OpenSlides/openslides/utils/utils.py
2019-01-18 17:37:36 +01:00

98 lines
3.0 KiB
Python

import re
from typing import Dict, Generator, Tuple, Type, Union
import roman
from django.apps import apps
from django.db.models import Model
CAMEL_CASE_TO_PSEUDO_SNAKE_CASE_CONVERSION_REGEX_1 = re.compile("(.)([A-Z][a-z]+)")
CAMEL_CASE_TO_PSEUDO_SNAKE_CASE_CONVERSION_REGEX_2 = re.compile("([a-z0-9])([A-Z])")
def convert_camel_case_to_pseudo_snake_case(text: str) -> str:
"""
Converts camel case to pseudo snake case using hyphen instead of
underscore.
E. g. ThisText is converted to this-text.
Credits: epost (http://stackoverflow.com/a/1176023)
"""
s1 = CAMEL_CASE_TO_PSEUDO_SNAKE_CASE_CONVERSION_REGEX_1.sub(r"\1-\2", text)
return CAMEL_CASE_TO_PSEUDO_SNAKE_CASE_CONVERSION_REGEX_2.sub(r"\1-\2", s1).lower()
def to_roman(number: int) -> str:
"""
Converts an arabic number within range from 1 to 4999 to the
corresponding roman number. Returns the input converted as string on error
conditions or higher numbers.
"""
try:
return roman.toRoman(number)
except (roman.NotIntegerError, roman.OutOfRangeError):
return str(number)
def get_element_id(collection_string: str, id: int) -> str:
"""
Returns a combined string from the collection_string and an id.
"""
return f"{collection_string}:{id}"
def split_element_id(element_id: Union[str, bytes]) -> Tuple[str, int]:
"""
Splits a combined element_id into the collection_string and the id.
"""
if isinstance(element_id, bytes):
element_id = element_id.decode()
collection_str, id = element_id.rsplit(":", 1)
return (collection_str, int(id))
def str_dict_to_bytes(str_dict: Dict[str, str]) -> Dict[bytes, bytes]:
"""
Converts the key and the value of a dict from str to bytes.
"""
out = {}
for key, value in str_dict.items():
out[key.encode()] = value.encode()
return out
_models_to_collection_string: Dict[str, Type[Model]] = {}
def get_model_from_collection_string(collection_string: str) -> Type[Model]:
"""
Returns a model class which belongs to the argument collection_string.
"""
def model_generator() -> Generator[Type[Model], None, None]:
"""
Yields all models of all apps.
"""
for app_config in apps.get_app_configs():
for model in app_config.get_models():
yield model
# On the first run, generate the dict. It can not change at runtime.
if not _models_to_collection_string:
for model in model_generator():
try:
get_collection_string = model.get_collection_string
except AttributeError:
# Skip models which do not have the method get_collection_string.
pass
else:
_models_to_collection_string[get_collection_string()] = model
try:
model = _models_to_collection_string[collection_string]
except KeyError:
raise ValueError(
f"Invalid message. A valid collection_string is missing. Got {collection_string}"
)
return model