radicale-sql/radicale_sql/__init__.py

#!/usr/bin/env python3
# -*- coding: utf-8 -*-

import os
import re
import binascii
import datetime
import zoneinfo
import uuid
import string
import itertools
import json
from hashlib import sha256
from typing import Optional, Union, Tuple, Iterable, Iterator, Mapping

import radicale
import radicale.config
import radicale.types
from radicale.storage import BaseStorage, BaseCollection
from radicale.log import logger
from radicale import item as radicale_item
import vobject
import sqlalchemy as sa

from . import db

PLUGIN_CONFIG_SCHEMA = {
    'storage': {
        'db_url': {
            'value': '',
            'type': str,
        },
        'generate_birthday_calendars': {
            'value': "False",
            'type': bool,
        },
    },
}

class Item(radicale_item.Item):

    def __init__(self, *args, last_modified: Optional[Union[str, datetime.datetime]]=None, **kwargs):
        if last_modified is not None and isinstance(last_modified, datetime.datetime):
            last_modified = last_modified.astimezone(tz=zoneinfo.ZoneInfo('GMT')).strftime('%a, %d %b %Y %H:%M:%S GMT')
        super().__init__(*args, last_modified=last_modified, **kwargs)

class Collection(BaseCollection):

    def __init__(self, storage: "Storage", id: uuid.UUID, path: str):
        self._storage = storage
        self._id = id
        self._path = path

    def __repr__(self) -> str:
        return f'Collection(id={self._id}, path={self._path})'

    @property
    def path(self) -> str:
        return self._path

    def _row_to_item(self, row) -> "radicale_item.Item":
        return Item(
            collection=self,
            href=row.name,
            last_modified=row.modified,
            text=row.data.decode(),
        )

    def _get_multi(self, hrefs: Iterable[str], *, connection) -> Iterable[Tuple[str, Optional["radicale_item.Item"]]]:
        item_table = self._storage._meta.tables['item']
        hrefs_ = list(hrefs)
        #hrefs_ = [(x,) for x in hrefs]
        if not hrefs_:
            return []
        select_stmt = sa.select(
            item_table.c,
        ).select_from(
            item_table,
        ).where(
            sa.and_(
                item_table.c.collection_id == self._id,
                item_table.c.name.in_(hrefs_)
            ),
        )
        l = []
        for row in connection.execute(select_stmt):
            l += [(row.name, self._row_to_item(row))]
        hrefs_set = set(hrefs_)
        hrefs_set_have = set([x[0] for x in l])
        l += [(x, None) for x in (hrefs_set - hrefs_set_have)]
        return l

    def get_multi(self, hrefs: Iterable[str]) -> Iterable[Tuple[str, Optional["radicale_item.Item"]]]:
        with self._storage._engine.begin() as c:
            return self._get_multi(hrefs=hrefs, connection=c)

    def _get_all(self, *, connection) -> Iterator["radicale_item.Item"]:
        item_table = self._storage._meta.tables['item']
        select_stmt = sa.select(
            item_table.c,
        ).select_from(
            item_table,
        ).where(
            item_table.c.collection_id == self._id,
        )
        for row in connection.execute(select_stmt):
            yield self._row_to_item(row)

    def get_all(self) -> Iterator["radicale_item.Item"]:
        with self._storage._engine.begin() as c:
            for i in self._get_all(connection=c):
                yield i

    def _upload(self, href: str, item: "radicale_item.Item", *, connection) -> "radicale_item.Item":
        item_table = self._storage._meta.tables['item']

        item_serialized = item.serialize().encode()
        select_stmt = sa.select(
            item_table.c,
        ).select_from(
            item_table,
        ).where(
            sa.and_(
                item_table.c.collection_id == self._id,
                item_table.c.name == href,
            ),
        )
        insert_stmt = sa.insert(
            item_table,
        ).values(
            collection_id=self._id,
            name=href,
            data=item_serialized,
        )
        update_stmt = sa.update(
            item_table,
        ).values(
            data=item_serialized,
        ).where(
            sa.and_(
                item_table.c.collection_id == self._id,
                item_table.c.name == href,
            ),
        )
        if connection.execute(select_stmt).one_or_none() is None:
            connection.execute(insert_stmt)
            self._storage._collection_updated(self._id, connection=connection)
        else:
            connection.execute(update_stmt)
            self._storage._item_updated(self._id, href, connection=connection)
        self._update_history_etag(href, item, connection=connection)
        res = list(self._get_multi([href], connection=connection))[0][1]
        assert res is not None
        return res

    def upload(self, href: str, item: "radicale_item.Item") -> "radicale_item.Item":
        with self._storage._engine.begin() as c:
            return self._upload(href, item, connection=c)

    def _delete(self, *, connection, href: Optional[str] = None) -> None:
        collection_table = self._storage._meta.tables['collection']
        item_table = self._storage._meta.tables['item']
        if href is None:
            delete_stmt = sa.delete(
                collection_table,
            ).where(
                collection_table.c.id == self._id,
            )
        else:
            delete_stmt = sa.delete(
                item_table,
            ).where(
                sa.and_(
                    item_table.c.collection_id == self._id,
                    item_table.c.name == href,
                ),
            )
            self._storage._item_updated(self._id, href, connection=connection)
        connection.execute(delete_stmt)

    def delete(self, href: Optional[str] = None) -> None:
        with self._storage._engine.begin() as c:
            return self._delete(connection=c, href=href)

    def _get_meta(self, *, connection, key: Optional[str] = None) -> Union[Mapping[str, str], Optional[str]]:
        collection_metadata = self._storage._meta.tables['collection_metadata']
        select_meta = sa.select(
            collection_metadata.c.key,
            collection_metadata.c.value,
        ).select_from(
            collection_metadata,
        ).where(
            collection_metadata.c.collection_id == self._id,
        )
        if key is not None:
            select_meta = select_meta.where(
                collection_metadata.c.key == key,
            )
        metadata = {}
        for row in connection.execute(select_meta):
            metadata[row.key] = row.value
        if key is not None:
            return metadata.get(key)
        return metadata

    def get_meta(self, key: Optional[str] = None) -> Union[Mapping[str, str], Optional[str]]:
        with self._storage._engine.begin() as c:
            return self._get_meta(connection=c, key=key)

    def _set_meta(self, props: Mapping[str, str], *, connection) -> None:
        collection_metadata = self._storage._meta.tables['collection_metadata']
        delete_stmt = sa.delete(
            collection_metadata,
        ).where(
            collection_metadata.c.collection_id == self._id,
        )
        insert_stmt = sa.insert(
            collection_metadata,
        ).values([dict(collection_id=self._id, key=k, value=v) for k, v in props.items()])
        connection.execute(delete_stmt)
        connection.execute(insert_stmt)
        self._storage._collection_updated(self._id, connection=connection)

    def set_meta(self, props: Mapping[str, str]) -> None:
        with self._storage._engine.begin() as c:
            return self._set_meta(props, connection=c)

    def _last_modified(self, *, connection) -> str:
        collection = self._storage._meta.tables['collection']
        select_stmt = sa.select(
            collection.c.modified,
        ).select_from(
            collection,
        ).where(
            collection.c.id == self._id,
        )
        c = connection.execute(select_stmt).one()
        return c.modified.strftime('%a, %d %b %Y %H:%M:%S GMT')
    
    @property
    def last_modified(self):
        with self._storage._engine.begin() as c:
            return self._last_modified(connection=c)

    def _update_history_etag(self, href: str, item: Optional["radicale_item.Item"], *, connection) -> str:
        item_history_table = self._storage._meta.tables['item_history']
        select_etag_stmt = sa.select(
            item_history_table.c,
        ).select_from(
            item_history_table,
        ).where(
            sa.and_(
                item_history_table.c.collection_id == self._id,
                item_history_table.c.name == href,
            ),
        )
        exists: bool
        item_history = connection.execute(select_etag_stmt).one_or_none()
        if item_history is not None:
            exists = True
            cache_etag = item_history.etag
            history_etag = item_history.history_etag
        else:
            exists = False
            cache_etag = ''
            history_etag = binascii.hexlify(os.urandom(16)).decode('ascii')
        etag = item.etag if item else ''
        if etag != cache_etag:
            history_etag = radicale_item.get_etag(history_etag + '/' + etag).strip('\"')
            if exists:
                upsert = sa.update(
                    item_history_table,
                ).values(
                    etag=etag,
                    history_etag=history_etag,
                ).where(
                    sa.and_(
                        item_history_table.c.collection_id == self._id,
                        item_history_table.c.name == href,
                    ),
                )
            else:
                upsert = sa.insert(
                    item_history_table,
                ).values(
                    collection_id=self._id,
                    name=href,
                    etag=etag,
                    history_etag=history_etag,
                )
            connection.execute(upsert)
        return history_etag

    def _get_deleted_history_refs(self, *, connection):
        item_table = self._storage._meta.tables['item']
        item_history_table = self._storage._meta.tables['item_history']
        select_stmt = sa.select(
            item_history_table.c.name,
        ).select_from(
            item_history_table.join(
                item_table,
                sa.and_(
                    item_history_table.c.collection_id == item_table.c.collection_id,
                    item_history_table.c.name == item_table.c.name,
                ),
                isouter=True,
            ),
        ).where(
            sa.and_(
                item_history_table.c.collection_id == self._id,
                item_table.c.id == None,
            ),
        )
        for row in connection.execute(select_stmt):
            yield row.name

    def _delete_history_refs(self, *, connection):
        item_history_table = self._storage._meta.tables['item_history']
        delete_stmt = sa.delete(
            item_history_table,
        ).where(
            sa.and_(
                item_history_table.c.href.in_(list(self._get_deleted_history_refs(connection=connection))),
                item_history_table.c.collection_id == self._id,
                item_history_table.c.modified < (datetime.datetime.now() - datetime.timedelta(seconds=self._storage.configuration.get('storage', 'max_sync_token_age')))
            ),
        )
        connection.execute(delete_stmt)

    def _sync(self, *, connection, old_token: str = '') -> Tuple[str, Iterable[str]]:
        # Parts of this method have been taken from
        # https://github.com/Kozea/Radicale/blob/6a56a6026f6ec463d6eb77da29e03c48c0c736c6/radicale/storage/multifilesystem/sync.py
        _prefix = 'http://radicale.org/ns/sync/'
        collection_state_table = self._storage._meta.tables['collection_state']

        def check_token_name(token_name: str) -> bool:
            if len(token_name) != 64:
                return False
            for c in token_name:
                if c not in string.hexdigits.lower():
                    return False
            return True

        old_token_name = ''
        if old_token:
            if not old_token.startswith(_prefix):
                raise ValueError(f'Malformed token: {old_token}')
            old_token_name = old_token[len(_prefix):]
            if not check_token_name(old_token_name):
                raise ValueError(f'Malformed token: {old_token}')

        # compute new state
        state = {}
        token_name_hash = sha256()
        for href, item in itertools.chain(
            ((item.href, item) for item in self._get_all(connection=connection)),
            ((href, None) for href in self._get_deleted_history_refs(connection=connection))
        ):
            assert isinstance(href, str)
            if href in state:
                # we don't want to overwrite states
                # this could happen with another storage collection
                # which doesn't store the items itself, but 
                # derives them from another one
                continue
            history_etag = self._update_history_etag(href, item, connection=connection)
            state[href] = history_etag
            token_name_hash.update((href + '/' + history_etag).encode())
        token_name = token_name_hash.hexdigest()
        token = _prefix + token_name

        # if new state hasn't changed: dont send any updates
        if token_name == old_token_name:
            return token, ()

        # load old state
        old_state = {}
        if old_token_name:
            select_stmt = sa.select(
                collection_state_table.c,
            ).select_from(
                collection_state_table,
            ).where(
                sa.and_(
                    collection_state_table.c.collection_id == self._id,
                    collection_state_table.c.name == old_token_name,
                ),
            )
            state_row = connection.execute(select_stmt).one_or_none()
            old_state = json.loads(state_row.state.decode()) if state_row is not None else {}
    
        # store new state
        select_new_state = sa.select(
            collection_state_table.c,
        ).select_from(
            collection_state_table,
        ).where(
            collection_state_table.c.collection_id == self._id,
            collection_state_table.c.name == token_name,
        )
        if connection.execute(select_new_state).one_or_none() is None:
            insert_stmt = sa.insert(
                collection_state_table,
            ).values(
                collection_id=self._id,
                name=token_name,
                state=json.dumps(state).encode(),
            )
            connection.execute(insert_stmt)

        changes = []
        for href, history_etag in state.items():
            if history_etag != old_state.get(href):
                changes += [href]
        for href, history_etag in old_state.items():
            if href not in state:
                changes += [href]

        return token, changes

    def sync(self, old_token: str = '') -> Tuple[str, Iterable[str]]:
        with self._storage._engine.begin() as c:
            return self._sync(connection=c, old_token=old_token)

class BdayCollection(Collection):

    R_FMT = (
        (re.compile('^[0-9]{8}$'), '%Y%m%d'),
        (re.compile('^--[0-9]{4}$'), '--%m%d'),
        (re.compile('^[0-9]{4}-[0-9]{2}-[0-9]{2}$'), '%Y-%m-%d'),
        (re.compile('^[0-9]{4}-[0-9]{2}-[0-9]{2}T[0-9]{2}:[0-9]{2}:[0-9]{2}Z$'), '%Y-%m-%dT%H:%M:%SZ'),
        (re.compile('^[0-9]{4}[0-9]{2}[0-9]{2}T[0-9]{2}[0-9]{2}[0-9]{2}Z$'), '%Y%m%dT%H%M%SZ'),
    )

    def __init__(self, storage: "Storage", id: uuid.UUID, path: str, birthday_source: uuid.UUID):
        super().__init__(storage, id, path)
        self._birthday_source = birthday_source
        self._birthday_source_collection = Collection(storage, birthday_source, '') # TODO: ugly hack, get the correct path

    def __repr__(self) -> str:
        return f'BdayCollection(id={self._id}, path={self._path}, birthday_source={self._birthday_source})'

    def _to_calendar_entry(self, o: vobject.base.Component) -> Optional[vobject.base.Component]:
        def vobj_str2date(content_line):
            v = content_line.value
            for r, f in self.R_FMT:
                if r.match(v):
                    return datetime.datetime.strptime(v, f)
            raise ValueError(f'cannot parse specified string {v}')
        cal = vobject.iCalendar()
        if 'bday' not in o.contents:
            return None
        date = vobj_str2date(o.bday)
        if date.year <= 1900:
            date = date.replace(year=datetime.datetime.now().year)
        date_end = date + datetime.timedelta(days=1)

        cal.add('vevent')
        cal.vevent_list[-1].add('uid').value = o.uid.value
        cal.vevent_list[-1].add('dtstamp').value = vobj_str2date(o.rev)
        cal.vevent_list[-1].add('summary').value = o.fn.value
        cal.vevent_list[-1].add('dtstart').value = date.date()
        cal.vevent_list[-1].add('dtend').value = date_end.date()
        cal.vevent_list[-1].add('rrule').value = 'FREQ=YEARLY'
        return cal

    def _item_transform(self, item: "radicale_item.Item") -> Optional["radicale_item.Item"]:
        new_vobject = self._to_calendar_entry(item.vobject_item)
        if new_vobject is None:
            return None
        assert item.href is not None
        return Item(
            collection=self,
            href=item.href,
            #href=item.href + '.ics',
            last_modified=item.last_modified,
            text=new_vobject.serialize().strip(),
        )

    def _get_multi(self, hrefs: Iterable[str], *, connection) -> Iterable[Tuple[str, Optional["radicale_item.Item"]]]:
        l = []
        for href, i in self._birthday_source_collection._get_multi(hrefs, connection=connection):
            l += [(href, self._item_transform(i) if i is not None else None)]
        return l

    def _get_all(self, *, connection) -> Iterator["radicale_item.Item"]:
        for i in self._birthday_source_collection._get_all(connection=connection):
            ni = self._item_transform(i)
            if ni is not None:
                yield ni

    def _upload(self, href: str, item: "radicale_item.Item", *, connection) -> "radicale_item.Item":
        raise NotImplementedError

    def _delete(self, *, connection, href: Optional[str] = None) -> None:
        if href is not None:
            raise NotImplementedError
        super()._delete(connection=connection, href=href)

    def _last_modified(self, *, connection) -> str:
        return self._birthday_source_collection._last_modified(connection=connection)

def create_collection(*args, birthday_source: Optional[uuid.UUID], **kwargs) -> Collection:
    if birthday_source is not None:
        c = BdayCollection
        kwargs['birthday_source'] = birthday_source
    else:
        c = Collection
    return c(*args, **kwargs)

class Storage(BaseStorage):

    def __init__(self, configuration: "radicale.config.Configuration"):
        super().__init__(configuration)
        self._meta = db.create_meta()
        self._engine, self._root_collection = db.create(self.configuration.get('storage', 'url'), self._meta)

    def _split_path(self, path: str):
        path_parts = path.split('/')
        if path_parts[0] == '':
            path_parts = path_parts[1:]
        if path_parts[-1] == '':
            path_parts = path_parts[:-1]
        return path_parts

    def _get_collection(self, id, *, connection) -> "BaseCollection":
        collection_table = self._meta.tables['collection']
        collection_metadata_table = self._meta.tables['collection_metadata']
        select_stmt = sa.select(
            collection_table.c,
            collection_metadata_table.c.value.cast(sa.Uuid()).label('birthday_source'),
        ).select_from(
            collection_table.join(
                collection_metadata_table,
                sa.and_(
                    collection_table.c.id == collection_metadata_table.c.collection_id,
                    collection_metadata_table.c.key == 'birthday_source',
                ),
                isouter=True,
            ),
        ).where(
            collection_table.c.id == id,
        )
        row = connection.execute(select_stmt).one()
        # TODO: path
        return create_collection(self, id, '', birthday_source=row.birthday_source)

    def _collection_updated(self, collection_id, *, connection):
        collection_table = self._meta.tables['collection']
        connection.execute(sa.update(
            collection_table,
        ).values(
            modified=datetime.datetime.now(),
        ).where(
            collection_table.c.id == collection_id,
        ))

    def _item_updated(self, collection_id: uuid.UUID, href: str, *, connection):
        item_table = self._meta.tables['item']
        item_row = connection.execute(sa.update(
            item_table,
        ).values(
            modified=datetime.datetime.now(),
        ).where(
            sa.and_(
                item_table.c.collection_id == collection_id,
                item_table.c.name == href,
            ),
        ).returning(item_table.c)).one()
        self._collection_updated(item_row.collection_id, connection=connection)

    def _discover(self, path: str, *, connection, depth: str = "0") -> Iterable["radicale.types.CollectionOrItem"]:
        if path == '/':
            return [create_collection(self, self._root_collection.id, '', birthday_source=None)]
        path_parts = self._split_path(path)

        collection_table = self._meta.tables['collection']
        collection_metadata_table = self._meta.tables['collection_metadata']
        item_table = self._meta.tables['item']

        # TODO: rename variable, it only selects collections now
        select_collection_or_item = sa.select(
            collection_table.c.id,
            collection_table.c.parent_id.label('parent_id'),
            collection_table.c.modified,
            collection_table.c.name,
            sa.literal(None, sa.LargeBinary()).label('data'),
            sa.literal('collection', sa.String(16)).label('type_'),
            collection_metadata_table.c.value.cast(sa.Uuid()).label('birthday_source'),
        ).select_from(
            collection_table.join(
                collection_metadata_table,
                sa.and_(
                    collection_table.c.id == collection_metadata_table.c.collection_id,
                    collection_metadata_table.c.key == 'birthday_source',
                ),
                isouter=True,
            )
        ).union_all(sa.select(
            item_table.c.id,
            item_table.c.collection_id.label('parent_id'),
            item_table.c.modified,
            item_table.c.name,
            item_table.c.data,
            sa.literal('item', sa.String(16)).label('type_'),
            sa.literal(None, sa.Uuid()).label('birthday_source'),
        ).select_from(
            item_table
        ))

        i = 0
        select_from = select_collection_or_item.alias('data')
        aliases = [select_from]
        for path in path_parts[::-1]:
            aliases += [select_collection_or_item.alias(f't{i}')]
            i += 1
            select_from = select_from.join(
                aliases[-1],
                sa.and_(
                    aliases[-2].c.parent_id == aliases[-1].c.id,
                    aliases[-2].c.name == path,
                ),
            )
        select_stmt = sa.select(
            aliases[0].c,
        ).select_from(
            select_from
        ).where(
            aliases[-1].c.parent_id == None,
        )

        l = []
        self_collection = connection.execute(select_stmt).one_or_none()
        if self_collection is None:
            # None found
            return []
        if self_collection.type_ != 'collection':
            # Item found
            return [Item(
                collection=self._get_collection(self_collection.parent_id, connection=connection),
                href=self_collection.name,
                last_modified=self_collection.modified,
                text=self_collection.data.decode(),
            )]

        # collection found
        self_collection = create_collection(self, self_collection.id, '/'.join(path_parts), birthday_source=self_collection.birthday_source)
        l += [self_collection]
        # collection should list contents
        if depth != "0":
            sub_stmt_select_from = select_collection_or_item.alias()
            select_sub_stmt = sa.select(
                sub_stmt_select_from.c,
            ).select_from(
                sub_stmt_select_from,
            ).where(
                sa.and_(
                    sub_stmt_select_from.c.parent_id == self_collection._id,
                    sub_stmt_select_from.c.type_ == 'collection',
                ),
            )
            for row in connection.execute(select_sub_stmt):
                path = '/'.join(path_parts)
                path += '/'
                path += row.name
                l += [create_collection(self, row.id, path, birthday_source=row.birthday_source)]
            l += list(self_collection._get_all(connection=connection))
        return l

    def discover(self, path: str, depth: str = "0") -> Iterable["radicale.types.CollectionOrItem"]:
        with self._engine.begin() as c:
            return self._discover(path, connection=c, depth=depth)

    def _move(self, item: "radicale_item.Item", to_collection: "BaseCollection", to_href: str, *, connection) -> None:
        assert isinstance(item.collection, Collection)
        assert isinstance(to_collection, Collection)
        src_collection_id = item.collection._id
        dst_collection_id = to_collection._id
        item_table = self._meta.tables['item']

        delete_stmt = sa.delete(
            item_table,
        ).where(
            sa.and_(
                item_table.c.collection_id == dst_collection_id,
                item_table.c.name == to_href,
            )
        )
        update_stmt = sa.update(
            item_table,
        ).values(
            collection_id=dst_collection_id,
            name=to_href,
        ).where(
            sa.and_(
                item_table.c.collection_id == src_collection_id,
                item_table.c.name == item.href,
            )
        )
        connection.execute(delete_stmt)
        connection.execute(update_stmt)
        self._collection_updated(src_collection_id, connection=connection)
        self._collection_updated(dst_collection_id, connection=connection)
        to_collection._update_history_etag(to_href, item, connection=connection)
        assert item.href is not None
        item.collection._update_history_etag(item.href, None, connection=connection)

    def move(self, item: "radicale_item.Item", to_collection: "BaseCollection", to_href: str) -> None:
        with self._engine.begin() as c:
            return self._move(item, to_collection, to_href, connection=c)

    def _create_bday_calendar(
        self,
        href: str,
        *,
        connection,
        address_book: "BaseCollection",
        address_props: Optional[Mapping[str, str]]=None,
    ) -> "BaseCollection":
        assert isinstance(address_book, Collection)
        calendar_props = {
            **(address_props or {}),
            'birthday_source': str(address_book._id),
            'tag': 'VCALENDAR',
        }
        calendar = self._create_collection(href, connection=connection, props=calendar_props)
        return calendar

    def _create_collection(
        self,
        href: str,
        *,
        connection,
        items: Optional[Iterable["radicale_item.Item"]]=None,
        props: Optional[Mapping[str, str]]=None,
    ) -> "BaseCollection":
        logger.debug('create_collection: %s, %s, %s', href, items, props)
        path = self._split_path(href)
        parent_id = self._root_collection.id
        collection_table = self._meta.tables['collection']
        collection_metadata_table = self._meta.tables['collection_metadata']
        item_table = self._meta.tables['item']

        for p in path:
            select_stmt = sa.select(
                collection_table.c,
            ).select_from(
                collection_table,
            ).where(
                sa.and_(
                    collection_table.c.parent_id == parent_id,
                    collection_table.c.name == p,
                ),
            )
            c = connection.execute(select_stmt).one_or_none()
            if c is None:
                insert_stmt = sa.insert(
                    collection_table,
                ).values(
                    parent_id=parent_id,
                    name=p,
                ).returning(
                    collection_table.c,
                )
                c = connection.execute(insert_stmt).one()
            parent_id = c.id
        if items is not None or props is not None:
            # drop all subcollections and items
            delete_collections_stmt = sa.delete(
                collection_table,
            ).where(
                collection_table.c.parent_id == parent_id,
            )
            delete_meta_stmt = sa.delete(
                collection_metadata_table,
            ).where(
                collection_metadata_table.c.collection_id == parent_id,
            )
            delete_items_stmt = sa.delete(
                item_table,
            ).where(
                item_table.c.collection_id == parent_id,
            )
            connection.execute(delete_collections_stmt)
            connection.execute(delete_meta_stmt)
            connection.execute(delete_items_stmt)
        if props is not None:
            insert_stmt = sa.insert(
                collection_metadata_table,
            ).values([dict(collection_id=parent_id, key=k, value=v) for k, v in props.items()])
            connection.execute(insert_stmt)
        c = Collection(self, parent_id, '/'.join(path))
        if self.configuration.get('storage', 'generate_birthday_calendars') \
                and props is not None and props.get('tag') == 'VADDRESSBOOK':
            bday_href = '/'.join(path[:-1] + [str(uuid.uuid4())])
            bday_href = f'/{bday_href}/'
            self._create_bday_calendar(bday_href, connection=connection, address_book=c, address_props=props)
        if props is not None and 'tag' in props and items is not None:
            suffix = '.bin'
            if props['tag'] == 'VADDRESSBOOK':
                suffix = '.vcf'
            elif props['tag'] == 'VCALENDAR':
                suffix = '.ics'
            for i in items:
                c._upload(i.uid + suffix, i, connection=connection)
        return c

    def create_collection(
        self,
        href: str,
        items: Optional[Iterable["radicale_item.Item"]]=None,
        props: Optional[Mapping[str, str]]=None,
    ) -> "BaseCollection":
        with self._engine.begin() as c:
            return self._create_collection(href, connection=c, items=items, props=props)


    @radicale.types.contextmanager
    def acquire_lock(self, mod: str, user: str = "") -> Iterator[None]:
        _ = mod, user
        yield

    def _verify(self, *, connection) -> bool:
        _ = connection
        return True

    def verify(self):
        with self._engine.begin() as c:
            return self._verify(connection=c)