Package sunlabs.brazil.proxy

Class HistoryFilter

  • All Implemented Interfaces:
    Filter, Handler
    public class HistoryFilter
extends java.lang.Object
implements Filter
    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)

    • Constructor Summary

      Constructors 
      Constructor Description
      HistoryFilter()  

    • Method Summary

      All Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      byte[] filter​(Request request, MimeHeaders headers, byte[] content)
      Returns the original content, since this filter does not change content.
      boolean init​(Server server, java.lang.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.

      • Methods inherited from class java.lang.Object

        clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

    • Field Detail

      • urlPrefix

        public java.lang.String urlPrefix

      • session

        public java.lang.String session

      • nosession

        public java.lang.String nosession

      • admin

        public java.lang.String admin

      • filter

        public Regexp filter

    • Constructor Detail

      • HistoryFilter

        public HistoryFilter()

    • Method Detail

      • init

        public boolean init​(Server server,
                    java.lang.String prefix)
        Initializes this filter by reading all its configuration properties.

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

        Specified by:
        init in interface Handler
        Parameters:
        server - The HTTP server.
        prefix - The configuration property prefix.
        Returns:
        true if this filter initialized successfully, false otherwise.

      • respond

        public boolean respond​(Request request)
        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.

        Specified by:
        respond in interface Handler
        Parameters:
        request - The Request object that represents the HTTP request.
        Returns:
        false, indicating that this respond method ran purely for its side effects.

      • shouldFilter

        public boolean shouldFilter​(Request request,
                            MimeHeaders headers)
        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.
        Specified by:
        shouldFilter in interface Filter
        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.

      • filter

        public byte[] filter​(Request request,
                     MimeHeaders headers,
                     byte[] content)
        Returns the original content, since this filter does not change content. Won't actually be invoked.
        Specified by:
        filter in interface Filter
        Parameters:
        request - The finished HTTP request.
        headers - The MIME headers generated by the Handler.
        content - The output from the Handler that this Filter may rewrite.
        Returns:
        The rewritten content. The Filter may return the original content unchanged. The Filter may return null to indicate that the FilterHandler should stop processing the request and should not return any content to the client.