between client and service. It is also possible that the implementation of the service and the communications protocols used may need to change about a year or so after the initial deployments.

However, I do know the list of methods that I want to present to the client and the data types to be used for parameters and responses. I also need to document and deliver a version of the client interface to a separate company who will add calls to my service to their existing .NET client application early in the project. So, I'd like to develop a client library that would initially be used to connect to a temporary test version of the service (which could be written in .NET) to return simulated responses. Later versions of the client library would look the same to the calling client application but connect to the real service instead.

WCF looks like it has the flexibility I need to allow me to design the client interface independently of the service and connection protocol to the service. But as I said above, app.config includes some information I wouldn't want a third party to modify and some information, such as the address (including port) of the service that I'd want to be configurable at installation.

Answer 1

You could go for ChennelFactory and you could indeed keep most of the configuration information in the database(ex: endpoint address), your client library which is supposed to handle the communication between the 3rd party client app and your service should read the service config details from the DB and invoke the required service and returns the result set the 3rd party app.

But why you need to hide the service details from the 3rd party application/users? service details are not something you don't want to expose to end users. why not simply expose the service with adequate WCF Security in place and let them call the relevant service.

if you are going for a separate client library/application to encapsulate the service details, if you need to do deliver any fix for this in the future and if the user base is large then you need to worry about upgrade mechanism and all. this will add more complexity.

Answer 2

If you can control the installation of the client, you could lock-down access to app.config file to certain user accounts.

Another option would be to encrypt the contents app.config file before deploying it.

It's all about a trade-off between how convenient you want to make configuring the client versus how difficult you want it to be to tamper with.

Edit: If your goal is to simply hide your port numbers and addresses, that's not realistically possible. Someone can just use a network traffic monitor to find out that information.