Source code for plone.app.blocks.transform

from lxml import etree

from repoze.xmliter.utils import getHTMLSerializer
from repoze.xmliter.serializer import XMLSerializer

from plone.transformchain.interfaces import ITransform
from plone.tiles.interfaces import ESI_HEADER

from zope.interface import implements

from plone.app.blocks import panel, tiles
from plone.tiles import esi


class DisableParsing(object):
    """A no-op transform which sets flags to stop plone.app.blocks
    transformations. You may register this for a particular published
    object or request as required. By default, it's registered for ESI-
    rendered tiles when they are fetched via ESI.
    """

    implements(ITransform)

    order = 8000

    def __init__(self, published, request):
        self.published = published
        self.request = request

    def transformString(self, result, encoding):
        self.request.set('plone.app.blocks.disabled', True)
        return None

    def transformUnicode(self, result, encoding):
        self.request.set('plone.app.blocks.disabled', True)
        return None

    def transformIterable(self, result, encoding):
        self.request.set('plone.app.blocks.disabled', True)
        return None


class ParseXML(object):
    """First stage in the 8000's chain: parse the content to an lxml tree
    encapsulated in an XMLSerializer.

    The subsequent steps in this package will assume their result inputs are
    XMLSerializer iterables, and do nothing if it is not. This also gives us
    the option to parse the content here, and if we decide it's not HTML,
    we can avoid trying to parse it again.
    """

    implements(ITransform)

    order = 8000

    # Tests set this to True
    pretty_print = False

    def __init__(self, published, request):
        self.published = published
        self.request = request

    def transformString(self, result, encoding):
        return self.transformIterable([result], encoding)

    def transformUnicode(self, result, encoding):
        return self.transformIterable([result], encoding)

    def transformIterable(self, result, encoding):
        if self.request.get('plone.app.blocks.disabled', False):
            return None

        content_type = self.request.response.getHeader('Content-Type')
        if content_type is None or not content_type.startswith('text/html'):
            return None

        contentEncoding = self.request.response.getHeader('Content-Encoding')
        if contentEncoding and contentEncoding in ('zip', 'deflate',
                                                   'compress',):
            return None

        try:
            result = getHTMLSerializer(result, pretty_print=self.pretty_print,
                                       encoding=encoding)
            self.request['plone.app.blocks.enabled'] = True
            return result
        except (TypeError, etree.ParseError):
            return None


class MergePanels(object):
    """Find the site layout and merge panels.
    """

    implements(ITransform)

    order = 8100

    def __init__(self, published, request):
        self.published = published
        self.request = request

    def transformString(self, result, encoding):
        return None

    def transformUnicode(self, result, encoding):
        return None

    def transformIterable(self, result, encoding):
        if not self.request.get('plone.app.blocks.enabled', False) or \
           not isinstance(result, XMLSerializer):
            return None

        tree = panel.merge(self.request, result.tree)
        if tree is None:
            return None

        # Set a marker in the request to let subsequent steps know the merging
        # has happened
        self.request['plone.app.blocks.merged'] = True

        result.tree = tree
        return result


class IncludeTiles(object):
    """Turn a panel-merged page into the final composition by including tiles.
    Assumes the input result is an lxml tree and returns an lxml tree for
    later serialization.
    """

    implements(ITransform)

    order = 8500

    def __init__(self, published, request):
        self.published = published
        self.request = request

    def transformString(self, result, encoding):
        return None

    def transformUnicode(self, result, encoding):
        return None

    def transformIterable(self, result, encoding):
        if not self.request.get('plone.app.blocks.enabled', False) or \
           not isinstance(result, XMLSerializer):
            return None

        result.tree = tiles.renderTiles(self.request, result.tree)
        return result


class ESIRender(object):
    """If ESI rendering was used, render the page down to a format that allows
    ESI to work.
    """

    implements(ITransform)

    order = 8900

    def __init__(self, published, request):
        self.published = published
        self.request = request

    def transformString(self, result, encoding):
        if self.request.getHeader(ESI_HEADER, 'false').lower() != 'true':
            return None

        return esi.substituteESILinks(result)

    def transformUnicode(self, result, encoding):
        if self.request.getHeader(ESI_HEADER, 'false').lower() != 'true':
            return None

        return esi.substituteESILinks(result)

    def transformIterable(self, result, encoding):
        if self.request.getHeader(ESI_HEADER, 'false').lower() != 'true':
            return None

        return esi.substituteESILinks("".join(result))