Inject, Factory and Injects

Esmerald dependency injection system is actually pretty simple and can be checked in the official dependency injection section for more details.

from esmerald import Inject, Injects, Factory, DiderectInjects

esmerald.Inject

Inject(dependency, use_cache=False, **kwargs)

Bases: ArbitraryHashableBaseModel

PARAMETER	DESCRIPTION
dependency	TYPE: AnyCallable
use_cache	TYPE: bool DEFAULT: False
**kwargs	TYPE: Any DEFAULT: {}

Source code in esmerald/injector.py

def __init__(self, dependency: "AnyCallable", use_cache: bool = False, **kwargs: Any):
    super().__init__(**kwargs)
    self.dependency = dependency
    self.signature_model: Optional["Type[Signature]"] = None
    self.use_cache = use_cache
    self.value: Any = Void

dependency instance-attribute

dependency = dependency

signature_model instance-attribute

signature_model = None

use_cache instance-attribute

use_cache = use_cache

value instance-attribute

value = Void

esmerald.Injects

Injects(default=Undefined, skip_validation=False, allow_none=True)

Bases: FieldInfo

Creates a FieldInfo class with extra parameters. This is used for dependencies and to inject them.

Example

@get(dependencies={"value": Inject(lambda: 13)})
def myview(value: Injects()):
    return {"value": value}

PARAMETER	DESCRIPTION
default	TYPE: Any DEFAULT: Undefined
skip_validation	TYPE: bool DEFAULT: False
allow_none	TYPE: bool DEFAULT: True

Source code in esmerald/params.py

def __init__(
    self,
    default: Any = Undefined,
    skip_validation: bool = False,
    allow_none: bool = True,
) -> None:
    self.allow_none = allow_none
    self.extra: Dict[str, Any] = {
        IS_DEPENDENCY: True,
        SKIP_VALIDATION: skip_validation,
        "allow_none": self.allow_none,
    }
    super().__init__(default=default, json_schema_extra=self.extra)

allow_none instance-attribute

allow_none = allow_none

extra instance-attribute

extra = {IS_DEPENDENCY: True, SKIP_VALIDATION: skip_validation, 'allow_none': allow_none}

esmerald.DirectInjects

DirectInjects(dependency=None, *, use_cache=True, allow_none=True)

This function should be only called if Inject/Injects is not used in the dependencies. This is a simple wrapper of the classic Inject().

PARAMETER	DESCRIPTION
dependency	TYPE: Optional[Callable[..., Any]] DEFAULT: None
use_cache	TYPE: bool DEFAULT: True
allow_none	TYPE: bool DEFAULT: True

Source code in esmerald/param_functions.py

def DirectInjects(
    dependency: Optional[Callable[..., Any]] = None,
    *,
    use_cache: bool = True,
    allow_none: bool = True,
) -> Any:
    """
    This function should be only called if Inject/Injects is not used in the dependencies.
    This is a simple wrapper of the classic Inject().
    """
    return DirectInject(dependency=dependency, use_cache=use_cache, allow_none=allow_none)

esmerald.Factory

Factory(provides, *args)

The provider can be passed in separate ways. Via direct callable or via string value where it will be automatically imported by the application.

PARAMETER	DESCRIPTION
provides	TYPE: Union[AnyCallable, str]
*args	TYPE: Any DEFAULT: ()

Source code in esmerald/injector.py

def __init__(self, provides: Union["AnyCallable", str], *args: Any) -> None:
    """
    The provider can be passed in separate ways. Via direct callable
    or via string value where it will be automatically imported by the application.
    """
    self.__args: Tuple[Any, ...] = ()
    self.set_args(*args)
    self.is_nested: bool = False

    if isinstance(provides, str):
        self.provides, self.is_nested = load_provider(provides)
    else:
        self.provides = provides

__args instance-attribute

__args = ()

is_nested instance-attribute

is_nested = False

provides instance-attribute

provides = provides

cls property

cls

Return provided type.

set_args

set_args(*args)

PARAMETER	DESCRIPTION
*args	TYPE: Any DEFAULT: ()

Source code in esmerald/injector.py

def set_args(self, *args: Any) -> None:
    self.__args = args