As described previously, a multisite application must be able to quickly determine what site a given request is associated with. To this end, the Core Platform supports two main URL management strategies:
In a path-based strategy, the domain name is the same for all sites, and the site is keyed off the context root in the URL. For example:
http://www.sports.com/baseball/
http://www.sports.com/football/
http://www.sports.com/basketball/An individual Web application (WAR file) can have only one context root, so to make it possible for all of these sites to be part of the same Web application, the system uses a technique called virtual context roots. Using virtual context roots, you map the sites’ context roots (in this case,
/baseball/,/football/, and/basketball/) to the actual context root of the Web application. The virtual context root still appears in the browser when a customer accesses the site.In a domain-based strategy, each site has a different domain name, and a request is associated with a site based on the domain name. There are two variants of this approach, depending on whether the subdomain changes or the parent domain does. If the parent domain changes, the domain names might be:
http://www.baseball.com/
http://www.football.com/
http://www.basketball.com/If the subdomain changes, the domain names might be:
http://baseball.sports.com/
http://football.sports.com/
http://basketball.sports.com/This strategy is more complicated to implement because it requires domain name registration as well as DNS server support. Also, application servers do not, by default, share cookies across domains. To handle this situation, the Core Platform provides a mechanism called session recovery, which is described in detail in the Platform Programming Guide.
When developing your multisite application, you must choose a strategy and implement it. For more details on the strategies themselves, see the URL Management section. For detailed information on implementing the strategies see Multisite URL Management in the Platform Programming Guide.
