Metadata Please

Common errors

• FileNotFoundError: [Errno 2] No such file or directory: 'non_existent_package-1.0.0.tar.gz'

  cause The path provided to `get_metadata` does not point to an existing file or directory.
  fix Verify that the path to your sdist, wheel, or project directory is correct and accessible. Use `pathlib.Path` to construct paths robustly.

• metadata_please.exceptions.InvalidMetadata: Could not extract metadata from provided path. No pyproject.toml, setup.py, or recognized artifact found.

  cause The provided file or directory is not a recognized Python distribution artifact (sdist/wheel) and does not contain `pyproject.toml` or `setup.py` for direct source metadata extraction.
  fix Ensure the input path points to a valid `.tar.gz` (sdist), `.whl` (wheel), or a directory containing standard Python project configuration files (`pyproject.toml` or `setup.py`).

• AttributeError: 'DistributionMetadata' object has no attribute 'unsupported_field'

  cause Attempting to access a metadata field that is not part of the standard Python core metadata or not extracted by the library. The `DistributionMetadata` object exposes common fields like `name`, `version`, `summary`, etc..
  fix Consult Python's Core metadata specifications or `metadata-please` documentation to understand available fields. If a field is missing, it might not be standard or could not be parsed.

Warnings

• gotcha The library primarily extracts *core metadata* as defined by Python packaging standards. While it can read `setup.py` and `pyproject.toml`, it may not extract all arbitrary fields or dynamic metadata generated by complex build systems (e.g., `setuptools_scm`).
  Fix: For comprehensive runtime introspection of *installed* packages, consider `importlib.metadata` (standard library for Python 3.8+ or `importlib_metadata` backport).
• gotcha Direct parsing of `setup.py` (added in v0.2.0) has inherent limitations as `setup.py` is executable Python code. `metadata-please` attempts to safely extract static metadata, but complex or dynamically generated values might not be fully captured without executing the file in a controlled environment.
  Fix: Ensure `setup.py` files conform to standard, readable patterns for metadata declaration. For projects using `pyproject.toml` (PEP 621), metadata extraction is generally more reliable.

Install

• pip install metadata-please Install with pip

Imports

• get_metadata

  from metadata_please import get_metadata

Quickstart

The `get_metadata` function is the primary entry point for `metadata-please`. It takes a `Path` object pointing to a Python artifact (sdist, wheel) or a project source directory (containing `pyproject.toml` or `setup.py`) and returns a metadata object. The example demonstrates usage for project source directories.

from metadata_please import get_metadata
from pathlib import Path
import tempfile
import shutil

# Create dummy files for demonstration
def create_dummy_sdist(path):
    path.mkdir(parents=True, exist_ok=True)
    with open(path / 'setup.py', 'w') as f:
        f.write("from setuptools import setup; setup(name='dummy_sdist', version='0.1.0')")
    # In a real scenario, you'd run `python setup.py sdist`
    # For this example, we'll just point to the dir as if it were an sdist source

def create_dummy_pyproject_toml(path):
    path.mkdir(parents=True, exist_ok=True)
    with open(path / 'pyproject.toml', 'w') as f:
        f.write('[project]\nname = "dummy-toml"\nversion = "0.2.0"')

with tempfile.TemporaryDirectory() as tmpdir:
    tmp_path = Path(tmpdir)

    # Example 1: Project directory with setup.py (simplified as source dir)
    sdist_source_dir = tmp_path / "dummy_sdist_project"
    create_dummy_sdist(sdist_source_dir)
    metadata_sdist = get_metadata(sdist_source_dir)
    print(f"sdist project Name: {metadata_sdist.name}, Version: {metadata_sdist.version}")

    # Example 2: Project directory with pyproject.toml
    pyproject_source_dir = tmp_path / "dummy_toml_project"
    create_dummy_pyproject_toml(pyproject_source_dir)
    metadata_toml = get_metadata(pyproject_source_dir)
    print(f"pyproject.toml project Name: {metadata_toml.name}, Version: {metadata_toml.version}")

    # Note: For actual .tar.gz (sdist) or .whl (wheel) files,
    # you would replace the paths with your actual artifact files.
    # Creating real sdist/wheel files dynamically for a quickstart is complex.
    # The library is designed to work with these file types directly.
    # Example (conceptual for artifact files):
    # real_sdist_path = Path("path/to/your_package-1.0.0.tar.gz")
    # metadata_real_sdist = get_metadata(real_sdist_path)
    # print(f"Real sdist Name: {metadata_real_sdist.name}")