feat: add a simple CLI

Signed-off-by: Henry Schreiner <[email protected]>

pyproject.toml

@@ -42,11 +42,19 @@ test = [
     'tomli>=1.0.0;python_version<"3.11"',
     'exceptiongroup;python_version<"3.11"',  # Optional
 ]
+cli = [
+    "tomli;python_version<'3.11'",
+    'exceptiongroup;python_version<"3.11"',
+]
 
 [project.urls]
 changelog = "https://pep621.readthedocs.io/en/stable/changelog.html"
 homepage = "https://github.com/pypa/pyproject-metadata"
 
+[project.scripts]
+pyproject-metadata = "pyproject_metadata.__main__:main"
+
+
 [tool.flit.sdist]
 include = ["LICENSE", "tests/**", "docs/**", ".gitignore"]
 

pyproject_metadata/__main__.py

@@ -0,0 +1,73 @@
+import argparse
+import json
+import sys
+from pathlib import Path
+
+import pyproject_metadata
+import pyproject_metadata.errors
+
+
+def json_command(args: argparse.Namespace) -> None:
+    if sys.version_info < (3, 11):
+        import tomli as tomllib
+        import exceptiongroup
+
+        pyproject_metadata.errors.ExceptionGroup = exceptiongroup.ExceptionGroup
+    else:
+        import tomllib
+
+    with args.input.open("rb") as f:
+        pyproject = tomllib.load(f)
+    metadata = pyproject_metadata.StandardMetadata.from_pyproject(pyproject, allow_extra_keys=True, all_errors=True)
+    json.dump(metadata.as_json(), sys.stdout, indent=2)
+
+
+def validate_command(args: argparse.Namespace) -> None:
+    if sys.version_info < (3, 11):
+        import tomli as tomllib
+        from exceptiongroup import ExceptionGroup
+
+        pyproject_metadata.errors.ExceptionGroup = ExceptionGroup
+
+    else:
+        import tomllib
+
+    with args.input.open("rb") as f:
+        pyproject = tomllib.load(f)
+    try:
+        pyproject_metadata.StandardMetadata.from_pyproject(pyproject, allow_extra_keys=False, all_errors=True)
+    except ExceptionGroup as e:
+        extra_keys_top = pyproject_metadata.extras_top_level(pyproject)
+        if extra_keys_top:
+            msg = f"Unknown keys in top-level of pyproject.toml: {', '.join(extra_keys_top)}"
+            e = ExceptionGroup(
+                e.message, (*e.exceptions, pyproject_metadata.errors.ConfigurationError(msg))
+            )
+        extra_keys_build = pyproject_metadata.extras_build_system(pyproject)
+        if extra_keys_build:
+            msg = f"Unknown keys in build-system of pyproject.toml: {', '.join(extra_keys_build)}"
+            e = ExceptionGroup(
+                e.message, (*e.exceptions, pyproject_metadata.errors.ConfigurationError(msg))
+            )
+        raise e from None
+
+def main() -> None:
+    parser = argparse.ArgumentParser()
+    parser.add_argument('-v,--version', action='version', version=f'validate-pyproject {pyproject_metadata.__version__}')
+
+    subparsers = parser.add_subparsers(required=True)
+
+    json_parser = subparsers.add_parser("json")
+    json_parser.add_argument("input", type=Path, nargs="?", help="Path to pyproject.toml file", default=Path("pyproject.toml"))
+    json_parser.set_defaults(func=json_command)
+
+    validate_parser = subparsers.add_parser("validate")
+    validate_parser.add_argument("input", type=Path, nargs="?", help="Path to pyproject.toml file", default=Path("pyproject.toml"))
+    validate_parser.set_defaults(func=validate_command)
+
+    args = parser.parse_args()
+    args.func(args)
+
+
+if __name__ == "__main__":
+    main()