Release 10.1A: OpenEdge Getting Started:
Application and Integration Services

Understanding the AppServer

The AppServer is an application server component that runs Progress 4GL procedures in response to direct client requests over a network. It helps you to build complex distributed applications by allowing a client application to call 4GL procedures or user-defined functions remotely as if they were running locally on the client machine. A remote procedure or remote user-defined function is thus a procedure or function that runs in an OpenEdge (AppServer) session that is separate from that of the client, and typically on a separate machine from the client. In a Progress 4GL client, you access and invoke a remote procedure or user-defined function using a variation of the RUN statement or the FUNCTION statement (and function invocation). In an Open Client or Web service client, you invoke the remote procedure as a method on an object defined by the Open Client or Progress 4GL Web service interface.

Note: OpenEdge supports Web services in two basic ways: (1) building Web services from AppServer application services and (2) invoking industry Web services from within a 4GL client. For more information on OpenEdge Web service support, see Chapter 6, " Web Services in OpenEdge—Architecture and Tools."