redis-om-python/redis_developer/orm/model.py
2021-09-29 20:42:02 -07:00

885 lines
30 KiB
Python

import abc
import dataclasses
import decimal
import inspect
import operator
import re
from copy import deepcopy, copy
from enum import Enum
from functools import reduce
from typing import (
AbstractSet,
Any,
Callable,
Dict,
Mapping,
Optional,
Set,
Tuple,
TypeVar,
Union,
Sequence,
no_type_check,
Protocol,
List,
Type,
Pattern
)
import uuid
import redis
from pydantic import BaseModel, validator
from pydantic.fields import FieldInfo as PydanticFieldInfo
from pydantic.fields import ModelField, Undefined, UndefinedType
from pydantic.main import ModelMetaclass
from pydantic.typing import NoArgAnyCallable
from pydantic.utils import Representation
from .encoders import jsonable_encoder
model_registry = {}
_T = TypeVar("_T")
class TokenEscaper:
"""
Escape punctuation within an input string.
"""
# Characters that RediSearch requires us to escape during queries.
# Source: https://oss.redis.com/redisearch/Escaping/#the_rules_of_text_field_tokenization
DEFAULT_ESCAPED_CHARS = r"[,.<>{}\[\]\\\"\':;!@#$%^&*()\-+=~\ ]"
def __init__(self, escape_chars_re: Optional[Pattern] = None):
if escape_chars_re:
self.escaped_chars_re = escape_chars_re
else:
self.escaped_chars_re = re.compile(self.DEFAULT_ESCAPED_CHARS)
def escape(self, string):
def escape_symbol(match):
value = match.group(0)
return f"\\{value}"
return self.escaped_chars_re.sub(escape_symbol, string)
escaper = TokenEscaper()
class RedisModelError(Exception):
pass
class NotFoundError(Exception):
"""A query found no results."""
class Operators(Enum):
EQ = 1
NE = 2
LT = 3
LE = 4
GT = 5
GE = 6
OR = 7
AND = 8
NOT = 9
IN = 10
NOT_IN = 11
LIKE = 12
ALL = 13
@dataclasses.dataclass
class NegatedExpression:
expression: 'Expression'
def __invert__(self):
return self.expression
def __and__(self, other):
return Expression(left=self, op=Operators.AND, right=other)
def __or__(self, other):
return Expression(left=self, op=Operators.OR, right=other)
@dataclasses.dataclass
class Expression:
op: Operators
left: Any
right: Any
def __invert__(self):
return NegatedExpression(self)
def __and__(self, other):
return Expression(left=self, op=Operators.AND, right=other)
def __or__(self, other):
return Expression(left=self, op=Operators.OR, right=other)
ExpressionOrNegated = Union[Expression, NegatedExpression]
class ExpressionProxy:
def __init__(self, field: ModelField):
self.field = field
def __eq__(self, other: Any) -> Expression:
return Expression(left=self.field, op=Operators.EQ, right=other)
def __ne__(self, other: Any) -> Expression:
return Expression(left=self.field, op=Operators.NE, right=other)
def __lt__(self, other: Any) -> Expression:
return Expression(left=self.field, op=Operators.LT, right=other)
def __le__(self, other: Any) -> Expression:
return Expression(left=self.field, op=Operators.LE, right=other)
def __gt__(self, other: Any) -> Expression:
return Expression(left=self.field, op=Operators.GT, right=other)
def __ge__(self, other: Any) -> Expression:
return Expression(left=self.field, op=Operators.GE, right=other)
class QueryNotSupportedError(Exception):
"""The attempted query is not supported."""
class RediSearchFieldTypes(Enum):
TEXT = 'TEXT'
TAG = 'TAG'
NUMERIC = 'NUMERIC'
GEO = 'GEO'
# TODO: How to handle Geo fields?
NUMERIC_TYPES = (float, int, decimal.Decimal)
DEFAULT_PAGE_SIZE = 10
class FindQuery:
def __init__(self,
expressions: Sequence[ExpressionOrNegated],
model: Type['RedisModel'],
offset: int = 0,
limit: int = DEFAULT_PAGE_SIZE,
page_size: int = DEFAULT_PAGE_SIZE,
sort_fields: Optional[List[str]] = None):
self.expressions = expressions
self.model = model
self.offset = offset
self.limit = limit
self.page_size = page_size
if sort_fields:
self.sort_fields = self.validate_sort_fields(sort_fields)
else:
self.sort_fields = []
self._expression = None
self._query = None
self._pagination = []
self._model_cache = []
@property
def pagination(self):
if self._pagination:
return self._pagination
self._pagination = self.resolve_redisearch_pagination()
return self._pagination
@property
def expression(self):
if self._expression:
return self._expression
if self.expressions:
self._expression = reduce(operator.and_, self.expressions)
else:
self._expression = Expression(left=None, right=None, op=Operators.ALL)
return self._expression
@property
def query(self):
return self.resolve_redisearch_query(self.expression)
def validate_sort_fields(self, sort_fields):
for sort_field in sort_fields:
field_name = sort_field.lstrip("-")
if field_name not in self.model.__fields__:
raise QueryNotSupportedError(f"You tried sort by {field_name}, but that field "
f"does not exist on the model {self.model}")
field_proxy = getattr(self.model, field_name)
if not getattr(field_proxy.field.field_info, 'sortable', False):
raise QueryNotSupportedError(f"You tried sort by {field_name}, but {self.model} does "
"not define that field as sortable. See docs: XXX")
return sort_fields
@staticmethod
def resolve_field_type(field: ModelField) -> RediSearchFieldTypes:
if getattr(field.field_info, 'primary_key', None) is True:
return RediSearchFieldTypes.TAG
elif getattr(field.field_info, 'full_text_search', None) is True:
return RediSearchFieldTypes.TEXT
field_type = field.outer_type_
# TODO: GEO
if any(issubclass(field_type, t) for t in NUMERIC_TYPES):
return RediSearchFieldTypes.NUMERIC
else:
# TAG fields are the default field type.
# TODO: A ListField or ArrayField that supports multiple values
# and contains logic.
return RediSearchFieldTypes.TAG
@staticmethod
def expand_tag_value(value):
err = RedisModelError(f"Using the IN operator requires passing a sequence of "
"possible values. You passed: {value}")
if isinstance(str, value):
raise err
try:
expanded_value = "|".join([escaper.escape(v) for v in value])
except TypeError:
raise err
return expanded_value
@classmethod
def resolve_value(cls, field_name: str, field_type: RediSearchFieldTypes,
op: Operators, value: Any) -> str:
result = ""
if field_type is RediSearchFieldTypes.TEXT:
result = f"@{field_name}:"
if op is Operators.EQ:
result += f'"{value}"'
elif op is Operators.NE:
result = f'-({result}"{value}")'
elif op is Operators.LIKE:
result += value
else:
raise QueryNotSupportedError("Only equals (=), not-equals (!=), and like() "
"comparisons are supported for TEXT fields. See "
"docs: TODO.")
elif field_type is RediSearchFieldTypes.NUMERIC:
if op is Operators.EQ:
result += f"@{field_name}:[{value} {value}]"
elif op is Operators.NE:
# TODO: Is this enough or do we also need a clause for all values
# ([-inf +inf]) from which we then subtract the undesirable value?
result += f"-(@{field_name}:[{value} {value}])"
elif op is Operators.GT:
result += f"@{field_name}:[({value} +inf]"
elif op is Operators.LT:
result += f"@{field_name}:[-inf ({value}]"
elif op is Operators.GE:
result += f"@{field_name}:[{value} +inf]"
elif op is Operators.LE:
result += f"@{field_name}:[-inf {value}]"
elif field_type is RediSearchFieldTypes.TAG:
if op is Operators.EQ:
value = escaper.escape(value)
result += f"@{field_name}:{{{value}}}"
elif op is Operators.NE:
value = escaper.escape(value)
result += f"-(@{field_name}:{{{value}}})"
elif op is Operators.IN:
expanded_value = cls.expand_tag_value(value)
result += f"(@{field_name}:{{{expanded_value}}})"
elif op is Operators.NOT_IN:
expanded_value = cls.expand_tag_value(value)
result += f"-(@{field_name}:{{{expanded_value}}})"
return result
def resolve_redisearch_pagination(self):
"""Resolve pagination options for a query."""
return ["LIMIT", self.offset, self.limit]
def resolve_redisearch_sort_fields(self):
"""Resolve sort options for a query."""
if not self.sort_fields:
return
fields = []
for f in self.sort_fields:
direction = "desc" if f.startswith('-') else 'asc'
fields.extend([f.lstrip('-'), direction])
if self.sort_fields:
return ["SORTBY", *fields]
@classmethod
def resolve_redisearch_query(cls, expression: ExpressionOrNegated):
"""Resolve an expression to a string RediSearch query."""
field_type = None
field_name = None
encompassing_expression_is_negated = False
result = ""
if isinstance(expression, NegatedExpression):
encompassing_expression_is_negated = True
expression = expression.expression
if expression.op is Operators.ALL:
if encompassing_expression_is_negated:
# TODO: Is there a use case for this, perhaps for dynamic
# scoring purposes?
raise QueryNotSupportedError("You cannot negate a query for all results.")
return "*"
if isinstance(expression.left, Expression) or \
isinstance(expression.left, NegatedExpression):
result += f"({cls.resolve_redisearch_query(expression.left)})"
elif isinstance(expression.left, ModelField):
field_type = cls.resolve_field_type(expression.left)
field_name = expression.left.name
else:
import ipdb; ipdb.set_trace()
raise QueryNotSupportedError(f"A query expression should start with either a field "
f"or an expression enclosed in parenthesis. See docs: "
f"TODO")
right = expression.right
if isinstance(right, Expression) or isinstance(right, NegatedExpression):
if expression.op == Operators.AND:
result += " "
elif expression.op == Operators.OR:
result += "| "
else:
raise QueryNotSupportedError("You can only combine two query expressions with"
"AND (&) or OR (|). See docs: TODO")
if isinstance(right, NegatedExpression):
result += "-"
# We're handling the RediSearch operator in this call ("-"), so resolve the
# inner expression instead of the NegatedExpression.
right = right.expression
result += f"({cls.resolve_redisearch_query(right)})"
else:
if isinstance(right, ModelField):
raise QueryNotSupportedError("Comparing fields is not supported. See docs: TODO")
else:
# TODO: Optionals causing IDE errors here
result += cls.resolve_value(field_name, field_type, expression.op, right)
if encompassing_expression_is_negated:
result = f"-({result})"
return result
def execute(self, exhaust_results=True):
args = ["ft.search", self.model.Meta.index_name, self.query, *self.pagination]
if self.sort_fields:
args += self.resolve_redisearch_sort_fields()
# Reset the cache if we're executing from offset 0.
if self.offset == 0:
self._model_cache.clear()
# If the offset is greater than 0, we're paginating through a result set,
# so append the new results to results already in the cache.
raw_result = self.model.db().execute_command(*args)
count = raw_result[0]
results = self.model.from_redis(raw_result)
self._model_cache += results
if not exhaust_results:
return self._model_cache
# The query returned all results, so we have no more work to do.
if count <= len(results):
return self._model_cache
# Transparently (to the user) make subsequent requests to paginate
# through the results and finally return them all.
query = self
while True:
# Make a query for each pass of the loop, with a new offset equal to the
# current offset plus `page_size`, until we stop getting results back.
query = FindQuery(expressions=query.expressions,
model=query.model,
offset=query.offset + query.page_size,
page_size=query.page_size,
limit=query.limit)
_results = query.execute(exhaust_results=False)
if not _results:
break
self._model_cache += _results
return self._model_cache
def first(self):
query = FindQuery(expressions=self.expressions, model=self.model,
offset=0, limit=1, sort_fields=self.sort_fields)
return query.execute()[0]
def all(self, batch_size=10):
if batch_size != self.page_size:
# TODO: There's probably a copy-with-change mechanism in Pydantic,
# or can we use one from dataclasses?
query = FindQuery(expressions=self.expressions,
model=self.model,
offset=self.offset,
page_size=batch_size,
limit=batch_size,
sort_fields=self.sort_fields)
return query.execute()
return self.execute()
def sort_by(self, *fields: str):
if not fields:
return self
return FindQuery(expressions=self.expressions,
model=self.model,
offset=self.offset,
page_size=self.page_size,
limit=self.limit,
sort_fields=list(fields))
def update(self, **kwargs):
"""Update all matching records in this query."""
# TODO
def delete(cls, **field_values):
"""Delete all matching records in this query."""
for field_name, value in field_values:
valid_attr = hasattr(cls.model, field_name)
if not valid_attr:
raise RedisModelError(f"Can't update field {field_name} because "
f"the field does not exist on the model {cls}")
return cls
def __iter__(self):
if self._model_cache:
for m in self._model_cache:
yield m
else:
for m in self.execute():
yield m
def __getitem__(self, item: int):
"""
Given this code:
Model.find()[1000]
We should return only the 1000th result.
1. If the result is loaded in the query cache for this query,
we can return it directly from the cache.
2. If the query cache does not have enough elements to return
that result, then we should clone the current query and
give it a new offset and limit: offset=n, limit=1.
"""
if self._model_cache and len(self._model_cache) >= item:
return self._model_cache[item]
query = FindQuery(expressions=self.expressions,
model=self.model,
offset=item,
sort_fields=self.sort_fields,
limit=1)
return query.execute()[0]
class PrimaryKeyCreator(Protocol):
def create_pk(self, *args, **kwargs) -> str:
"""Create a new primary key"""
class Uuid4PrimaryKey:
def create_pk(self, *args, **kwargs) -> str:
return str(uuid.uuid4())
def __dataclass_transform__(
*,
eq_default: bool = True,
order_default: bool = False,
kw_only_default: bool = False,
field_descriptors: Tuple[Union[type, Callable[..., Any]], ...] = (()),
) -> Callable[[_T], _T]:
return lambda a: a
class FieldInfo(PydanticFieldInfo):
def __init__(self, default: Any = Undefined, **kwargs: Any) -> None:
primary_key = kwargs.pop("primary_key", False)
sortable = kwargs.pop("sortable", Undefined)
index = kwargs.pop("index", Undefined)
full_text_search = kwargs.pop("full_text_search", Undefined)
super().__init__(default=default, **kwargs)
self.primary_key = primary_key
self.sortable = sortable
self.index = index
self.full_text_search = full_text_search
class RelationshipInfo(Representation):
def __init__(
self,
*,
back_populates: Optional[str] = None,
link_model: Optional[Any] = None,
) -> None:
self.back_populates = back_populates
self.link_model = link_model
def Field(
default: Any = Undefined,
*,
default_factory: Optional[NoArgAnyCallable] = None,
alias: str = None,
title: str = None,
description: str = None,
exclude: Union[
AbstractSet[Union[int, str]], Mapping[Union[int, str], Any], Any
] = None,
include: Union[
AbstractSet[Union[int, str]], Mapping[Union[int, str], Any], Any
] = None,
const: bool = None,
gt: float = None,
ge: float = None,
lt: float = None,
le: float = None,
multiple_of: float = None,
min_items: int = None,
max_items: int = None,
min_length: int = None,
max_length: int = None,
allow_mutation: bool = True,
regex: str = None,
primary_key: bool = False,
sortable: Union[bool, UndefinedType] = Undefined,
index: Union[bool, UndefinedType] = Undefined,
full_text_search: Union[bool, UndefinedType] = Undefined,
schema_extra: Optional[Dict[str, Any]] = None,
) -> Any:
current_schema_extra = schema_extra or {}
field_info = FieldInfo(
default,
default_factory=default_factory,
alias=alias,
title=title,
description=description,
exclude=exclude,
include=include,
const=const,
gt=gt,
ge=ge,
lt=lt,
le=le,
multiple_of=multiple_of,
min_items=min_items,
max_items=max_items,
min_length=min_length,
max_length=max_length,
allow_mutation=allow_mutation,
regex=regex,
primary_key=primary_key,
sortable=sortable,
index=index,
full_text_search=full_text_search,
**current_schema_extra,
)
field_info._validate()
return field_info
@dataclasses.dataclass
class PrimaryKey:
name: str
field: ModelField
class DefaultMeta:
# TODO: Should this really be optional here?
global_key_prefix: Optional[str] = None
model_key_prefix: Optional[str] = None
primary_key_pattern: Optional[str] = None
database: Optional[redis.Redis] = None
primary_key: Optional[PrimaryKey] = None
primary_key_creator_cls: Optional[Type[PrimaryKeyCreator]] = None
index_name: Optional[str] = None
abstract: Optional[bool] = False
class ModelMeta(ModelMetaclass):
def add_to_class(cls, name, value):
if _has_contribute_to_class(value):
value.contribute_to_class(cls, name)
else:
setattr(cls, name, value)
def __new__(cls, name, bases, attrs, **kwargs): # noqa C901
meta = attrs.pop('Meta', None)
new_class = super().__new__(cls, name, bases, attrs, **kwargs)
meta = meta or getattr(new_class, 'Meta', None)
base_meta = getattr(new_class, '_meta', None)
if meta and meta != DefaultMeta and meta != base_meta:
new_class.Meta = meta
new_class._meta = meta
elif base_meta:
new_class._meta = deepcopy(base_meta)
new_class.Meta = new_class._meta
# Unset inherited values we don't want to reuse (typically based on the model name).
new_class._meta.abstract = False
new_class._meta.model_key_prefix = None
new_class._meta.index_name = None
else:
new_class._meta = deepcopy(DefaultMeta)
new_class.Meta = new_class._meta
# Create proxies for each model field so that we can use the field
# in queries, like Model.get(Model.field_name == 1)
for field_name, field in new_class.__fields__.items():
setattr(new_class, field_name, ExpressionProxy(field))
# Check if this is our FieldInfo version with extended ORM metadata.
if isinstance(field.field_info, FieldInfo):
if field.field_info.primary_key:
new_class._meta.primary_key = PrimaryKey(name=field_name, field=field)
if not getattr(new_class._meta, 'global_key_prefix', None):
new_class._meta.global_key_prefix = getattr(base_meta, "global_key_prefix", "")
if not getattr(new_class._meta, 'model_key_prefix', None):
# Don't look at the base class for this.
new_class._meta.model_key_prefix = f"{new_class.__module__}.{new_class.__name__}"
if not getattr(new_class._meta, 'primary_key_pattern', None):
new_class._meta.primary_key_pattern = getattr(base_meta, "primary_key_pattern",
"{pk}")
if not getattr(new_class._meta, 'database', None):
new_class._meta.database = getattr(base_meta, "database",
redis.Redis(decode_responses=True))
if not getattr(new_class._meta, 'primary_key_creator_cls', None):
new_class._meta.primary_key_creator_cls = getattr(base_meta, "primary_key_creator_cls",
Uuid4PrimaryKey)
if not getattr(new_class._meta, 'index_name', None):
new_class._meta.index_name = f"{new_class._meta.global_key_prefix}:" \
f"{new_class._meta.model_key_prefix}:index"
return new_class
class RedisModel(BaseModel, abc.ABC, metaclass=ModelMeta):
pk: Optional[str] = Field(default=None, primary_key=True)
Meta = DefaultMeta
# TODO: Missing _meta here is causing IDE warnings.
class Config:
orm_mode = True
arbitrary_types_allowed = True
extra = 'allow'
def __init__(__pydantic_self__, **data: Any) -> None:
super().__init__(**data)
__pydantic_self__.validate_primary_key()
def __lt__(self, other):
"""Default sort: compare all shared model fields."""
my_keys = set(self.__fields__.keys())
other_keys = set(other.__fields__.keys())
shared_keys = list(my_keys & other_keys)
lt = [getattr(self, k) < getattr(other, k) for k in shared_keys]
return len(lt) > len(shared_keys) / 2
@validator("pk", always=True)
def validate_pk(cls, v):
if not v:
v = cls._meta.primary_key_creator_cls().create_pk()
return v
@classmethod
def validate_primary_key(cls):
"""Check for a primary key. We need one (and only one)."""
primary_keys = 0
for name, field in cls.__fields__.items():
if getattr(field.field_info, 'primary_key', None):
primary_keys += 1
if primary_keys == 0:
raise RedisModelError("You must define a primary key for the model")
elif primary_keys > 1:
raise RedisModelError("You must define only one primary key for a model")
@classmethod
def make_key(cls, part: str):
global_prefix = getattr(cls._meta, 'global_key_prefix', '').strip(":")
model_prefix = getattr(cls._meta, 'model_key_prefix', '').strip(":")
return f"{global_prefix}:{model_prefix}:{part}"
@classmethod
def make_primary_key(cls, pk: Any):
"""Return the Redis key for this model."""
return cls.make_key(cls._meta.primary_key_pattern.format(pk=pk))
def key(self):
"""Return the Redis key for this model."""
pk = getattr(self, self._meta.primary_key.field.name)
return self.make_primary_key(pk)
@classmethod
def db(cls):
return cls._meta.database
@classmethod
def find(cls, *expressions: Expression):
return FindQuery(expressions=expressions, model=cls)
@classmethod
def from_redis(cls, res: Any):
# TODO: Parsing logic borrowed from redisearch-py. Evaluate.
import six
from six.moves import xrange, zip as izip
def to_string(s):
if isinstance(s, six.string_types):
return s
elif isinstance(s, six.binary_type):
return s.decode('utf-8', 'ignore')
else:
return s # Not a string we care about
docs = []
step = 2 # Because the result has content
offset = 1 # The first item is the count of total matches.
for i in xrange(1, len(res), step):
fields_offset = offset
fields = dict(
dict(izip(map(to_string, res[i + fields_offset][::2]),
map(to_string, res[i + fields_offset][1::2])))
)
try:
del fields['id']
except KeyError:
pass
doc = cls(**fields)
docs.append(doc)
return docs
@classmethod
def add(cls, models: Sequence['RedisModel']) -> Sequence['RedisModel']:
return [model.save() for model in models]
@classmethod
def update(cls, **field_values):
"""Update this model instance."""
return cls
@classmethod
def values(cls):
"""Return raw values from Redis instead of model instances."""
return cls
def delete(self):
return self.db().delete(self.key())
def save(self, *args, **kwargs) -> 'RedisModel':
raise NotImplementedError
@classmethod
def redisearch_schema(cls):
raise NotImplementedError
class HashModel(RedisModel, abc.ABC):
def __init_subclass__(cls, **kwargs):
super().__init_subclass__(**kwargs)
for name, field in cls.__fields__.items():
if issubclass(field.outer_type_, RedisModel):
raise RedisModelError(f"HashModels cannot have embedded model "
f"fields. Field: {name}")
for typ in (Set, Mapping, List):
if issubclass(field.outer_type_, typ):
raise RedisModelError(f"HashModels cannot have set, list,"
f" or mapping fields. Field: {name}")
def save(self, *args, **kwargs) -> 'HashModel':
document = jsonable_encoder(self.dict())
success = self.db().hset(self.key(), mapping=document)
return success
@classmethod
def get(cls, pk: Any) -> 'HashModel':
document = cls.db().hgetall(cls.make_primary_key(pk))
if not document:
raise NotFoundError
return cls.parse_obj(document)
@classmethod
@no_type_check
def _get_value(cls, *args, **kwargs) -> Any:
"""
Always send None as an empty string.
TODO: We do this because redis-py's hset() method requires non-null
values. Is there a better way?
"""
val = super()._get_value(*args, **kwargs)
if val is None:
return ""
return val
@classmethod
def schema_for_type(cls, name, typ: Type, field_info: FieldInfo):
if any(issubclass(typ, t) for t in NUMERIC_TYPES):
return f"{name} NUMERIC"
elif issubclass(typ, str):
if getattr(field_info, 'full_text_search', False) is True:
return f"{name} TAG {name}_fts TEXT"
else:
return f"{name} TAG"
else:
return f"{name} TAG"
@classmethod
def redisearch_schema(cls):
hash_prefix = cls.make_key(cls._meta.primary_key_pattern.format(pk=""))
schema_prefix = f"ON HASH PREFIX 1 {hash_prefix} SCHEMA"
schema_parts = [schema_prefix]
for name, field in cls.__fields__.items():
_type = field.outer_type_
if getattr(field.field_info, 'primary_key', None):
if issubclass(_type, str):
redisearch_field = f"{name} TAG"
else:
redisearch_field = cls.schema_for_type(name, _type, field.field_info)
schema_parts.append(redisearch_field)
elif getattr(field.field_info, 'index', None) is True:
schema_parts.append(cls.schema_for_type(name, _type, field.field_info))
if getattr(field.field_info, 'sortable', False) is True:
schema_parts.append("SORTABLE")
return " ".join(schema_parts)
class JsonModel(RedisModel, abc.ABC):
def save(self, *args, **kwargs) -> 'JsonModel':
success = self.db().execute_command('JSON.SET', self.key(), ".", self.json())
return success
@classmethod
def get(cls, pk: Any) -> 'JsonModel':
document = cls.db().execute_command("JSON.GET", cls.make_primary_key(pk))
if not document:
raise NotFoundError
return cls.parse_raw(document)