Release 10.1A: OpenEdge Development:
Open Client Introduction and Programming

Types of connections

Open Clients support two types of AppServer connections, depending on the type of Open Client:

Internet connections
Intranet connections

Internet connections

.NET and Java Open Clients can access an AppServer over the Internet using the AppServer Internet Adapter (AIA), which is a Java servlet running on a Web server that converts HTTP requests from Open Clients into direct requests from the AIA to the AppServer and returns the results back to the Open Client from the AppServer. As such, the AIA allows any AppServer client to access the AppServer from anywhere on the Internet.

Web service clients access the AppServer over the Internet using the Web Services Adapter (WSA), which is also a Java servlet running on a Web server that converts HTTP requests from Web service clients into direct requests from the WSA to the AppServer and returns the results back to the Web service client from the AppServer.

The difference between .NET/Java Open Clients and Web service clients accessing the AppServer over the Internet is in how the AppServer interface appears to the client. For .NET/Java Open Clients, the interface maps in “native mode” directly to the application service supported by the AppServer. For Web service clients, the interface maps to an industry-standard Web service interface, which in turn maps directly to the application service supported by the AppServer. Each type of client connects to the same functionality, regardless of the type of interface.

Intranet connections

Only .NET and Java Open Clients can access an AppServer over an intranet, using an OpenEdge-proprietary AppServer protocol to transport requests. For this type of connection, the Open Client interface maps to the application service in a “native mode” supported by the Open Client proxy using a connection that directly accesses the AppServer. As such, the interface to an AppServer, whether it is over the Internet or over the intranet, appears identical to the Open Client. Only the protocol used to make the connection is different between the two.

Note: The performance of Internet connections to the AppServer are inherently slower than for intranet connections because of the Web server needed to support the Internet.