The
PIA servlets are not part of the application server; they are its clients. It
is important to understand their relationship with the application server.
When
you boot a WebLogic server, you are effectively starting a JVM that runs a
servlet engine. Various PIA servlets are then registered with this servlet
engine. The WebLogic server is simply shipped with a servlet that acts as a web
server.
The PIA
connects to the application server:
·
HTTP requests for the PeopleSoft
servlet are received by the web server listener and routed to the servlet. When
a PIA session is established, a new servlet thread is created. That thread is
the operator’s session and it is stateful. HTTP messages are not stateful, but
an in-memory cookie is sent back to the browser, and that cookie is then sent
to the web server with subsequent HTTP requests to identify the user’s servlet
thread.
·
Each servlet thread makes a persistent connection
to the application server via one of the JSH processes. The JSL ports are
specified in the servlet configuration file, configuration.properties. All of the HTML, JavaScript, and graphics are generated by
application server and are sent back to the servlet in a single message from
Tuxedo.
·
The servlet unpacks the message, writing the
static files (JavaScript and graphics) to the physical file system that is
referenced by the web server. The main HTML page is sent back via the web
server thread to the client.
·
The main HTML page sent back to the
client will contain references to the static files. If those files have not
already been cached locally, the browser will make further HTTP requests for
those files that will be served by the web server without further reference to
the servlet.
