What is more suitable: A windows service or WCF service?

Question

I am creating a web app. I want to create a listening service (TCP) that listens continuously and updates web page according to that.

A Windows service or a WCF service?

At the end I just want a background service that listens on a socket continuously and update data in database. and when database is updated I will use signal r to show that in my page.

Right now I am trying with WCF but I am wondering if it can be done with Windows service also. And right now this application will work on LAN. But in the future, it can also be in the cloud.

Answer 1

First of all, it is important to understand that a Windows service and a WCF service are not the same.

• A Windows service is a specialized executable that runs in the background on Windows.
• A WCF service is a specialized piece of code that exposes some functionality through a well-defined endpoint. It does not run on its own, but instead must be hosted by some parent process, like IIS, a desktop application, or even a Windows service.

In thinking about the problem you've described, I suppose the most fundamental question to ask is whether or not you have control over the data that will be received via the TCP connection. WCF is built on the notion of the ABCs (Address, Binding, and Contract), all of which have to match in order to facilitate data exchange between WCF endpoints. For example, if you wish to expose a WCF endpoint via IIS that accepts TCP connections from some remote WCF endpoint, the remote WCF endpoint needs to send data to your IIS-hosted WCF endpoint using the agreed-upon data contract. Absent that, WCF will not work. So, if you cannot define the data contract to be used between WCF endpoints, then you'll need to find another option. An option that will work is to open a TCP listener within a Windows service, process the data as it is received, update your database, and listen for more data.

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By way of example, I work on a project that has a front-end desktop application that communicates with a back-end Windows service. We build both the application and the Windows service, so we have full control over the data exchange between the two processes. At one point in time, we used WCF as the mechanism for data exchange. The Windows service would host a WCF service that exposed a NetNamedPipeBinding , which we later on changed to NetTcpBinding to get around some system administration issues. The application would then create its own endpoint to communicate with the WCF service being hosted within the Windows service.

This worked fine.

As our system got more mature, we needed to start sending more and more information from the Windows service to the application. If I recall correctly, I believe we experimented with streaming within WCF and concluded that the overhead was not something we could tolerate. So, we used WCF to exchange commands and status information between the application and the Windows service, but we simultaneously used a TCP socket connection to stream the data from the Windows service to the application.

This worked fine.

When we got a chance to update the Windows service software, we decided that it would be better to have a single communication mechanism between the Windows service and the application. So, we replaced WCF altogether with a TCP socket connection that uses a homegrown messaging protocol to exchange information in both directions - application to Windows service and Windows service to application.

This works fine and is the approach we've used for a couple of years now.

HTH