aea.helpers.io

Wrapper over built-in "open" function.

This module contains a wrapper to the built-in 'open' function, the 'open_file' function, that fixes the keyword argument 'newline' to be equal to "\n" (the UNIX line separator). This will force the line separator to be "\n" both for incoming and outgoing data.

The reason of this is that files written in an AEA package need to have "\n" as line separator, on all platforms. Otherwise, the fingerprint of the packages involved would change across platforms just because the line separators are replaced.

For instance, the 'open' function on Windows, by default (newline=None), would replace the line separators "\n" with "\r\n". This has an impact in the computation of the fingerprint.

Hence, any usage of file system functionalities should either use 'open_file', or set 'newline="\n"' when calling the 'open' or the 'pathlib.Path.open' functions.

open_file

def open_file(file: PathNameTypes,
              mode: str = "r",
              buffering: int = -1,
              encoding: Optional[str] = None,
              errors: Optional[str] = None) -> TextIO

Open a file.

Behaviour, kwargs and return type are the same for built-in 'open' and pathlib.Path.open, except for 'newline', which is fixed to '\n'.

For more details on the keyword arguments, please refer to the documentation for the built-in 'open':

https://docs.python.org/3/library/functions.html#open

Arguments:

• file: either a pathlib.Path object or the type accepted by 'open', i.e. a string, bytes or integer.
• mode: the mode in which the file is opened.
• buffering: the buffering policy.
• encoding: the name of the encoding used to decode or encode the file.
• errors: how encoding errors are to be handled

Returns:

the IO object.

to_csv

def to_csv(data: Dict[str, str], path: Path) -> None

Outputs a dictionary to CSV.

from_csv

def from_csv(path: Path) -> Dict[str, str]

Load a CSV into a dictionary.