How WebSphere Application
Server plug-in works:
This article
for beginners who don't know about WebSphere plug-in. We know plug-in forwards
the HTTP requests from web server to
application server. It is plug-in primary work. Now, Look about how the plug-in
works. Mainly plug-in work is divided into 4 operations.
1)Initialization
2)URL matching and server determination
3)Sending the request to the application
server
4) receiving the response from application server.
Before discussion of these operations, we must know how the
web server will send the request to the plug-in.
The Web server gives an opportunity to handle every request to WebSphere plug-in first, Then ,if WebSphere plugin is not configured to serve that URL(request), Then the request go to the Web server for
servicing.(This is the primary work of web server).
1)Initialization:
If we configure web server and
plug-in, 2 lines are added In httpd.conf file of web server.
1)LoadModule ibm_app_server_http_module
/bin/mod_ibm_app_server_http.dll
2)WebSpherePluginConfig \config\cells\plugin-cfg.xml
Here LoadModule points to the
plug-in DLL, and WebSpherePluginConfig points to the plugin-cfg.xml
file, which lists all the URLs that are to be serviced by the WebSphere cell.
When web server is starting, the plug-in DLL will be loaded in web server process, then
It loads "plugin-cfg.xml"
into plug-in process
check the
"plugin-cfg.xml" file(i.e. parsing) and validates plug-in
configuration file.
After this work, plug-in
is ready for receiving http requests.
2)URL matching and
server determination:
Based on WebSphere plug-in
configuration, the plug-in will match the URL and send the request to
application server. This redirection is based on a set of rules dependent upon
the WebSphere Application Server configuration.
3)Sending the request to
the application server:
Here plug-in will do 2 steps
1)Once server is determined.
the plug-in add one http client object with data from the user request. Once
this new HTTP client object has been populated, it is ready to be sent.
2)The request is sent.
4. Receiving response
from the application server:
After
sending a request to the application server, the plug-in goes into a wait state
(waiting for the response). The end of this wait state can be reached in the
following ways:
1) Expected behaviour (If everything is
fine).
2) Unexpected behaviour (U know
about it. We don't like it. but it will happen).
Finally I conclude this article here only,
but future I will provide more information about this operations and
"plugin-cfg.xml" file (Important parameters in this file) and many
more related plug-in.
Thanks for reading.
WebSphere Jungle.
