HistoryFilter (Brazil 2.3)

The HistoryFilter is both a Handler and a Filter that keeps a record of all pages visited by a given session.

The HistoryFilter can be used to make a user's session "mobile" as follows: A user's history is normally stored with the browser being used, on the user's machine. If the user runs a different browser or goes to a different machine, the user's history will not be there. Instead, the user can access the web via a proxy that keeps track of their history. No matter which browser the user chooses or machine the user is at, a server running with the HistoryFilter will automatically remember and be able to present the user's history.

The history is kept with respect to a Session ID.

This filter uses the following configuration properties:

prefix: This handler will only process URLs beginning with this string. The default value is "", which matches all URLs.
session: The name of the request property that holds the Session ID. The default value is "SessionID".
nosession: The Session ID to use if the Session ID was not specified. The default value is "common".
admin: URLs beginning with this prefix cause the HistoryFilter to store the history information for the current Session in the request properties
filter: If specified, then this is a Regexp pattern to match against the "Content-Type" of the result. Setting this also implies that the HistoryFilter will be invoked as a Filter and not a Handler. The default value is "", which indicates that the "Content-Type" is not examined and that this HistoryFilter will be invoked as a Handler.

Version: 2.2

Author: Colin Stevens (colin.stevens@sun.com)

Field Summary
String	admin
Regexp	filter
String	nosession
String	session
String	urlPrefix

Method Summary
byte[]	filter(Request request, MimeHeaders headers, byte[] content) Returns the original content, since this filter does not change content.
boolean	init(Server server, String prefix) Initializes this filter by reading all its configuration properties.
boolean	respond(Request request) If the `admin` prefix is seen, store the history information associated with the session in the request properties.
boolean	shouldFilter(Request request, MimeHeaders headers) Called when invoked as a `Filter`.

Initializes this filter by reading all its configuration properties.

It is an error if the filter is specified but malformed.

Parameters: server The HTTP server. prefix The configuration property prefix.

Returns: true if this filter initialized successfully, false otherwise.

respond

If the admin prefix is seen, store the history information associated with the session in the request properties.

If invoked as a Handler and the URL matches the prefix, records this page's address in the history.

Parameters: request The Request object that represents the HTTP request.

Returns: false, indicating that this respond method ran purely for its side effects.

shouldFilter

Called when invoked as a Filter. If the URL matches the prefix and the returned "Content-Type" matches the filter, records this page's address in the history.

Parameters: request The in-progress HTTP request. headers The MIME headers from the result.

Returns: false indicating that this Filter does not want to modify the content.

Class HistoryFilter