Files
specklepy/speckle/serialization/base_object_serializer.py
T
2020-11-30 16:59:31 +00:00

164 lines
5.5 KiB
Python

import json
import hashlib
from uuid import uuid4
from typing import Any, Dict, List, Tuple
from speckle.objects.base import Base
from speckle.logging.exceptions import SerializationException, SpeckleException
from speckle.transports.abstract_transport import AbstractTransport
PRIMITIVES = (int, float, str, bool)
def hash_obj(obj: Any) -> str:
return hashlib.sha256(json.dumps(obj).encode()).hexdigest()[:32]
class BaseObjectSerializer:
read_transport: AbstractTransport
write_transports: List[AbstractTransport]
detach_lineage: List[bool] = [] # tracks depth and whether or not to detach
lineage: List[str] = [] # keeps track of hash chain through the object tree
family_tree: Dict[str, Dict[str, int]] = {}
closure_table: Dict[str, Dict[str, int]] = {}
def __init__(
self, write_transports: List[AbstractTransport] = [], read_transport=None
) -> None:
self.write_transports = write_transports
self.read_transport = read_transport
def write_json(self, base: Base):
self.detach_lineage = [True]
hash, obj = self.traverse_base(base)
return hash, json.dumps(obj)
def traverse_base(self, base: Base) -> Tuple[str, Dict]:
"""Decomposes the given base object and builds a serializable dictionary
Arguments:
base {Base} -- the base object to be decomposed and serialized
Returns:
(str, dict) -- a tuple containing the hash (id) of the base object and the constructed serializable dictionary
"""
if not self.detach_lineage:
self.detach_lineage = [True]
self.lineage.append(uuid4().hex)
object_builder = {"id": ""}
obj, props = base, base.get_member_names()
while props:
prop = props.pop(0)
value = obj[prop]
# skip nulls or props marked to be ignored with "__"
if not value or prop.startswith("__"):
continue
detach = True if prop.startswith("@") else False
# 1. handle primitives (ints, floats, strings, and bools)
if isinstance(value, PRIMITIVES):
object_builder[prop] = value
continue
# 2. handle Base objects
elif isinstance(value, Base):
child_obj = self.traverse_value(value, detach=detach)
if detach:
ref_hash = child_obj["id"]
object_builder[prop] = self.detach_helper(ref_hash=ref_hash)
# 3. handle all other cases
else:
child_obj = self.traverse_value(value)
object_builder[prop] = child_obj
hash = hash_obj(object_builder)
object_builder["id"] = hash
detached = self.detach_lineage.pop()
# add closures to the object
if self.lineage[-1] in self.family_tree:
object_builder["__closure"] = self.closure_table[hash] = {
ref: depth - len(self.detach_lineage)
for ref, depth in self.family_tree[self.lineage[-1]].items()
}
# write detached or root objects to transports
if detached:
for t in self.write_transports:
t.save_object(id=hash, serialized_object=json.dumps(object_builder))
del self.lineage[-1]
return hash, object_builder
def traverse_value(self, obj: Any, detach: bool = False) -> Any:
"""Decomposes a given object and constructs a serializable object or dictionary
Arguments:
obj {Any} -- the value to decompose
Returns:
Any -- a serializable version of the given object
"""
if isinstance(obj, PRIMITIVES):
return obj
elif isinstance(obj, (list, set)):
return [self.traverse_value(o) for o in obj]
elif isinstance(obj, dict):
for k, v in obj.items():
if isinstance(v, PRIMITIVES):
continue
else:
obj[k] = self.traverse_value(v)
return obj
elif isinstance(obj, Base):
self.detach_lineage.append(detach)
_, base_obj = self.traverse_base(obj)
return base_obj
else:
try:
return obj.dict()
except:
SerializationException(
message=f"Failed to handle {type(obj)} in `BaseObjectSerializer.traverse_value`",
object=obj,
)
return str(obj)
def detach_helper(self, ref_hash: str) -> Dict[str, str]:
"""Helper to keep track of detached objects and their depth in the family tree and create reference objects to place in the parent object
Arguments:
ref_hash {str} -- the hash of the fully traversed object
Returns:
dict -- a reference object to be inserted into the given object's parent
"""
for parent in self.lineage:
if parent not in self.family_tree:
self.family_tree[parent] = {}
if ref_hash not in self.family_tree[parent] or self.family_tree[parent][
ref_hash
] > len(self.detach_lineage):
self.family_tree[parent][ref_hash] = len(self.detach_lineage)
return {
"referencedId": ref_hash,
"speckle_type": "reference",
}
def write_to_transports(self, hash: str, obj: Dict) -> None:
for t in self.write_transports:
t.save_object(id=hash, serialized_object=json.dumps(obj))