Source code for univention.admin.rest.async_client

#!/usr/bin/python3
#
# Univention Directory Manager
#  REST API async client
#
# SPDX-FileCopyrightText: 2019-2025 Univention GmbH
# SPDX-License-Identifier: AGPL-3.0-only
"""
Sample asynchronous client for the UDM REST API.

>>> import asyncio
>>> from univention.admin.rest.async_client import UDM
>>>
>>> uri = 'http://localhost/univention/udm/'
>>> async def main():
>>>     async with UDM.http(uri, 'Administrator', 'univention') as udm:
>>>         module = await udm.get('users/user')
>>>         print(f'Found {module}')
>>>         objs = module.search()
>>>         async for obj in objs:
>>>             if not obj:
>>>                 continue
>>>             obj = await obj.open()
>>>             print(f'Object {obj}')
>>>             for group in obj.objects.groups:
>>>                 grp = await group.open()
>>>                 print(f'Group {grp}')
>>>
>>> asyncio.run(main())
"""

from __future__ import annotations

import asyncio
import copy
from typing import TYPE_CHECKING, Any

import aiohttp
import uritemplate


if TYPE_CHECKING:
    from collections.abc import AsyncIterator, Callable, Iterator, Mapping

try:
    aiter  # noqa: B018
except NameError:  # Python 3.7
    class _AsyncIterable:
        def __init__(self, iterable):
            self.iterable = iterable

        def __aiter__(self):
            return self

        async def __anext__(self):
            return await anext(self.iterable)

    def anext(iterable):
        return iterable.__anext__()

    def aiter(iterable):
        return _AsyncIterable(iterable)


[docs] class HTTPError(Exception): __slots__ = ('code', 'error_details', 'response') def __init__(self, code: int, message: str, response: aiohttp.ClientResponse | None, error_details: dict | None = None) -> None: self.code = code self.response = response self.error_details = error_details super().__init__(message)
[docs] class BadRequest(HTTPError): pass
[docs] class Unauthorized(HTTPError): pass
[docs] class Forbidden(HTTPError): pass
[docs] class NotFound(HTTPError): pass
[docs] class PreconditionFailed(HTTPError): pass
[docs] class UnprocessableEntity(HTTPError): pass
[docs] class ServerError(HTTPError): pass
[docs] class ServiceUnavailable(HTTPError): pass
[docs] class ConnectionError(Exception): pass
[docs] class UnexpectedResponse(ConnectionError): pass
class _NoRelation(Exception): pass
[docs] class Response: # noqa: B903 __slots__ = ('data', 'response', 'uri') def __init__(self, response: aiohttp.ClientResponse, data: Any, uri: str) -> None: self.response = response self.data = data self.uri = uri
[docs] class Session: __slots__ = ('credentials', 'default_headers', 'enable_caching', 'language', 'reconnect', 'session', 'user_agent') def __init__(self, credentials: UDM, language: str = 'en-US', reconnect: bool = True, user_agent: str = 'univention.lib/1.0', enable_caching: bool = False, concurrency_limit: int = 10) -> None: self.language = language self.credentials = credentials self.reconnect = reconnect self.user_agent = user_agent self.enable_caching = enable_caching self.default_headers = { 'Accept': 'application/hal+json; q=1, application/json; q=0.9; text/html; q=0.2, */*; q=0.1', 'Accept-Language': self.language, 'User-Agent': self.user_agent, } self.session = self.create_session(concurrency_limit) async def __aenter__(self): await self.session.__aenter__() return self async def __aexit__(self, exc, etype, etraceback): await self.session.__aexit__(exc, etype, etraceback)
[docs] def create_session(self, concurrency_limit: int = 10) -> aiohttp.ClientSession: connector = aiohttp.TCPConnector(limit=concurrency_limit) auth = aiohttp.BasicAuth(self.credentials.username, self.credentials.password) return aiohttp.ClientSession(connector=connector, auth=auth)
[docs] def get_method(self, method: str) -> Callable[..., aiohttp.ClientResponse]: sess = self.session return { 'GET': sess.get, 'POST': sess.post, 'PUT': sess.put, 'DELETE': sess.delete, 'PATCH': sess.patch, 'OPTIONS': sess.options, }.get(method.upper(), sess.get)
[docs] async def request(self, method: str, uri: str, data: dict | None = None, expect_json: bool = False, **headers: str) -> Any: return (await self.make_request(method, uri, data, expect_json=expect_json, **headers)).data # type: ignore # <https://github.com/python/mypy/issues/10008>
[docs] async def make_request(self, method: str, uri: str, data: dict | None = None, expect_json: bool = False, allow_redirects: bool = True, custom_redirect_handling: bool = False, **headers: str) -> Response: if method in ('GET', 'HEAD'): params = data json = None else: params = None json = data async def doit() -> Response: try: response = await self.get_method(method)(uri, params=params, json=json, headers=dict(self.default_headers, **headers), allow_redirects=allow_redirects) except aiohttp.ClientConnectionError as exc: # pragma: no cover raise ConnectionError(exc) if custom_redirect_handling: response = await self._follow_redirection(response) data = await self.eval_response(response, expect_json=expect_json) return Response(response, data, uri) for _i in range(5): try: return await doit() except ServiceUnavailable as exc: # TODO: same for ConnectionError? python-request does it itself. if not self.reconnect: # pragma: no cover raise try: assert exc.response is not None retry_after = min(5, int(exc.response.headers.get('Retry-After', 1))) except ValueError: # pragma: no cover retry_after = 1 await asyncio.sleep(retry_after) return await doit()
async def _follow_redirection(self, response: Response) -> Response: location = response.headers.get('Location') # aiohttp doesn't follow redirects for 202? if location and response.status in (201, 202): response = (await self.make_request('GET', location, allow_redirects=False)).response # prevent allow_redirects because it does not wait Retry-After time causing a break up after 30 fast redirections while 300 <= response.status <= 399 and 'Location' in response.headers: location = response.headers['Location'] if response.headers.get('Retry-After', '').isdigit(): await asyncio.sleep(min(30, max(0, int(response.headers['Retry-After'])))) response = (await self.make_request(self._select_method(response), location, allow_redirects=False)).response return response def _select_method(self, response: Response) -> str: if response.status in (300, 301, 303) and response.request_info.method != 'HEAD': return 'GET' return response.request_info.method # pragma: no cover
[docs] async def eval_response(self, response: aiohttp.ClientResponse, expect_json: bool = False) -> Any: if response.status >= 399: msg = f'{response.request_info.method} {response.url}: {response.status}' error_details = None try: json = await response.json() except (ValueError, aiohttp.client_exceptions.ContentTypeError): # pragma: no cover pass else: if isinstance(json, dict): error_details = json.get('error', {}) try: error_details['error'] = [error async for error in self.resolve_relations(json, 'udm:error')] except _NoRelation: # pragma: no cover pass if error_details: server_message = error_details.get('message') # traceback = error_details.get('traceback') if server_message: msg += f'\n{server_message}' errors = {400: BadRequest, 404: NotFound, 403: Forbidden, 401: Unauthorized, 412: PreconditionFailed, 422: UnprocessableEntity, 500: ServerError, 503: ServiceUnavailable} cls = HTTPError cls = errors.get(response.status, cls) raise cls(response.status, msg, response, error_details=error_details) if response.headers.get('Content-Type') in ('application/json', 'application/hal+json'): return await response.json() elif expect_json: # pragma: no cover raise UnexpectedResponse(await response.text()) return await response.text()
[docs] def get_relations(self, entry: dict, relation: str, name: str | None = None, template: dict[str, Any] | None = None) -> Iterator[dict[str, str]]: links = copy.deepcopy(entry.get('_links', {})) links = links.get(relation, [None]) links = links if links and isinstance(links, list) else [links] links = [link for link in links if isinstance(link, dict) and (not name or link.get('name') == name)] for link in sorted(links, key=lambda x: not x.get('templated', False) if template else x.get('templated', False)): if link.get('deprecation'): pass # TODO: log warning if link.get('templated'): link['href'] = uritemplate.expand(link['href'], template) yield link
[docs] def get_relation(self, entry: dict, relation: str, name: str | None = None, template: dict[str, Any] | None = None) -> dict[str, str]: rel = next(self.get_relations(entry, relation, name, template), None) if rel is None: # pragma: no cover raise _NoRelation(relation) return rel
[docs] async def resolve_relations(self, entry: dict, relation: str, name: str | None = None, template: dict[str, Any] | None = None) -> AsyncIterator[Any]: embedded = entry.get('_embedded', {}) if isinstance(embedded, dict) and relation in embedded: # yield from embedded[relation] for x in embedded[relation]: yield x return for rel in self.get_relations(entry, relation, name, template): yield (await self.make_request('GET', rel['href'])).data
[docs] async def resolve_relation(self, entry: dict, relation: str, name: str | None = None, template: dict[str, Any] | None = None) -> Any: rel = await anext(self.resolve_relations(entry, relation, name, template), None) if rel is None: raise _NoRelation(relation) return rel
[docs] class Client: # noqa: B903 __slots__ = ('client',) def __init__(self, client: Session) -> None: self.client = client
[docs] class UDM(Client): __slots__ = ('bearer_token', 'entry', 'password', 'uri', 'username')
[docs] @classmethod def http(cls, uri: str, username: str, password: str) -> UDM: return cls(uri, username, password)
[docs] @classmethod # pragma: no cover def bearer(cls, uri: str, bearer_token: str) -> UDM: return cls(uri, None, None, bearer_token=bearer_token)
def __init__(self, uri: str, username: str | None, password: str | None, *args: Any, **kwargs: Any) -> None: self.uri = uri self.username = username self.password = password self.bearer_token = kwargs.pop('bearer_token', None) self.entry: dict | Any | None = None super().__init__(Session(self, *args, **kwargs)) async def __aenter__(self): await self.client.__aenter__() return self async def __aexit__(self, exc, etype, etraceback): await self.client.__aexit__(exc, etype, etraceback)
[docs] async def load(self) -> None: # FIXME: use HTTP caching instead of memory caching if self.entry is None: await self.reload()
[docs] async def reload(self) -> None: self.entry = await self.client.request('GET', self.uri, expect_json=True)
[docs] async def get_ldap_base(self) -> str | None: await self.load() return Object.from_data(self, await self.client.resolve_relation(self.entry, 'udm:ldap-base')).dn
[docs] async def modules(self, name: str | None = None) -> AsyncIterator[Module]: await self.load() async for module in self.client.resolve_relations(self.entry, 'udm:object-modules'): for module_info in self.client.get_relations(module, 'udm:object-types', name): yield Module(self, module_info['href'], module_info['name'], module_info['title'])
[docs] async def obj_by_dn(self, dn: str) -> Object: await self.load() return Object.from_data(self, await self.client.resolve_relation(self.entry, 'udm:object/get-by-dn', template={'dn': dn}))
[docs] async def obj_by_uuid(self, uuid: str) -> Object: await self.load() return Object.from_data(self, await self.client.resolve_relation(self.entry, 'udm:object/get-by-uuid', template={'uuid': uuid}))
[docs] async def get(self, name: str) -> Module | None: async for module in self.modules(name): return module return None
[docs] async def get_object(self, object_type: str, dn: str) -> Object | None: mod = await self.get(object_type) assert mod obj = await mod.get(dn) return obj
def __repr__(self) -> str: return f'UDM(uri={self.uri!r}, username={self.username!r}, password=***)'
[docs] class Module(Client): __slots__ = ('name', 'password', 'relations', 'title', 'udm', 'uri', 'username') def __init__(self, udm: UDM, uri: str, name: str, title: str, *args: Any, **kwargs: Any) -> None: super().__init__(udm.client, *args, **kwargs) self.udm = udm self.uri = uri self.username = udm.username self.password = udm.password self.name = name self.title = title self.relations: dict = {}
[docs] async def load_relations(self) -> None: if self.relations: return self.relations = await self.client.request('GET', self.uri)
def __repr__(self) -> str: return f'Module(uri={self.uri!r}, name={self.name!r})'
[docs] async def new(self, position: str | None = None, superordinate: str | None = None, template: dict[str, Any] | None = None) -> Object: await self.load_relations() data = {'position': position, 'superordinate': superordinate, 'template': template} resp = await self.client.resolve_relation(self.relations, 'create-form', template=data) return Object.from_data(self.udm, resp)
[docs] async def get(self, dn: str, properties: list[str] | None = None) -> Object | None: # TODO: use a link relation instead of a search async for obj in self._search_closed(position=dn, scope='base', properties=properties): return await obj.open() raise NotFound(404, 'Wrong object type!?', None) # FIXME: object exists but is of different module. should be fixed on the server.
[docs] async def get_by_entry_uuid(self, uuid: str, properties: list[str] | None = None) -> Object | None: # TODO: use a link relation instead of a search # return self.udm.get_by_uuid(uuid) async for obj in self._search_closed(filter={'entryUUID': uuid}, scope='base', properties=properties): return await obj.open() raise NotFound(404, 'Wrong object type!?', None) # FIXME: object exists but is of different module. should be fixed on the server.
[docs] async def get_by_id(self, dn: str, properties: list[str] | None = None) -> Object | None: # pragma: no cover # TODO: Needed? raise NotImplementedError()
[docs] async def search(self, filter: dict[str, str] | str | bytes | None = None, position: str | None = None, scope: str | None = 'sub', hidden: bool = False, superordinate: str | None = None, opened: bool = False, properties: list[str] | None = None) -> AsyncIterator[Any]: if opened: async for entry in aiter(self._search_opened(filter, position, scope, hidden, superordinate, properties)): yield entry else: async for entry in aiter(self._search_closed(filter, position, scope, hidden, superordinate, properties)): yield entry
async def _search_opened(self, filter: dict[str, str] | str | bytes | None = None, position: str | None = None, scope: str | None = 'sub', hidden: bool = False, superordinate: str | None = None, properties: list[str] | None = None) -> AsyncIterator[Object]: async for obj in self._search(filter, position, scope, hidden, superordinate, True, properties): yield Object.from_data(self.udm, obj) # NOTE: this is missing last-modified, therefore no conditional request is done on modification! async def _search_closed(self, filter: dict[str, str] | str | bytes | None = None, position: str | None = None, scope: str | None = 'sub', hidden: bool = False, superordinate: str | None = None, properties: list[str] | None = None) -> AsyncIterator[ShallowObject]: async for obj in self._search(filter, position, scope, hidden, superordinate, False, properties): objself = self.client.get_relation(obj, 'self') uri = objself['href'] dn = objself['name'] yield ShallowObject(self.udm, dn, uri) async def _search(self, filter: dict[str, str] | str | bytes | None = None, position: str | None = None, scope: str | None = 'sub', hidden: bool = False, superordinate: str | None = None, opened: bool = False, properties: list[str] | None = None) -> AsyncIterator[Any]: data = { 'position': position, 'scope': scope, 'hidden': '1' if hidden else '0', } if isinstance(filter, dict): for prop, val in filter.items(): data.setdefault('query', {})[f'query[{prop}]'] = val elif isinstance(filter, str): data['filter'] = filter if superordinate: data['superordinate'] = superordinate if not opened: data['opened'] = '0' data['properties'] = ['dn'] if properties: data['properties'] = properties await self.load_relations() entries = await self.client.resolve_relation(self.relations, 'search', template=data) async for entry in self.client.resolve_relations(entries, 'udm:object'): yield entry
[docs] async def get_layout(self) -> Any | None: await self.load_relations() relation = await self.udm.client.resolve_relation(self.relations, 'udm:layout') return relation.get('layout')
[docs] async def get_properties(self) -> Any | None: await self.load_relations() return (await self.udm.client.resolve_relation(self.relations, 'udm:properties')).get('properties')
[docs] async def get_property_choices(self, property: str) -> Any | None: await self.load_relations() relations = await self.udm.client.resolve_relation(self.relations, 'udm:properties') return (await self.udm.client.resolve_relation(relations, 'udm:property-choices', name=property)).get('choices')
[docs] async def policy_result(self, policy_module: str, position: str, policy: str | None = None) -> dict: await self.load_relations() policy_result = await self.udm.client.resolve_relation(self.relations, 'udm:policy-result', name=policy_module, template={'position': position, 'policy': policy}) policy_result.pop('_links', None) policy_result.pop('_embedded', None) return policy_result
[docs] async def get_report_types(self) -> list[str]: await self.load_relations() return [x['name'] for x in self.udm.client.get_relations(self.relations, 'udm:report', template={'dn': ''}) if x.get('name')]
[docs] async def create_report(self, report_type: str, object_dns: list[str]) -> Any: await self.load_relations() return await self.udm.client.resolve_relation(self.relations, 'udm:report', name=report_type, template={'dn': object_dns})
[docs] class ShallowObject(Client): __slots__ = ('dn', 'udm', 'uri') def __init__(self, udm: UDM, dn: str | None, uri: str, *args: Any, **kwargs: Any) -> None: super().__init__(udm.client, *args, **kwargs) self.dn = dn self.udm = udm self.uri = uri
[docs] async def open(self) -> Object: return Object.from_response(self.udm, await self.client.make_request('GET', self.uri))
def __repr__(self) -> str: return f'ShallowObject(dn={self.dn!r})'
[docs] class References: __slots__ = ('obj', 'udm') def __init__(self, obj: Object | None = None) -> None: self.obj = obj self.udm = self.obj.udm if self.obj is not None else None def __getitem__(self, item: str) -> list[ShallowObject]: assert self.obj assert self.udm return [ ShallowObject(self.obj.udm, x['name'], x['href']) for x in self.udm.client.get_relations(self.obj.hal, f'udm:object/property/reference/{item}') ] def __getattribute__(self, key): try: return super().__getattribute__(key) except AttributeError: return self[key] def __get__(self, obj: Any, cls: type | None = None) -> References: return type(self)(obj)
[docs] class Object(Client): objects = References() @property def module(self): # FIXME: use "type" relation link # object_type = self.udm.get_relation(self.hal, 'type')['href'] return self.udm.get(self.object_type) @property def object_type(self) -> str: return self.representation['objectType'] @property def dn(self) -> str | None: return self.representation.get('dn') @property def properties(self): return self.representation['properties'] @property def options(self) -> dict: return self.representation.get('options', {}) @property def policies(self) -> dict: return self.representation.get('policies', {}) @property def superordinate(self) -> str | None: return self.representation.get('superordinate') @superordinate.setter def superordinate(self, superordinate: str) -> None: self.representation['superordinate'] = superordinate @property def position(self) -> str | None: return self.representation.get('position') @position.setter def position(self, position: str) -> None: self.representation['position'] = position @property def uri(self) -> str | None: try: uri = self.client.get_relation(self.hal, 'self') except _NoRelation: uri = None if uri: return uri['href'] return self.representation.get('uri')
[docs] @classmethod def from_response(cls, udm: UDM, response: Response) -> Object: return cls.from_data(udm, response.data, response.response.headers)
[docs] @classmethod def from_data(cls, udm: UDM, entry: dict, headers: Mapping[str, str] | None = None) -> Object: headers = headers or {} return cls(udm, entry, etag=headers.get('Etag'), last_modified=headers.get('Last-Modified'))
__slots__ = ('etag', 'hal', 'last_modified', 'representation', 'udm') def __init__(self, udm: UDM, representation: dict, etag: str | None = None, last_modified: str | None = None, *args: Any, **kwargs: Any) -> None: super().__init__(udm.client, *args, **kwargs) self.udm = udm self.representation = representation self.hal = { '_links': representation.pop('_links', {}), '_embedded': representation.pop('_embedded', {}), } self.etag = etag self.last_modified = last_modified def __repr__(self) -> str: return f'Object(module={self.object_type!r}, dn={self.dn!r}, uri={self.uri!r})'
[docs] async def reload(self) -> None: try: uri = self.client.get_relation(self.hal, 'self') except _NoRelation: uri = None if uri: obj = await ShallowObject(self.udm, self.dn, uri['href']).open() else: obj = await (await self.module).get(self.dn) self._copy_from_obj(obj)
[docs] async def save(self, reload: bool = True) -> Response: if self.dn: return await self._modify(reload) else: return await self._create(reload)
[docs] async def json_patch(self, patch: dict, reload: bool = True) -> Response: if self.dn: return await self._patch(patch, reload=reload) else: uri = self.client.get_relation(self.hal, 'create') return await self._request('POST', uri['href'], patch, {'Content-Type': 'application/json-patch+json'})
[docs] async def delete(self, remove_referring: bool = False) -> bytes: assert self.uri headers = {key: value for key, value in { 'If-Unmodified-Since': self.last_modified, 'If-Match': self.etag, }.items() if value} return await self.client.request('DELETE', self.uri, **headers) # type: ignore # <https://github.com/python/mypy/issues/10008>
[docs] async def restore(self, reload: bool = True) -> Response: """Restore an object from the recyclebin.""" uri = self.client.get_relation(self.hal, 'udm:restore')['href'] return await self._request('POST', uri, {}, {}, reload=reload)
[docs] async def move(self, position: str, reload: bool = True) -> None: self.position = position await self.save(reload=reload)
async def _modify(self, reload: bool = True) -> Response: assert self.uri headers = {key: value for key, value in { 'If-Unmodified-Since': self.last_modified, 'If-Match': self.etag, }.items() if value} return await self._request('PUT', self.uri, self.representation, headers, reload=reload) async def _patch(self, data: dict, reload: bool = True) -> Response: assert self.uri headers = {key: value for key, value in { 'If-Unmodified-Since': self.last_modified, 'If-Match': self.etag, 'Content-Type': 'application/json-patch+json', }.items() if value} return await self._request('PATCH', self.uri, data, headers, reload=reload) async def _create(self, reload: bool = True) -> Response: uri = self.client.get_relation(self.hal, 'create') return await self._request('POST', uri['href'], self.representation, {}, reload=reload) async def _request(self, method: str, uri: str, data: dict, headers: dict, reload: bool = True) -> Response: response = await self.client.make_request(method, uri, data=data, allow_redirects=False, custom_redirect_handling=True, **headers) # type: ignore # <https://github.com/python/mypy/issues/10008> await self._reload_from_response(response, reload) return response async def _reload_from_response(self, response: Response, reload: bool) -> None: if reload and 200 <= response.response.status <= 299 and 'Location' in response.response.headers: uri = response.response.headers['Location'] obj = ShallowObject(self.udm, None, uri) self._copy_from_obj(await obj.open()) return if response.response.status == 200: # the response already contains a new representation self._copy_from_obj(Object.from_response(self.udm, response)) return if reload: # pragma: no cover await self.reload() def _copy_from_obj(self, obj: Object) -> None: self.udm = obj.udm self.representation = copy.deepcopy(obj.representation) self.hal = copy.deepcopy(obj.hal) self.etag = obj.etag self.last_modified = obj.last_modified
[docs] async def generate_service_specific_password(self, service: str) -> Any | None: uri = self.client.get_relation(self.hal, 'udm:service-specific-password')['href'] response = await self.client.make_request('POST', uri, data={"service": service}) return response.data.get('password', None)
[docs] async def get_layout(self) -> Any | None: return (await self.udm.client.resolve_relation(self.hal, 'udm:layout')).get('layout')
[docs] async def get_properties(self) -> Any | None: return (await self.udm.client.resolve_relation(self.hal, 'udm:properties')).get('properties')
[docs] async def get_property_choices(self, property: str) -> Any | None: hal = await self.udm.client.resolve_relation(self.hal, 'udm:properties') return (await self.udm.client.resolve_relation(hal, 'udm:property-choices', name=property)).get('choices')
[docs] async def policy_result(self, policy_module: str, policy: str | None = None) -> dict: policy_result = await self.udm.client.resolve_relation(self.hal, 'udm:policy-result', name=policy_module, template={'policy': policy}) policy_result.pop('_links', None) policy_result.pop('_embedded', None) return policy_result
[docs] class PatchDocument: """application/json-patch+json representation""" __slots__ = ('patch',) def __init__(self): self.patch = []
[docs] def add(self, path_segments, value): self.patch.append({ 'op': 'add', 'path': self.expand_path(path_segments), 'value': value, })
[docs] def replace(self, path_segments, value): self.patch.append({ 'op': 'replace', 'path': self.expand_path(path_segments), 'value': value, })
[docs] def remove(self, path_segments, value): self.patch.append({ 'op': 'remove', 'path': self.expand_path(path_segments), 'value': value, # TODO: not official })
[docs] def move(self, path_segments, from_segments): # pragma: no cover self.patch.append({ 'op': 'move', 'path': self.expand_path(path_segments), 'from': self.expand_path(from_segments), })
[docs] def copy(self, path_segments, from_segments): # pragma: no cover self.patch.append({ 'op': 'copy', 'path': self.expand_path(path_segments), 'from': self.expand_path(from_segments), })
[docs] def test(self, path_segments, value): # pragma: no cover self.patch.append({ 'op': 'test', 'path': self.expand_path(path_segments), 'value': value, })
[docs] def expand_path(self, path_segments): return '/'.join(path.replace('~', '~0').replace('/', '~1') for path in ['', *path_segments])