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Use the msgpack ext type for a more compact representation of custom types

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Kovid Goyal 2017-05-01 13:44:24 +05:30
parent fb4ea11ce2
commit c5dd2977eb
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GPG Key ID: 06BC317B515ACE7C
1 changed files with 21 additions and 17 deletions
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36
src/calibre/utils/serialize.py
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@ -16,28 +16,31 @@ MSGPACK_MIME = 'application/x-msgpack'
CANARY = 'jPoAv3zOyHvQ5JFNYg4hJ9' CANARY = 'jPoAv3zOyHvQ5JFNYg4hJ9'
def encoded(typ, data): def encoded(typ, data, for_json):
if for_json:
return {CANARY: typ, 'v': data} return {CANARY: typ, 'v': data}
return msgpack.ExtType(typ, msgpack_dumps(data))
def encoder(obj, for_json=False): def encoder(obj, for_json=False):
if isinstance(obj, datetime): if isinstance(obj, datetime):
return encoded(0, unicode(obj.isoformat())) return encoded(0, unicode(obj.isoformat()), for_json)
if isinstance(obj, (set, frozenset)): if isinstance(obj, (set, frozenset)):
return encoded(1, tuple(obj)) return encoded(1, tuple(obj), for_json)
if hasattr(obj, '__calibre_serializable__'): if hasattr(obj, '__calibre_serializable__'):
from calibre.ebooks.metadata.book.base import Metadata from calibre.ebooks.metadata.book.base import Metadata
from calibre.library.field_metadata import FieldMetadata, fm_as_dict from calibre.library.field_metadata import FieldMetadata, fm_as_dict
if isinstance(obj, Metadata): if isinstance(obj, Metadata):
from calibre.ebooks.metadata.book.serialize import metadata_as_dict from calibre.ebooks.metadata.book.serialize import metadata_as_dict
return encoded(2, metadata_as_dict(obj, encode_cover_data=for_json)) return encoded(
2, metadata_as_dict(obj, encode_cover_data=for_json), for_json
)
elif isinstance(obj, FieldMetadata): elif isinstance(obj, FieldMetadata):
return encoded(3, fm_as_dict(obj)) return encoded(3, fm_as_dict(obj), for_json)
raise TypeError('Cannot serialize objects of type {}'.format(type(obj))) raise TypeError('Cannot serialize objects of type {}'.format(type(obj)))
def msgpack_dumps(data): msgpack_dumps = partial(msgpack.packb, default=encoder, use_bin_type=True)
return msgpack.packb(data, use_bin_type=True, default=encoder)
def json_dumps(data, **kw): def json_dumps(data, **kw):
@ -65,23 +68,24 @@ def decode_field_metadata(x, for_json):
decoders = ( decoders = (
lambda x, fj: parse_iso8601(x, assume_utc=True), lambda x, fj: parse_iso8601(x, assume_utc=True), lambda x, fj: set(x),
lambda x, fj: set(x), decode_metadata, decode_field_metadata,
decode_metadata,
decode_field_metadata,
) )
def decoder(obj, for_json=False): def json_decoder(obj):
typ = obj.get(CANARY) typ = obj.get(CANARY)
if typ is None: if typ is None:
return obj return obj
return decoders[typ](obj['v'], for_json) return decoders[typ](obj['v'], True)
def msgpack_loads(data): def msgpack_decoder(code, data):
return msgpack.unpackb(data, encoding='utf-8', object_hook=decoder) return decoders[code](msgpack_loads(data), False)
msgpack_loads = partial(msgpack.unpackb, encoding='utf-8', ext_hook=msgpack_decoder)
def json_loads(data): def json_loads(data):
return json.loads(data, object_hook=partial(decoder, for_json=True)) return json.loads(data, object_hook=json_decoder)