typelib ¶

The top-level API for typelib.

Typical Usage

>>> import dataclasses
>>> import typelib
>>>
>>> @dataclasses.dataclass
... class Data:
...     attr: int
...     key: str
...
>>>
>>> typelib.unmarshal(Data, '{"key":"string","attr":"1"}')
Data(attr=1, key='string')
>>> typelib.marshal(Data(attr=1, key='string'))
{'attr': 1, 'key': 'string'}
>>> codec = typelib.codec(Data)
>>> codec.encode(Data(attr=1, key='string'))
b'{"attr":1,"key":"string"}'
>>> codec.decode(b'{"key":"string","attr":1}')
Data(attr=1, key='string')

AbstractMarshaller ¶

AbstractMarshaller(t: type[T], context: ContextT, *, var: str | None = None)

Bases: ABC, Generic[T]

Abstract base class defining the common interface for marshallers.

Marshallers are custom callables which maintain type-specific information. They use this information to provide robust, performant logic reducing Python objects into their primitive representations for over-the-wire encoding.

Marshallers support contextual serialization, which enables the marshalling of nested types.

Attributes:

t (type[T]) –

The root type of this marshaller.
origin (type[T]) –

If t is a generic, this will be an actionable runtime type related to t, otherwise it is the same as t.
context (ContextT) –

The complete type context for this unmarshaller.
var (str | None) –

If this unmarshaller is used in a nested context, this will reference the field/parameter/index at which this unmarshaller should be used.

Parameters:

t (type[T]) –

The root type of this marshaller.
context (ContextT) –

The complete type context for this marshaller.
var (str | None, default: None ) –

The associated field or parameter name for this unmarshaller (optional).

Source code in src/typelib/marshals/routines.py

def __init__(self, t: type[T], context: ContextT, *, var: str | None = None):
    """Construct a marshaller instance.

    Args:
        t: The root type of this marshaller.
        context: The complete type context for this marshaller.
        var: The associated field or parameter name for this unmarshaller (optional).
    """
    self.t = t
    self.origin = inspection.origin(self.t)
    self.context = context
    self.var = var

AbstractUnmarshaller ¶

AbstractUnmarshaller(t: type[T], context: ContextT, *, var: str | None = None)

Bases: ABC, Generic[T]

Abstract base class defining the common interface for unmarshallers.

Unmarshallers are custom callables which maintain type-specific information. They use this information to provide robust, performant logic for decoding and converting primtive Python objects or JSON-endcoded data into their target type.

Unmarshallers support contextual deserialization, which enables the unmarshalling of nested types.

Attributes:

t (type[T]) –

The root type of this unmarshaller.
origin (type[T]) –

If t is a generic, this will be an actionable runtime type related to t, otherwise it is the same as t.
context (ContextT) –

The complete type context for this unmarshaller.
var (str | None) –

If this unmarshaller is used in a nested context, this will reference the field/parameter/index at which this unmarshaller should be used.

Parameters:

t (type[T]) –

The root type of this unmarshaller.
context (ContextT) –

The complete type context for this unmarshaller.
var (str | None, default: None ) –

The associated field or parameter name for this unmarshaller (optional).

Source code in src/typelib/unmarshals/routines.py

def __init__(self, t: type[T], context: ContextT, *, var: str | None = None):
    """Construct an unmarshaller instance.

    Args:
        t: The root type of this unmarshaller.
        context: The complete type context for this unmarshaller.
        var: The associated field or parameter name for this unmarshaller (optional).
    """
    self.t = t
    self.origin = inspection.origin(self.t)
    self.context = context
    self.var = var

call `abstractmethod` ¶

__call__(val: Any) -> T

Unmarshall a Python object into its target type.

Not implemented for the abstract base class.

Source code in src/typelib/unmarshals/routines.py

@abc.abstractmethod
def __call__(self, val: tp.Any) -> T:
    """Unmarshall a Python object into its target type.

    Not implemented for the abstract base class.
    """

Codec `dataclass` ¶

Codec(marshal: AbstractMarshaller[T], unmarshal: AbstractUnmarshaller[T], encoder: EncoderT, decoder: DecoderT)

Bases: Generic[T]

A standard wire protocol (codec).

This codec enables you to directly encode and decode your data model into your wire protocol.

decoder `instance-attribute` ¶

decoder: DecoderT

The decoder used to deserialize a bytes-like object into a Python data structure for marshalling into T.

encoder `instance-attribute` ¶

encoder: EncoderT

The encoder used to serialize a marshalled T into bytes.

marshal `instance-attribute` ¶

marshal: AbstractMarshaller[T]

The marshaller used to convert an instance of T to a serializable object.

unmarshal `instance-attribute` ¶

unmarshal: AbstractUnmarshaller[T]

The unmarshaller used to convert a deserialized object into an instance of T.

decode ¶

decode(value: bytes) -> T

Decode an instance of T from bytes.

We will first decode the data from bytes using the decoder, then unmarshal the data into an instance of T using unmarshal.

Parameters:

value (bytes) –

The bytes to decode.

Source code in src/typelib/codecs.py

def decode(self, value: bytes) -> T:
    """Decode an instance of `T` from bytes.

    We will first decode the data from bytes using the
    [`decoder`][typelib.Codec.decoder], then unmarshal the data into an
    instance of `T` using [`unmarshal`][typelib.Codec.unmarshal].

    Args:
        value: The bytes to decode.
    """
    decoded = self.decoder(value)
    unmarshalled = self.unmarshal(decoded)
    return unmarshalled

encode ¶

encode(value: T) -> bytes

Encode an instance of T to bytes.

We will first marshal the given instance using the marshal, then encode the marshalled data into bytes using the encoder.

Parameters:

value (T) –

The instance to encode.

Source code in src/typelib/codecs.py

def encode(self, value: T) -> bytes:
    """Encode an instance of `T` to bytes.

    We will first marshal the given instance using the
    [`marshal`][typelib.Codec.marshal], then encode the marshalled data
    into bytes using the [`encoder`][typelib.Codec.encoder].

    Args:
        value: The instance to encode.
    """
    marshalled = self.marshal(value)
    encoded = self.encoder(marshalled)
    return encoded

codec ¶

codec(t: type[T], *, marshaller: AbstractMarshaller[T] | None = None, unmarshaller: AbstractUnmarshaller[T] | None = None, encoder: EncoderT = compat.json.dumps, decoder: DecoderT = compat.json.loads, codec_cls: type[CodecT[T]] | None = None) -> CodecT[T]

Factory function for creating a Codec instance.

Note

In the simplest case, all that needs be provided is the first parameter (t). We will generate a marshaller, unmarshaller and build a codec. However, we provide ample means for customization:

You can pass in a subclass of Codec to codec_cls.
You may supply custom marshaller or unmarshaller callables - we will generate one using the high-level APIs from marshals and unmarshals if not supplied.
The encoder and decoder default to JSON, using either stdlib json or orjson if available. You may provide custom encoder and decoder callables, the only requirement is they ser/des to/from bytes.

Tip

If you installed the json extra when you installed this library, then you have installed orjson.

Parameters:

t (type[T]) –

The type to create the interchange protocol for.
marshaller (AbstractMarshaller[T] | None, default: None ) –

The marshaller used to marshal inputs into the associated type. (optional)
unmarshaller (AbstractUnmarshaller[T] | None, default: None ) –

The unmarshaller used to unmarshal inputs into the associated type. (optional)
encoder (EncoderT, default: dumps ) –

The encoder for encoding data for over-the-wire (defaults to JSON).
decoder (DecoderT, default: loads ) –

The decoder for decoding data from over-the-wire (defaults to JSON).
codec_cls (type[CodecT[T]] | None, default: None ) –

The codec class definition, if overloading (optional).

Source code in src/typelib/codecs.py

@compat.cache
def codec(
    t: type[T],
    *,
    marshaller: marshals.AbstractMarshaller[T] | None = None,
    unmarshaller: unmarshals.AbstractUnmarshaller[T] | None = None,
    encoder: EncoderT = compat.json.dumps,
    decoder: DecoderT = compat.json.loads,
    codec_cls: type[CodecT[T]] | None = None,
) -> CodecT[T]:
    """Factory function for creating a [`Codec`][typelib.Codec] instance.

    Note:
        In the simplest case, all that needs be provided is the first parameter (`t`). We will
        generate a marshaller, unmarshaller and build a codec. However, we provide ample
        means for customization:

        - You can pass in a subclass of [`Codec`][typelib.codecs.Codec] to `codec_cls`.
        - You may supply custom `marshaller` or `unmarshaller` callables - we will generate
          one using the high-level APIs from [`marshals`][typelib.marshals] and
          [`unmarshals`][typelib.unmarshals] if not supplied.
        - The `encoder` and `decoder` default to JSON, using either
          stdlib [`json`][] or [`orjson`](https://github.com/ijl/orjson){.external}
          if available. You may provide custom `encoder` and `decoder` callables, the only
          requirement is they ser/des to/from `bytes`.

        /// tip
        If you installed the `json` extra when you installed this library, then you have
        installed [`orjson`](https://github.com/ijl/orjson){.external}.
        ///

    Args:
        t: The type to create the interchange protocol for.
        marshaller: The marshaller used to marshal inputs into the associated type. (optional)
        unmarshaller: The unmarshaller used to unmarshal inputs into the associated type. (optional)
        encoder: The encoder for encoding data for over-the-wire (defaults to JSON).
        decoder: The decoder for decoding data from over-the-wire (defaults to JSON).
        codec_cls: The codec class definition, if overloading (optional).

    """
    marshal = marshaller or marshals.marshaller(t=t)
    unmarshal = unmarshaller or unmarshals.unmarshaller(t=t)
    cls = codec_cls or Codec
    if inspection.isbytestype(t):
        cdc = cls(
            marshal=marshal,
            unmarshal=unmarshal,
            encoder=lambda v: v,  # type: ignore[arg-type,return-value]
            decoder=lambda v: v,  # type: ignore[arg-type,return-value]
        )
        return cdc
    cdc = cls(
        marshal=marshal,
        unmarshal=unmarshal,
        encoder=encoder,
        decoder=decoder,
    )
    return cdc

decode ¶

decode(t: type[T] | ForwardRef | str, value: bytes, *, decoder: DecoderT = compat.json.loads) -> T

Decode a bytes object into an instance of t.

Parameters:

t (type[T] | ForwardRef | str) –

A type hint for resolving the unmarshaller.
value (bytes) –

The value to decode.
decoder (DecoderT, default: loads ) –

A callable that takes a bytes object and returns a Python value.

Source code in src/typelib/api.py

def decode(
    t: type[T] | refs.ForwardRef | str,
    value: bytes,
    *,
    decoder: DecoderT = compat.json.loads,
) -> T:
    """Decode a bytes object into an instance of `t`.

    Args:
        t: A type hint for resolving the unmarshaller.
        value: The value to decode.
        decoder: A callable that takes a bytes object and returns a Python value.
    """
    decoded = decoder(value)
    unmarshalled = unmarshal(t=t, value=decoded)
    return unmarshalled

encode ¶

encode(value: T, *, t: type[T] | ForwardRef | str | None = None, encoder: EncoderT = compat.json.dumps) -> bytes

Encode a value into a bytes object.

Parameters:

value (T) –

The value to encode.
t (type[T] | ForwardRef | str | None, default: None ) –

A type hint for resolving the marshaller.
encoder (EncoderT, default: dumps ) –

A callable that takes a value and returns a bytes object.

Source code in src/typelib/api.py

def encode(
    value: T,
    *,
    t: type[T] | refs.ForwardRef | str | None = None,
    encoder: EncoderT = compat.json.dumps,
) -> bytes:
    """Encode a value into a bytes object.

    Args:
        value: The value to encode.
        t: A type hint for resolving the marshaller.
        encoder: A callable that takes a value and returns a bytes object.
    """
    marshalled = marshal(value=value, t=t)
    encoded = encoder(marshalled)
    return encoded

marshal ¶

marshal(value: Any, *, t: type[T] | ForwardRef | str | None = None) -> MarshalledValueT

Marshal value from typ into MarshalledValueT.

Parameters:

value (Any) –

The value to reduce to a simple, encode-able type.
t (type[T] | ForwardRef | str | None, default: None ) –

The type to use for building the marshaller (optional). If not provided, we'll default to the type of the input value.

Source code in src/typelib/marshals/api.py

def marshal(
    value: tp.Any, *, t: type[T] | refs.ForwardRef | str | None = None
) -> serdes.MarshalledValueT:
    """Marshal `value` from `typ` into [`MarshalledValueT`][typelib.serdes.MarshalledValueT].

    Args:
        value: The value to reduce to a simple, encode-able type.
        t:
            The type to use for building the marshaller (optional).
            If not provided, we'll default to the type of the input value.
    """
    typ = value.__class__ if t is None else t
    routine: routines.AbstractMarshaller[T] = marshaller(typ)
    unmarshalled = routine(value)
    return unmarshalled

marshaller ¶

marshaller(t: type[T] | ForwardRef | TypeAliasType | str) -> AbstractMarshaller[T]

Get a marshaller routine for a given type.

Parameters:

t (type[T] | ForwardRef | TypeAliasType | str) –

The type annotation to generate a marshaller for. Can be a type, type alias, typing.ForwardRef, or string reference.

Source code in src/typelib/marshals/api.py

@compat.cache
def marshaller(
    t: type[T] | refs.ForwardRef | compat.TypeAliasType | str,
) -> routines.AbstractMarshaller[T]:
    """Get a marshaller routine for a given type.

    Args:
        t:
            The type annotation to generate a marshaller for. Can be a type, type alias,
            [`typing.ForwardRef`][], or string reference.
    """
    nodes = graph.static_order(t)
    context: ctx.TypeContext[routines.AbstractMarshaller] = ctx.TypeContext()
    if not nodes:
        return routines.NoOpMarshaller(t=t, context=context, var=None)  # type: ignore[arg-type]

    # "root" type will always be the final node in the sequence.
    root = nodes[-1]
    for node in nodes:
        context[node.type] = _get_unmarshaller(node, context=context)
        context[node.unwrapped] = context[node.type]

    return context[root.type]

unmarshal ¶

unmarshal(t: type[T] | ForwardRef | str, value: Any) -> T

Unmarshal value into typ.

Parameters:

t (type[T] | ForwardRef | str) –

The type annotation or reference to unmarshal into.
value (Any) –

The value to unmarshal.

Source code in src/typelib/unmarshals/api.py

def unmarshal(t: type[T] | refs.ForwardRef | str, value: tp.Any) -> T:
    """Unmarshal `value` into `typ`.

    Args:
        t: The type annotation or reference to unmarshal into.
        value: The value to unmarshal.
    """
    routine = unmarshaller(t)
    unmarshalled = routine(value)
    return unmarshalled

unmarshaller ¶

unmarshaller(t: type[T] | ForwardRef | TypeAliasType | str) -> AbstractUnmarshaller[T]

Get an un-marshaller routine for a given type.

Parameters:

t (type[T] | ForwardRef | TypeAliasType | str) –

The type annotation to generate an unmarshaller for. May be a type, type alias, typing.ForwardRef, or string reference.

Source code in src/typelib/unmarshals/api.py

@compat.cache
def unmarshaller(
    t: type[T] | refs.ForwardRef | compat.TypeAliasType | str,
) -> routines.AbstractUnmarshaller[T]:
    """Get an un-marshaller routine for a given type.

    Args:
        t: The type annotation to generate an unmarshaller for.
             May be a type, type alias, [`typing.ForwardRef`][], or string reference.
    """
    nodes = graph.static_order(t)
    context: ctx.TypeContext[routines.AbstractUnmarshaller] = ctx.TypeContext()
    if not nodes:
        return routines.NoOpUnmarshaller(t=t, context=context, var=None)  # type: ignore[arg-type]

    # "root" type will always be the final node in the sequence.
    root = nodes[-1]
    for node in nodes:
        context[node.type] = _get_unmarshaller(node, context=context)
        context[node.unwrapped] = context[node.type]

    return context[root.type]

typelib ¶

AbstractMarshaller ¶

AbstractUnmarshaller ¶

__call__ abstractmethod ¶

Codec dataclass ¶

decoder instance-attribute ¶

encoder instance-attribute ¶

marshal instance-attribute ¶

unmarshal instance-attribute ¶

decode ¶

encode ¶

codec ¶

decode ¶

encode ¶

marshal ¶

marshaller ¶

unmarshal ¶

unmarshaller ¶

call `abstractmethod` ¶

Codec `dataclass` ¶

decoder `instance-attribute` ¶

encoder `instance-attribute` ¶

marshal `instance-attribute` ¶

unmarshal `instance-attribute` ¶