3-36 Oracle Fusion Middleware Concepts Guide
OHS allows developers to program their sites in a variety of languages and technologies, such as Java, Perl, C, C++, PHP, and PLSQL. Additionally, it can serve
as either a forward or reverse proxy server.
For more information about OHS see the Oracle Fusion Middleware Administrators Guide for Oracle HTTP Server.
3.13 Oracle Web Cache
This section describes Oracle Web Cache. It includes the following two topics:
■
Reverse Proxying
■
Request Filtering
3.13.1 Reverse Proxying
Oracle Web Cache is a content-aware server accelerator, or reverse proxy, for the Web tier that improves the performance, scalability, and availability of Web sites that run
on any Web server or application server, such as Oracle HTTP Server and Oracle WebLogic Server.
Oracle Web Cache is the primary caching mechanism provided with Oracle Fusion Middleware. Caching improves the performance, scalability, and availability of Web
sites that run on Oracle Fusion Middleware by storing frequently accessed URLs in memory.
By storing frequently accessed URLs in memory, Oracle Web Cache eliminates the need to repeatedly process requests for those URLs on the application Web server and
database tiers. Unlike legacy proxies that handle only static objects, Oracle Web Cache caches both static and dynamically generated content from one or more application
Web servers. Because Oracle Web Cache can cache more content than legacy proxies, it provides optimal performance by greatly reducing the load on application Web server
and database tiers. As an external cache, Oracle Web Cache is also an order of magnitude faster than object caches that run within the application tier.
Because Web Cache is fully compliant with HTTP 1.0 and 1.1 specifications, it can accelerate Web sites that are hosted by any standard Web servers, such as Apache
Tomcat and Microsoft IIS. In Oracle Fusion Middleware, Oracle Web Cache resides in front of one or more instances of Oracle HTTP Server. Responses to browser based
HTTP requests are directed to the Oracle HTTP Server instance and transmitted through Oracle Web Cache. The Oracle Web Cache instance can handle any Web
content transmitted with the standard HTTP protocol.
For more information about reverse proxying see the Oracle Fusion Middleware Administrators Guide for Oracle Web Cache.
3.13.2 Request Filtering
Oracle Web Cache provides request filters to filter incoming HTTP or HTTPS requests to configured sites on the origin server.
Request filtering aids administrators in controlling access to Web sites and providing the following:
■
The planting of malicious code within the Web site that, when executed, steals a users identity or personal information
■
Attacks that try to exploit software vulnerabilities on the site that enable the attacker to execute arbitrary code on the application server
Oracle Fusion Middleware Components 3-37
■
Attacks that try to render a Web site unusable by bombarding it with extremely high volumes of bogus requests that effectively consume the application server
resources or bandwidth, thereby preventing access for other users
In addition, request filtering controls which clients and requests are allowed to access to a Web site or certain parts of a Web site.
For more information about request filtering, see the Oracle Fusion Middleware Administrators Guide for Oracle Web Cache.
3.14 Oracle Web Services
