~launchpad-pqm/launchpad/devel

# Copyright 2009 Canonical Ltd.  This software is licensed under the

# GNU Affero General Public License version 3 (see the file LICENSE).

"""Base classes for HTTP resources."""

__metaclass__ = type

__all__ = [

    'LibraryBackedByteStorage',

]

from cStringIO import StringIO

from lazr.restful.interfaces import IByteStorage

from zope.component import (

    getMultiAdapter,

    getUtility,

    )

from zope.interface import implements

from lp.services.webapp.interfaces import ICanonicalUrlData

from lp.services.librarian.interfaces import (

    ILibraryFileAliasSet,

    ILibraryFileAliasWithParent,

    )

class LibraryBackedByteStorage:

    """See `IByteStorage`."""

    implements(IByteStorage, ICanonicalUrlData)

    def __init__(self, entry, field):

        """Initialize as the backing storage for one entry's field."""

        self.entry = entry

        self.field = field

        self.file_alias = getattr(self.entry, self.field.__name__)

    @property

    def rootsite(self):

        """See `ICanonicalUrlData`"""

        return None

    @property

    def inside(self):

        """See `ICanonicalUrlData`"""

        return self.entry.context

    @property

    def path(self):

        """See `ICanonicalUrlData`"""

        return self.field.__name__

    @property

    def alias_url(self):

        """See `IByteStorage`."""

        if self.file_alias.restricted:

            lfa_with_parent = getMultiAdapter(

                (self.file_alias, self.entry.context),

                ILibraryFileAliasWithParent)

            token = lfa_with_parent.createToken()

            return self.file_alias.private_url + '?token=%s' % token

        return self.file_alias.getURL()

    @property

    def filename(self):

        """See `IByteStorage`."""

        if self.is_stored:

            return self.file_alias.filename

        return self.field.__name__

    @property

    def is_stored(self):

        """See `IByteStorage`."""

        return self.file_alias is not None

    def createStored(self, mediaType, representation, filename=None):

        """See `IByteStorage`."""

        if filename is None:

            filename = self.filename

        stored = getUtility(ILibraryFileAliasSet).create(

            name=filename, size=len(representation),

            file=StringIO(representation), contentType=mediaType)

        setattr(self.entry, self.field.__name__, stored)

    def deleteStored(self):

        """See `IByteStorage`."""

        setattr(self.entry, self.field.__name__, None)