Transformers

This page describe internal utility classes use to parse or help with converting data from Tor to python structures. Most of these classes rely on pydantic to handle the heavy lifting.

class aiostem.utils.transformers.TrAfterAsTimezone

Post-validator that enforces a timezone.

timezone: tzinfo

Timezone to map this date to.

from_value(value: datetime) → datetime

Apply the timezone of change the offset.

Parameters:

value (datetime) – The original datetime to change.

Returns:

datetime – A new datetime with the proper timezone applied.

class aiostem.utils.transformers.TrBeforeSetToNone

Pre-validator that sets a value to None.

values: Set[Any]

List of values mapped to None.

from_value(value: Any) → Any

Set the return value to None when applicable.

Parameters:

value (Any) – The value to check against values.

Returns:

Any – The same value of None when matching any value in values.

class aiostem.utils.transformers.TrBeforeStringSplit

Deserialize sequences from/to strings.

model_config: ClassVar[ConfigDict | None] = None

Base pydantic configuration to apply when serializing.

maxsplit: int

Maximum number of string split.

separator: str

How to split this string sequence.

dict_keys: Sequence[str] | None

Optional list of keys when converted to a dictionary.

when_used: Literal['always', 'unless-none', 'json', 'json-unless-none']

When serialization is supposed to be used.

class aiostem.utils.transformers.TrBeforeTimedelta

Pre-validator that gets a timedelta from an int or float.

unit: Literal['milliseconds', 'seconds', 'minutes']

Unit used to serialize and deserialize.

is_float: bool

Whether to serialize / deserialize to a float number.

from_number(value: float) → timedelta

Parse the input value as an integer or float timedelta.

Parameters:

value (float) – The input value we want to create a timedelta from.

Returns:

timedelta – A simple timedelta built from the provided value.

to_number(delta: timedelta) → float | int

Convert the timedelta value to a float or int.

Parameters:

delta (timedelta) – The timedelta value we want to serialize.

Returns:

float | int – A float or integer value.

class aiostem.utils.transformers.TrCast

Pre-validator that converts to the target type.

target: type[Any]

Type we want to cast this to!

mode: Literal['before', 'after']

Whether to apply this transformation before or after the main handler.

class aiostem.utils.transformers.TrEd25519PrivateKey

Transform bytes into an ed25519 private key.

Note

Tor’s implementation of Ed25519 is donna-ed25519 and uses the expanded form as the private key (64 bytes). Unfortunately cryptography does not provide such interface, which means that we are left with this implementation.

expanded: bool

Whether to generate the expanded form while serializing.

Note

This makes parsing impossible…

from_bytes(data: bytes) → Ed25519PrivateKey

Build an ed25519 private key out of the provided bytes.

Parameters:

data (bytes) – a 32 bytes seed representing a secret key.

Returns:

Ed25519PrivateKey – An instance of an ed25519 private key.

to_bytes(key: Ed25519PrivateKey) → bytes

Serialize the provided private key to bytes.

See also

• to_expanded_bytes()

• to_seed_bytes()

Returns:

bytes – 32 or 64 bytes corresponding to the private key.

to_expanded_bytes(key: Ed25519PrivateKey) → bytes

Serialize to the expanded form.

Returns:

bytes – 64 bytes corresponding to the expanded private key.

to_seed_bytes(key: Ed25519PrivateKey) → bytes

Serialize the seed bytes, which is the default behavior.

Returns:

bytes – 32 bytes corresponding to the private key.

class aiostem.utils.transformers.TrEd25519PublicKey

Transform bytes into a ed25519 public key.

from_bytes(data: bytes) → Ed25519PublicKey

Build an ed25519 public key out of the provided bytes.

Returns:

Ed25519PublicKey – An instance of an ed25519 public key.

to_bytes(key: Ed25519PublicKey) → bytes

Serialize the provided public key to bytes.

Returns:

bytes – 32 bytes corresponding to the public key.

class aiostem.utils.transformers.TrRSAPrivateKey

Transform bytes into a RSA private key.

encoding: Encoding

Encoding format for the public RSA key.

format: PrivateFormat

Key format used while serializing.

from_bytes(data: bytes) → RSAPrivateKey

Build a RSA private key out of the provided bytes.

Returns:

RSAPrivateKey – An instance of a RSA private key.

to_bytes(key: RSAPrivateKey) → bytes

Serialize the provided private key to bytes.

Return type:

bytes

class aiostem.utils.transformers.TrRSAPublicKey

Transform bytes into a RSA public key.

encoding: Encoding

Encoding format for the public RSA key.

format: PublicFormat

Key format used while serializing.

from_bytes(data: bytes) → RSAPublicKey

Build a RSA public key out of the provided bytes.

Returns:

RSAPublicKey – An instance of a RSA public key.

to_bytes(key: RSAPublicKey) → bytes

Serialize the provided public key to bytes.

Return type:

bytes

class aiostem.utils.transformers.TrX25519PrivateKey

Transform bytes into a X25519 private key.

from_bytes(data: bytes) → X25519PrivateKey

Build a X25519 private key out of the provided bytes.

Returns:

X25519PrivateKey – An instance of a X25519 private key.

to_bytes(key: X25519PrivateKey) → bytes

Serialize the provided private key to bytes.

Returns:

bytes – 32 bytes corresponding to the private key.

class aiostem.utils.transformers.TrX25519PublicKey

Transform bytes into a X25519 public key.

from_bytes(data: bytes) → X25519PublicKey

Build a X25519 public key out of the provided bytes.

Returns:

X25519PublicKey – An instance of a X25519 public key.

to_bytes(key: X25519PublicKey) → bytes

Serialize the provided public key to bytes.

Returns:

bytes – 32 bytes corresponding to the public key.