Module Utilities

pcapkit.utilities holds the cross-cutting services pcapkit is built with, and imports nothing from pcapkit outside itself (see Choosing Between utilities and corekit):

• user-refined exceptions and warnings, and logging;

• the tunable limits of config;

• a compatibility layer, timestamp conversion and pickle reductions;

• the context variables its modules share, lazy imports for a package’s exports, and an abstract-class check that reads no interpreter flag;

• wrappers around third-party libraries.

• User Defined Exceptions
  • Loud and Quiet Errors
  • TypeError Category
  • AttributeError Category
  • IOError Category
  • FileExistsError Category
  • FileNotFoundError Category
  • IndexError Category
  • ValueError Category
  • NotImplementedError Category
  • struct.error Category
  • EOFError Category
  • KeyError Category
  • ModuleNotFoundError Category
  • io.UnsupportedOperation Category
  • Error Handling Utilities
• User Defined Warnings
  • Reporting a Warning
  • Silencing pcapkit Warnings
  • ImportWarning Category
  • RuntimeWarning Category
  • ResourceWarning Category
  • DeprecationWarning Category
• Logging System
  • The Logger Hierarchy
  • DEBUG Logging
  • Configuring the Output
  • Environment Variables
  • Compatibility Note
• Configuration
  • Limits
  • Flags
  • Readers
• Character Set Detection
• Timestamp Conversion
• Pickle Reductions
• Shared Context Variables
• Lazy Imports
• Abstract Classes

Version Compatibility

pcapkit.utilities.compat covers these objects on interpreters older than the version listed:

Compatibility Target	Minimal Required Version
collections.abc.Mapping[KT, VT]	Python 3.9
tuple[T, ...]	Python 3.9
list[T]	Python 3.9
dict[KT, VT]	Python 3.9
urllib.parse.unquote() on bytes	Python 3.9
enum.StrEnum	Python 3.11
typing.final()	Python 3.11
decimal.localcontext(ctx=None, **kwargs)	Python 3.11
enum.show_flag_values()	Python 3.11
typing.TypeAlias	Python 3.10
threading.__excepthook__, as default_threading_excepthook	Python 3.10
inspect.get_annotations(), of a class	Python 3.10
types.UnionType, or None below it	Python 3.10

It also exports pathlib, ModuleNotFoundError, collections.abc.Collection and functools.cached_property() straight from the standard library, since 1.5.0 requires Python 3.8 or later (#2051).

pcapkit.utilities.compat.final(f)

typing.final() from Python 3.11 on, and typing_extensions.final below it. Both record __final__ = True on the decorated object at runtime, which Info and Schema read to refuse a class marked @final without info_final() or schema_final(). Plain typing.final() records nothing below 3.11 (gh-90500).

Changed in version 1.5.0: Taken from typing_extensions below Python 3.11 rather than 3.8, so that __final__ is recorded on every supported version (#778).

pcapkit.utilities.compat.unquote(string, encoding='utf-8', errors='replace')

urllib.parse.unquote(), which accepts bytes from Python 3.9 on. Below 3.9, a bytes string is unquoted to octets with urllib.parse.unquote_to_bytes() and then decoded with encoding and errors.

pcapkit.utilities.compat.default_threading_excepthook

The interpreter’s own default thread exception hook, even when threading.excepthook() has been replaced: threading.__excepthook__ from Python 3.10 on, and _thread._excepthook on 3.8 and 3.9.

class pcapkit.utilities.compat.cached_property(func)

functools.cached_property() itself.

Changed in version 1.5.0: No longer a backport below Python 3.8, which 1.5.0 does not install on (#2051).