When using HTTP, all requests between the client and the AppServer go through a Web server that forwards each request to the AppServer. Depending on the client type, an AppServer client specifies HTTP tunneling for use with OpenEdge as follows:
For an ABL client, including WebClient, the client uses the -URL connection parameters of the server handle by specifying a URL with an HTTP protocol.
For an Open Client, you specify the URL in the AppObject proxy object that you can create with ProxyGen.
The URL contains the host and port of the Web server, the path to the AIA instance, as well as the requested application service. For information about how a client connects to an AppServer using HTTP:
For ABL clients, see OpenEdge Application Server: Developing AppServer Applications
For Open Clients, see OpenEdge Development: Open Client Introduction and Programming
Each AIA instance can either connect directly to an AppServer or use a controlling NameServer to connect. How the connection is made is specified when you configure the AIA instance. Each request sent from an AppServer client to the Web server is encapsulated within one or more standard HTTP post requests. The URL contained within the post request indicates to the Web server that it should forward the request to AIA.
When the AIA instance receives the connection request from an AppServer client, the requested application service name is included along with the userid, password, and appserver-info values that are normally passed in a connection request to an AppServer. AIA then passes the application service name either to the controlling NameServer and the Name Server passes the request to the AppServer, or AIA passes the request directly to the AppServer. For more information, see the information on configuring and managing the AppServer Internet Adapter in OpenEdge Application Server: Administration.
Note: Because the HTTP protocol is connectionless, you cannot use the termination of the connection with the AppServer client as an indication that the AppServer client’s connection to the AppServer should be terminated. Because of failures at the client site, as well as the network between the client site and the Web server, it is possible that an AppServer client could connect to an AppServer and never gracefully disconnect. To guard against the possibility of an AIA instance maintaining orphaned connections, you can use the idleConnectionTimeout property in the ubroker.properties file to configure an AIA instance to automatically terminate the connection if a connection is idle for more than the specified time. For more information, see OpenEdge Application Server: Administration. For information on modifying the ubroker.properties file using the mergeprop utility, see OpenEdge Getting Started: Installation and Configuration.
For an ABL client, including WebClient, the client uses the -URL connection parameters of the server handle by specifying a URL with an HTTP protocol.
