rtoml

A better TOML library for python implemented in rust.

Why Use rtoml

• Correctness: rtoml is based on the widely used and very stable toml-rs library, it passes all the standard TOML tests as well as having 100% coverage on python code. Other TOML libraries for python I tried all failed to parse some valid TOML.
• Performance: see github.com/pwwang/toml-bench - rtoml is the fastest Python TOML libraries at the time of writing.
• None-value handling: rtoml has flexible support for None values, instead of simply ignoring them.

Install

Requires python>=3.9, binaries are available from PyPI for Linux, macOS and Windows, see here.

pip install rtoml

If no binary is available on pypi for you system configuration; you'll need rust stable installed before you can install rtoml.

Usage

load

def load(toml: Union[str, Path, TextIO], *, none_value: Optional[str] = None) -> Dict[str, Any]: ...

Parse TOML via a string or file and return a python dictionary.

• toml: a str, Path or file object from open().
• none_value: controlling which value in toml is loaded as None in python. By default, none_value is None, which means nothing is loaded as None

loads

def loads(toml: str, *, none_value: Optional[str] = None) -> Dict[str, Any]: ...

Parse a TOML string and return a python dictionary. (provided to match the interface of json and similar libraries)

• toml: a str containing TOML.
• none_value: controlling which value in toml is loaded as None in python. By default, none_value is None, which means nothing is loaded as None

dumps

def dumps(obj: Any, *, pretty: bool = False, none_value: Optional[str] = "null") -> str: ...

Serialize a python object to TOML.

• obj: a python object to be serialized.
• pretty: if True the output has a more "pretty" format.
• none_value: controlling how None values in obj are serialized. none_value=None means None values are ignored.

dump

def dump(
    obj: Any, file: Union[Path, TextIO], *, pretty: bool = False, none_value: Optional[str] = "null"
) -> int: ...

Serialize a python object to TOML and write it to a file.

• obj: a python object to be serialized.
• file: a Path or file object from open().
• pretty: if True the output has a more "pretty" format.
• none_value: controlling how None values in obj are serialized. none_value=None means None values are ignored.

Examples

from datetime import datetime, timezone, timedelta
import rtoml

obj = {
    'title': 'TOML Example',
    'owner': {
        'dob': datetime(1979, 5, 27, 7, 32, tzinfo=timezone(timedelta(hours=-8))),
        'name': 'Tom Preston-Werner',
    },
    'database': {
        'connection_max': 5000,
        'enabled': True,
        'ports': [8001, 8001, 8002],
        'server': '192.168.1.1',
    },
}

loaded_obj = rtoml.load("""\
# This is a TOML document.

title = "TOML Example"

[owner]
name = "Tom Preston-Werner"
dob = 1979-05-27T07:32:00-08:00 # First class dates

[database]
server = "192.168.1.1"
ports = [8001, 8001, 8002]
connection_max = 5000
enabled = true
""")

assert loaded_obj == obj

assert rtoml.dumps(obj) == """\
title = "TOML Example"

[owner]
dob = 1979-05-27T07:32:00-08:00
name = "Tom Preston-Werner"

[database]
connection_max = 5000
enabled = true
server = "192.168.1.1"
ports = [8001, 8001, 8002]
"""

An example of None-value handling:

obj = {
    'a': None,
    'b': 1,
    'c': [1, 2, None, 3],
}

# Ignore None values
assert rtoml.dumps(obj, none_value=None) == """\
b = 1
c = [1, 2, 3]
"""

# Serialize None values as '@None'
assert rtoml.dumps(obj, none_value='@None') == """\
a = "@None"
b = 1
c = [1, 2, "@None", 3]
"""

# Deserialize '@None' back to None
assert rtoml.load("""\
a = "@None"
b = 1
c = [1, 2, "@None", 3]
""", none_value='@None') == obj