    from Common import *
    from Response import Response
    from WebKit.Cookie import Cookie
    from types import *

    # time.gmtime() no longer returns a tuple, and there is no globally defined type
    # for this at the moment.
    TimeTupleType = type(time.gmtime(0))

    # Import mxDateTime if it exists, but we can get along with it
    # if not.
    try:
        from mx import DateTime
    except ImportError:
        try:
            import DateTime
        except ImportError:
            DateTime = None
    from MiscUtils.DateInterval import timeDecode

    debug = 0

    class HTTPResponse(Response):

        ## Init ##

        def __init__(self, transaction, strmOut, headers=None):
            """ Initializes the request. """

            Response.__init__(self, transaction, strmOut)

            self._committed = 0

            if headers is None:
                self._headers = {}#{'Content-type': 'text/html'}
                self.setHeader('Content-type','text/html')
            else:
                self._headers = headers

            self._cookies   = {}

        ## Headers ##

        def header(self, name, default=NoDefault):
            """ Returns the value of the specified header. """
            if default is NoDefault:
                return self._headers[name.lower()]
            else:
                return self._headers.get(name.lower(), default)

        def hasHeader(self, name):
            return self._headers.has_key(name.lower())

        def setHeader(self, name, value):
            """Sets a specific header by name.

            Parameters:
                name: Header Name
                value: Header Value

            """
            assert self._committed == 0, "Headers have already been sent"
            self._headers[name.lower()] = value

        def addHeader(self, name, value):
            """Adds a specific header by name."""
            print "addHeader is deprecated. Use setHeader()."
            assert self._committed == 0
            self.setHeader(name, value)

        def headers(self, name=None):
            """ Returns a dictionary-style object of all Header objects contained by this request. """
            return self._headers

        def clearHeaders(self):
            """Clears all the headers.

            You might consider a setHeader('Content-type', 'text/html')
            or something similar after this.

            """
            assert self._committed == 0
            self._headers = {}

        ## Cookies ##

        def cookie(self, name):
            """Returns the value of the specified cookie."""
            return self._cookies[name]

        def hasCookie(self, name):
            """Returns True if the specified cookie is present."""
            return self._cookies.has_key(name)

        def setCookie(self, name, value, path='/', expires='ONCLOSE',
                  secure=False):
            """Set a cookie.

            You can also set the path (which defaults to /).
            You can also set when it expires. It can expire:
              'NOW': this is the same as trying to delete it, but it
                doesn't really seem to work in IE
              'ONCLOSE': the default behavior for cookies (expires when
                         the browser closes)
              'NEVER': some time in the far, far future.
              integer: a timestamp value
              tuple: a tuple, as created by the time module
              DateTime: an mxDateTime object for the time (assumed to
                be *local*, not GMT time)
              DateTimeDelta: a interval from the present, e.g.,
                DateTime.DateTimeDelta(month=1) (1 month in the future)
                '+...': a time in the future, '...' should be something like
                1w (1 week), 3h46m (3:45), etc.  You can use y (year),
                b (month), w (week), d (day), h (hour), m (minute),
                s (second). This is done by the MiscUtils.DateInterval.

            """
            cookie = Cookie(name, value)
            if expires == 'ONCLOSE' or not expires:
                pass # this is already default behavior
            elif expires == 'NOW':
                cookie.delete()
                return
            elif expires == 'NEVER':
                t = time.gmtime(time.time())
                if expires == 'NEVER':
                    t = (t[0] + 10,) + t[1:]
                t = time.strftime("%a, %d-%b-%Y %H:%M:%S GMT", t)
                cookie.setExpires(t)
            else:
                t = expires
                if type(t) is StringType and t and t[0] == '+':
                    interval = timeDecode(t[1:])
                    t = time.time() + interval
                if type(t) in (IntType, LongType, FloatType):
                    t = time.gmtime(t)
                if type(t) in (TupleType, TimeTupleType):
                    t = time.strftime("%a, %d-%b-%Y %H:%M:%S GMT", t)
                if DateTime and \
                        (type(t) is DateTime.DateTimeDeltaType
                    or isinstance(t, DateTime.RelativeDateTime)):
                    t = DateTime.now() + t
                if DateTime and type(t) is DateTime.DateTimeType:
                    t = (t - t.gmtoffset()).strftime("%a, %d-%b-%Y %H:%M:%S GMT")
                cookie.setExpires(t)
            if path:
                cookie.setPath(path)
            if secure:
                cookie.setSecure(secure)
            self.addCookie(cookie)

        def addCookie(self, cookie):
            """Adds a cookie that will be sent with this response.

            cookie is a Cookie object instance. See WebKit.Cookie.

            """
            assert self._committed == 0
            assert isinstance(cookie, Cookie)
            self._cookies[cookie.name()] = cookie

        def delCookie(self, name):
            """Deletes a cookie at the browser.

            To do so, one has to create and send to the browser a cookie with
            parameters that will cause the browser to delete it.

            """
            if self._cookies.has_key(name):
                self._cookies[name].delete()
            else:
                cookie = Cookie(name, None)
                cookie.delete()
                self.addCookie(cookie)

        def cookies(self):
            """Get all the cookies.

            Returns a dictionary-style object of all Cookie objects that will
            be sent with this response.

            """
            return self._cookies

        def clearCookies(self):
            """Clears all the cookies."""
            assert self._committed == 0
            self._cookies = {}

        ## Status ##

        def setStatus(self, code, msg=''):
            """Set the status code of the response, such as 200, 'OK'."""
            assert self._committed == 0, "Headers already sent."
            self.setHeader('Status', str(code) + ' ' + msg)

        ## Special responses ##

        def sendError(self, code, msg=''):
            """Sets the status code to the specified code and message."""
            assert self._committed == 0, "Response already partially sent"
            self.setStatus(code, msg)

        def sendRedirect(self, url):
            """Redirect to another url.

            This method sets the headers and content for the redirect, but does
            NOT change the cookies. Use clearCookies() as appropriate.

            @@ 2002-03-21 ce: I thought cookies were ignored by user agents if a
            redirect occurred. We should verify and update code or docs as appropriate.

            """
            # ftp://ftp.isi.edu/in-notes/rfc2616.txt
            # Sections: 10.3.3 and others

            assert self._committed == 0, "Headers already sent"

            self.setHeader('Status', '302 Redirect')
            self.setHeader('Location', url)
            self.setHeader('Content-type', 'text/html')

            self.write('<html><body>This page has been redirected'
                ' to <a href="%s">%s</a>.</body> </html>' % (url, url))

        ## Output ##

        def write(self, charstr=None):
            """Write charstr to the response stream."""
            if charstr: self._strmOut.write(charstr)
            if not self._committed and self._strmOut._needCommit:
                self.commit()

        def flush(self, autoFlush=1):
            """Send all accumulated response data now.

            Commits the response headers and tells the underlying stream to flush.
            if autoFlush is 1, the responseStream will flush itself automatically
            from now on.

            """
            if not self._committed:
                self.commit()
            self._strmOut.flush()
            self._strmOut.autoCommit(autoFlush)

        def isCommitted(self):
            """Checks whether response is already commited.

            Checks whether the reponse has already been partially or completely sent.
            If this returns true, no new headers/cookies can be added
            to the response.

            """
            return self._committed

        def deliver(self):
            """Deliver response.

            The final step in the processing cycle.
            Not used for much with responseStreams added.

            """
            if debug:
                print "HTTPResponse deliver called"
            self.recordEndTime()
            if not self._committed: self.commit()

        def commit(self):
            """Commit response.

            Write out all headers to the reponse stream, and tell the underlying
            response stream it can start sending data.

            """
            if debug:
                print "HTTPResponse commit"
            self.recordSession()
            self.writeHeaders()
            self._committed = 1
            self._strmOut.commit()

        def writeHeaders(self):
            """Write headers to the response stream. Used internally."""
            if self._committed:
                print "response.writeHeaders called when already committed"
                return
            headers = []
            headerstring = ''
            for key, value in self._headers.items():
                headers.append((key, value))
            for cookie in self._cookies.values():
                headers.append(('Set-Cookie', cookie.headerValue()))
            for i in headers:
                hdrstr = i[0] + ': ' + i[1] + '\r\n'
                if i[0].lower() == 'status':
                    headerstring = ''.join((hdrstr, headerstring))
                else:
                    headerstring = ''.join((headerstring, hdrstr))
            headerstring = ''.join((headerstring,'\r\n'))
            self._strmOut.prepend(headerstring)

        def recordSession(self):
            """Record session id.

            Invoked by commit() to record the session id in the response
            (if a session exists). This implementation sets a cookie for
            that purpose. For people who don't like sweets, a future version
            could check a setting and instead of using cookies, could parse
            the HTML and update all the relevant URLs to include the session id
            (which implies a big performance hit). Or we could require site
            developers to always pass their URLs through a function which adds
            the session id (which implies pain). Personally, I'd rather just
            use cookies. You can experiment with different techniques by
            subclassing Session and overriding this method. Just make sure
            Application knows which "session" class to use.

            """
            if not self._transaction.application().setting('UseCookieSessions', True):
                return
            sess = self._transaction._session
            if debug: prefix = '>> recordSession:'
            if sess:
                cookie = Cookie('_SID_', sess.identifier())
                cookie.setPath('/')
                if sess.isExpired() or sess.timeout() == 0:
                    # Invalid -- tell client to forget the cookie.
                    cookie.delete()
                self.addCookie(cookie)
                if debug: print prefix, 'setting sid =', sess.identifier()
            else:
                if debug: print prefix, 'did not set sid'

        def reset(self):
            """Reset the response (such as headers, cookies and contents)."""
            assert self._committed == 0, "Cannot reset the response; it has already been sent."
            self._headers = {}
            self.setHeader('Content-type','text/html')
            self._cookies = {}
            self._strmOut.clear()

        def rawResponse(self):
            """Return the final contents of the response.

            Don't invoke this method until after deliver().

            Returns a dictionary representing the response containing only
            strings, numbers, lists, tuples, etc. with no backreferences.
            That means you don't need any special imports to examine the contents
            and you can marshal it. Currently there are two keys. 'headers' is
            list of tuples each of which contains two strings: the header and
            it's value. 'contents' is a string (that may be binary, for example,
            if an image were being returned).

            """
            headers = []
            for key, value in self._headers.items():
                headers.append((key, value))
            for cookie in self._cookies.values():
                headers.append(('Set-Cookie', cookie.headerValue()))
            return {
                'headers': headers,
                'contents': self._strmOut.buffer()
            }

        def size(self):
            """Return the size of the final contents of the response.

            Don't invoke this method until after deliver().

            """
            return self._strmOut.size()

        #def appendRawResponse(self, rawRes):
        #   """Appends the contents of the raw response.
        #
        #   The contents returned by some transaction's rawResponse() are added
        #   to this response. The headers of the receiving response take precedence
        #   over the appended response. This method was built primarily to support
        #   Application.forwardRequest().
        #
        #   """
        #   assert self._committed == 0
        #   headers = rawRes.get('headers', [])
        #   for key, value in headers:
        #       if not self._headers.has_key(key):
        #           self._headers[key] = value
        #   self.write(rawRes['contents'])

        def mergeTextHeaders(self, headerstr):
            """Merge text into our headers.

            Given a string of headers (separated by newlines),
            merge them into our headers.

            """
            linesep = "\n"
            lines = headerstr.split("\n")
            for line in lines:
                sep = line.find(":")
                if sep:
                    self.setHeader(line[:sep], line[sep+1:].rstrip())

        ## Exception reporting ##

        exceptionReportAttrNames = Response.exceptionReportAttrNames + [
            'committed', 'headers', 'cookies']

        def displayError(self, err):
            """Display HTTPException errors, with status codes."""

            assert not self._committed, "Already committed"
            for header, value in err.headers().items():
                self.setHeader(header, value)
            self.setHeader('Status',
                '%s %s' % (err.code(), err.codeMessage()))
            self._strmOut.clear()
            self.setHeader('Content-type', 'text/html')
            self._strmOut.write(err.html())
            uri = self._transaction.request().uri()
            print 'HTTPResponse: %s: %s' % (uri, err.codeMessage())
            self.commit()