sunlabs.brazil.tcl
Class TclHandler

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

All Implemented Interfaces:

Handler

public class TclHandler
extends Object
implements Handler

Handler for writing handlers in tcl. Anytime a request is made, call the respond callback in the tcl code, which is provided with the Request object as an argument.

This provides a bare-bones tcl interface. The startup script, which is sourced once upon startup, should provide a friendlier interface.

One Tcl interpreter is started for each session. The SessionID property of the request is used to choose the session. if no Session ID is available, a single interpreter is used for each request. The interpreter is Initialized the first time it is referenced for a session, or if the "SessionID" variable is NOT set.

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

The following server properties are used:

callback

The name of the TCL script to call at each request. Defaults to respond.

prefix, suffix, glob, match

Specify the URL that triggers this handler. (See MatchString).

script

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

Constructor Summary

TclHandler()

Method Summary

boolean	init(Server server, String prefix) Create a tcl interp, extract the properties, and run the init script
boolean	respond(Request request) Responds to an HTTP request.

Methods inherited from class java.lang.Object

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

Constructor Detail

TclHandler

public TclHandler()

Method Detail

init

public boolean init(Server server,
                    String prefix)

Create a tcl interp, extract the properties, and run the init script

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)
                throws IOException

Description copied from interface: Handler

Responds to an HTTP 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.

Throws:

IOException - if there was an I/O error while sending the response to the client. Typically, in that case, the Server will (try to) send an error message to the client and then close the client's connection.

The IOException should not be used to silently ignore problems such as being unable to access some server-side resource (for example getting a FileNotFoundException due to not being able to open a file). In that case, the Handler's duty is to turn that IOException into a HTTP response indicating, in this case, that a file could not be found.