cpython/Lib/packaging/metadata.py

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"""Implementation of the Metadata for Python packages PEPs.
Supports all metadata formats (1.0, 1.1, 1.2).
"""
import re
import logging
from io import StringIO
from email import message_from_file
from packaging import logger
from packaging.markers import interpret
from packaging.version import (is_valid_predicate, is_valid_version,
is_valid_versions)
from packaging.errors import (MetadataMissingError,
MetadataConflictError,
MetadataUnrecognizedVersionError)
try:
# docutils is installed
from docutils.utils import Reporter
from docutils.parsers.rst import Parser
from docutils import frontend
from docutils import nodes
class SilentReporter(Reporter):
def __init__(self, source, report_level, halt_level, stream=None,
debug=0, encoding='ascii', error_handler='replace'):
self.messages = []
super(SilentReporter, self).__init__(
source, report_level, halt_level, stream,
debug, encoding, error_handler)
def system_message(self, level, message, *children, **kwargs):
self.messages.append((level, message, children, kwargs))
_HAS_DOCUTILS = True
except ImportError:
# docutils is not installed
_HAS_DOCUTILS = False
# public API of this module
__all__ = ['Metadata', 'PKG_INFO_ENCODING', 'PKG_INFO_PREFERRED_VERSION']
# Encoding used for the PKG-INFO files
PKG_INFO_ENCODING = 'utf-8'
# preferred version. Hopefully will be changed
# to 1.2 once PEP 345 is supported everywhere
PKG_INFO_PREFERRED_VERSION = '1.0'
_LINE_PREFIX = re.compile('\n \|')
_241_FIELDS = ('Metadata-Version', 'Name', 'Version', 'Platform',
'Summary', 'Description',
'Keywords', 'Home-page', 'Author', 'Author-email',
'License')
_314_FIELDS = ('Metadata-Version', 'Name', 'Version', 'Platform',
'Supported-Platform', 'Summary', 'Description',
'Keywords', 'Home-page', 'Author', 'Author-email',
'License', 'Classifier', 'Download-URL', 'Obsoletes',
'Provides', 'Requires')
_314_MARKERS = ('Obsoletes', 'Provides', 'Requires', 'Classifier',
'Download-URL')
_345_FIELDS = ('Metadata-Version', 'Name', 'Version', 'Platform',
'Supported-Platform', 'Summary', 'Description',
'Keywords', 'Home-page', 'Author', 'Author-email',
'Maintainer', 'Maintainer-email', 'License',
'Classifier', 'Download-URL', 'Obsoletes-Dist',
'Project-URL', 'Provides-Dist', 'Requires-Dist',
'Requires-Python', 'Requires-External')
_345_MARKERS = ('Provides-Dist', 'Requires-Dist', 'Requires-Python',
'Obsoletes-Dist', 'Requires-External', 'Maintainer',
'Maintainer-email', 'Project-URL')
_ALL_FIELDS = set()
_ALL_FIELDS.update(_241_FIELDS)
_ALL_FIELDS.update(_314_FIELDS)
_ALL_FIELDS.update(_345_FIELDS)
def _version2fieldlist(version):
if version == '1.0':
return _241_FIELDS
elif version == '1.1':
return _314_FIELDS
elif version == '1.2':
return _345_FIELDS
raise MetadataUnrecognizedVersionError(version)
def _best_version(fields):
"""Detect the best version depending on the fields used."""
def _has_marker(keys, markers):
for marker in markers:
if marker in keys:
return True
return False
keys = list(fields)
possible_versions = ['1.0', '1.1', '1.2']
# first let's try to see if a field is not part of one of the version
for key in keys:
if key not in _241_FIELDS and '1.0' in possible_versions:
possible_versions.remove('1.0')
if key not in _314_FIELDS and '1.1' in possible_versions:
possible_versions.remove('1.1')
if key not in _345_FIELDS and '1.2' in possible_versions:
possible_versions.remove('1.2')
# possible_version contains qualified versions
if len(possible_versions) == 1:
return possible_versions[0] # found !
elif len(possible_versions) == 0:
raise MetadataConflictError('Unknown metadata set')
# let's see if one unique marker is found
is_1_1 = '1.1' in possible_versions and _has_marker(keys, _314_MARKERS)
is_1_2 = '1.2' in possible_versions and _has_marker(keys, _345_MARKERS)
if is_1_1 and is_1_2:
raise MetadataConflictError('You used incompatible 1.1 and 1.2 fields')
# we have the choice, either 1.0, or 1.2
# - 1.0 has a broken Summary field but works with all tools
# - 1.1 is to avoid
# - 1.2 fixes Summary but is not widespread yet
if not is_1_1 and not is_1_2:
# we couldn't find any specific marker
if PKG_INFO_PREFERRED_VERSION in possible_versions:
return PKG_INFO_PREFERRED_VERSION
if is_1_1:
return '1.1'
# default marker when 1.0 is disqualified
return '1.2'
_ATTR2FIELD = {
'metadata_version': 'Metadata-Version',
'name': 'Name',
'version': 'Version',
'platform': 'Platform',
'supported_platform': 'Supported-Platform',
'summary': 'Summary',
'description': 'Description',
'keywords': 'Keywords',
'home_page': 'Home-page',
'author': 'Author',
'author_email': 'Author-email',
'maintainer': 'Maintainer',
'maintainer_email': 'Maintainer-email',
'license': 'License',
'classifier': 'Classifier',
'download_url': 'Download-URL',
'obsoletes_dist': 'Obsoletes-Dist',
'provides_dist': 'Provides-Dist',
'requires_dist': 'Requires-Dist',
'requires_python': 'Requires-Python',
'requires_external': 'Requires-External',
'requires': 'Requires',
'provides': 'Provides',
'obsoletes': 'Obsoletes',
'project_url': 'Project-URL',
}
_PREDICATE_FIELDS = ('Requires-Dist', 'Obsoletes-Dist', 'Provides-Dist')
_VERSIONS_FIELDS = ('Requires-Python',)
_VERSION_FIELDS = ('Version',)
_LISTFIELDS = ('Platform', 'Classifier', 'Obsoletes',
'Requires', 'Provides', 'Obsoletes-Dist',
'Provides-Dist', 'Requires-Dist', 'Requires-External',
'Project-URL', 'Supported-Platform')
_LISTTUPLEFIELDS = ('Project-URL',)
_ELEMENTSFIELD = ('Keywords',)
_UNICODEFIELDS = ('Author', 'Maintainer', 'Summary', 'Description')
_MISSING = object()
_FILESAFE = re.compile('[^A-Za-z0-9.]+')
class Metadata:
"""The metadata of a release.
Supports versions 1.0, 1.1 and 1.2 (auto-detected). You can
instantiate the class with one of these arguments (or none):
- *path*, the path to a METADATA file
- *fileobj* give a file-like object with METADATA as content
- *mapping* is a dict-like object
"""
# TODO document that execution_context and platform_dependent are used
# to filter on query, not when setting a key
# also document the mapping API and UNKNOWN default key
def __init__(self, path=None, platform_dependent=False,
execution_context=None, fileobj=None, mapping=None):
self._fields = {}
self.requires_files = []
self.docutils_support = _HAS_DOCUTILS
self.platform_dependent = platform_dependent
self.execution_context = execution_context
if [path, fileobj, mapping].count(None) < 2:
raise TypeError('path, fileobj and mapping are exclusive')
if path is not None:
self.read(path)
elif fileobj is not None:
self.read_file(fileobj)
elif mapping is not None:
self.update(mapping)
def _set_best_version(self):
self._fields['Metadata-Version'] = _best_version(self._fields)
def _write_field(self, file, name, value):
file.write('%s: %s\n' % (name, value))
def __getitem__(self, name):
return self.get(name)
def __setitem__(self, name, value):
return self.set(name, value)
def __delitem__(self, name):
field_name = self._convert_name(name)
# we let a KeyError propagate
del self._fields[field_name]
self._set_best_version()
def __contains__(self, name):
return (name in self._fields or
self._convert_name(name) in self._fields)
def _convert_name(self, name):
if name in _ALL_FIELDS:
return name
name = name.replace('-', '_').lower()
return _ATTR2FIELD.get(name, name)
def _default_value(self, name):
if name in _LISTFIELDS or name in _ELEMENTSFIELD:
return []
return 'UNKNOWN'
def _check_rst_data(self, data):
"""Return warnings when the provided data has syntax errors."""
source_path = StringIO()
parser = Parser()
settings = frontend.OptionParser().get_default_values()
settings.tab_width = 4
settings.pep_references = None
settings.rfc_references = None
reporter = SilentReporter(source_path,
settings.report_level,
settings.halt_level,
stream=settings.warning_stream,
debug=settings.debug,
encoding=settings.error_encoding,
error_handler=settings.error_encoding_error_handler)
document = nodes.document(settings, reporter, source=source_path)
document.note_source(source_path, -1)
try:
parser.parse(data, document)
except AttributeError:
reporter.messages.append((-1, 'Could not finish the parsing.',
'', {}))
return reporter.messages
def _platform(self, value):
if not self.platform_dependent or ';' not in value:
return True, value
value, marker = value.split(';')
return interpret(marker, self.execution_context), value
def _remove_line_prefix(self, value):
return _LINE_PREFIX.sub('\n', value)
#
# Public API
#
def get_fullname(self, filesafe=False):
"""Return the distribution name with version.
If filesafe is true, return a filename-escaped form."""
name, version = self['Name'], self['Version']
if filesafe:
# For both name and version any runs of non-alphanumeric or '.'
# characters are replaced with a single '-'. Additionally any
# spaces in the version string become '.'
name = _FILESAFE.sub('-', name)
version = _FILESAFE.sub('-', version.replace(' ', '.'))
return '%s-%s' % (name, version)
def is_metadata_field(self, name):
"""return True if name is a valid metadata key"""
name = self._convert_name(name)
return name in _ALL_FIELDS
def is_multi_field(self, name):
name = self._convert_name(name)
return name in _LISTFIELDS
def read(self, filepath):
"""Read the metadata values from a file path."""
with open(filepath, 'r', encoding='utf-8') as fp:
self.read_file(fp)
def read_file(self, fileob):
"""Read the metadata values from a file object."""
msg = message_from_file(fileob)
self._fields['Metadata-Version'] = msg['metadata-version']
for field in _version2fieldlist(self['Metadata-Version']):
if field in _LISTFIELDS:
# we can have multiple lines
values = msg.get_all(field)
if field in _LISTTUPLEFIELDS and values is not None:
values = [tuple(value.split(',')) for value in values]
self.set(field, values)
else:
# single line
value = msg[field]
if value is not None and value != 'UNKNOWN':
self.set(field, value)
def write(self, filepath):
"""Write the metadata fields to filepath."""
with open(filepath, 'w', encoding='utf-8') as fp:
self.write_file(fp)
def write_file(self, fileobject):
"""Write the PKG-INFO format data to a file object."""
self._set_best_version()
for field in _version2fieldlist(self['Metadata-Version']):
values = self.get(field)
if field in _ELEMENTSFIELD:
self._write_field(fileobject, field, ','.join(values))
continue
if field not in _LISTFIELDS:
if field == 'Description':
values = values.replace('\n', '\n |')
values = [values]
if field in _LISTTUPLEFIELDS:
values = [','.join(value) for value in values]
for value in values:
self._write_field(fileobject, field, value)
def update(self, other=None, **kwargs):
"""Set metadata values from the given iterable `other` and kwargs.
Behavior is like `dict.update`: If `other` has a ``keys`` method,
they are looped over and ``self[key]`` is assigned ``other[key]``.
Else, ``other`` is an iterable of ``(key, value)`` iterables.
Keys that don't match a metadata field or that have an empty value are
dropped.
"""
# XXX the code should just use self.set, which does tbe same checks and
# conversions already, but that would break packaging.pypi: it uses the
# update method, which does not call _set_best_version (which set
# does), and thus allows having a Metadata object (as long as you don't
# modify or write it) with extra fields from PyPI that are not fields
# defined in Metadata PEPs. to solve it, the best_version system
# should be reworked so that it's called only for writing, or in a new
# strict mode, or with a new, more lax Metadata subclass in p7g.pypi
def _set(key, value):
if key in _ATTR2FIELD and value:
self.set(self._convert_name(key), value)
if not other:
# other is None or empty container
pass
elif hasattr(other, 'keys'):
for k in other.keys():
_set(k, other[k])
else:
for k, v in other:
_set(k, v)
if kwargs:
for k, v in kwargs.items():
_set(k, v)
def set(self, name, value):
"""Control then set a metadata field."""
name = self._convert_name(name)
if ((name in _ELEMENTSFIELD or name == 'Platform') and
not isinstance(value, (list, tuple))):
if isinstance(value, str):
value = [v.strip() for v in value.split(',')]
else:
value = []
elif (name in _LISTFIELDS and
not isinstance(value, (list, tuple))):
if isinstance(value, str):
value = [value]
else:
value = []
if logger.isEnabledFor(logging.WARNING):
project_name = self['Name']
if name in _PREDICATE_FIELDS and value is not None:
for v in value:
# check that the values are valid predicates
if not is_valid_predicate(v.split(';')[0]):
logger.warning(
'%r: %r is not a valid predicate (field %r)',
project_name, v, name)
# FIXME this rejects UNKNOWN, is that right?
elif name in _VERSIONS_FIELDS and value is not None:
if not is_valid_versions(value):
logger.warning('%r: %r is not a valid version (field %r)',
project_name, value, name)
elif name in _VERSION_FIELDS and value is not None:
if not is_valid_version(value):
logger.warning('%r: %r is not a valid version (field %r)',
project_name, value, name)
if name in _UNICODEFIELDS:
if name == 'Description':
value = self._remove_line_prefix(value)
self._fields[name] = value
self._set_best_version()
def get(self, name, default=_MISSING):
"""Get a metadata field."""
name = self._convert_name(name)
if name not in self._fields:
if default is _MISSING:
default = self._default_value(name)
return default
if name in _UNICODEFIELDS:
value = self._fields[name]
return value
elif name in _LISTFIELDS:
value = self._fields[name]
if value is None:
return []
res = []
for val in value:
valid, val = self._platform(val)
if not valid:
continue
if name not in _LISTTUPLEFIELDS:
res.append(val)
else:
# That's for Project-URL
res.append((val[0], val[1]))
return res
elif name in _ELEMENTSFIELD:
valid, value = self._platform(self._fields[name])
if not valid:
return []
if isinstance(value, str):
return value.split(',')
valid, value = self._platform(self._fields[name])
if not valid:
return None
return value
def check(self, strict=False, restructuredtext=False):
"""Check if the metadata is compliant. If strict is False then raise if
no Name or Version are provided"""
# XXX should check the versions (if the file was loaded)
missing, warnings = [], []
for attr in ('Name', 'Version'): # required by PEP 345
if attr not in self:
missing.append(attr)
if strict and missing != []:
msg = 'missing required metadata: %s' % ', '.join(missing)
raise MetadataMissingError(msg)
for attr in ('Home-page', 'Author'):
if attr not in self:
missing.append(attr)
if _HAS_DOCUTILS and restructuredtext:
warnings.extend(self._check_rst_data(self['Description']))
# checking metadata 1.2 (XXX needs to check 1.1, 1.0)
if self['Metadata-Version'] != '1.2':
return missing, warnings
def is_valid_predicates(value):
for v in value:
if not is_valid_predicate(v.split(';')[0]):
return False
return True
for fields, controller in ((_PREDICATE_FIELDS, is_valid_predicates),
(_VERSIONS_FIELDS, is_valid_versions),
(_VERSION_FIELDS, is_valid_version)):
for field in fields:
value = self.get(field, None)
if value is not None and not controller(value):
warnings.append('Wrong value for %r: %s' % (field, value))
return missing, warnings
def todict(self):
"""Return fields as a dict.
Field names will be converted to use the underscore-lowercase style
instead of hyphen-mixed case (i.e. home_page instead of Home-page).
"""
data = {
'metadata_version': self['Metadata-Version'],
'name': self['Name'],
'version': self['Version'],
'summary': self['Summary'],
'home_page': self['Home-page'],
'author': self['Author'],
'author_email': self['Author-email'],
'license': self['License'],
'description': self['Description'],
'keywords': self['Keywords'],
'platform': self['Platform'],
'classifier': self['Classifier'],
'download_url': self['Download-URL'],
}
if self['Metadata-Version'] == '1.2':
data['requires_dist'] = self['Requires-Dist']
data['requires_python'] = self['Requires-Python']
data['requires_external'] = self['Requires-External']
data['provides_dist'] = self['Provides-Dist']
data['obsoletes_dist'] = self['Obsoletes-Dist']
data['project_url'] = [','.join(url) for url in
self['Project-URL']]
elif self['Metadata-Version'] == '1.1':
data['provides'] = self['Provides']
data['requires'] = self['Requires']
data['obsoletes'] = self['Obsoletes']
return data
# Mapping API
# XXX these methods should return views or sets in 3.x
def keys(self):
return list(_version2fieldlist(self['Metadata-Version']))
def __iter__(self):
for key in self.keys():
yield key
def values(self):
return [self[key] for key in self.keys()]
def items(self):
return [(key, self[key]) for key in self.keys()]