Building Distributed
Applications
Using the Progress AppServer
Accessing AppServer Resources from a Client
In order to run remote procedures on an AppServer, a client application must first establish a connection with the required AppServer. When done with the connection, the client application can then disconnect from the AppServer.
There are five steps that a 4GL client application follows to connect and then run remote procedures on an AppServer:
- Create a server object handle.
- Use the CONNECT( ) method on the server object handle to connect an AppServer instance.
- Invoke remote procedure requests using the RUN statement.
- Use the DISCONNECT( ) method on the server object handle to disconnect a client application from the AppServer.
- Delete the server object handle.
The following sections provide more information and code examples for each step in this process.
Following is a list of general points that describe the relationship between a client application and the AppServer environment.
- A client application can have connections to multiple AppServers simultaneously.
- The choice of AppServer for each connection is determined by the NameServer based on the Application Service name provided by the client. The actual location of the AppServer is completely transparent to the client.
- How the AppServer allocates Application Server processes to service requests received on the connection depends on the AppServer operating mode, which is completely transparent to the client.
- An AppServer can manage transactions in a number of ways. The transaction management mechanism used by the AppServer is completely transparent to the client. The client has no direct control over the transaction mechanics used by the AppServer.
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