What Is ATL Server?

With Windows NT/2000 and Internet Information Services (IIS), Microsoft has introduced a platform capable of handling the mission-critical tasks described previously. Combine IIS with Internet Server Application Programming Interface (ISAPI) development and developers are capable of getting the flexibility, control, performance, reliability, and scalability they desire . Unfortunately, ISAPI development is difficult, and theres a lot of infrastructure that the developers themselves must provide before they can even think of working on their application logic.

With Visual C++ .NET, the Visual C++ libraries team has created a library that greatly aids ISAPI development. That library is ATL Server.

The ATL Server library has been designed to be a lightweight, thin wrapper over ISAPI. As such, the library allows developers to maintain complete control over their Web applications (by plugging directly into the underlying layers wherever they deem it necessary) while also greatly reducing development time by giving developers much of the code that they would normally have to write, test, and document themselves.

The ATL Server classes are well-contained, separate parts that come together to form a complete framework that helps developers create ISAPI applications much more productively. The classes are built on top of one another, with high-level functionality built on top of low-level functionality, so nothing is hidden and the pieces can be easily replaced and changed without affecting other portions of the application.

ATL Server doesnt use COM, nor does it require developers to have any COM knowledge to develop with it. Its predominantly a class library based on top of ISAPI using ATL. ATL Server does have some template usage, but this is reserved (compared to traditional ATL) mainly for areas of the library that require the flexibility that templates allow.