115 lines
3.2 KiB
Python

import inspect
import string
from typing import Callable
from typing import List
from typing import Optional
TEMPLATE_FRAGMENT_KEY_TEMPLATE = "_template_fragment_cache_%s%s"
# Used to remove control characters and whitespace from cache keys.
valid_chars = set(string.ascii_letters + string.digits + "_.")
del_chars = "".join(c for c in map(chr, range(256)) if c not in valid_chars)
null_control = ({k: None for k in del_chars},)
def wants_args(f: Callable) -> bool:
"""Check if the function wants any arguments"""
arg_spec = inspect.getfullargspec(f)
return bool(arg_spec.args or arg_spec.varargs or arg_spec.varkw)
def get_function_parameters(f: Callable) -> List:
"""Get function parameters
:param f
:return: Parameter list of function
"""
return list(inspect.signature(f).parameters.values())
def get_arg_names(f: Callable) -> List[str]:
"""Return arguments of function
:param f:
:return: String list of arguments
"""
return [
parameter.name
for parameter in get_function_parameters(f)
if parameter.kind == parameter.POSITIONAL_OR_KEYWORD
]
def get_arg_default(f: Callable, position: int):
arg = get_function_parameters(f)[position]
arg_def = arg.default
return arg_def if arg_def != inspect.Parameter.empty else None
def get_id(obj):
return getattr(obj, "__caching_id__", repr)(obj)
def function_namespace(f, args=None):
"""Attempts to returns unique namespace for function"""
m_args = get_arg_names(f)
instance_token = None
instance_self = getattr(f, "__self__", None)
if instance_self and not inspect.isclass(instance_self):
instance_token = get_id(f.__self__)
elif m_args and m_args[0] == "self" and args:
instance_token = get_id(args[0])
module = f.__module__
if m_args and m_args[0] == "cls" and not inspect.isclass(args[0]):
raise ValueError(
"When using `delete_memoized` on a "
"`@classmethod` you must provide the "
"class as the first argument"
)
if hasattr(f, "__qualname__"):
name = f.__qualname__
else:
klass = getattr(f, "__self__", None)
if klass and not inspect.isclass(klass):
klass = klass.__class__
if not klass:
klass = getattr(f, "im_class", None)
if not klass:
if m_args and args:
if m_args[0] == "self":
klass = args[0].__class__
elif m_args[0] == "cls":
klass = args[0]
if klass:
name = klass.__name__ + "." + f.__name__
else:
name = f.__name__
ns = ".".join((module, name)).translate(*null_control)
ins = (
".".join((module, name, instance_token)).translate(*null_control)
if instance_token
else None
)
return ns, ins
def make_template_fragment_key(
fragment_name: str, vary_on: Optional[List[str]] = None
) -> str:
"""Make a cache key for a specific fragment name."""
if vary_on:
fragment_name = "%s_" % fragment_name
else:
vary_on = []
return TEMPLATE_FRAGMENT_KEY_TEMPLATE % (fragment_name, "_".join(vary_on))