Brett Cannon | 07fbd78 | 2014-02-06 09:46:08 -0500 | [diff] [blame] | 1 | :mod:`importlib` -- The implementation of :keyword:`import` |
| 2 | =========================================================== |
Brett Cannon | afccd63 | 2009-01-20 02:21:27 +0000 | [diff] [blame] | 3 | |
| 4 | .. module:: importlib |
Brett Cannon | 07fbd78 | 2014-02-06 09:46:08 -0500 | [diff] [blame] | 5 | :synopsis: The implementation of the import machinery. |
Brett Cannon | afccd63 | 2009-01-20 02:21:27 +0000 | [diff] [blame] | 6 | |
| 7 | .. moduleauthor:: Brett Cannon <brett@python.org> |
| 8 | .. sectionauthor:: Brett Cannon <brett@python.org> |
| 9 | |
| 10 | .. versionadded:: 3.1 |
| 11 | |
| 12 | |
| 13 | Introduction |
| 14 | ------------ |
| 15 | |
Brett Cannon | 07fbd78 | 2014-02-06 09:46:08 -0500 | [diff] [blame] | 16 | The purpose of the :mod:`importlib` package is two-fold. One is to provide the |
Brett Cannon | afccd63 | 2009-01-20 02:21:27 +0000 | [diff] [blame] | 17 | implementation of the :keyword:`import` statement (and thus, by extension, the |
| 18 | :func:`__import__` function) in Python source code. This provides an |
Tarek Ziadé | 434caaa | 2009-05-14 12:48:09 +0000 | [diff] [blame] | 19 | implementation of :keyword:`import` which is portable to any Python |
Brett Cannon | 07fbd78 | 2014-02-06 09:46:08 -0500 | [diff] [blame] | 20 | interpreter. This also provides an implementation which is easier to |
Brett Cannon | f23e374 | 2010-06-27 23:57:46 +0000 | [diff] [blame] | 21 | comprehend than one implemented in a programming language other than Python. |
Brett Cannon | afccd63 | 2009-01-20 02:21:27 +0000 | [diff] [blame] | 22 | |
Brett Cannon | f23e374 | 2010-06-27 23:57:46 +0000 | [diff] [blame] | 23 | Two, the components to implement :keyword:`import` are exposed in this |
Brett Cannon | afccd63 | 2009-01-20 02:21:27 +0000 | [diff] [blame] | 24 | package, making it easier for users to create their own custom objects (known |
Brett Cannon | debb98d | 2009-02-16 04:18:01 +0000 | [diff] [blame] | 25 | generically as an :term:`importer`) to participate in the import process. |
Brett Cannon | afccd63 | 2009-01-20 02:21:27 +0000 | [diff] [blame] | 26 | |
| 27 | .. seealso:: |
| 28 | |
| 29 | :ref:`import` |
| 30 | The language reference for the :keyword:`import` statement. |
| 31 | |
Georg Brandl | b7354a6 | 2014-10-29 10:57:37 +0100 | [diff] [blame] | 32 | `Packages specification <http://legacy.python.org/doc/essays/packages.html>`__ |
Brett Cannon | afccd63 | 2009-01-20 02:21:27 +0000 | [diff] [blame] | 33 | Original specification of packages. Some semantics have changed since |
Georg Brandl | 375aec2 | 2011-01-15 17:03:02 +0000 | [diff] [blame] | 34 | the writing of this document (e.g. redirecting based on ``None`` |
Brett Cannon | afccd63 | 2009-01-20 02:21:27 +0000 | [diff] [blame] | 35 | in :data:`sys.modules`). |
| 36 | |
| 37 | The :func:`.__import__` function |
Brett Cannon | 0e13c94 | 2010-06-29 18:26:11 +0000 | [diff] [blame] | 38 | The :keyword:`import` statement is syntactic sugar for this function. |
Brett Cannon | afccd63 | 2009-01-20 02:21:27 +0000 | [diff] [blame] | 39 | |
| 40 | :pep:`235` |
| 41 | Import on Case-Insensitive Platforms |
| 42 | |
| 43 | :pep:`263` |
| 44 | Defining Python Source Code Encodings |
| 45 | |
| 46 | :pep:`302` |
Brett Cannon | f23e374 | 2010-06-27 23:57:46 +0000 | [diff] [blame] | 47 | New Import Hooks |
Brett Cannon | afccd63 | 2009-01-20 02:21:27 +0000 | [diff] [blame] | 48 | |
| 49 | :pep:`328` |
| 50 | Imports: Multi-Line and Absolute/Relative |
| 51 | |
| 52 | :pep:`366` |
| 53 | Main module explicit relative imports |
| 54 | |
Brett Cannon | 07fbd78 | 2014-02-06 09:46:08 -0500 | [diff] [blame] | 55 | :pep:`451` |
| 56 | A ModuleSpec Type for the Import System |
| 57 | |
Brett Cannon | 8917d5e | 2010-01-13 19:21:00 +0000 | [diff] [blame] | 58 | :pep:`3120` |
Brett Cannon | afccd63 | 2009-01-20 02:21:27 +0000 | [diff] [blame] | 59 | Using UTF-8 as the Default Source Encoding |
| 60 | |
Brett Cannon | 30b7a90 | 2010-06-27 21:49:22 +0000 | [diff] [blame] | 61 | :pep:`3147` |
| 62 | PYC Repository Directories |
| 63 | |
Brett Cannon | afccd63 | 2009-01-20 02:21:27 +0000 | [diff] [blame] | 64 | |
| 65 | Functions |
| 66 | --------- |
| 67 | |
Brett Cannon | cb4996a | 2012-08-06 16:34:44 -0400 | [diff] [blame] | 68 | .. function:: __import__(name, globals=None, locals=None, fromlist=(), level=0) |
Brett Cannon | afccd63 | 2009-01-20 02:21:27 +0000 | [diff] [blame] | 69 | |
Brett Cannon | f23e374 | 2010-06-27 23:57:46 +0000 | [diff] [blame] | 70 | An implementation of the built-in :func:`__import__` function. |
Brett Cannon | afccd63 | 2009-01-20 02:21:27 +0000 | [diff] [blame] | 71 | |
| 72 | .. function:: import_module(name, package=None) |
| 73 | |
Brett Cannon | 33418c8 | 2009-01-22 18:37:20 +0000 | [diff] [blame] | 74 | Import a module. The *name* argument specifies what module to |
Brett Cannon | afccd63 | 2009-01-20 02:21:27 +0000 | [diff] [blame] | 75 | import in absolute or relative terms |
| 76 | (e.g. either ``pkg.mod`` or ``..mod``). If the name is |
Guido van Rossum | 0961354 | 2009-03-30 20:34:57 +0000 | [diff] [blame] | 77 | specified in relative terms, then the *package* argument must be set to |
| 78 | the name of the package which is to act as the anchor for resolving the |
Brett Cannon | afccd63 | 2009-01-20 02:21:27 +0000 | [diff] [blame] | 79 | package name (e.g. ``import_module('..mod', 'pkg.subpkg')`` will import |
Brett Cannon | 2c318a1 | 2009-02-07 01:15:27 +0000 | [diff] [blame] | 80 | ``pkg.mod``). |
Brett Cannon | 78246b6 | 2009-01-25 04:56:30 +0000 | [diff] [blame] | 81 | |
Brett Cannon | 2c318a1 | 2009-02-07 01:15:27 +0000 | [diff] [blame] | 82 | The :func:`import_module` function acts as a simplifying wrapper around |
Brett Cannon | 9f4cb1c | 2009-04-01 23:26:47 +0000 | [diff] [blame] | 83 | :func:`importlib.__import__`. This means all semantics of the function are |
| 84 | derived from :func:`importlib.__import__`, including requiring the package |
| 85 | from which an import is occurring to have been previously imported |
| 86 | (i.e., *package* must already be imported). The most important difference |
Brett Cannon | 98620d8 | 2013-12-13 13:57:41 -0500 | [diff] [blame] | 87 | is that :func:`import_module` returns the specified package or module |
| 88 | (e.g. ``pkg.mod``), while :func:`__import__` returns the |
Guido van Rossum | 0961354 | 2009-03-30 20:34:57 +0000 | [diff] [blame] | 89 | top-level package or module (e.g. ``pkg``). |
| 90 | |
Brett Cannon | 98620d8 | 2013-12-13 13:57:41 -0500 | [diff] [blame] | 91 | .. versionchanged:: 3.3 |
| 92 | Parent packages are automatically imported. |
| 93 | |
Brett Cannon | ee78a2b | 2012-05-12 17:43:17 -0400 | [diff] [blame] | 94 | .. function:: find_loader(name, path=None) |
| 95 | |
| 96 | Find the loader for a module, optionally within the specified *path*. If the |
| 97 | module is in :attr:`sys.modules`, then ``sys.modules[name].__loader__`` is |
Brett Cannon | 3279923 | 2013-03-13 11:09:08 -0700 | [diff] [blame] | 98 | returned (unless the loader would be ``None`` or is not set, in which case |
Brett Cannon | ee78a2b | 2012-05-12 17:43:17 -0400 | [diff] [blame] | 99 | :exc:`ValueError` is raised). Otherwise a search using :attr:`sys.meta_path` |
| 100 | is done. ``None`` is returned if no loader is found. |
| 101 | |
Brett Cannon | 56b4ca7 | 2012-11-17 09:30:55 -0500 | [diff] [blame] | 102 | A dotted name does not have its parent's implicitly imported as that requires |
| 103 | loading them and that may not be desired. To properly import a submodule you |
| 104 | will need to import all parent packages of the submodule and use the correct |
| 105 | argument to *path*. |
Brett Cannon | ee78a2b | 2012-05-12 17:43:17 -0400 | [diff] [blame] | 106 | |
Brett Cannon | 3279923 | 2013-03-13 11:09:08 -0700 | [diff] [blame] | 107 | .. versionadded:: 3.3 |
| 108 | |
| 109 | .. versionchanged:: 3.4 |
| 110 | If ``__loader__`` is not set, raise :exc:`ValueError`, just like when the |
| 111 | attribute is set to ``None``. |
| 112 | |
Eric Snow | ca2d854 | 2013-12-16 23:06:52 -0700 | [diff] [blame] | 113 | .. deprecated:: 3.4 |
Eric Snow | 6029e08 | 2014-01-25 15:32:46 -0700 | [diff] [blame] | 114 | Use :func:`importlib.util.find_spec` instead. |
Eric Snow | ca2d854 | 2013-12-16 23:06:52 -0700 | [diff] [blame] | 115 | |
Antoine Pitrou | c541f8e | 2012-02-20 01:48:16 +0100 | [diff] [blame] | 116 | .. function:: invalidate_caches() |
| 117 | |
Brett Cannon | f4dc920 | 2012-08-10 12:21:12 -0400 | [diff] [blame] | 118 | Invalidate the internal caches of finders stored at |
| 119 | :data:`sys.meta_path`. If a finder implements ``invalidate_caches()`` then it |
Brett Cannon | 4067aa2 | 2013-04-27 23:20:32 -0400 | [diff] [blame] | 120 | will be called to perform the invalidation. This function should be called |
| 121 | if any modules are created/installed while your program is running to |
| 122 | guarantee all finders will notice the new module's existence. |
Antoine Pitrou | c541f8e | 2012-02-20 01:48:16 +0100 | [diff] [blame] | 123 | |
| 124 | .. versionadded:: 3.3 |
| 125 | |
Brett Cannon | 3fe35e6 | 2013-06-14 15:04:26 -0400 | [diff] [blame] | 126 | .. function:: reload(module) |
| 127 | |
| 128 | Reload a previously imported *module*. The argument must be a module object, |
| 129 | so it must have been successfully imported before. This is useful if you |
| 130 | have edited the module source file using an external editor and want to try |
| 131 | out the new version without leaving the Python interpreter. The return value |
Brett Cannon | 8ad3786 | 2013-10-25 13:52:46 -0400 | [diff] [blame] | 132 | is the module object (which can be different if re-importing causes a |
| 133 | different object to be placed in :data:`sys.modules`). |
Brett Cannon | 3fe35e6 | 2013-06-14 15:04:26 -0400 | [diff] [blame] | 134 | |
Brett Cannon | 8ad3786 | 2013-10-25 13:52:46 -0400 | [diff] [blame] | 135 | When :func:`reload` is executed: |
Brett Cannon | 3fe35e6 | 2013-06-14 15:04:26 -0400 | [diff] [blame] | 136 | |
Larry Hastings | 3732ed2 | 2014-03-15 21:13:56 -0700 | [diff] [blame] | 137 | * Python module's code is recompiled and the module-level code re-executed, |
Brett Cannon | 3fe35e6 | 2013-06-14 15:04:26 -0400 | [diff] [blame] | 138 | defining a new set of objects which are bound to names in the module's |
| 139 | dictionary by reusing the :term:`loader` which originally loaded the |
| 140 | module. The ``init`` function of extension modules is not called a second |
| 141 | time. |
| 142 | |
| 143 | * As with all other objects in Python the old objects are only reclaimed |
| 144 | after their reference counts drop to zero. |
| 145 | |
| 146 | * The names in the module namespace are updated to point to any new or |
| 147 | changed objects. |
| 148 | |
| 149 | * Other references to the old objects (such as names external to the module) are |
| 150 | not rebound to refer to the new objects and must be updated in each namespace |
| 151 | where they occur if that is desired. |
| 152 | |
| 153 | There are a number of other caveats: |
| 154 | |
Brett Cannon | 3fe35e6 | 2013-06-14 15:04:26 -0400 | [diff] [blame] | 155 | When a module is reloaded, its dictionary (containing the module's global |
| 156 | variables) is retained. Redefinitions of names will override the old |
| 157 | definitions, so this is generally not a problem. If the new version of a |
| 158 | module does not define a name that was defined by the old version, the old |
| 159 | definition remains. This feature can be used to the module's advantage if it |
| 160 | maintains a global table or cache of objects --- with a :keyword:`try` |
| 161 | statement it can test for the table's presence and skip its initialization if |
| 162 | desired:: |
| 163 | |
| 164 | try: |
| 165 | cache |
| 166 | except NameError: |
| 167 | cache = {} |
| 168 | |
Robert Collins | 1ae28d2 | 2015-08-05 08:20:53 +1200 | [diff] [blame] | 169 | It is generally not very useful to reload built-in or dynamically loaded |
| 170 | modules. Reloading :mod:`sys`, :mod:`__main__`, :mod:`builtins` and other |
| 171 | key modules is not recommended. In many cases extension modules are not |
| 172 | designed to be initialized more than once, and may fail in arbitrary ways |
| 173 | when reloaded. |
Brett Cannon | 3fe35e6 | 2013-06-14 15:04:26 -0400 | [diff] [blame] | 174 | |
| 175 | If a module imports objects from another module using :keyword:`from` ... |
| 176 | :keyword:`import` ..., calling :func:`reload` for the other module does not |
| 177 | redefine the objects imported from it --- one way around this is to |
| 178 | re-execute the :keyword:`from` statement, another is to use :keyword:`import` |
| 179 | and qualified names (*module.name*) instead. |
| 180 | |
| 181 | If a module instantiates instances of a class, reloading the module that |
| 182 | defines the class does not affect the method definitions of the instances --- |
| 183 | they continue to use the old class definition. The same is true for derived |
| 184 | classes. |
| 185 | |
| 186 | .. versionadded:: 3.4 |
| 187 | |
Brett Cannon | 78246b6 | 2009-01-25 04:56:30 +0000 | [diff] [blame] | 188 | |
Brett Cannon | 2a922ed | 2009-03-09 03:35:50 +0000 | [diff] [blame] | 189 | :mod:`importlib.abc` -- Abstract base classes related to import |
| 190 | --------------------------------------------------------------- |
| 191 | |
| 192 | .. module:: importlib.abc |
| 193 | :synopsis: Abstract base classes related to import |
| 194 | |
| 195 | The :mod:`importlib.abc` module contains all of the core abstract base classes |
| 196 | used by :keyword:`import`. Some subclasses of the core abstract base classes |
| 197 | are also provided to help in implementing the core ABCs. |
| 198 | |
Andrew Svetlov | a865654 | 2012-08-13 22:19:01 +0300 | [diff] [blame] | 199 | ABC hierarchy:: |
| 200 | |
| 201 | object |
Brett Cannon | 1b79918 | 2012-08-17 14:08:24 -0400 | [diff] [blame] | 202 | +-- Finder (deprecated) |
Andrew Svetlov | a865654 | 2012-08-13 22:19:01 +0300 | [diff] [blame] | 203 | | +-- MetaPathFinder |
| 204 | | +-- PathEntryFinder |
| 205 | +-- Loader |
| 206 | +-- ResourceLoader --------+ |
| 207 | +-- InspectLoader | |
| 208 | +-- ExecutionLoader --+ |
| 209 | +-- FileLoader |
| 210 | +-- SourceLoader |
Andrew Svetlov | a865654 | 2012-08-13 22:19:01 +0300 | [diff] [blame] | 211 | |
Brett Cannon | 2a922ed | 2009-03-09 03:35:50 +0000 | [diff] [blame] | 212 | |
| 213 | .. class:: Finder |
| 214 | |
Brett Cannon | 1b79918 | 2012-08-17 14:08:24 -0400 | [diff] [blame] | 215 | An abstract base class representing a :term:`finder`. |
| 216 | |
| 217 | .. deprecated:: 3.3 |
| 218 | Use :class:`MetaPathFinder` or :class:`PathEntryFinder` instead. |
Brett Cannon | 2a922ed | 2009-03-09 03:35:50 +0000 | [diff] [blame] | 219 | |
Brett Cannon | f4dc920 | 2012-08-10 12:21:12 -0400 | [diff] [blame] | 220 | .. method:: find_module(fullname, path=None) |
Brett Cannon | b46a179 | 2012-02-27 18:15:42 -0500 | [diff] [blame] | 221 | |
Brett Cannon | f4dc920 | 2012-08-10 12:21:12 -0400 | [diff] [blame] | 222 | An abstact method for finding a :term:`loader` for the specified |
| 223 | module. Originally specified in :pep:`302`, this method was meant |
| 224 | for use in :data:`sys.meta_path` and in the path-based import subsystem. |
Nick Coghlan | 8a9080f | 2012-08-02 21:26:03 +1000 | [diff] [blame] | 225 | |
Brett Cannon | 100883f | 2013-04-09 16:59:39 -0400 | [diff] [blame] | 226 | .. versionchanged:: 3.4 |
| 227 | Returns ``None`` when called instead of raising |
| 228 | :exc:`NotImplementedError`. |
| 229 | |
Nick Coghlan | 8a9080f | 2012-08-02 21:26:03 +1000 | [diff] [blame] | 230 | |
Brett Cannon | 077ef45 | 2012-08-02 17:50:06 -0400 | [diff] [blame] | 231 | .. class:: MetaPathFinder |
Nick Coghlan | 8a9080f | 2012-08-02 21:26:03 +1000 | [diff] [blame] | 232 | |
Brett Cannon | f4dc920 | 2012-08-10 12:21:12 -0400 | [diff] [blame] | 233 | An abstract base class representing a :term:`meta path finder`. For |
| 234 | compatibility, this is a subclass of :class:`Finder`. |
Nick Coghlan | 8a9080f | 2012-08-02 21:26:03 +1000 | [diff] [blame] | 235 | |
| 236 | .. versionadded:: 3.3 |
| 237 | |
Eric Snow | ca2d854 | 2013-12-16 23:06:52 -0700 | [diff] [blame] | 238 | .. method:: find_spec(fullname, path, target=None) |
| 239 | |
| 240 | An abstract method for finding a :term:`spec <module spec>` for |
| 241 | the specified module. If this is a top-level import, *path* will |
| 242 | be ``None``. Otherwise, this is a search for a subpackage or |
| 243 | module and *path* will be the value of :attr:`__path__` from the |
| 244 | parent package. If a spec cannot be found, ``None`` is returned. |
| 245 | When passed in, ``target`` is a module object that the finder may |
| 246 | use to make a more educated about what spec to return. |
| 247 | |
| 248 | .. versionadded:: 3.4 |
| 249 | |
Nick Coghlan | 8a9080f | 2012-08-02 21:26:03 +1000 | [diff] [blame] | 250 | .. method:: find_module(fullname, path) |
| 251 | |
Eric Snow | ca2d854 | 2013-12-16 23:06:52 -0700 | [diff] [blame] | 252 | A legacy method for finding a :term:`loader` for the specified |
Nick Coghlan | 8a9080f | 2012-08-02 21:26:03 +1000 | [diff] [blame] | 253 | module. If this is a top-level import, *path* will be ``None``. |
Ezio Melotti | 1f67e80 | 2012-10-21 07:24:13 +0300 | [diff] [blame] | 254 | Otherwise, this is a search for a subpackage or module and *path* |
Nick Coghlan | 8a9080f | 2012-08-02 21:26:03 +1000 | [diff] [blame] | 255 | will be the value of :attr:`__path__` from the parent |
| 256 | package. If a loader cannot be found, ``None`` is returned. |
| 257 | |
Brett Cannon | 8d94229 | 2014-01-07 15:52:42 -0500 | [diff] [blame] | 258 | If :meth:`find_spec` is defined, backwards-compatible functionality is |
| 259 | provided. |
| 260 | |
Brett Cannon | 100883f | 2013-04-09 16:59:39 -0400 | [diff] [blame] | 261 | .. versionchanged:: 3.4 |
| 262 | Returns ``None`` when called instead of raising |
Brett Cannon | 8d94229 | 2014-01-07 15:52:42 -0500 | [diff] [blame] | 263 | :exc:`NotImplementedError`. Can use :meth:`find_spec` to provide |
| 264 | functionality. |
Brett Cannon | 100883f | 2013-04-09 16:59:39 -0400 | [diff] [blame] | 265 | |
Eric Snow | ca2d854 | 2013-12-16 23:06:52 -0700 | [diff] [blame] | 266 | .. deprecated:: 3.4 |
| 267 | Use :meth:`find_spec` instead. |
| 268 | |
Brett Cannon | f4dc920 | 2012-08-10 12:21:12 -0400 | [diff] [blame] | 269 | .. method:: invalidate_caches() |
| 270 | |
| 271 | An optional method which, when called, should invalidate any internal |
Brett Cannon | a6e8581 | 2012-08-11 19:41:27 -0400 | [diff] [blame] | 272 | cache used by the finder. Used by :func:`importlib.invalidate_caches` |
| 273 | when invalidating the caches of all finders on :data:`sys.meta_path`. |
Brett Cannon | f4dc920 | 2012-08-10 12:21:12 -0400 | [diff] [blame] | 274 | |
Brett Cannon | 100883f | 2013-04-09 16:59:39 -0400 | [diff] [blame] | 275 | .. versionchanged:: 3.4 |
| 276 | Returns ``None`` when called instead of ``NotImplemented``. |
| 277 | |
Nick Coghlan | 8a9080f | 2012-08-02 21:26:03 +1000 | [diff] [blame] | 278 | |
Brett Cannon | 077ef45 | 2012-08-02 17:50:06 -0400 | [diff] [blame] | 279 | .. class:: PathEntryFinder |
Nick Coghlan | 8a9080f | 2012-08-02 21:26:03 +1000 | [diff] [blame] | 280 | |
Brett Cannon | f4dc920 | 2012-08-10 12:21:12 -0400 | [diff] [blame] | 281 | An abstract base class representing a :term:`path entry finder`. Though |
| 282 | it bears some similarities to :class:`MetaPathFinder`, ``PathEntryFinder`` |
| 283 | is meant for use only within the path-based import subsystem provided |
| 284 | by :class:`PathFinder`. This ABC is a subclass of :class:`Finder` for |
Brett Cannon | 100883f | 2013-04-09 16:59:39 -0400 | [diff] [blame] | 285 | compatibility reasons only. |
Nick Coghlan | 8a9080f | 2012-08-02 21:26:03 +1000 | [diff] [blame] | 286 | |
| 287 | .. versionadded:: 3.3 |
| 288 | |
Eric Snow | ca2d854 | 2013-12-16 23:06:52 -0700 | [diff] [blame] | 289 | .. method:: find_spec(fullname, target=None) |
| 290 | |
| 291 | An abstract method for finding a :term:`spec <module spec>` for |
| 292 | the specified module. The finder will search for the module only |
| 293 | within the :term:`path entry` to which it is assigned. If a spec |
| 294 | cannot be found, ``None`` is returned. When passed in, ``target`` |
| 295 | is a module object that the finder may use to make a more educated |
| 296 | about what spec to return. |
| 297 | |
| 298 | .. versionadded:: 3.4 |
| 299 | |
Brett Cannon | 4067aa2 | 2013-04-27 23:20:32 -0400 | [diff] [blame] | 300 | .. method:: find_loader(fullname) |
Nick Coghlan | 8a9080f | 2012-08-02 21:26:03 +1000 | [diff] [blame] | 301 | |
Eric Snow | ca2d854 | 2013-12-16 23:06:52 -0700 | [diff] [blame] | 302 | A legacy method for finding a :term:`loader` for the specified |
Brett Cannon | f4dc920 | 2012-08-10 12:21:12 -0400 | [diff] [blame] | 303 | module. Returns a 2-tuple of ``(loader, portion)`` where ``portion`` |
| 304 | is a sequence of file system locations contributing to part of a namespace |
| 305 | package. The loader may be ``None`` while specifying ``portion`` to |
| 306 | signify the contribution of the file system locations to a namespace |
| 307 | package. An empty list can be used for ``portion`` to signify the loader |
Brett Cannon | 100883f | 2013-04-09 16:59:39 -0400 | [diff] [blame] | 308 | is not part of a namespace package. If ``loader`` is ``None`` and |
| 309 | ``portion`` is the empty list then no loader or location for a namespace |
| 310 | package were found (i.e. failure to find anything for the module). |
| 311 | |
Brett Cannon | 8d94229 | 2014-01-07 15:52:42 -0500 | [diff] [blame] | 312 | If :meth:`find_spec` is defined then backwards-compatible functionality is |
| 313 | provided. |
| 314 | |
Brett Cannon | 100883f | 2013-04-09 16:59:39 -0400 | [diff] [blame] | 315 | .. versionchanged:: 3.4 |
| 316 | Returns ``(None, [])`` instead of raising :exc:`NotImplementedError`. |
Brett Cannon | 8d94229 | 2014-01-07 15:52:42 -0500 | [diff] [blame] | 317 | Uses :meth:`find_spec` when available to provide functionality. |
Brett Cannon | f4dc920 | 2012-08-10 12:21:12 -0400 | [diff] [blame] | 318 | |
Eric Snow | ca2d854 | 2013-12-16 23:06:52 -0700 | [diff] [blame] | 319 | .. deprecated:: 3.4 |
| 320 | Use :meth:`find_spec` instead. |
| 321 | |
Brett Cannon | 4067aa2 | 2013-04-27 23:20:32 -0400 | [diff] [blame] | 322 | .. method:: find_module(fullname) |
Brett Cannon | f4dc920 | 2012-08-10 12:21:12 -0400 | [diff] [blame] | 323 | |
| 324 | A concrete implementation of :meth:`Finder.find_module` which is |
| 325 | equivalent to ``self.find_loader(fullname)[0]``. |
| 326 | |
Eric Snow | ca2d854 | 2013-12-16 23:06:52 -0700 | [diff] [blame] | 327 | .. deprecated:: 3.4 |
| 328 | Use :meth:`find_spec` instead. |
| 329 | |
Brett Cannon | f4dc920 | 2012-08-10 12:21:12 -0400 | [diff] [blame] | 330 | .. method:: invalidate_caches() |
| 331 | |
| 332 | An optional method which, when called, should invalidate any internal |
Brett Cannon | a6e8581 | 2012-08-11 19:41:27 -0400 | [diff] [blame] | 333 | cache used by the finder. Used by :meth:`PathFinder.invalidate_caches` |
Brett Cannon | f4dc920 | 2012-08-10 12:21:12 -0400 | [diff] [blame] | 334 | when invalidating the caches of all cached finders. |
Brett Cannon | b46a179 | 2012-02-27 18:15:42 -0500 | [diff] [blame] | 335 | |
Brett Cannon | 2a922ed | 2009-03-09 03:35:50 +0000 | [diff] [blame] | 336 | |
| 337 | .. class:: Loader |
| 338 | |
| 339 | An abstract base class for a :term:`loader`. |
Guido van Rossum | 0961354 | 2009-03-30 20:34:57 +0000 | [diff] [blame] | 340 | See :pep:`302` for the exact definition for a loader. |
Brett Cannon | 2a922ed | 2009-03-09 03:35:50 +0000 | [diff] [blame] | 341 | |
Eric Snow | ca2d854 | 2013-12-16 23:06:52 -0700 | [diff] [blame] | 342 | .. method:: create_module(spec) |
| 343 | |
| 344 | An optional method that returns the module object to use when |
| 345 | importing a module. create_module() may also return ``None``, |
| 346 | indicating that the default module creation should take place |
| 347 | instead. |
| 348 | |
| 349 | .. versionadded:: 3.4 |
| 350 | |
| 351 | .. method:: exec_module(module) |
| 352 | |
| 353 | An abstract method that executes the module in its own namespace |
| 354 | when a module is imported or reloaded. The module should already |
| 355 | be initialized when exec_module() is called. |
| 356 | |
| 357 | .. versionadded:: 3.4 |
| 358 | |
Brett Cannon | 9c751b7 | 2009-03-09 16:28:16 +0000 | [diff] [blame] | 359 | .. method:: load_module(fullname) |
Brett Cannon | 2a922ed | 2009-03-09 03:35:50 +0000 | [diff] [blame] | 360 | |
Eric Snow | ca2d854 | 2013-12-16 23:06:52 -0700 | [diff] [blame] | 361 | A legacy method for loading a module. If the module cannot be |
Brett Cannon | 2a922ed | 2009-03-09 03:35:50 +0000 | [diff] [blame] | 362 | loaded, :exc:`ImportError` is raised, otherwise the loaded module is |
| 363 | returned. |
| 364 | |
Guido van Rossum | 0961354 | 2009-03-30 20:34:57 +0000 | [diff] [blame] | 365 | If the requested module already exists in :data:`sys.modules`, that |
Brett Cannon | 2a922ed | 2009-03-09 03:35:50 +0000 | [diff] [blame] | 366 | module should be used and reloaded. |
Guido van Rossum | 0961354 | 2009-03-30 20:34:57 +0000 | [diff] [blame] | 367 | Otherwise the loader should create a new module and insert it into |
| 368 | :data:`sys.modules` before any loading begins, to prevent recursion |
| 369 | from the import. If the loader inserted a module and the load fails, it |
Brett Cannon | 2a922ed | 2009-03-09 03:35:50 +0000 | [diff] [blame] | 370 | must be removed by the loader from :data:`sys.modules`; modules already |
| 371 | in :data:`sys.modules` before the loader began execution should be left |
Eric Snow | b523f84 | 2013-11-22 09:05:39 -0700 | [diff] [blame] | 372 | alone (see :func:`importlib.util.module_for_loader`). |
Brett Cannon | 2a922ed | 2009-03-09 03:35:50 +0000 | [diff] [blame] | 373 | |
Guido van Rossum | 0961354 | 2009-03-30 20:34:57 +0000 | [diff] [blame] | 374 | The loader should set several attributes on the module. |
| 375 | (Note that some of these attributes can change when a module is |
Eric Snow | b523f84 | 2013-11-22 09:05:39 -0700 | [diff] [blame] | 376 | reloaded): |
Brett Cannon | 2a922ed | 2009-03-09 03:35:50 +0000 | [diff] [blame] | 377 | |
| 378 | - :attr:`__name__` |
| 379 | The name of the module. |
| 380 | |
| 381 | - :attr:`__file__` |
| 382 | The path to where the module data is stored (not set for built-in |
| 383 | modules). |
| 384 | |
Brett Cannon | 2cefb3c | 2013-05-25 11:26:11 -0400 | [diff] [blame] | 385 | - :attr:`__cached__` |
| 386 | The path to where a compiled version of the module is/should be |
| 387 | stored (not set when the attribute would be inappropriate). |
| 388 | |
Brett Cannon | 2a922ed | 2009-03-09 03:35:50 +0000 | [diff] [blame] | 389 | - :attr:`__path__` |
Guido van Rossum | 0961354 | 2009-03-30 20:34:57 +0000 | [diff] [blame] | 390 | A list of strings specifying the search path within a |
Brett Cannon | 2a922ed | 2009-03-09 03:35:50 +0000 | [diff] [blame] | 391 | package. This attribute is not set on modules. |
| 392 | |
| 393 | - :attr:`__package__` |
| 394 | The parent package for the module/package. If the module is |
| 395 | top-level then it has a value of the empty string. The |
Brett Cannon | 100883f | 2013-04-09 16:59:39 -0400 | [diff] [blame] | 396 | :func:`importlib.util.module_for_loader` decorator can handle the |
| 397 | details for :attr:`__package__`. |
Brett Cannon | 2a922ed | 2009-03-09 03:35:50 +0000 | [diff] [blame] | 398 | |
| 399 | - :attr:`__loader__` |
Brett Cannon | 100883f | 2013-04-09 16:59:39 -0400 | [diff] [blame] | 400 | The loader used to load the module. The |
| 401 | :func:`importlib.util.module_for_loader` decorator can handle the |
| 402 | details for :attr:`__package__`. |
| 403 | |
Brett Cannon | 8d94229 | 2014-01-07 15:52:42 -0500 | [diff] [blame] | 404 | When :meth:`exec_module` is available then backwards-compatible |
| 405 | functionality is provided. |
| 406 | |
Brett Cannon | 100883f | 2013-04-09 16:59:39 -0400 | [diff] [blame] | 407 | .. versionchanged:: 3.4 |
| 408 | Raise :exc:`ImportError` when called instead of |
Brett Cannon | 8d94229 | 2014-01-07 15:52:42 -0500 | [diff] [blame] | 409 | :exc:`NotImplementedError`. Functionality provided when |
| 410 | :meth:`exec_module` is available. |
Brett Cannon | 2a922ed | 2009-03-09 03:35:50 +0000 | [diff] [blame] | 411 | |
Eric Snow | ca2d854 | 2013-12-16 23:06:52 -0700 | [diff] [blame] | 412 | .. deprecated:: 3.4 |
| 413 | The recommended API for loading a module is :meth:`exec_module` |
| 414 | (and optionally :meth:`create_module`). Loaders should implement |
| 415 | it instead of load_module(). The import machinery takes care of |
| 416 | all the other responsibilities of load_module() when exec_module() |
| 417 | is implemented. |
| 418 | |
Barry Warsaw | d7d2194 | 2012-07-29 16:36:17 -0400 | [diff] [blame] | 419 | .. method:: module_repr(module) |
| 420 | |
Eric Snow | ca2d854 | 2013-12-16 23:06:52 -0700 | [diff] [blame] | 421 | A legacy method which when implemented calculates and returns the |
Brett Cannon | 100883f | 2013-04-09 16:59:39 -0400 | [diff] [blame] | 422 | given module's repr, as a string. The module type's default repr() will |
| 423 | use the result of this method as appropriate. |
Barry Warsaw | d7d2194 | 2012-07-29 16:36:17 -0400 | [diff] [blame] | 424 | |
Georg Brandl | 526575d | 2013-04-11 16:10:13 +0200 | [diff] [blame] | 425 | .. versionadded:: 3.3 |
Barry Warsaw | d7d2194 | 2012-07-29 16:36:17 -0400 | [diff] [blame] | 426 | |
Brett Cannon | 100883f | 2013-04-09 16:59:39 -0400 | [diff] [blame] | 427 | .. versionchanged:: 3.4 |
Georg Brandl | 526575d | 2013-04-11 16:10:13 +0200 | [diff] [blame] | 428 | Made optional instead of an abstractmethod. |
Brett Cannon | 100883f | 2013-04-09 16:59:39 -0400 | [diff] [blame] | 429 | |
Eric Snow | ca2d854 | 2013-12-16 23:06:52 -0700 | [diff] [blame] | 430 | .. deprecated:: 3.4 |
| 431 | The import machinery now takes care of this automatically. |
| 432 | |
Brett Cannon | 2a922ed | 2009-03-09 03:35:50 +0000 | [diff] [blame] | 433 | |
| 434 | .. class:: ResourceLoader |
| 435 | |
| 436 | An abstract base class for a :term:`loader` which implements the optional |
| 437 | :pep:`302` protocol for loading arbitrary resources from the storage |
| 438 | back-end. |
| 439 | |
Brett Cannon | 9c751b7 | 2009-03-09 16:28:16 +0000 | [diff] [blame] | 440 | .. method:: get_data(path) |
Brett Cannon | 2a922ed | 2009-03-09 03:35:50 +0000 | [diff] [blame] | 441 | |
| 442 | An abstract method to return the bytes for the data located at *path*. |
Guido van Rossum | 0961354 | 2009-03-30 20:34:57 +0000 | [diff] [blame] | 443 | Loaders that have a file-like storage back-end |
Brett Cannon | 16248a4 | 2009-04-01 20:47:14 +0000 | [diff] [blame] | 444 | that allows storing arbitrary data |
Guido van Rossum | 0961354 | 2009-03-30 20:34:57 +0000 | [diff] [blame] | 445 | can implement this abstract method to give direct access |
Andrew Svetlov | 08af000 | 2014-04-01 01:13:30 +0300 | [diff] [blame] | 446 | to the data stored. :exc:`OSError` is to be raised if the *path* cannot |
Brett Cannon | 2a922ed | 2009-03-09 03:35:50 +0000 | [diff] [blame] | 447 | be found. The *path* is expected to be constructed using a module's |
Brett Cannon | 16248a4 | 2009-04-01 20:47:14 +0000 | [diff] [blame] | 448 | :attr:`__file__` attribute or an item from a package's :attr:`__path__`. |
Brett Cannon | 2a922ed | 2009-03-09 03:35:50 +0000 | [diff] [blame] | 449 | |
Brett Cannon | 100883f | 2013-04-09 16:59:39 -0400 | [diff] [blame] | 450 | .. versionchanged:: 3.4 |
Andrew Svetlov | 08af000 | 2014-04-01 01:13:30 +0300 | [diff] [blame] | 451 | Raises :exc:`OSError` instead of :exc:`NotImplementedError`. |
Brett Cannon | 100883f | 2013-04-09 16:59:39 -0400 | [diff] [blame] | 452 | |
Brett Cannon | 2a922ed | 2009-03-09 03:35:50 +0000 | [diff] [blame] | 453 | |
| 454 | .. class:: InspectLoader |
| 455 | |
| 456 | An abstract base class for a :term:`loader` which implements the optional |
Guido van Rossum | 0961354 | 2009-03-30 20:34:57 +0000 | [diff] [blame] | 457 | :pep:`302` protocol for loaders that inspect modules. |
Brett Cannon | 2a922ed | 2009-03-09 03:35:50 +0000 | [diff] [blame] | 458 | |
Brett Cannon | a113ac5 | 2009-03-15 01:41:33 +0000 | [diff] [blame] | 459 | .. method:: get_code(fullname) |
Brett Cannon | 2a922ed | 2009-03-09 03:35:50 +0000 | [diff] [blame] | 460 | |
R David Murray | 0ae7ae1 | 2014-01-08 18:16:02 -0500 | [diff] [blame] | 461 | Return the code object for a module, or ``None`` if the module does not |
| 462 | have a code object (as would be the case, for example, for a built-in |
| 463 | module). Raise an :exc:`ImportError` if loader cannot find the |
| 464 | requested module. |
Brett Cannon | 2a922ed | 2009-03-09 03:35:50 +0000 | [diff] [blame] | 465 | |
Brett Cannon | 3b62ca8 | 2013-05-27 21:11:04 -0400 | [diff] [blame] | 466 | .. note:: |
| 467 | While the method has a default implementation, it is suggested that |
| 468 | it be overridden if possible for performance. |
| 469 | |
R David Murray | 1b00f25 | 2012-08-15 10:43:58 -0400 | [diff] [blame] | 470 | .. index:: |
| 471 | single: universal newlines; importlib.abc.InspectLoader.get_source method |
| 472 | |
Brett Cannon | 100883f | 2013-04-09 16:59:39 -0400 | [diff] [blame] | 473 | .. versionchanged:: 3.4 |
Brett Cannon | 3b62ca8 | 2013-05-27 21:11:04 -0400 | [diff] [blame] | 474 | No longer abstract and a concrete implementation is provided. |
Brett Cannon | 100883f | 2013-04-09 16:59:39 -0400 | [diff] [blame] | 475 | |
Brett Cannon | 9c751b7 | 2009-03-09 16:28:16 +0000 | [diff] [blame] | 476 | .. method:: get_source(fullname) |
Brett Cannon | 2a922ed | 2009-03-09 03:35:50 +0000 | [diff] [blame] | 477 | |
| 478 | An abstract method to return the source of a module. It is returned as |
R David Murray | 1b00f25 | 2012-08-15 10:43:58 -0400 | [diff] [blame] | 479 | a text string using :term:`universal newlines`, translating all |
R David Murray | ee0a945 | 2012-08-15 11:05:36 -0400 | [diff] [blame] | 480 | recognized line separators into ``'\n'`` characters. Returns ``None`` |
| 481 | if no source is available (e.g. a built-in module). Raises |
| 482 | :exc:`ImportError` if the loader cannot find the module specified. |
Brett Cannon | 2a922ed | 2009-03-09 03:35:50 +0000 | [diff] [blame] | 483 | |
Brett Cannon | 100883f | 2013-04-09 16:59:39 -0400 | [diff] [blame] | 484 | .. versionchanged:: 3.4 |
| 485 | Raises :exc:`ImportError` instead of :exc:`NotImplementedError`. |
| 486 | |
Brett Cannon | a113ac5 | 2009-03-15 01:41:33 +0000 | [diff] [blame] | 487 | .. method:: is_package(fullname) |
Brett Cannon | 2a922ed | 2009-03-09 03:35:50 +0000 | [diff] [blame] | 488 | |
Brett Cannon | a113ac5 | 2009-03-15 01:41:33 +0000 | [diff] [blame] | 489 | An abstract method to return a true value if the module is a package, a |
| 490 | false value otherwise. :exc:`ImportError` is raised if the |
| 491 | :term:`loader` cannot find the module. |
Brett Cannon | 2a922ed | 2009-03-09 03:35:50 +0000 | [diff] [blame] | 492 | |
Brett Cannon | 100883f | 2013-04-09 16:59:39 -0400 | [diff] [blame] | 493 | .. versionchanged:: 3.4 |
| 494 | Raises :exc:`ImportError` instead of :exc:`NotImplementedError`. |
| 495 | |
Brett Cannon | 9ffe85e | 2013-05-26 16:45:10 -0400 | [diff] [blame] | 496 | .. method:: source_to_code(data, path='<string>') |
| 497 | |
| 498 | Create a code object from Python source. |
| 499 | |
| 500 | The *data* argument can be whatever the :func:`compile` function |
| 501 | supports (i.e. string or bytes). The *path* argument should be |
| 502 | the "path" to where the source code originated from, which can be an |
| 503 | abstract concept (e.g. location in a zip file). |
| 504 | |
| 505 | .. versionadded:: 3.4 |
| 506 | |
Eric Snow | ca2d854 | 2013-12-16 23:06:52 -0700 | [diff] [blame] | 507 | .. method:: exec_module(module) |
| 508 | |
| 509 | Implementation of :meth:`Loader.exec_module`. |
| 510 | |
| 511 | .. versionadded:: 3.4 |
| 512 | |
Brett Cannon | 0dbb4c7 | 2013-05-31 18:56:47 -0400 | [diff] [blame] | 513 | .. method:: load_module(fullname) |
| 514 | |
Eric Snow | ca2d854 | 2013-12-16 23:06:52 -0700 | [diff] [blame] | 515 | Implementation of :meth:`Loader.load_module`. |
| 516 | |
| 517 | .. deprecated:: 3.4 |
| 518 | use :meth:`exec_module` instead. |
Brett Cannon | 0dbb4c7 | 2013-05-31 18:56:47 -0400 | [diff] [blame] | 519 | |
Brett Cannon | 2a922ed | 2009-03-09 03:35:50 +0000 | [diff] [blame] | 520 | |
Brett Cannon | 6919427 | 2009-07-20 04:23:48 +0000 | [diff] [blame] | 521 | .. class:: ExecutionLoader |
| 522 | |
| 523 | An abstract base class which inherits from :class:`InspectLoader` that, |
Brett Cannon | 2346029 | 2009-07-20 22:59:00 +0000 | [diff] [blame] | 524 | when implemented, helps a module to be executed as a script. The ABC |
Brett Cannon | 6919427 | 2009-07-20 04:23:48 +0000 | [diff] [blame] | 525 | represents an optional :pep:`302` protocol. |
| 526 | |
| 527 | .. method:: get_filename(fullname) |
| 528 | |
Brett Cannon | f23e374 | 2010-06-27 23:57:46 +0000 | [diff] [blame] | 529 | An abstract method that is to return the value of :attr:`__file__` for |
Brett Cannon | 6919427 | 2009-07-20 04:23:48 +0000 | [diff] [blame] | 530 | the specified module. If no path is available, :exc:`ImportError` is |
| 531 | raised. |
| 532 | |
Brett Cannon | f23e374 | 2010-06-27 23:57:46 +0000 | [diff] [blame] | 533 | If source code is available, then the method should return the path to |
| 534 | the source file, regardless of whether a bytecode was used to load the |
| 535 | module. |
| 536 | |
Brett Cannon | 100883f | 2013-04-09 16:59:39 -0400 | [diff] [blame] | 537 | .. versionchanged:: 3.4 |
| 538 | Raises :exc:`ImportError` instead of :exc:`NotImplementedError`. |
| 539 | |
Brett Cannon | f23e374 | 2010-06-27 23:57:46 +0000 | [diff] [blame] | 540 | |
Brett Cannon | 938d44d | 2012-04-22 19:58:33 -0400 | [diff] [blame] | 541 | .. class:: FileLoader(fullname, path) |
| 542 | |
| 543 | An abstract base class which inherits from :class:`ResourceLoader` and |
Andrew Svetlov | a60de4f | 2013-02-17 16:55:58 +0200 | [diff] [blame] | 544 | :class:`ExecutionLoader`, providing concrete implementations of |
Brett Cannon | 938d44d | 2012-04-22 19:58:33 -0400 | [diff] [blame] | 545 | :meth:`ResourceLoader.get_data` and :meth:`ExecutionLoader.get_filename`. |
| 546 | |
| 547 | The *fullname* argument is a fully resolved name of the module the loader is |
| 548 | to handle. The *path* argument is the path to the file for the module. |
| 549 | |
| 550 | .. versionadded:: 3.3 |
| 551 | |
| 552 | .. attribute:: name |
| 553 | |
| 554 | The name of the module the loader can handle. |
| 555 | |
| 556 | .. attribute:: path |
| 557 | |
| 558 | Path to the file of the module. |
| 559 | |
Barry Warsaw | d7d2194 | 2012-07-29 16:36:17 -0400 | [diff] [blame] | 560 | .. method:: load_module(fullname) |
Brett Cannon | c049952 | 2012-05-11 14:48:41 -0400 | [diff] [blame] | 561 | |
Barry Warsaw | d7d2194 | 2012-07-29 16:36:17 -0400 | [diff] [blame] | 562 | Calls super's ``load_module()``. |
Brett Cannon | c049952 | 2012-05-11 14:48:41 -0400 | [diff] [blame] | 563 | |
Eric Snow | ca2d854 | 2013-12-16 23:06:52 -0700 | [diff] [blame] | 564 | .. deprecated:: 3.4 |
| 565 | Use :meth:`Loader.exec_module` instead. |
| 566 | |
Brett Cannon | 938d44d | 2012-04-22 19:58:33 -0400 | [diff] [blame] | 567 | .. method:: get_filename(fullname) |
| 568 | |
Barry Warsaw | d7d2194 | 2012-07-29 16:36:17 -0400 | [diff] [blame] | 569 | Returns :attr:`path`. |
Brett Cannon | 938d44d | 2012-04-22 19:58:33 -0400 | [diff] [blame] | 570 | |
| 571 | .. method:: get_data(path) |
| 572 | |
Brett Cannon | 3b62ca8 | 2013-05-27 21:11:04 -0400 | [diff] [blame] | 573 | Reads *path* as a binary file and returns the bytes from it. |
Brett Cannon | 938d44d | 2012-04-22 19:58:33 -0400 | [diff] [blame] | 574 | |
| 575 | |
Brett Cannon | f23e374 | 2010-06-27 23:57:46 +0000 | [diff] [blame] | 576 | .. class:: SourceLoader |
| 577 | |
| 578 | An abstract base class for implementing source (and optionally bytecode) |
| 579 | file loading. The class inherits from both :class:`ResourceLoader` and |
| 580 | :class:`ExecutionLoader`, requiring the implementation of: |
| 581 | |
| 582 | * :meth:`ResourceLoader.get_data` |
| 583 | * :meth:`ExecutionLoader.get_filename` |
Brett Cannon | 6dfbff3 | 2010-07-21 09:48:31 +0000 | [diff] [blame] | 584 | Should only return the path to the source file; sourceless |
Brett Cannon | a81d527 | 2013-06-16 19:17:12 -0400 | [diff] [blame] | 585 | loading is not supported. |
Brett Cannon | f23e374 | 2010-06-27 23:57:46 +0000 | [diff] [blame] | 586 | |
| 587 | The abstract methods defined by this class are to add optional bytecode |
Brett Cannon | 5650e4f | 2012-11-18 10:03:31 -0500 | [diff] [blame] | 588 | file support. Not implementing these optional methods (or causing them to |
| 589 | raise :exc:`NotImplementedError`) causes the loader to |
Brett Cannon | f23e374 | 2010-06-27 23:57:46 +0000 | [diff] [blame] | 590 | only work with source code. Implementing the methods allows the loader to |
| 591 | work with source *and* bytecode files; it does not allow for *sourceless* |
| 592 | loading where only bytecode is provided. Bytecode files are an |
| 593 | optimization to speed up loading by removing the parsing step of Python's |
| 594 | compiler, and so no bytecode-specific API is exposed. |
| 595 | |
Brett Cannon | 773468f | 2012-08-02 17:35:34 -0400 | [diff] [blame] | 596 | .. method:: path_stats(path) |
Antoine Pitrou | 5136ac0 | 2012-01-13 18:52:16 +0100 | [diff] [blame] | 597 | |
| 598 | Optional abstract method which returns a :class:`dict` containing |
| 599 | metadata about the specifed path. Supported dictionary keys are: |
| 600 | |
| 601 | - ``'mtime'`` (mandatory): an integer or floating-point number |
| 602 | representing the modification time of the source code; |
| 603 | - ``'size'`` (optional): the size in bytes of the source code. |
| 604 | |
| 605 | Any other keys in the dictionary are ignored, to allow for future |
Andrew Svetlov | 08af000 | 2014-04-01 01:13:30 +0300 | [diff] [blame] | 606 | extensions. If the path cannot be handled, :exc:`OSError` is raised. |
Antoine Pitrou | 5136ac0 | 2012-01-13 18:52:16 +0100 | [diff] [blame] | 607 | |
| 608 | .. versionadded:: 3.3 |
| 609 | |
Brett Cannon | 100883f | 2013-04-09 16:59:39 -0400 | [diff] [blame] | 610 | .. versionchanged:: 3.4 |
Andrew Svetlov | 08af000 | 2014-04-01 01:13:30 +0300 | [diff] [blame] | 611 | Raise :exc:`OSError` instead of :exc:`NotImplementedError`. |
Brett Cannon | 100883f | 2013-04-09 16:59:39 -0400 | [diff] [blame] | 612 | |
Brett Cannon | 773468f | 2012-08-02 17:35:34 -0400 | [diff] [blame] | 613 | .. method:: path_mtime(path) |
Brett Cannon | f23e374 | 2010-06-27 23:57:46 +0000 | [diff] [blame] | 614 | |
| 615 | Optional abstract method which returns the modification time for the |
| 616 | specified path. |
| 617 | |
Antoine Pitrou | 5136ac0 | 2012-01-13 18:52:16 +0100 | [diff] [blame] | 618 | .. deprecated:: 3.3 |
| 619 | This method is deprecated in favour of :meth:`path_stats`. You don't |
| 620 | have to implement it, but it is still available for compatibility |
Andrew Svetlov | 08af000 | 2014-04-01 01:13:30 +0300 | [diff] [blame] | 621 | purposes. Raise :exc:`OSError` if the path cannot be handled. |
Brett Cannon | 100883f | 2013-04-09 16:59:39 -0400 | [diff] [blame] | 622 | |
Georg Brandl | df48b97 | 2014-03-24 09:06:18 +0100 | [diff] [blame] | 623 | .. versionchanged:: 3.4 |
Andrew Svetlov | 08af000 | 2014-04-01 01:13:30 +0300 | [diff] [blame] | 624 | Raise :exc:`OSError` instead of :exc:`NotImplementedError`. |
Antoine Pitrou | 5136ac0 | 2012-01-13 18:52:16 +0100 | [diff] [blame] | 625 | |
Brett Cannon | 773468f | 2012-08-02 17:35:34 -0400 | [diff] [blame] | 626 | .. method:: set_data(path, data) |
Brett Cannon | f23e374 | 2010-06-27 23:57:46 +0000 | [diff] [blame] | 627 | |
| 628 | Optional abstract method which writes the specified bytes to a file |
Brett Cannon | 61b1425 | 2010-07-03 21:48:25 +0000 | [diff] [blame] | 629 | path. Any intermediate directories which do not exist are to be created |
| 630 | automatically. |
| 631 | |
| 632 | When writing to the path fails because the path is read-only |
Brett Cannon | 2cefb3c | 2013-05-25 11:26:11 -0400 | [diff] [blame] | 633 | (:attr:`errno.EACCES`/:exc:`PermissionError`), do not propagate the |
| 634 | exception. |
Brett Cannon | f23e374 | 2010-06-27 23:57:46 +0000 | [diff] [blame] | 635 | |
Brett Cannon | 100883f | 2013-04-09 16:59:39 -0400 | [diff] [blame] | 636 | .. versionchanged:: 3.4 |
| 637 | No longer raises :exc:`NotImplementedError` when called. |
| 638 | |
Brett Cannon | 773468f | 2012-08-02 17:35:34 -0400 | [diff] [blame] | 639 | .. method:: get_code(fullname) |
Brett Cannon | f23e374 | 2010-06-27 23:57:46 +0000 | [diff] [blame] | 640 | |
| 641 | Concrete implementation of :meth:`InspectLoader.get_code`. |
| 642 | |
Eric Snow | ca2d854 | 2013-12-16 23:06:52 -0700 | [diff] [blame] | 643 | .. method:: exec_module(module) |
| 644 | |
| 645 | Concrete implementation of :meth:`Loader.exec_module`. |
| 646 | |
| 647 | .. versionadded:: 3.4 |
| 648 | |
Brett Cannon | 773468f | 2012-08-02 17:35:34 -0400 | [diff] [blame] | 649 | .. method:: load_module(fullname) |
Brett Cannon | f23e374 | 2010-06-27 23:57:46 +0000 | [diff] [blame] | 650 | |
Eric Snow | ca2d854 | 2013-12-16 23:06:52 -0700 | [diff] [blame] | 651 | Concrete implementation of :meth:`Loader.load_module`. |
| 652 | |
| 653 | .. deprecated:: 3.4 |
| 654 | Use :meth:`exec_module` instead. |
Brett Cannon | f23e374 | 2010-06-27 23:57:46 +0000 | [diff] [blame] | 655 | |
Brett Cannon | 773468f | 2012-08-02 17:35:34 -0400 | [diff] [blame] | 656 | .. method:: get_source(fullname) |
Brett Cannon | f23e374 | 2010-06-27 23:57:46 +0000 | [diff] [blame] | 657 | |
| 658 | Concrete implementation of :meth:`InspectLoader.get_source`. |
| 659 | |
Brett Cannon | 773468f | 2012-08-02 17:35:34 -0400 | [diff] [blame] | 660 | .. method:: is_package(fullname) |
Brett Cannon | f23e374 | 2010-06-27 23:57:46 +0000 | [diff] [blame] | 661 | |
| 662 | Concrete implementation of :meth:`InspectLoader.is_package`. A module |
Brett Cannon | ea0b823 | 2012-06-15 20:00:53 -0400 | [diff] [blame] | 663 | is determined to be a package if its file path (as provided by |
| 664 | :meth:`ExecutionLoader.get_filename`) is a file named |
| 665 | ``__init__`` when the file extension is removed **and** the module name |
| 666 | itself does not end in ``__init__``. |
Brett Cannon | f23e374 | 2010-06-27 23:57:46 +0000 | [diff] [blame] | 667 | |
Brett Cannon | 6919427 | 2009-07-20 04:23:48 +0000 | [diff] [blame] | 668 | |
Brett Cannon | 78246b6 | 2009-01-25 04:56:30 +0000 | [diff] [blame] | 669 | :mod:`importlib.machinery` -- Importers and path hooks |
| 670 | ------------------------------------------------------ |
| 671 | |
| 672 | .. module:: importlib.machinery |
| 673 | :synopsis: Importers and path hooks |
| 674 | |
| 675 | This module contains the various objects that help :keyword:`import` |
| 676 | find and load modules. |
| 677 | |
Brett Cannon | cb66eb0 | 2012-05-11 12:58:42 -0400 | [diff] [blame] | 678 | .. attribute:: SOURCE_SUFFIXES |
| 679 | |
| 680 | A list of strings representing the recognized file suffixes for source |
| 681 | modules. |
| 682 | |
| 683 | .. versionadded:: 3.3 |
| 684 | |
| 685 | .. attribute:: DEBUG_BYTECODE_SUFFIXES |
| 686 | |
| 687 | A list of strings representing the file suffixes for non-optimized bytecode |
| 688 | modules. |
| 689 | |
| 690 | .. versionadded:: 3.3 |
| 691 | |
| 692 | .. attribute:: OPTIMIZED_BYTECODE_SUFFIXES |
| 693 | |
| 694 | A list of strings representing the file suffixes for optimized bytecode |
| 695 | modules. |
| 696 | |
| 697 | .. versionadded:: 3.3 |
| 698 | |
| 699 | .. attribute:: BYTECODE_SUFFIXES |
| 700 | |
| 701 | A list of strings representing the recognized file suffixes for bytecode |
| 702 | modules. Set to either :attr:`DEBUG_BYTECODE_SUFFIXES` or |
| 703 | :attr:`OPTIMIZED_BYTECODE_SUFFIXES` based on whether ``__debug__`` is true. |
| 704 | |
| 705 | .. versionadded:: 3.3 |
| 706 | |
| 707 | .. attribute:: EXTENSION_SUFFIXES |
| 708 | |
Nick Coghlan | 76e0770 | 2012-07-18 23:14:57 +1000 | [diff] [blame] | 709 | A list of strings representing the recognized file suffixes for |
Brett Cannon | cb66eb0 | 2012-05-11 12:58:42 -0400 | [diff] [blame] | 710 | extension modules. |
| 711 | |
| 712 | .. versionadded:: 3.3 |
| 713 | |
Nick Coghlan | c5afd42 | 2012-07-18 23:59:08 +1000 | [diff] [blame] | 714 | .. function:: all_suffixes() |
Nick Coghlan | 76e0770 | 2012-07-18 23:14:57 +1000 | [diff] [blame] | 715 | |
| 716 | Returns a combined list of strings representing all file suffixes for |
Nick Coghlan | c5afd42 | 2012-07-18 23:59:08 +1000 | [diff] [blame] | 717 | modules recognized by the standard import machinery. This is a |
Nick Coghlan | 76e0770 | 2012-07-18 23:14:57 +1000 | [diff] [blame] | 718 | helper for code which simply needs to know if a filesystem path |
Nick Coghlan | c5afd42 | 2012-07-18 23:59:08 +1000 | [diff] [blame] | 719 | potentially refers to a module without needing any details on the kind |
Martin Panter | d21e0b5 | 2015-10-10 10:36:22 +0000 | [diff] [blame] | 720 | of module (for example, :func:`inspect.getmodulename`). |
Nick Coghlan | 76e0770 | 2012-07-18 23:14:57 +1000 | [diff] [blame] | 721 | |
| 722 | .. versionadded:: 3.3 |
| 723 | |
| 724 | |
Brett Cannon | 78246b6 | 2009-01-25 04:56:30 +0000 | [diff] [blame] | 725 | .. class:: BuiltinImporter |
| 726 | |
Brett Cannon | 2a922ed | 2009-03-09 03:35:50 +0000 | [diff] [blame] | 727 | An :term:`importer` for built-in modules. All known built-in modules are |
| 728 | listed in :data:`sys.builtin_module_names`. This class implements the |
Nick Coghlan | 8a9080f | 2012-08-02 21:26:03 +1000 | [diff] [blame] | 729 | :class:`importlib.abc.MetaPathFinder` and |
| 730 | :class:`importlib.abc.InspectLoader` ABCs. |
Brett Cannon | 78246b6 | 2009-01-25 04:56:30 +0000 | [diff] [blame] | 731 | |
| 732 | Only class methods are defined by this class to alleviate the need for |
| 733 | instantiation. |
| 734 | |
Eric Snow | ca2d854 | 2013-12-16 23:06:52 -0700 | [diff] [blame] | 735 | .. note:: |
| 736 | Due to limitations in the extension module C-API, for now |
| 737 | BuiltinImporter does not implement :meth:`Loader.exec_module`. |
| 738 | |
Brett Cannon | 78246b6 | 2009-01-25 04:56:30 +0000 | [diff] [blame] | 739 | |
| 740 | .. class:: FrozenImporter |
| 741 | |
Brett Cannon | 2a922ed | 2009-03-09 03:35:50 +0000 | [diff] [blame] | 742 | An :term:`importer` for frozen modules. This class implements the |
Nick Coghlan | 8a9080f | 2012-08-02 21:26:03 +1000 | [diff] [blame] | 743 | :class:`importlib.abc.MetaPathFinder` and |
| 744 | :class:`importlib.abc.InspectLoader` ABCs. |
Brett Cannon | 78246b6 | 2009-01-25 04:56:30 +0000 | [diff] [blame] | 745 | |
| 746 | Only class methods are defined by this class to alleviate the need for |
| 747 | instantiation. |
| 748 | |
Brett Cannon | debb98d | 2009-02-16 04:18:01 +0000 | [diff] [blame] | 749 | |
Nick Coghlan | ff79486 | 2012-08-02 21:45:24 +1000 | [diff] [blame] | 750 | .. class:: WindowsRegistryFinder |
| 751 | |
| 752 | :term:`Finder` for modules declared in the Windows registry. This class |
Nick Coghlan | 4941774 | 2012-08-02 23:03:58 +1000 | [diff] [blame] | 753 | implements the :class:`importlib.abc.Finder` ABC. |
Nick Coghlan | ff79486 | 2012-08-02 21:45:24 +1000 | [diff] [blame] | 754 | |
| 755 | Only class methods are defined by this class to alleviate the need for |
| 756 | instantiation. |
| 757 | |
| 758 | .. versionadded:: 3.3 |
| 759 | |
| 760 | |
Brett Cannon | debb98d | 2009-02-16 04:18:01 +0000 | [diff] [blame] | 761 | .. class:: PathFinder |
| 762 | |
Brett Cannon | 1b79918 | 2012-08-17 14:08:24 -0400 | [diff] [blame] | 763 | A :term:`Finder` for :data:`sys.path` and package ``__path__`` attributes. |
| 764 | This class implements the :class:`importlib.abc.MetaPathFinder` ABC. |
Brett Cannon | debb98d | 2009-02-16 04:18:01 +0000 | [diff] [blame] | 765 | |
Brett Cannon | 1b79918 | 2012-08-17 14:08:24 -0400 | [diff] [blame] | 766 | Only class methods are defined by this class to alleviate the need for |
| 767 | instantiation. |
Brett Cannon | debb98d | 2009-02-16 04:18:01 +0000 | [diff] [blame] | 768 | |
Eric Snow | ca2d854 | 2013-12-16 23:06:52 -0700 | [diff] [blame] | 769 | .. classmethod:: find_spec(fullname, path=None, target=None) |
| 770 | |
| 771 | Class method that attempts to find a :term:`spec <module spec>` |
| 772 | for the module specified by *fullname* on :data:`sys.path` or, if |
| 773 | defined, on *path*. For each path entry that is searched, |
| 774 | :data:`sys.path_importer_cache` is checked. If a non-false object |
| 775 | is found then it is used as the :term:`path entry finder` to look |
| 776 | for the module being searched for. If no entry is found in |
| 777 | :data:`sys.path_importer_cache`, then :data:`sys.path_hooks` is |
| 778 | searched for a finder for the path entry and, if found, is stored |
| 779 | in :data:`sys.path_importer_cache` along with being queried about |
| 780 | the module. If no finder is ever found then ``None`` is both |
| 781 | stored in the cache and returned. |
| 782 | |
| 783 | .. versionadded:: 3.4 |
| 784 | |
Brett Cannon | 1b79918 | 2012-08-17 14:08:24 -0400 | [diff] [blame] | 785 | .. classmethod:: find_module(fullname, path=None) |
Brett Cannon | debb98d | 2009-02-16 04:18:01 +0000 | [diff] [blame] | 786 | |
Eric Snow | ca2d854 | 2013-12-16 23:06:52 -0700 | [diff] [blame] | 787 | A legacy wrapper around :meth:`find_spec`. |
| 788 | |
| 789 | .. deprecated:: 3.4 |
| 790 | Use :meth:`find_spec` instead. |
Brett Cannon | d2e7b33 | 2009-02-17 02:45:03 +0000 | [diff] [blame] | 791 | |
Brett Cannon | f4dc920 | 2012-08-10 12:21:12 -0400 | [diff] [blame] | 792 | .. classmethod:: invalidate_caches() |
| 793 | |
Eric Snow | ca2d854 | 2013-12-16 23:06:52 -0700 | [diff] [blame] | 794 | Calls :meth:`importlib.abc.PathEntryFinder.invalidate_caches` on all |
| 795 | finders stored in :attr:`sys.path_importer_cache`. |
Brett Cannon | f4dc920 | 2012-08-10 12:21:12 -0400 | [diff] [blame] | 796 | |
Eric Snow | ca2d854 | 2013-12-16 23:06:52 -0700 | [diff] [blame] | 797 | .. versionchanged:: 3.4 |
| 798 | Calls objects in :data:`sys.path_hooks` with the current working |
| 799 | directory for ``''`` (i.e. the empty string). |
Brett Cannon | 27e27f7 | 2013-10-18 11:39:04 -0400 | [diff] [blame] | 800 | |
Brett Cannon | d2e7b33 | 2009-02-17 02:45:03 +0000 | [diff] [blame] | 801 | |
Brett Cannon | 938d44d | 2012-04-22 19:58:33 -0400 | [diff] [blame] | 802 | .. class:: FileFinder(path, \*loader_details) |
| 803 | |
Nick Coghlan | 8a9080f | 2012-08-02 21:26:03 +1000 | [diff] [blame] | 804 | A concrete implementation of :class:`importlib.abc.PathEntryFinder` which |
| 805 | caches results from the file system. |
Brett Cannon | 938d44d | 2012-04-22 19:58:33 -0400 | [diff] [blame] | 806 | |
| 807 | The *path* argument is the directory for which the finder is in charge of |
| 808 | searching. |
| 809 | |
Brett Cannon | ac9f2f3 | 2012-08-10 13:47:54 -0400 | [diff] [blame] | 810 | The *loader_details* argument is a variable number of 2-item tuples each |
| 811 | containing a loader and a sequence of file suffixes the loader recognizes. |
Brett Cannon | 29b2f17 | 2013-06-21 18:31:55 -0400 | [diff] [blame] | 812 | The loaders are expected to be callables which accept two arguments of |
| 813 | the module's name and the path to the file found. |
Brett Cannon | 938d44d | 2012-04-22 19:58:33 -0400 | [diff] [blame] | 814 | |
| 815 | The finder will cache the directory contents as necessary, making stat calls |
| 816 | for each module search to verify the cache is not outdated. Because cache |
| 817 | staleness relies upon the granularity of the operating system's state |
| 818 | information of the file system, there is a potential race condition of |
| 819 | searching for a module, creating a new file, and then searching for the |
| 820 | module the new file represents. If the operations happen fast enough to fit |
| 821 | within the granularity of stat calls, then the module search will fail. To |
| 822 | prevent this from happening, when you create a module dynamically, make sure |
| 823 | to call :func:`importlib.invalidate_caches`. |
| 824 | |
| 825 | .. versionadded:: 3.3 |
| 826 | |
| 827 | .. attribute:: path |
| 828 | |
| 829 | The path the finder will search in. |
| 830 | |
Eric Snow | ca2d854 | 2013-12-16 23:06:52 -0700 | [diff] [blame] | 831 | .. method:: find_spec(fullname, target=None) |
| 832 | |
| 833 | Attempt to find the spec to handle *fullname* within :attr:`path`. |
| 834 | |
| 835 | .. versionadded:: 3.4 |
| 836 | |
Brett Cannon | 1d75382 | 2013-06-16 19:06:55 -0400 | [diff] [blame] | 837 | .. method:: find_loader(fullname) |
Brett Cannon | 938d44d | 2012-04-22 19:58:33 -0400 | [diff] [blame] | 838 | |
| 839 | Attempt to find the loader to handle *fullname* within :attr:`path`. |
| 840 | |
| 841 | .. method:: invalidate_caches() |
| 842 | |
| 843 | Clear out the internal cache. |
| 844 | |
| 845 | .. classmethod:: path_hook(\*loader_details) |
| 846 | |
| 847 | A class method which returns a closure for use on :attr:`sys.path_hooks`. |
| 848 | An instance of :class:`FileFinder` is returned by the closure using the |
| 849 | path argument given to the closure directly and *loader_details* |
| 850 | indirectly. |
| 851 | |
| 852 | If the argument to the closure is not an existing directory, |
| 853 | :exc:`ImportError` is raised. |
| 854 | |
| 855 | |
| 856 | .. class:: SourceFileLoader(fullname, path) |
| 857 | |
| 858 | A concrete implementation of :class:`importlib.abc.SourceLoader` by |
| 859 | subclassing :class:`importlib.abc.FileLoader` and providing some concrete |
| 860 | implementations of other methods. |
| 861 | |
| 862 | .. versionadded:: 3.3 |
| 863 | |
| 864 | .. attribute:: name |
| 865 | |
| 866 | The name of the module that this loader will handle. |
| 867 | |
| 868 | .. attribute:: path |
| 869 | |
| 870 | The path to the source file. |
| 871 | |
| 872 | .. method:: is_package(fullname) |
| 873 | |
| 874 | Return true if :attr:`path` appears to be for a package. |
| 875 | |
| 876 | .. method:: path_stats(path) |
| 877 | |
| 878 | Concrete implementation of :meth:`importlib.abc.SourceLoader.path_stats`. |
| 879 | |
| 880 | .. method:: set_data(path, data) |
| 881 | |
| 882 | Concrete implementation of :meth:`importlib.abc.SourceLoader.set_data`. |
| 883 | |
Brett Cannon | 062fcac | 2014-05-09 11:55:49 -0400 | [diff] [blame] | 884 | .. method:: load_module(name=None) |
| 885 | |
| 886 | Concrete implementation of :meth:`importlib.abc.Loader.load_module` where |
| 887 | specifying the name of the module to load is optional. |
| 888 | |
Brett Cannon | 938d44d | 2012-04-22 19:58:33 -0400 | [diff] [blame] | 889 | |
Marc-Andre Lemburg | 4fe29c9 | 2012-04-25 02:31:37 +0200 | [diff] [blame] | 890 | .. class:: SourcelessFileLoader(fullname, path) |
Brett Cannon | 938d44d | 2012-04-22 19:58:33 -0400 | [diff] [blame] | 891 | |
| 892 | A concrete implementation of :class:`importlib.abc.FileLoader` which can |
| 893 | import bytecode files (i.e. no source code files exist). |
| 894 | |
Marc-Andre Lemburg | 4fe29c9 | 2012-04-25 02:31:37 +0200 | [diff] [blame] | 895 | Please note that direct use of bytecode files (and thus not source code |
| 896 | files) inhibits your modules from being usable by all Python |
| 897 | implementations or new versions of Python which change the bytecode |
| 898 | format. |
Brett Cannon | 938d44d | 2012-04-22 19:58:33 -0400 | [diff] [blame] | 899 | |
| 900 | .. versionadded:: 3.3 |
| 901 | |
| 902 | .. attribute:: name |
| 903 | |
| 904 | The name of the module the loader will handle. |
| 905 | |
| 906 | .. attribute:: path |
| 907 | |
| 908 | The path to the bytecode file. |
| 909 | |
| 910 | .. method:: is_package(fullname) |
| 911 | |
| 912 | Determines if the module is a package based on :attr:`path`. |
| 913 | |
| 914 | .. method:: get_code(fullname) |
| 915 | |
| 916 | Returns the code object for :attr:`name` created from :attr:`path`. |
| 917 | |
| 918 | .. method:: get_source(fullname) |
| 919 | |
| 920 | Returns ``None`` as bytecode files have no source when this loader is |
| 921 | used. |
| 922 | |
Brett Cannon | 062fcac | 2014-05-09 11:55:49 -0400 | [diff] [blame] | 923 | .. method:: load_module(name=None) |
| 924 | |
| 925 | Concrete implementation of :meth:`importlib.abc.Loader.load_module` where |
| 926 | specifying the name of the module to load is optional. |
| 927 | |
Brett Cannon | 938d44d | 2012-04-22 19:58:33 -0400 | [diff] [blame] | 928 | |
| 929 | .. class:: ExtensionFileLoader(fullname, path) |
| 930 | |
Eric Snow | 5179445 | 2013-10-03 12:08:55 -0600 | [diff] [blame] | 931 | A concrete implementation of :class:`importlib.abc.ExecutionLoader` for |
Brett Cannon | 938d44d | 2012-04-22 19:58:33 -0400 | [diff] [blame] | 932 | extension modules. |
| 933 | |
| 934 | The *fullname* argument specifies the name of the module the loader is to |
| 935 | support. The *path* argument is the path to the extension module's file. |
| 936 | |
| 937 | .. versionadded:: 3.3 |
| 938 | |
| 939 | .. attribute:: name |
| 940 | |
| 941 | Name of the module the loader supports. |
| 942 | |
| 943 | .. attribute:: path |
| 944 | |
| 945 | Path to the extension module. |
| 946 | |
Brett Cannon | 062fcac | 2014-05-09 11:55:49 -0400 | [diff] [blame] | 947 | .. method:: load_module(name=None) |
Brett Cannon | 938d44d | 2012-04-22 19:58:33 -0400 | [diff] [blame] | 948 | |
Brett Cannon | c049952 | 2012-05-11 14:48:41 -0400 | [diff] [blame] | 949 | Loads the extension module if and only if *fullname* is the same as |
| 950 | :attr:`name` or is ``None``. |
Brett Cannon | 938d44d | 2012-04-22 19:58:33 -0400 | [diff] [blame] | 951 | |
Eric Snow | ca2d854 | 2013-12-16 23:06:52 -0700 | [diff] [blame] | 952 | .. note:: |
| 953 | Due to limitations in the extension module C-API, for now |
| 954 | ExtensionFileLoader does not implement :meth:`Loader.exec_module`. |
| 955 | |
Brett Cannon | 938d44d | 2012-04-22 19:58:33 -0400 | [diff] [blame] | 956 | .. method:: is_package(fullname) |
| 957 | |
Brett Cannon | ac9f2f3 | 2012-08-10 13:47:54 -0400 | [diff] [blame] | 958 | Returns ``True`` if the file path points to a package's ``__init__`` |
| 959 | module based on :attr:`EXTENSION_SUFFIXES`. |
Brett Cannon | 938d44d | 2012-04-22 19:58:33 -0400 | [diff] [blame] | 960 | |
| 961 | .. method:: get_code(fullname) |
| 962 | |
| 963 | Returns ``None`` as extension modules lack a code object. |
| 964 | |
| 965 | .. method:: get_source(fullname) |
| 966 | |
| 967 | Returns ``None`` as extension modules do not have source code. |
| 968 | |
Eric Snow | 5179445 | 2013-10-03 12:08:55 -0600 | [diff] [blame] | 969 | .. method:: get_filename(fullname) |
| 970 | |
| 971 | Returns :attr:`path`. |
| 972 | |
Eric Snow | dcd01b4 | 2013-10-04 20:35:34 -0600 | [diff] [blame] | 973 | .. versionadded:: 3.4 |
| 974 | |
Brett Cannon | 938d44d | 2012-04-22 19:58:33 -0400 | [diff] [blame] | 975 | |
Eric Snow | b523f84 | 2013-11-22 09:05:39 -0700 | [diff] [blame] | 976 | .. class:: ModuleSpec(name, loader, *, origin=None, loader_state=None, is_package=None) |
| 977 | |
| 978 | A specification for a module's import-system-related state. |
| 979 | |
| 980 | .. versionadded:: 3.4 |
| 981 | |
| 982 | .. attribute:: name |
| 983 | |
| 984 | (``__name__``) |
| 985 | |
| 986 | A string for the fully-qualified name of the module. |
| 987 | |
| 988 | .. attribute:: loader |
| 989 | |
| 990 | (``__loader__``) |
| 991 | |
| 992 | The loader to use for loading. For namespace packages this should be |
| 993 | set to None. |
| 994 | |
| 995 | .. attribute:: origin |
| 996 | |
| 997 | (``__file__``) |
| 998 | |
| 999 | Name of the place from which the module is loaded, e.g. "builtin" for |
| 1000 | built-in modules and the filename for modules loaded from source. |
| 1001 | Normally "origin" should be set, but it may be None (the default) |
| 1002 | which indicates it is unspecified. |
| 1003 | |
| 1004 | .. attribute:: submodule_search_locations |
| 1005 | |
| 1006 | (``__path__``) |
| 1007 | |
| 1008 | List of strings for where to find submodules, if a package (None |
| 1009 | otherwise). |
| 1010 | |
| 1011 | .. attribute:: loader_state |
| 1012 | |
| 1013 | Container of extra module-specific data for use during loading (or |
| 1014 | None). |
| 1015 | |
| 1016 | .. attribute:: cached |
| 1017 | |
| 1018 | (``__cached__``) |
| 1019 | |
| 1020 | String for where the compiled module should be stored (or None). |
| 1021 | |
| 1022 | .. attribute:: parent |
| 1023 | |
| 1024 | (``__package__``) |
| 1025 | |
| 1026 | (Read-only) Fully-qualified name of the package to which the module |
| 1027 | belongs as a submodule (or None). |
| 1028 | |
| 1029 | .. attribute:: has_location |
| 1030 | |
Eric Snow | b282b3d | 2013-12-10 22:16:41 -0700 | [diff] [blame] | 1031 | Boolean indicating whether or not the module's "origin" |
Eric Snow | b523f84 | 2013-11-22 09:05:39 -0700 | [diff] [blame] | 1032 | attribute refers to a loadable location. |
| 1033 | |
Brett Cannon | d2e7b33 | 2009-02-17 02:45:03 +0000 | [diff] [blame] | 1034 | :mod:`importlib.util` -- Utility code for importers |
| 1035 | --------------------------------------------------- |
| 1036 | |
| 1037 | .. module:: importlib.util |
Brett Cannon | 75321e8 | 2012-03-02 11:58:25 -0500 | [diff] [blame] | 1038 | :synopsis: Utility code for importers |
Brett Cannon | d2e7b33 | 2009-02-17 02:45:03 +0000 | [diff] [blame] | 1039 | |
| 1040 | This module contains the various objects that help in the construction of |
| 1041 | an :term:`importer`. |
| 1042 | |
Brett Cannon | 05a647d | 2013-06-14 19:02:34 -0400 | [diff] [blame] | 1043 | .. attribute:: MAGIC_NUMBER |
| 1044 | |
| 1045 | The bytes which represent the bytecode version number. If you need help with |
| 1046 | loading/writing bytecode then consider :class:`importlib.abc.SourceLoader`. |
| 1047 | |
| 1048 | .. versionadded:: 3.4 |
| 1049 | |
Brett Cannon | a3c9615 | 2013-06-14 22:26:30 -0400 | [diff] [blame] | 1050 | .. function:: cache_from_source(path, debug_override=None) |
| 1051 | |
| 1052 | Return the :pep:`3147` path to the byte-compiled file associated with the |
| 1053 | source *path*. For example, if *path* is ``/foo/bar/baz.py`` the return |
| 1054 | value would be ``/foo/bar/__pycache__/baz.cpython-32.pyc`` for Python 3.2. |
| 1055 | The ``cpython-32`` string comes from the current magic tag (see |
| 1056 | :func:`get_tag`; if :attr:`sys.implementation.cache_tag` is not defined then |
| 1057 | :exc:`NotImplementedError` will be raised). The returned path will end in |
Serhiy Storchaka | 0e90e99 | 2013-11-29 12:19:53 +0200 | [diff] [blame] | 1058 | ``.pyc`` when ``__debug__`` is ``True`` or ``.pyo`` for an optimized Python |
| 1059 | (i.e. ``__debug__`` is ``False``). By passing in ``True`` or ``False`` for |
Brett Cannon | a3c9615 | 2013-06-14 22:26:30 -0400 | [diff] [blame] | 1060 | *debug_override* you can override the system's value for ``__debug__`` for |
| 1061 | extension selection. |
| 1062 | |
| 1063 | *path* need not exist. |
| 1064 | |
| 1065 | .. versionadded:: 3.4 |
| 1066 | |
| 1067 | |
| 1068 | .. function:: source_from_cache(path) |
| 1069 | |
| 1070 | Given the *path* to a :pep:`3147` file name, return the associated source code |
| 1071 | file path. For example, if *path* is |
| 1072 | ``/foo/bar/__pycache__/baz.cpython-32.pyc`` the returned path would be |
| 1073 | ``/foo/bar/baz.py``. *path* need not exist, however if it does not conform |
| 1074 | to :pep:`3147` format, a ``ValueError`` is raised. If |
| 1075 | :attr:`sys.implementation.cache_tag` is not defined, |
| 1076 | :exc:`NotImplementedError` is raised. |
| 1077 | |
| 1078 | .. versionadded:: 3.4 |
| 1079 | |
Brett Cannon | f24fecd | 2013-06-16 18:37:53 -0400 | [diff] [blame] | 1080 | .. function:: decode_source(source_bytes) |
| 1081 | |
| 1082 | Decode the given bytes representing source code and return it as a string |
| 1083 | with universal newlines (as required by |
| 1084 | :meth:`importlib.abc.InspectLoader.get_source`). |
| 1085 | |
| 1086 | .. versionadded:: 3.4 |
| 1087 | |
Brett Cannon | d200bf5 | 2012-05-13 13:45:09 -0400 | [diff] [blame] | 1088 | .. function:: resolve_name(name, package) |
| 1089 | |
| 1090 | Resolve a relative module name to an absolute one. |
| 1091 | |
| 1092 | If **name** has no leading dots, then **name** is simply returned. This |
| 1093 | allows for usage such as |
| 1094 | ``importlib.util.resolve_name('sys', __package__)`` without doing a |
| 1095 | check to see if the **package** argument is needed. |
| 1096 | |
| 1097 | :exc:`ValueError` is raised if **name** is a relative module name but |
| 1098 | package is a false value (e.g. ``None`` or the empty string). |
| 1099 | :exc:`ValueError` is also raised a relative name would escape its containing |
| 1100 | package (e.g. requesting ``..bacon`` from within the ``spam`` package). |
| 1101 | |
| 1102 | .. versionadded:: 3.3 |
| 1103 | |
Eric Snow | 6029e08 | 2014-01-25 15:32:46 -0700 | [diff] [blame] | 1104 | .. function:: find_spec(name, package=None) |
| 1105 | |
| 1106 | Find the :term:`spec <module spec>` for a module, optionally relative to |
| 1107 | the specified **package** name. If the module is in :attr:`sys.modules`, |
| 1108 | then ``sys.modules[name].__spec__`` is returned (unless the spec would be |
| 1109 | ``None`` or is not set, in which case :exc:`ValueError` is raised). |
| 1110 | Otherwise a search using :attr:`sys.meta_path` is done. ``None`` is |
| 1111 | returned if no spec is found. |
| 1112 | |
| 1113 | If **name** is for a submodule (contains a dot), the parent module is |
| 1114 | automatically imported. |
| 1115 | |
| 1116 | **name** and **package** work the same as for :func:`import_module`. |
| 1117 | |
| 1118 | .. versionadded:: 3.4 |
| 1119 | |
Georg Brandl | 8a1caa2 | 2010-07-29 16:01:11 +0000 | [diff] [blame] | 1120 | .. decorator:: module_for_loader |
Brett Cannon | d2e7b33 | 2009-02-17 02:45:03 +0000 | [diff] [blame] | 1121 | |
Brett Cannon | a22faca | 2013-05-28 17:50:14 -0400 | [diff] [blame] | 1122 | A :term:`decorator` for :meth:`importlib.abc.Loader.load_module` |
Guido van Rossum | 0961354 | 2009-03-30 20:34:57 +0000 | [diff] [blame] | 1123 | to handle selecting the proper |
Brett Cannon | d2e7b33 | 2009-02-17 02:45:03 +0000 | [diff] [blame] | 1124 | module object to load with. The decorated method is expected to have a call |
Brett Cannon | 2a922ed | 2009-03-09 03:35:50 +0000 | [diff] [blame] | 1125 | signature taking two positional arguments |
| 1126 | (e.g. ``load_module(self, module)``) for which the second argument |
Guido van Rossum | 0961354 | 2009-03-30 20:34:57 +0000 | [diff] [blame] | 1127 | will be the module **object** to be used by the loader. |
Brett Cannon | efad00d | 2012-04-27 17:27:14 -0400 | [diff] [blame] | 1128 | Note that the decorator will not work on static methods because of the |
| 1129 | assumption of two arguments. |
Brett Cannon | d2e7b33 | 2009-02-17 02:45:03 +0000 | [diff] [blame] | 1130 | |
Guido van Rossum | 0961354 | 2009-03-30 20:34:57 +0000 | [diff] [blame] | 1131 | The decorated method will take in the **name** of the module to be loaded |
| 1132 | as expected for a :term:`loader`. If the module is not found in |
Brett Cannon | 3dc48d6 | 2013-05-28 18:35:54 -0400 | [diff] [blame] | 1133 | :data:`sys.modules` then a new one is constructed. Regardless of where the |
| 1134 | module came from, :attr:`__loader__` set to **self** and :attr:`__package__` |
| 1135 | is set based on what :meth:`importlib.abc.InspectLoader.is_package` returns |
| 1136 | (if available). These attributes are set unconditionally to support |
| 1137 | reloading. |
Brett Cannon | efad00d | 2012-04-27 17:27:14 -0400 | [diff] [blame] | 1138 | |
| 1139 | If an exception is raised by the decorated method and a module was added to |
Brett Cannon | a87e31c | 2013-09-13 16:52:19 -0400 | [diff] [blame] | 1140 | :data:`sys.modules`, then the module will be removed to prevent a partially |
| 1141 | initialized module from being in left in :data:`sys.modules`. If the module |
| 1142 | was already in :data:`sys.modules` then it is left alone. |
Brett Cannon | d2e7b33 | 2009-02-17 02:45:03 +0000 | [diff] [blame] | 1143 | |
Brett Cannon | efad00d | 2012-04-27 17:27:14 -0400 | [diff] [blame] | 1144 | .. versionchanged:: 3.3 |
Georg Brandl | 61063cc | 2012-06-24 22:48:30 +0200 | [diff] [blame] | 1145 | :attr:`__loader__` and :attr:`__package__` are automatically set |
| 1146 | (when possible). |
Brett Cannon | 57b46f5 | 2009-03-02 14:38:26 +0000 | [diff] [blame] | 1147 | |
Brett Cannon | 3dc48d6 | 2013-05-28 18:35:54 -0400 | [diff] [blame] | 1148 | .. versionchanged:: 3.4 |
Brett Cannon | 0dbb4c7 | 2013-05-31 18:56:47 -0400 | [diff] [blame] | 1149 | Set :attr:`__name__`, :attr:`__loader__` :attr:`__package__` |
| 1150 | unconditionally to support reloading. |
| 1151 | |
| 1152 | .. deprecated:: 3.4 |
Eric Snow | b523f84 | 2013-11-22 09:05:39 -0700 | [diff] [blame] | 1153 | The import machinery now directly performs all the functionality |
| 1154 | provided by this function. |
Brett Cannon | 3dc48d6 | 2013-05-28 18:35:54 -0400 | [diff] [blame] | 1155 | |
Georg Brandl | 8a1caa2 | 2010-07-29 16:01:11 +0000 | [diff] [blame] | 1156 | .. decorator:: set_loader |
Brett Cannon | 2cf03a8 | 2009-03-10 05:17:37 +0000 | [diff] [blame] | 1157 | |
Brett Cannon | a22faca | 2013-05-28 17:50:14 -0400 | [diff] [blame] | 1158 | A :term:`decorator` for :meth:`importlib.abc.Loader.load_module` |
| 1159 | to set the :attr:`__loader__` |
| 1160 | attribute on the returned module. If the attribute is already set the |
| 1161 | decorator does nothing. It is assumed that the first positional argument to |
| 1162 | the wrapped method (i.e. ``self``) is what :attr:`__loader__` should be set |
| 1163 | to. |
Brett Cannon | 2cf03a8 | 2009-03-10 05:17:37 +0000 | [diff] [blame] | 1164 | |
Brett Cannon | 4802bec | 2013-03-13 10:41:36 -0700 | [diff] [blame] | 1165 | .. versionchanged:: 3.4 |
Brett Cannon | 4c14b5d | 2013-05-04 13:56:58 -0400 | [diff] [blame] | 1166 | Set ``__loader__`` if set to ``None``, as if the attribute does not |
Brett Cannon | 4802bec | 2013-03-13 10:41:36 -0700 | [diff] [blame] | 1167 | exist. |
| 1168 | |
Eric Snow | ca2d854 | 2013-12-16 23:06:52 -0700 | [diff] [blame] | 1169 | .. deprecated:: 3.4 |
| 1170 | The import machinery takes care of this automatically. |
| 1171 | |
Georg Brandl | 8a1caa2 | 2010-07-29 16:01:11 +0000 | [diff] [blame] | 1172 | .. decorator:: set_package |
Brett Cannon | 57b46f5 | 2009-03-02 14:38:26 +0000 | [diff] [blame] | 1173 | |
Brett Cannon | a22faca | 2013-05-28 17:50:14 -0400 | [diff] [blame] | 1174 | A :term:`decorator` for :meth:`importlib.abc.Loader.load_module` to set the :attr:`__package__` attribute on the returned module. If :attr:`__package__` |
| 1175 | is set and has a value other than ``None`` it will not be changed. |
Brett Cannon | 16248a4 | 2009-04-01 20:47:14 +0000 | [diff] [blame] | 1176 | |
Eric Snow | ca2d854 | 2013-12-16 23:06:52 -0700 | [diff] [blame] | 1177 | .. deprecated:: 3.4 |
| 1178 | The import machinery takes care of this automatically. |
| 1179 | |
Eric Snow | b523f84 | 2013-11-22 09:05:39 -0700 | [diff] [blame] | 1180 | .. function:: spec_from_loader(name, loader, *, origin=None, is_package=None) |
| 1181 | |
| 1182 | A factory function for creating a :class:`ModuleSpec` instance based |
| 1183 | on a loader. The parameters have the same meaning as they do for |
| 1184 | ModuleSpec. The function uses available :term:`loader` APIs, such as |
| 1185 | :meth:`InspectLoader.is_package`, to fill in any missing |
| 1186 | information on the spec. |
| 1187 | |
| 1188 | .. versionadded:: 3.4 |
| 1189 | |
| 1190 | .. function:: spec_from_file_location(name, location, *, loader=None, submodule_search_locations=None) |
| 1191 | |
| 1192 | A factory function for creating a :class:`ModuleSpec` instance based |
| 1193 | on the path to a file. Missing information will be filled in on the |
| 1194 | spec by making use of loader APIs and by the implication that the |
| 1195 | module will be file-based. |
| 1196 | |
| 1197 | .. versionadded:: 3.4 |