    #!/usr/bin/env python

    from Common import *
    from UserDict import UserDict
    from Object import Object
    from types import FloatType, ClassType

    from ExceptionHandler import ExceptionHandler

    from ConfigurableForServerSidePath import ConfigurableForServerSidePath

    from TaskKit.Scheduler import Scheduler

    from HTTPRequest import HTTPRequest
    from Transaction import Transaction
    from Session import Session
    import URLParser
    import HTTPExceptions

    debug = 0

    class EndResponse(Exception):
        """End response exception.

        Used to prematurely break out of the awake()/respond()/sleep()
        cycle without reporting a traceback. During servlet processing,
        if this exception is caught during awake() or respond() then sleep()
        is called and the response is sent. If caught during sleep(),
        processing ends and the response is sent.

        """
        pass

    class Application(ConfigurableForServerSidePath, Object):
        """The Application singleton.

        `Application` and `AppServer` work together to setup up and dispatch
        requests. The distinction between the two is largely historical, but
        AppServer communicates directly with Adapters (or speaks protocols like
        HTTP), and Application receives the (slightly) processed input from
        AppServer and turns it into `Transaction`, `HTTPRequest`, `HTTPResponse`,
        and `Session`.

        Application is a singleton, which belongs to the AppServer. You can get
        access through the Transaction object (``transaction.application()``),
        or you can do::

            from AppServer import globalAppServer
            application = AppServer.application()

        Settings for Application are taken from ``Configs/Application.config``,
        and it is used for many global settings, even if they aren't closely tied
        to the Application object itself.

        """

        ## Init ##

        def __init__(self, server):
            """Called only by `AppServer`, sets up the Application."""

            self._server = server
            self._serverSidePath = server.serverSidePath()

            ConfigurableForServerSidePath.__init__(self)
            Object.__init__(self)

            if self.setting('PrintConfigAtStartUp'):
                self.printConfig()

            self.initVersions()

            self._shutDownHandlers = []

            # For TaskManager:
            if self._server.isPersistent():
                self._taskManager = Scheduler(1)
                self._taskManager.start()

            # Define this before initializing URLParser, so that contexts have a
            # chance to override this. Also be sure to define it before loading the
            # sessions, in case the loading of the sessions causes an exception.
            self._exceptionHandlerClass = ExceptionHandler

            # For session store:
            sessionStore = 'Session%sStore' % self.setting('SessionStore')
            exec 'from %s import %s' % (sessionStore, sessionStore)
            klass = locals()[sessionStore]
            assert isinstance(klass, ClassType) or issubclass(klass, Object)
            self._sessions = klass(self)

            print 'Current directory:', os.getcwd()

            URLParser.initApp(self)
            self._rootURLParser = URLParser.ContextParser(self)

            self.running = 1

            self.startSessionSweeper()

            try: # try to get a 404 error page from the working dir
                self._404Page = open(os.path.join(self._serverSidePath,
                    "404Text.txt")).read()
            except: # if not found in the working dir,
                try: # then try the directory this file is located in
                    self._404Page = open(os.path.join(
                        os.path.dirname(os.path.abspath(__file__)),
                        "404Text.txt")).read()
                except: # otherwise fall back to standard exception
                    self._404Page = None

        def initVersions(self):
            """Get and store versions.

            Initialize attributes that store the Webware and WebKit versions as
            both tuples and strings. These are stored in the Properties.py files.

            """
            from MiscUtils.PropertiesObject import PropertiesObject
            props = PropertiesObject(os.path.join(self.webwarePath(),
                                  'Properties.py'))
            self._webwareVersion = props['version']
            self._webwareVersionString = props['versionString']

            props = PropertiesObject(os.path.join(self.webKitPath(),
                                  'Properties.py'))
            self._webKitVersion = props['version']
            self._webKitVersionString = props['versionString']

        def taskManager(self):
            """Accessor: `TaskKit.Scheduler` instance."""
            return self._taskManager

        def startSessionSweeper(self):
            """Start session sweeper.

            Starts the session sweeper, `WebKit.Tasks.SessionTask`, which deletes
            session objects (and disk copies of those objects) that have expired.

            """
            from Tasks import SessionTask
            import time
            task = SessionTask.SessionTask(self._sessions)
            tm = self.taskManager()
            sweepinterval = self.setting('SessionTimeout')*60/10
            tm.addPeriodicAction(time.time()+sweepinterval,
                         sweepinterval, task, "SessionSweeper")
            print "Session Sweeper started"

        def shutDown(self):
            """Shut down the application.

            Called by AppServer when it is shuting down.  The `__del__` function
            of Application probably won't be called due to circular references.

            """
            print "Application is shutting down..."
            self.running = 0
            if hasattr(self, '_sessSweepThread'):
                # We don't always have this, hence the 'if' above
                self._closeEvent.set()
                self._sessSweepThread.join()
                del self._sessSweepThread
            self._sessions.storeAllSessions()
            if self._server.isPersistent():
                self.taskManager().stop()
            del self._sessions
            del self._server

            # Call all registered shutdown handlers
            for shutDownHandler in self._shutDownHandlers:
                shutDownHandler()
            del self._shutDownHandlers

            print "Application has been succesfully shutdown."

        def addShutDownHandler(self, func):
            """Add a shutdown handler.

            Functions added through `addShutDownHandler` will be called when
            the AppServer is shutting down. You can use this hook to close
            database connections, clean up resources, save data to disk, etc.

            """
            self._shutDownHandlers.append(func)

        ## Config ##

        def defaultConfig(self):
            """The default Application.config."""
            return {
                'PrintConfigAtStartUp': 1,
                'LogActivity': 1,
                'ActivityLogFilename': 'Logs/Activity.csv',
                'ActivityLogColumns': [
                    'request.remoteAddress', 'request.method',
                    'request.uri', 'response.size',
                    'servlet.name', 'request.timeStamp',
                    'transaction.duration',
                    'transaction.errorOccurred'
                    ],
                'SessionStore': 'Dynamic',
                'SessionTimeout': 60,
                'IgnoreInvalidSession': 1,
                'UseAutomaticPathSessions': 0,
                'ShowDebugInfoOnErrors': 1,
                'IncludeFancyTraceback': 0,
                'FancyTracebackContext': 5,
                'UserErrorMessage': 'The site is having technical difficulties'
                    ' with this page. An error has been logged, and the problem'
                    ' will be fixed as soon as possible. Sorry!',
                'LogErrors': 1,
                'ErrorLogFilename': 'Logs/Errors.csv',
                'SaveErrorMessages': 1,
                'ErrorMessagesDir': 'ErrorMsgs',
                'EmailErrors': 0,
                'ErrorEmailServer': 'localhost',
                'ErrorEmailHeaders': {
                    'From': 'webware@mydomain',
                    'To': ['webware@mydomain'],
                    'Reply-to': 'webware@mydomain',
                    'content-type': 'text/html',
                    'Subject': 'Error'
                    },
                'MaxValueLengthInExceptionReport': 500,
                'RPCExceptionReturn': 'traceback',
                'ReportRPCExceptionsInWebKit': 1,
                'Contexts': {
                    'default': 'Examples',
                    'Admin': 'Admin',
                    'Examples': 'Examples',
                    'Testing': 'Testing',
                    'Docs': 'Docs',
                    },
                'Debug': {
                    'Sessions': 0,
                    },
                'EnterDebuggerOnException': 0,
                'DirectoryFile': ['index', 'Index', 'main', 'Main'],
                'UseCascadingExtensions': 1,
                'ExtensionCascadeOrder': ['.py','.psp','.kid','.html'],
                'ExtraPathInfo': 1,
                'ExtensionsToIgnore': ['.pyc', '.pyo', '.py~',
                    '.psp~', '.kid~', '.html~', '.bak', '.tmpl'
                    ],
                'ExtensionsToServe': [],
                'FilesToHide': ['.*','*~', '*.bak', '*.tmpl',
                    '*.config', '__init__.*', '*.pyc', '*.pyo'
                    ],
                'FilesToServe': [],
                'UnknownFileTypes': {
                    'ReuseServlets': 1,
                    'Technique': 'serveContent',
                    'CacheContent': 0,
                    },
            }

        def configFilename(self):
            return self.serverSidePath('Configs/Application.config')

        def configReplacementValues(self):
            return self._server.configReplacementValues()

        ## Versions ##

        def version(self):
            """Return the version of the application.

            This implementation returns '0.1'. Subclasses should
            override to return the correct version number.

            """
            # @@ 2000-05-01 ce: Maybe this could be a setting 'AppVersion'
            # @@ 2003-03 ib: Does anyone care about this?  What's this
            # version even supposed to mean?
            return '0.1'

        def webwareVersion(self):
            """Return the Webware version as a tuple."""
            return self._webwareVersion

        def webwareVersionString(self):
            """Return the Webware version as a printable string."""
            return self._webwareVersionString

        def webKitVersion(self):
            """ Return the WebKit version as a tuple."""
            # @@ 2003-03 ib: This is synced with Webware now, should be removed
            # because redundant (and not that useful anyway)
            return self._webKitVersion

        def webKitVersionString(self):
            """Return the WebKit version as a printable string."""
            return self._webKitVersionString

        ## Sessions ##

        def session(self, sessionId, default=NoDefault):
            """The session object for `sessionId`.

            Raises ``KeyError`` if session not found and no default is given.

            """
            if default is NoDefault:
                return self._sessions[sessionId]
            else:
                return self._sessions.get(sessionId, default)

        def hasSession(self, sessionId):
            """Check whether session `sessionId` exists."""
            return self._sessions.has_key(sessionId)

        def sessions(self):
            """A dictionary of all the session objects."""
            return self._sessions

        def createSessionForTransaction(self, transaction):
            """Get the session object for the transaction.

            If the session already exists, returns that, otherwise creates
            a new session.

            Finding the session ID is done in `Transaction.sessionId`.

            """
            debug = self.setting('Debug').get('Sessions')
            if debug:
                prefix = '>> [session] createSessionForTransaction:'
            sessId = transaction.request().sessionId()
            if debug:
                print prefix, 'sessId =', sessId
            if sessId:
                try:
                    session = self.session(sessId)
                    if debug: print prefix, 'retrieved session =', session
                except KeyError:
                    sessId = None
            if not sessId:
                session = Session(transaction)
                self._sessions[session.identifier()] = session
                if debug: print prefix, 'created session =', session
            transaction.setSession(session)
            return session

        def createSessionWithID(self, transaction, sessionID):
            # Create a session object with our session ID
            sess = Session(transaction, sessionID)
            # Replace the session if it didn't already exist,
            # otherwise we just throw it away.  setdefault is an atomic
            # operation so this guarantees that 2 different
            # copies of the session with the same ID never get placed into
            # the session store, even if multiple threads are calling
            # this method simultaneously.
            transaction.application()._sessions.setdefault(sessionID, sess)

        ## Misc Access ##

        def server(self):
            """Acessor: the AppServer"""
            return self._server

        def serverSidePath(self, path=None):
            """Get the serve-side-path.

            Returns the absolute server-side path of the WebKit application.
            If the optional path is passed in, then it is joined with the
            server side directory to form a path relative to the app server.

            """
            if path:
                return os.path.normpath(
                    os.path.join(self._serverSidePath, path))
            else:
                return self._serverSidePath

        def webwarePath(self):
            """The path of the ``Webware/`` directory."""
            return self._server.webwarePath()

        def webKitPath(self):
            """The Path of the ``Webware/WebKit/`` directory."""
            return self._server.webKitPath()

        def name(self):
            """The name by which this was started. Usually ``AppServer``."""
            # @@ 2003-03 ib: unconfirmed
            return sys.argv[0]

        ## Activity Log ##

        def writeActivityLog(self, transaction):
            """Write an entry to the activity log.

            Writes an entry to the script log file. Uses settings
            ``ActivityLogFilename`` and ``ActivityLogColumns``.

            """
            filename = self.serverSidePath(
                self.setting('ActivityLogFilename'))
            if os.path.exists(filename):
                file = open(filename, 'a')
            else:
                file = open(filename, 'w')
                file.write(','.join(self.setting('ActivityLogColumns'))+'\n')
            values = []
            # We use UserDict on the next line because we know it inherits
            # NamedValueAccess and reponds to valueForName()
            objects = UserDict({
                'application': self,
                'transaction': transaction,
                'request':   transaction.request(),
                'response': transaction.response(),
                'servlet':   transaction.servlet(),
                'session':   transaction._session, #don't cause creation of session
            })
            for column in self.setting('ActivityLogColumns'):
                try:
                    value = objects.valueForName(column)
                except:
                    value = '(unknown)'
                if type(value) is FloatType:
                    # probably need more flexibility in the future
                    value = '%0.2f' % value
                else:
                    value = str(value)
                values.append(value)
            file.write(','.join(values)+'\n')
            file.close()

            for i in objects.keys():
                objects[i] = None

        ## Request Dispatching ##

        # These are the entry points from `AppServer`, which take a raw request,
        # turn it into a transaction, run the transaction, and clean up.

        def dispatchRawRequest(self, requestDict, strmOut):
            """Dispatch a raw request.

            Dispatch a request as passed from the Adapter through the AppServer.
            This method creates the request, response, and transaction object,
            then runs (via `runTransaction`) the transaction. It also catches any
            exceptions, which are then passed on to `handleExceptionInTransaction`.

            """
            trans = None
            try:
                request = self.createRequestForDict(requestDict)
                trans = Transaction(application=self, request=request)
                request.setTransaction(trans)
                response = request.responseClass()(trans, strmOut)
                trans.setResponse(response)
                self.runTransaction(trans)
                trans.response().deliver()
            except:
                if trans:
                    trans.setErrorOccurred(1)
                if self.setting('EnterDebuggerOnException') and sys.stdin.isatty():
                    import pdb
                    pdb.post_mortem(sys.exc_info()[2])
                self.handleExceptionInTransaction(sys.exc_info(), trans)
                trans.response().deliver()

            if self.setting('LogActivity'):
                self.writeActivityLog(trans)
            request.clearTransaction()
            response.clearTransaction()
            return trans

        def createRequestForDict(self, requestDict):
            """Create request object for a given dictionary.

            Create a request object (subclass of `Request`) given the raw
            dictionary as passed by the adapter.

            The class of the request may be based on the contents of the
            dictionary (though only `HTTPRequest` is currently created),
            and the request will later determine the class of the response.

            Called by `dispatchRawRequest`.

            """
            format = requestDict['format']
            # Maybe an EmailAdapter would make a request with a
            # format of Email, and an EmailRequest would be
            # generated.  For now just CGI/HTTPRequest.
            assert format == 'CGI'
            return HTTPRequest(requestDict)

        def runTransaction(self, trans):
            """Run transation.

            Executes the transaction, handling HTTPException errors.
            Finds the servlet (using the root parser, probably
            `URLParser.ContextParser`, to find the servlet for the
            transaction, then calling `runTransactionViaServlet`.

            Called by `dispatchRawRequest`.

            """
            # @@ gtalvola: I'm guessing this is not the ideal place
            # @@ to put this code. But, it works.
            if self.setting('UseAutomaticPathSessions'):
                request = trans.request()
                request_has_cookie_session = request.hasCookieSession()
                request_has_path_session = request.hasPathSession()
                if request_has_cookie_session and request_has_path_session:
                    self.handleUnnecessaryPathSession(trans)
                    return
                elif not request_has_cookie_session and not request_has_path_session:
                    self.handleMissingPathSession(trans)
                    return
            servlet = None
            try:
                servlet = self._rootURLParser.findServletForTransaction(trans)
                self.runTransactionViaServlet(servlet, trans)
            except HTTPExceptions.HTTPException, err:
                err.setTransaction(trans)
                trans.response().displayError(err)
            except EndResponse:
                pass
            if servlet:
                # Return the servlet to its pool
                self.returnServlet(servlet, trans)

        def runTransactionViaServlet(self, servlet, trans):
            """Execute the transaction using the servlet.

            This is the `awake`/`respond`/`sleep` sequence of calls, or if
            the servlet supports it, a single `runTransaction` call (which is
            presumed to make the awake/respond/sleep calls on its own). Using
            `runTransaction` allows the servlet to override the basic call
            sequence, or catch errors from that sequence.

            Called by `runTransaction`.

            """
            trans.setServlet(servlet)
            if hasattr(servlet, 'runTransaction'):
                servlet.runTransaction(trans)
            else:
                # For backward compatibility (Servlet.runTransaction implements
                # this same sequence of calls, but by keeping it in the servlet
                # it's easier for the servlet to catch exceptions).
                try:
                    trans.awake()
                    trans.respond()
                finally:
                    trans.sleep()

        def forward(self, trans, url, context=None):
            """Forward the request to a different (internal) url.

            The transaction's URL is changed to point to the new servlet,
            and the transaction is simply run again.

            Output is _not_ accumulated, so if the original servlet had any output,
            the new output will _replace_ the old output.

            You can change the request in place to control the servlet you are
            forwarding to -- using methods like `HTTPRequest.setField`.

            @@ 2003-03 ib: how does the forwarded servlet knows that it's not
            the original servlet?

            """
            # Reset the response to a "blank slate"
            trans.response().reset()

            # Include the other servlet
            self.includeURL(trans, url, context)

            # Raise an exception to end processing of this request
            raise EndResponse

        def callMethodOfServlet(self, trans, url, method, *args, **kw):
            """Call method of another servlet.

            Call a method of the servlet referred to by the url, potentially in
            a particular context (use the context keyword argument). Calls sleep()
            and awake() before and after the method call. Or, if the servlet
            defines it, then `runMethodForTransaction` is used (analogous to the
            use of `runTransaction` in `forward`).

            The entire process is similar to `forward`, except that instead of
            `respond`, `method` is called (`method` should be a string, ``*args``
            and ``**kw`` are passed as arguments to that method).

            A `context` keyword argument (as used in `forward`) is also allowed,
            though it isn't present in the method signature.

            """
            # 3-03 ib@@: Does anyone actually use this method?
            # 2003-04-08 jdh: I use callMethodOfServlet, but I don't use
            # this little context trick.  Not sure what you were referring to.
            if kw.has_key('context'):
                context = kw['context']
                del kw['context']
            else:
                context = None

            urlPath = self.resolveInternalRelativePath(trans, url, context)
            req = trans.request()
            currentPath = req.urlPath()
            currentServlet = trans._servlet
            currentServerSidePath = req._serverSidePath
            currentServerSideContextPath = req._serverSideContextPath
            currentContextName = req._contextName
            currentServerRootPath = req._serverRootPath
            currentPathInfo = req._pathInfo
            currentExtraURLPath = req._extraURLPath
            req.setURLPath(urlPath)
            req.addParent(currentServlet)

            servlet = self._rootURLParser.findServletForTransaction(trans)
            trans._servlet = servlet
            if hasattr(servlet, 'runMethodForTransaction'):
                result = servlet.runMethodForTransaction(trans, method, *args, **kw)
            else:
                servlet.awake(trans)
                result = getattr(servlet, method)(*args, **kw)
                servlet.sleep(trans)

            # Put things back
            req.setURLPath(currentPath)
            req._serverSidePath = currentServerSidePath
            req._serverSideContextPath = currentServerSideContextPath
            req._contextName = currentContextName
            req._serverRootPath = currentServerRootPath
            req._pathInfo = currentPathInfo
            req._extraURLPath = currentExtraURLPath
            req.popParent()
            trans._servlet = currentServlet

            return result

        def includeURL(self, trans, url, context=None):
            """Include another servlet.

            Include the servlet given by the url, potentially in context (or
            current context). Like `forward`, except control is ultimately
            returned to the servlet.

            """
            urlPath = self.resolveInternalRelativePath(trans, url, context)
            req = trans.request()
            currentPath = req.urlPath()
            currentServlet = trans._servlet
            currentServerSidePath = req._serverSidePath
            currentServerSideContextPath = req._serverSideContextPath
            currentContextName = req._contextName
            req.setURLPath(urlPath)
            req.addParent(currentServlet)
            # We use a try/finally to make sure everything gets restored properly
            # in the event of an exception in an included servlet.
            try:
                servlet = self._rootURLParser.findServletForTransaction(trans)
                trans._servlet = servlet
                # We will interpret an EndResponse in an included page to mean that
                # the current page may continue processing.
                try:
                    servlet.runTransaction(trans)
                except EndResponse:
                    pass
                self.returnServlet(servlet, trans)
            finally:
                req.popParent()
                req.setURLPath(currentPath)
                req._serverSidePath = currentServerSidePath
                req._serverSideContextPath = currentServerSideContextPath
                req._contextName = currentContextName
                trans._servlet = currentServlet

        def resolveInternalRelativePath(self, trans, url, context=None):
            """Return the absolute internal path.

            Given a URL and an optional context, return the absolute
            internal URL. URLs are assumed relative to the current URL.

            Absolute paths are returned unchanged.

            """
            req = trans.request()
            if not url.startswith('/'):
                origPath = req.urlPath()
                if origPath.endswith('/'):
                    origDir = origPath
                else:
                    origDir = os.path.dirname(origPath)
                    if not origDir.endswith('/'):
                        origDir += '/'
                path = origDir + url
            else:
                if context is None:
                    context = req._contextName
                path = '/%s%s' % (context, url)
            # Deal with .. in the path
            parts = []
            for part in path.split('/'):
                if part == '..':
                    parts.pop()
                else:
                    parts.append(part)
            return '/'.join(parts)

        def returnServlet(self, servlet, trans):
            servlet.close(trans)

        def handleException(self):
            """Handle exceptions.

            This should only be used in cases where there is no transaction object,
            for example if an exception occurs when attempting to save a session
            to disk.

            """
            self._exceptionHandlerClass(self, None, sys.exc_info())

        def handleExceptionInTransaction(self, excInfo, transaction):
            """Handle exception with info.

            Handles exception `excInfo` (as returned by ``sys.exc_info()``)
            that was generated by `transaction`. It may display the exception
            report, email the report, etc., handled by
            `ExceptionHandler.ExceptionHandler`.

            """
            req = transaction.request()
            editlink = req.adapterName() + "/Admin/EditFile"
            self._exceptionHandlerClass(self, transaction, excInfo,
                             {"editlink": editlink})

        def rootURLParser(self):
            """Accessor: the Rool URL parser.

            URL parsing (as defined by subclasses of `URLParser.URLParser`)
            starts here. Other parsers are called in turn by this parser.

            """
            return self._rootURLParser

        def hasContext(self, name):
            """Checks whether context `name` exist."""
            return self._rootURLParser._contexts.has_key(name)

        def addContext(self, name, path):
            """Add a context by named `name`, rooted at `path`.

            This gets imported as a package, and the last directory
            of `path` does not have to match the context name.
            (The package will be named `name`, regardless of `path`).

            Delegated to `URLParser.ContextParser`.

            """
            self._rootURLParser.addContext(name, path)

        def addServletFactory(self, factory):
            """Add a ServletFactory.

            Delegated to the `URLParser.ServletFactoryManager` singleton.

            """
            URLParser.ServletFactoryManager.addServletFactory(factory)

        def contexts(self):
            """Return a dictionary of context-name: context-path."""
            return self._rootURLParser._contexts

        def writeExceptionReport(self, handler):
            # @@ 2003-02 ib: does anyone care?
            pass

        def handleMissingPathSession(self,transaction):
            """Redirect requests without session info in the path.

            if UseAutomaticPathSessions is enabled in Application.config
            we redirect the browser to a url with SID in path
            http://gandalf/a/_SID_=2001080221301877755/Examples/
            _SID_ is extracted and removed from path in HTTPRequest.py

            This is for convinient building of webapps that must not
            depend on cookie support.

            """
            newSid = transaction.session().identifier()
            request = transaction.request()
            url = request.adapterName() + '/_SID_='+ newSid + '/' \
                + request.pathInfo() + (request.extraURLPath() or '')
            if request.queryString():
                url = url + '?' + request.queryString()
            if self.setting('Debug')['Sessions']:
                print '>> [sessions] handling UseAutomaticPathSessions,' \
                    ' redirecting to', url
            transaction.response().sendRedirect(url)

        def handleUnnecessaryPathSession(self, transaction):
            """Redirect request with unnecessary session info in the path.

            This is called if it has been determined that the request has a path
            session, but also cookies. In that case we redirect to eliminate the
            unnecessary path session.

            """
            request = transaction.request()
            url = request.adapterName() + '/' + request.pathInfo() + (request.extraURLPath() or '')

            if request.queryString():
                url = url + '?' + request.queryString()
            if self.setting('Debug')['Sessions']:
                print ">> [sessions] handling unnecessary path session, redirecting to", url
            transaction.response().sendRedirect(url)

    ## Main ##

    def main(requestDict):
        """Return a raw reponse.

        This method is mostly used by OneShotAdapter.py.

        """
        from WebUtils.HTMLForException import HTMLForException
        try:
            assert type(requestDict) is type({})
            app = Application(useSessionSweeper=0)
            return app.runRawRequest(requestDict).response().rawResponse()
        except:
            return {
                'headers': [('Content-type', 'text/html')],
                'contents': '<html><body>%s</html></body>' % HTMLForException()
            }

    """
    You can run Application as a main script, in which case it expects a
    single argument which is a file containing a dictionary representing
    a request. This technique isn't very popular as Application itself
    could raise exceptions that aren't caught. See `CGIAdapter` and
    `AppServer` for a better example of how things should be done.

    Largely historical.
    """

    if __name__=='__main__':
        if len(sys.argv)!=2:
            sys.stderr.write('WebKit: Application: Expecting one filename argument.\n')
        requestDict = eval(open(sys.argv[1]).read())
        main(requestDict)