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authorBrett Cannon <brettcannon@users.noreply.github.com>2017-12-16 00:29:35 (GMT)
committerGitHub <noreply@github.com>2017-12-16 00:29:35 (GMT)
commit4ac5150e068a3a795ef00465f6dff51747b62b91 (patch)
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parentd2b02310acbfe6c978a8ad3cd3ac8b3f12927442 (diff)
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bpo-32248: Implement importlib.abc.ResourceReader (GH-4892)
Diffstat (limited to 'Doc/library')
-rw-r--r--Doc/library/importlib.rst66
1 files changed, 66 insertions, 0 deletions
diff --git a/Doc/library/importlib.rst b/Doc/library/importlib.rst
index 3cafb41..eeccc9d 100644
--- a/Doc/library/importlib.rst
+++ b/Doc/library/importlib.rst
@@ -233,6 +233,7 @@ ABC hierarchy::
| +-- MetaPathFinder
| +-- PathEntryFinder
+-- Loader
+ +-- ResourceReader
+-- ResourceLoader --------+
+-- InspectLoader |
+-- ExecutionLoader --+
@@ -468,6 +469,71 @@ ABC hierarchy::
The import machinery now takes care of this automatically.
+.. class:: ResourceReader
+
+ An :term:`abstract base class` for :term:`package`
+ :term:`loaders <loader>` to provide the ability to read
+ *resources*.
+
+ From the perspective of this ABC, a *resource* is a binary
+ artifact that is shipped within a package. Typically this is
+ something like a data file that lives next to the ``__init__.py``
+ file of the package. The purpose of this class is to help abstract
+ out the accessing of such data files so that it does not matter if
+ the package and its data file(s) are stored in a e.g. zip file
+ versus on the file system.
+
+ For any of methods of this class, a *resource* argument is
+ expected to be a :term:`file-like object` which represents
+ conceptually just a file name. This means that no subdirectory
+ paths should be included in the *resource* argument. This is
+ because the location of the package that the loader is for acts
+ as the "directory". Hence the metaphor for directories and file
+ names is packages and resources, respectively. This is also why
+ instances of this class are expected to directly correlate to
+ a specific package (instead of potentially representing multiple
+ packages or a module).
+
+ .. versionadded:: 3.7
+
+ .. abstractmethod:: open_resource(resource)
+
+ Returns an opened, :term:`file-like object` for binary reading
+ of the *resource*.
+
+ If the resource cannot be found, :exc:`FileNotFoundError` is
+ raised.
+
+ .. abstractmethod:: resource_path(resource)
+
+ Returns the file system path to the *resource*.
+
+ If the resource does not concretely exist on the file system,
+ raise :exc:`FileNotFoundError`.
+
+ .. abstractmethod:: is_resource(name)
+
+ Returns ``True`` if the named *name* is considered a resource.
+ :exc:`FileNotFoundError` is raised if *name* does not exist.
+
+ .. abstractmethod:: contents()
+
+ Returns an :term:`iterator` of strings over the contents of
+ the package. Do note that it is not required that all names
+ returned by the iterator be actual resources, e.g. it is
+ acceptable to return names for which :meth:`is_resource` would
+ be false.
+
+ Allowing non-resource names to be returned is to allow for
+ situations where how a package and its resources are stored
+ are known a priori and the non-resource names would be useful.
+ For instance, returning subdirectory names is allowed so that
+ when it is known that the package and resources are stored on
+ the file system then those subdirectory names can be used.
+
+ The abstract method returns an empty iterator.
+
+
.. class:: ResourceLoader
An abstract base class for a :term:`loader` which implements the optional