cpython/Doc/library/zipimport.rst
Desmond Cheong 3abf6f0102
bpo-14678: Update zipimport to support importlib.invalidate_caches() (GH-24159)
Added an invalidate_caches() method to the zipimport.zipimporter class based on the implementation of importlib.FileFinder.invalidate_caches(). This was done by adding a get_files() method and an _archive_mtime attribute to zipimport.zipimporter to check for updates or cache invalidation whenever the cache of files and toc entry information in the zipimporter is accessed.
2021-03-08 12:06:02 -08:00

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:mod:`zipimport` --- Import modules from Zip archives
=====================================================
.. module:: zipimport
:synopsis: Support for importing Python modules from ZIP archives.
.. moduleauthor:: Just van Rossum <just@letterror.com>
**Source code:** :source:`Lib/zipimport.py`
--------------
This module adds the ability to import Python modules (:file:`\*.py`,
:file:`\*.pyc`) and packages from ZIP-format archives. It is usually not
needed to use the :mod:`zipimport` module explicitly; it is automatically used
by the built-in :keyword:`import` mechanism for :data:`sys.path` items that are paths
to ZIP archives.
Typically, :data:`sys.path` is a list of directory names as strings. This module
also allows an item of :data:`sys.path` to be a string naming a ZIP file archive.
The ZIP archive can contain a subdirectory structure to support package imports,
and a path within the archive can be specified to only import from a
subdirectory. For example, the path :file:`example.zip/lib/` would only
import from the :file:`lib/` subdirectory within the archive.
Any files may be present in the ZIP archive, but only files :file:`.py` and
:file:`.pyc` are available for import. ZIP import of dynamic modules
(:file:`.pyd`, :file:`.so`) is disallowed. Note that if an archive only contains
:file:`.py` files, Python will not attempt to modify the archive by adding the
corresponding :file:`.pyc` file, meaning that if a ZIP archive
doesn't contain :file:`.pyc` files, importing may be rather slow.
.. versionchanged:: 3.8
Previously, ZIP archives with an archive comment were not supported.
.. seealso::
`PKZIP Application Note <https://pkware.cachefly.net/webdocs/casestudies/APPNOTE.TXT>`_
Documentation on the ZIP file format by Phil Katz, the creator of the format and
algorithms used.
:pep:`273` - Import Modules from Zip Archives
Written by James C. Ahlstrom, who also provided an implementation. Python 2.3
follows the specification in :pep:`273`, but uses an implementation written by Just
van Rossum that uses the import hooks described in :pep:`302`.
:mod:`importlib` - The implementation of the import machinery
Package providing the relevant protocols for all importers to
implement.
This module defines an exception:
.. exception:: ZipImportError
Exception raised by zipimporter objects. It's a subclass of :exc:`ImportError`,
so it can be caught as :exc:`ImportError`, too.
.. _zipimporter-objects:
zipimporter Objects
-------------------
:class:`zipimporter` is the class for importing ZIP files.
.. class:: zipimporter(archivepath)
Create a new zipimporter instance. *archivepath* must be a path to a ZIP
file, or to a specific path within a ZIP file. For example, an *archivepath*
of :file:`foo/bar.zip/lib` will look for modules in the :file:`lib` directory
inside the ZIP file :file:`foo/bar.zip` (provided that it exists).
:exc:`ZipImportError` is raised if *archivepath* doesn't point to a valid ZIP
archive.
.. method:: create_module(spec)
Implementation of :meth:`importlib.abc.Loader.create_module` that returns
:const:`None` to explicitly request the default semantics.
.. versionadded:: 3.10
.. method:: exec_module(module)
Implementation of :meth:`importlib.abc.Loader.exec_module`.
.. versionadded:: 3.10
.. method:: find_loader(fullname, path=None)
An implementation of :meth:`importlib.abc.PathEntryFinder.find_loader`.
.. deprecated:: 3.10
Use :meth:`find_spec` instead.
.. method:: find_module(fullname, path=None)
Search for a module specified by *fullname*. *fullname* must be the fully
qualified (dotted) module name. It returns the zipimporter instance itself
if the module was found, or :const:`None` if it wasn't. The optional
*path* argument is ignored---it's there for compatibility with the
importer protocol.
.. deprecated:: 3.10
Use :meth:`find_spec` instead.
.. method:: find_spec(fullname, target=None)
An implementation of :meth:`importlib.abc.PathEntryFinder.find_spec`.
.. versionadded:: 3.10
.. method:: get_code(fullname)
Return the code object for the specified module. Raise
:exc:`ZipImportError` if the module couldn't be imported.
.. method:: get_data(pathname)
Return the data associated with *pathname*. Raise :exc:`OSError` if the
file wasn't found.
.. versionchanged:: 3.3
:exc:`IOError` used to be raised instead of :exc:`OSError`.
.. method:: get_filename(fullname)
Return the value ``__file__`` would be set to if the specified module
was imported. Raise :exc:`ZipImportError` if the module couldn't be
imported.
.. versionadded:: 3.1
.. method:: get_source(fullname)
Return the source code for the specified module. Raise
:exc:`ZipImportError` if the module couldn't be found, return
:const:`None` if the archive does contain the module, but has no source
for it.
.. method:: is_package(fullname)
Return ``True`` if the module specified by *fullname* is a package. Raise
:exc:`ZipImportError` if the module couldn't be found.
.. method:: load_module(fullname)
Load the module specified by *fullname*. *fullname* must be the fully
qualified (dotted) module name. Returns the imported module on success,
raises :exc:`ZipImportError` on failure.
.. deprecated:: 3.10
Use :meth:`exec_module` instead.
.. method:: invalidate_caches()
Clear out the internal cache of information about files found within
the ZIP archive.
.. versionadded:: 3.10
.. attribute:: archive
The file name of the importer's associated ZIP file, without a possible
subpath.
.. attribute:: prefix
The subpath within the ZIP file where modules are searched. This is the
empty string for zipimporter objects which point to the root of the ZIP
file.
The :attr:`archive` and :attr:`prefix` attributes, when combined with a
slash, equal the original *archivepath* argument given to the
:class:`zipimporter` constructor.
.. _zipimport-examples:
Examples
--------
Here is an example that imports a module from a ZIP archive - note that the
:mod:`zipimport` module is not explicitly used.
.. code-block:: shell-session
$ unzip -l example.zip
Archive: example.zip
Length Date Time Name
-------- ---- ---- ----
8467 11-26-02 22:30 jwzthreading.py
-------- -------
8467 1 file
$ ./python
Python 2.3 (#1, Aug 1 2003, 19:54:32)
>>> import sys
>>> sys.path.insert(0, 'example.zip') # Add .zip file to front of path
>>> import jwzthreading
>>> jwzthreading.__file__
'example.zip/jwzthreading.py'