Understand what the dispatcher does and identify which dispatcher to use with a specific
Web server.
Types of GAS Dispatchers
There are different GAS dispatchers, each designed for a specific Web server:
- httpdispatch: standalone dispatcher for development only, provided to simplify
your development setup and configuration through a direct connection without a Web server See Dispatcher: httpdispatch.
-
isapidispatch: dispatcher for Internet Information Services (IIS). See Dispatcher: isapidispatch.
-
fastcgidispatch: dispatcher for Fast CGI compliant Web servers like Apache, see
Dispatcher: fastcgidispatch
Each dispatcher performs the same role of forwarding an application request to the appropriate
proxy, and the proxy in turn processes the request by launching the DVM.
GAS Dispatcher and VMProxy
The GAS dispatcher starts a VMProxy to handle the application request. Each session requesting an
application results in a VMProxy starting up, so several VMProxies may be running concurrently. The
dispatcher tracks the session and proxy information in a persistent session table and routes
requests to the correct proxy.
Note: The presence of this information in the session table ensures that if a dispatcher is killed
or restarted, the information needed to return to the proxy and running application is still
present.
GAS Dispatcher responsibilities
The GAS Dispatcher, in summary, is responsible for the following:
- Launching VMProxies
- Handling and validating the application or service configuration
- Providing the application configuration to the VMProxy via environment variables
- Handling a persistent and shared session table that manages the forwarding of application
requests to the corresponding VMProxies
- Stopping the VMProxies when the Web Server shuts down
- Handling static file requests