#!/usr/bin/env python

"""

Resources for use with WebStack.

Copyright (C) 2005 Paul Boddie <paul@boddie.org.uk>

This library is free software; you can redistribute it and/or

modify it under the terms of the GNU Lesser General Public

License as published by the Free Software Foundation; either

version 2.1 of the License, or (at your option) any later version.

This library is distributed in the hope that it will be useful,

but WITHOUT ANY WARRANTY; without even the implied warranty of

MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

Lesser General Public License for more details.

You should have received a copy of the GNU Lesser General Public

License along with this library; if not, write to the Free Software

Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307  USA

"""

import WebStack.Generic

import XSLForms.Fields

import XSLForms.Prepare

import XSLForms.Output

import XSLOutput

import os

class XSLFormsResource:

    """

    A generic XSLForms resource for use with WebStack.

    When overriding this class, define the following attributes appropriately:

      * template_resources    - a dictionary mapping output identifiers to

                                (template_filename, output_filename) tuples,

                                indicating the template and stylesheet filenames

                                to be employed

      * in_page_resources     - a dictionary mapping fragment identifiers to

                                (output_filename, node_identifier) tuples,

                                indicating the stylesheet filename to be

                                employed, along with the node identifier used in

                                the original template and output documents to

                                mark a region of those documents as the fragment

                                to be updated upon "in-page" requests

      * transform_resources   - a dictionary mapping transform identifiers to

                                lists of stylesheet filenames for use with the

                                transformation methods

      * document_resources    - a dictionary mapping document identifiers to

                                single filenames for use as source documents or

                                as references with the transformation methods

      * resource_dir          - the absolute path of the directory in which

                                stylesheet resources are to reside

    All filenames shall be simple leafnames for files residing in the resource's

    special resource directory 'resource_dir'.

    The following attributes may also be specified:

      * path_encoding         - the assumed encoding of characters in request

                                paths

      * encoding              - the assumed encoding of characters in request

                                bodies

    """

    path_encoding = "iso-8859-1"

    encoding = "utf-8"

    template_resources = {}

    in_page_resources = {}

    transform_resources = {}

    document_resources = {}

    resource_dir = None

    def get_fields_from_body(self, trans, encoding):

        """

        From the given transaction 'trans' and using the stated text 'encoding'

        get the field values from the request body and return a dictionary

        mapping field names to lists of such values.

        """

        text = trans.get_request_stream().read().decode(encoding)

        parameters = {}

        for text_line in text.split("\r\n"):

            text_parts = text_line.split("=")

            text_name, text_value = text_parts[0], "=".join(text_parts[1:])

            if not parameters.has_key(text_name):

                parameters[text_name] = []

            # NOTE: Workaround from posted text.

            if len(text_value) > 0 and text_value[-1] == "\x00":

                text_value = text_value[:-1]

            parameters[text_name].append(text_value)

        return parameters

    def prepare_output(self, output_identifier):

        """

        Prepare the output stylesheets using the given 'output_identifier' to

        indicate which templates and stylesheets are to be employed in the

        production of output from the resource.

        The 'output_identifier' is used as a key to the 'template_resources'

        dictionary attribute.

        Return the full path to the output stylesheet for use with 'send_output'

        or 'get_result'.

        """

        template_filename, output_filename = self.template_resources[output_identifier]

        output_path = os.path.join(self.resource_dir, output_filename)

        template_path = os.path.join(self.resource_dir, template_filename)

        XSLForms.Prepare.ensure_stylesheet(template_path, output_path)

        return output_path

    def prepare_fragment(self, output_identifier, fragment_identifier):

        """

        Prepare the output stylesheets for the given 'output_identifier' and

        'fragment_identifier', indicating which templates and stylesheets are to

        be employed in the production of output from the resource.

        The 'output_identifier' is used as a key to the 'template_resources'

        dictionary attribute; the 'fragment_identifier' is used as a key to the

        'in_page_resources' dictionary attribute.

        Return the full path to the output stylesheet for use with 'send_output'

        or 'get_result'.

        """

        output_path = self.prepare_output(output_identifier)

        fragment_filename, node_identifier = self.in_page_resources[fragment_identifier]

        fragment_path = os.path.join(self.resource_dir, fragment_filename)

        XSLForms.Prepare.ensure_stylesheet_fragment(output_path, fragment_path, node_identifier)

        return fragment_path

    def send_output(self, trans, stylesheet_filenames, document, stylesheet_parameters=None, references=None):

        """

        Send the output from the resource to the user employing the transaction

        'trans', stylesheets having the given 'stylesheet_filenames', the

        'document' upon which the output will be based, the optional parameters

        as defined in the 'stylesheet_parameters' dictionary, and the optional

        'references' to external documents.

        """

        proc = XSLOutput.Processor(stylesheet_filenames, parameters=stylesheet_parameters, references=references)

        proc.send_output(trans.get_response_stream(), trans.get_response_stream_encoding(),

            document)

    def get_result(self, stylesheet_filenames, document, stylesheet_parameters=None, references=None):

        """

        Get the result of applying a transformation using stylesheets with the

        given 'stylesheet_filenames', the 'document' upon which the result will

        be based, the optional parameters as defined in the

        'stylesheet_parameters' dictionary, and the optional 'references' to

        external documents.

        """

        proc = XSLOutput.Processor(stylesheet_filenames, parameters=stylesheet_parameters, references=references)

        return proc.get_result(document)

    def prepare_transform(self, transform_identifier):

        """

        Prepare a transformation using the given 'transform_identifier'.

        Return a list of full paths to the output stylesheets for use with

        'send_output' or 'get_result'.

        """

        filenames = self.transform_resources[transform_identifier]

        paths = []

        for filename in filenames:

            paths.append(os.path.join(self.resource_dir, filename))

        return paths

    def prepare_document(self, document_identifier):

        """

        Prepare a document using the given 'document_identifier'.

        Return the full path of the document for use either as the source

        document or as a reference with 'send_output' or 'get_result'.

        """

        filename = self.document_resources[document_identifier]

        return os.path.join(self.resource_dir, filename)

    def get_in_page_resource(self, trans):

        """

        Return the in-page resource being referred to in the given transaction

        'trans'.

        """

        return trans.get_path_info().split("/")[-1]

    def respond(self, trans):

        """

        Respond to the request described by the given transaction 'trans'.

        """

        # Only obtain field information according to the stated method.

        method = trans.get_request_method()

        in_page_resource = self.get_in_page_resource(trans)

        # Handle typical request methods, processing request information.

        if method == "GET":

            # Get the fields from the request path (URL).

            form = XSLForms.Fields.Form(encoding=self.path_encoding, values_are_lists=1)

            parameters = trans.get_fields_from_path()

            form.set_parameters(parameters)

        elif method == "POST":

            # Get the fields from the request body.

            form = XSLForms.Fields.Form(encoding=self.encoding, values_are_lists=1)

            # Handle requests for in-page updates.

            if in_page_resource in self.in_page_resources.keys():

                parameters = self.get_fields_from_body(trans, self.encoding)

            else:

                parameters = trans.get_fields_from_body(self.encoding)

            # Get the XML representation of the request.

            form.set_parameters(parameters)

        else:

            # Initialise empty containers.

            parameters = {}

            documents = {}

        # Call an overridden method with the processed request information.

        self.respond_to_form(trans, form)

    def respond_to_form(self, trans, form):

        """

        Respond to the request described by the given transaction 'trans', using

        the given 'form' object to conveniently retrieve field (request

        parameter) information and structured form information (as DOM-style XML

        documents).

        """

        trans.set_response_code(500)

        raise WebStack.Generic.EndOfResponse

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