How to use ESI invalidate tag to invalidate cached content
OracleAS Web Cache : How to use ESI invalidate tag
Date:
January 28, 2003
How to use ESI invalidate
tag to invalidate cached content
After completing
this How-To you should be able to:
Use
ESI invalidate tag to invalidate cached content.
Introduction
OracleAS
Web Cache is content-aware cache server, capable of caching both static and dynamic
content. Once the document is cached, all the request to the cached
document will be served from the cache server until the document is invalidated.
The document has to be invalidated, when the content of the document changes.
The cached content can be invalidated by using one of the following methods.
Time-based - When the cache document expires, based on the expiration
policy set for the cached document.
Event-based - On occurrence of an
application event, which changes the data. Following methods can be used to invalidate
cached document.
JESI/ESI tags
Java API's
PL/SQL API's
Manually
invalidating the pages - using OracleAS Web Cache Administrator tool.
This
How-To explains how to invalidate multi version document by using the ESI invalidate
tag. The sample displays all the product id's available, in the welcome page.
User can select any product id for its detailed information. When the welcome
page is submitted, product id is saved in a cookie named productId and passed
to display page, display.jsp. The cached display page in Web Cache will have multiple
version based on the productid cookie. The display page can be invalidated for
the selected product id by clicking on the 'Invalidate' button. This will forward
the request to the invalidate page, invalidate.jsp. This invalidate page is responsible
to create the invalidation request and to invalidate the page for the selected
product id. The code snippet is shown in the next section.
Code
snippet
Following is the code snippet used to invalidate
the cached content.
Oracle
Application Server (9.0.3 or above). This can be downloaded from here
Oracle JDeveloper (9.0.3 or above). This can be downloaded from here. This
is optional and required only if you wish to deploy from JDeveloper.
Deploying
the Sample
The complete source code for this sample
is available here. This section discusses the
instruction to run the sample application
Step 1
Unjar
EsiInvalidation.jar using Winzip, or using the following
command:
> jar xvf EsiInvalidation.jar
This creates a directory EsiInvalidation.
Step 2
If you are using JDeveloper then, follow these steps
Open
Oracle9i JDeveloper and use File/Open option to select the
EsiInvalidation.jws from the EsiInvalidation directory.
Next, select Project/Make
EsiInvalidation.jpr from main menu.
Create
an application server connection
Go to Connections -> Application
Server Connection. Right Click and click New connection..
In step 1, enter
connection name and select Oracle9i Application Server
In step 2, enter
user name and password
In step 3, enter Enterprise Manager's host name,
port number and Remote Oracle AS home directory(required only if deployed on remote
machine).
In step 4, click Next and Test the connection. Click Finish
button.
Now, Right click EsiInvalidation.deploy
and select Deploy to <connection name>, to the application server connection,
which you have created in the previous step.
Step
3
To deploy the application using EM, follow
the steps.
Go to EM web site -> default oc4j
home.
Choose Deploy EAR file.
Enter J2EE Application name, Click
the Browse button and choose EsiInvalidation.ear from <SAMPLE_HOME>/deploy/EsiInvalidation.ear.
Enter the Application name as Personalize and click next.
Enter
URL mapping as /EsiInvalidation and click Finish.
Click Deploy to deploy
the application.
Step
4
Configuring the OracleAS Web Cache for
multi version document.
Start the OracleAS Web
Cache Admin Tool using the browser. By default the administration port is 4000.
Access the Admin tool on the browser using the url. http://<hostname>:4000/webcacheadmin/
, where <hostname> is the machine on which OracleAS is installed. For
example, http://incq185b.idc.oracle.com:4000/webcacheadmin Login as "administrator".
The default password is 'administrator'.
Select 'Cookie Definitions'
link under 'Rules for Caching, Personalization, and Compression' section.
a) Click on 'Add' button to create new cookie definition b) 'Enter the cookie
name' as 'productId' and select 'No' option for 'Also cache documents whose
requests do not contain this cookie?'.
Now select 'Caching, Personalization,
and Compression Rules' link under 'Rules for Caching, Personalization, and Compression'
section. a) Click on 'Create Global Rule'. b) In 'URL Expression' window
enter 'EsiInvalidation/display\.jsp'. c) Click 'GET' check box option in front
of 'HTTP Method(s)'. d) Select 'Cache' radio button in front of 'Caching Policy'.
e) Check the 'productId: no cache w/o cookie' check box in front of 'Multiple
Documents with the Same Selector by Cookies' and click 'Submit;'
Apply
the changes by clicking the 'Apply Changes' button on top. Choose 'Cache Operations'
link under 'Operations'.
Restart the Web Cache.
Running the Sample
Access
the page on the browser, using the following URL
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