loops/external/element.py

#
#  Copyright (c) 2008 Helmut Merz helmutm@cy55.de
#
#  This program is free software; you can redistribute it and/or modify
#  it under the terms of the GNU General Public License as published by
#  the Free Software Foundation; either version 2 of the License, or
#  (at your option) any later version.
#
#  This program 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 General Public License for more details.
#
#  You should have received a copy of the GNU General Public License
#  along with this program; if not, write to the Free Software
#  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
#

"""
Basic implementation of the elements used for the intermediate format for export
and import of loops objects.

$Id$
"""

import os
from zope.cachedescriptors.property import Lazy
from zope.dottedname.resolve import resolve
from zope.interface import Interface, implements
from zope.traversing.api import getName, traverse

from loops.external.interfaces import IElement
from loops.i18n.common import I18NValue


class Element(dict):

    implements(IElement)

    elementType = ''
    posArgs = ()
    object = None
    parent = None
    subElements = None

    def __init__(self, name, title, type=None, *args, **kw):
        self['name'] = name
        self['title'] = title
        if type:
            self['type'] = type
        for k, v in kw.items():
            self[k] = v

    def __getitem__(self, key):
        if isinstance(key, Element):
            key = (key,)
        if isinstance(key, tuple):
            for item in key:
                item.parent = self
                self.add(item)
            return key
        return super(Element, self).__getitem__(key)

    def processExport(self, extractor):
        pass

    def add(self, element):
        if self.subElements is None:
            self.subElements = []
        self.subElements.append(element)

    def execute(self, loader):
        pass


class ConceptElement(Element):

    elementType = 'concept'
    posArgs = ('name', 'title', 'type')

    def execute(self, loader):
        type = loader.concepts[self['type']]
        kw = dict((k, v) for k, v in self.items()
                         if k not in self.posArgs)
        self.object = loader.addConcept(self['name'], self['title'], type, **kw)


class TypeElement(ConceptElement):

    elementType = 'type'
    posArgs = ('name', 'title')

    def __init__(self, name, title, *args, **kw):
        super(TypeElement, self).__init__(name, title, *args, **kw)
        ti = self.get('typeInterface')
        if ti:
            if not isinstance(ti, basestring):
                self['typeInterface'] = '.'.join((ti.__module__, ti.__name__))

    def execute(self, loader):
        kw = dict((k, v) for k, v in self.items()
                if k not in ('name', 'title', 'type', 'typeInterface'))
        ti = self.get('typeInterface')
        if ti:
            kw['typeInterface'] = resolve(ti)
        self.object = loader.addConcept(self['name'], self['title'],
                            loader.typeConcept, **kw)


class ChildElement(Element):

    elementType = 'child'
    posArgs = ('first', 'second', 'predicate', 'order', 'relevance')

    def __init__(self, *args):
        for idx, arg in enumerate(args):
            self[self.posArgs[idx]] = arg

    def __call__(self, loader):
        loader.assignChild(self['first'], self['second'], self['predicate'])


class ResourceElement(Element):

    elementType = 'resource'
    posArgs = ('name', 'title', 'type')

    def processExport(self, extractor):
        content = self.pop('data', '')
        fileFlags = 'wb'
        if (self.get('contentType', '').startswith('text/')
            and isinstance(content, unicode)):
            content = content.encode('UTF-8')
            fileFlags = 'wt'
        dataPath = os.path.join(extractor.resourceDirectory, self['name'])
        f = open(dataPath, fileFlags)
        f.write(content)
        f.close()

    def execute(self, loader):
        type = loader.concepts[self['type']]
        kw = dict((k, v) for k, v in self.items()
                         if k not in self.posArgs)
        dataPath = os.path.join(loader.resourceDirectory, self['name'])
        if os.path.exists(dataPath):
            f = open(dataPath, 'r')
            content = f.read()
            if self.get('contentType', '').startswith('text/'):
                content = content.decode('UTF-8')
            kw['data'] = content
            f.close()
        self.object = loader.addResource(self['name'], self['title'], type, **kw)


class ResourceRelationElement(ChildElement):

    elementType = 'resourceRelation'

    def execute(self, loader):
        loader.assignResource(self['first'], self['second'], self['predicate'])


class NodeElement(Element):

    elementType = 'node'
    posArgs = ('name', 'title', 'path', 'type')

    def __init__(self, *args, **kw):
        for idx, arg in enumerate(args):
            self[self.posArgs[idx]] = arg
        for k, v in kw.items():
            self[k] = v

    def execute(self, loader):
        type = self['type']
        cont = traverse(loader.views, self['path'])
        target = self.pop('target', None)
        kw = dict((k, v) for k, v in self.items()
                         if k not in self.posArgs)
        node = loader.addNode(self['name'], self['title'], cont, type, **kw)
        if target is not None:
            targetObject = traverse(loader.context, target, None)
            node.target = targetObject
        self.object = node


# element registry

elementTypes = dict(
    type=TypeElement,
    concept=ConceptElement,
    child=ChildElement,
    resource=ResourceElement,
    resourceRelation=ResourceRelationElement,
    node=NodeElement,
    I18NValue=I18NValue,
)

toplevelElements = ('type', 'concept', 'resource', 'resourceRelation', 'node')