akkudoktoreos.core.pydantic.PydanticModelNestedValueMixin

class akkudoktoreos.core.pydantic.PydanticModelNestedValueMixin

Bases: object

A mixin providing methods to get, set and track nested values within a Pydantic model.

The methods use a ‘/’-separated path to denote the nested values. Supports handling Optional, List, and Dict types, ensuring correct initialization of missing attributes.

Example

class Address(PydanticBaseModel):

city: str

class User(PydanticBaseModel):

name: str address: Address

def on_city_change(old, new, path):

print(f”{path}: {old} -> {new}”)

user = User(name=”Alice”, address=Address(city=”NY”)) user.track_nested_value(“address/city”, on_city_change) user.set_nested_value(“address/city”, “LA”) # triggers callback

__init__()

Methods

__init__()
get_nested_value(path)	Retrieve a nested value from the model using a '/'-separated path.
set_nested_value(path, value)	Set a nested value in the model using a '/'-separated path.
track_nested_value(path, callback)	Register a callback for a specific path (or subtree).

track_nested_value(path: str, callback: Callable[[Any, str, Any, Any], None]) → None

Register a callback for a specific path (or subtree).

Callback triggers if set path is equal or deeper.

Parameters:

• path (str) – ‘/’-separated path to track.

• callback (callable) – Function called as callback(model_instance, set_path, old_value, new_value).

get_nested_value(path: str) → Any

Retrieve a nested value from the model using a ‘/’-separated path.

Supports accessing nested attributes and list indices.

Parameters:

path (str) – A ‘/’-separated path to the nested attribute (e.g., “key1/key2/0”).

Returns:

The retrieved value.

Return type:

Any

Raises:

• KeyError – If a key is not found in the model.

• IndexError – If a list index is out of bounds or invalid.

Example

```python class Address(PydanticBaseModel):

city: str

class User(PydanticBaseModel):

name: str address: Address

user = User(name=”Alice”, address=Address(city=”New York”)) city = user.get_nested_value(“address/city”) print(city) # Output: “New York” ```

set_nested_value(path: str, value: Any) → None

Set a nested value in the model using a ‘/’-separated path.

Supports modifying nested attributes and list indices while preserving Pydantic validation. Automatically initializes missing Optional, Union, dict, and list fields if necessary. If a missing field cannot be initialized, raises an exception.

Triggers the callbacks registered by track_nested_value().

Parameters:

• path (str) – A ‘/’-separated path to the nested attribute (e.g., “key1/key2/0”).

• value (Any) – The new value to set.

Raises:

• KeyError – If a key is not found in the model.

• IndexError – If a list index is out of bounds or invalid.

• ValueError – If a validation error occurs.

• TypeError – If a missing field cannot be initialized.

Example

```python class Address(PydanticBaseModel):

city: Optional[str]

class User(PydanticBaseModel):

name: str address: Optional[Address] settings: Optional[Dict[str, Any]]

user = User(name=”Alice”, address=None, settings=None) user.set_nested_value(“address/city”, “Los Angeles”) user.set_nested_value(“settings/theme”, “dark”)

print(user.address.city) # Output: “Los Angeles” print(user.settings) # Output: {‘theme’: ‘dark’} ```