OpenSlides/openslides/utils/utils.py
2019-05-07 16:37:38 +02:00

117 lines
3.4 KiB
Python

import random
import re
import string
from typing import Dict, Generator, Optional, 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
_worker_id: Optional[str] = None
"""
The worker id. Accessable via `get_worker_id()`.
"""
def get_worker_id() -> str:
"""
Returns a random string of length 4 that identifies this
instance of this worker
"""
global _worker_id
if _worker_id is None:
_worker_id = "".join(random.sample(string.ascii_letters, 4))
return _worker_id