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