sunlabs.brazil.tcl
Class TclFilter

java.lang.Object
  sunlabs.brazil.tcl.TclFilter (view source)

All Implemented Interfaces:

Filter, Handler

public class TclFilter
extends Object
implements Filter

Wrapper for writing FilterHandler filters in TCL. Runs a tcl startup script when the handler is initialized. Any time a request is made, the tcl filter proc (which should be defined in the init script) is called, provided with the Request object as an argument.

This provides a bare-bones tcl interface. The startup script should provide a friendlier interface.

This handler requires the tcl.jar jar file, a version of jacl included in the release.

The following server properties are used:

script

The name of the TCL file sourced on startup. The init(sunlabs.brazil.server.Server, java.lang.String) parameters are made available as the global variables prefix and server.

Constructor Summary

TclFilter()

Method Summary

byte[]	filter(Request request, MimeHeaders headers, byte[] content) Filters the content generated by the wrapped Handler.
boolean	init(Server server, String prefix) extract the filter properties.
boolean	respond(Request request) We don't need to look at the request.
boolean	shouldFilter(Request request, MimeHeaders headers) For now, only filter text/html.

Methods inherited from class java.lang.Object

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

Constructor Detail

TclFilter

public TclFilter()

Method Detail

init

public boolean init(Server server,
                    String prefix)

extract the filter properties.

Specified by:

init in interface Handler

Parameters:

server - The HTTP server that created this Handler. Typical Handlers will use Server.props to obtain run-time configuration information.

prefix - The handlers name. The string this Handler may prepend to all of the keys that it uses to extract configuration information from Server.props. This is set (by the Server and ChainHandler) to help avoid configuration parameter namespace collisions.

Returns:

true if this Handler initialized successfully, false otherwise. If false is returned, this Handler should not be used.

respond

public boolean respond(Request request)

We don't need to look at the request.

Specified by:

respond in interface Handler

Parameters:

request - The Request object that represents the HTTP request.

Returns:

true if the request was handled. A request was handled if a response was supplied to the client, typically by calling Request.sendResponse() or Request.sendError.

shouldFilter

public boolean shouldFilter(Request request,
                            MimeHeaders headers)

For now, only filter text/html. This restriction will be lifted once I figure out how

Specified by:

shouldFilter in interface Filter

Parameters:

request - The in-progress HTTP request.

headers - The MIME headers generated by the wrapped Handler.

Returns:

true if this filter would like to examine and possibly rewrite the content, false otherwise.

filter

public byte[] filter(Request request,
                     MimeHeaders headers,
                     byte[] content)

Description copied from interface: Filter

Filters the content generated by the wrapped Handler. The content may be arbitrarily rewritten by this method.

The MIME headers may also be modified by this Filter, for instance, to change the "Content-Type" of a web page. The "Content-Length" will automatically be computed by the FilterHandler.

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.