pkgutil
— Utilitário de extensão de pacote¶
Código-fonte: Lib/pkgutil.py
Este módulo fornece utilitários para o sistema de importação, em particular suporte a pacotes.
- class pkgutil.ModuleInfo(module_finder, name, ispkg)¶
Um namedtuple que contém um breve resumo das informações de um módulo.
Adicionado na versão 3.6.
- pkgutil.extend_path(path, name)¶
Estende o caminho de pesquisa para os módulos que compõem um pacote. O uso pretendido é colocar o seguinte código no
__init__.py
de um pacote:from pkgutil import extend_path __path__ = extend_path(__path__, __name__)
For each directory on
sys.path
that has a subdirectory that matches the package name, add the subdirectory to the package’s__path__
. This is useful if one wants to distribute different parts of a single logical package as multiple directories.It also looks for
*.pkg
files beginning where*
matches the name argument. This feature is similar to*.pth
files (see thesite
module for more information), except that it doesn’t special-case lines starting withimport
. A*.pkg
file is trusted at face value: apart from skipping blank lines and ignoring comments, all entries found in a*.pkg
file are added to the path, regardless of whether they exist on the filesystem (this is a feature).If the input path is not a list (as is the case for frozen packages) it is returned unchanged. The input path is not modified; an extended copy is returned. Items are only appended to the copy at the end.
It is assumed that
sys.path
is a sequence. Items ofsys.path
that are not strings referring to existing directories are ignored. Unicode items onsys.path
that cause errors when used as filenames may cause this function to raise an exception (in line withos.path.isdir()
behavior).
- pkgutil.get_importer(path_item)¶
Retrieve a finder for the given path_item.
The returned finder is cached in
sys.path_importer_cache
if it was newly created by a path hook.The cache (or part of it) can be cleared manually if a rescan of
sys.path_hooks
is necessary.
- pkgutil.iter_importers(fullname='')¶
Yield finder objects for the given module name.
If fullname contains a
'.'
, the finders will be for the package containing fullname, otherwise they will be all registered top level finders (i.e. those on bothsys.meta_path
andsys.path_hooks
).If the named module is in a package, that package is imported as a side effect of invoking this function.
If no module name is specified, all top level finders are produced.
- pkgutil.iter_modules(path=None, prefix='')¶
Yields
ModuleInfo
for all submodules on path, or, if path isNone
, all top-level modules onsys.path
.path should be either
None
or a list of paths to look for modules in.prefix is a string to output on the front of every module name on output.
Nota
Only works for a finder which defines an
iter_modules()
method. This interface is non-standard, so the module also provides implementations forimportlib.machinery.FileFinder
andzipimport.zipimporter
.
- pkgutil.walk_packages(path=None, prefix='', onerror=None)¶
Yields
ModuleInfo
for all modules recursively on path, or, if path isNone
, all accessible modules.path should be either
None
or a list of paths to look for modules in.prefix is a string to output on the front of every module name on output.
Note that this function must import all packages (not all modules!) on the given path, in order to access the
__path__
attribute to find submodules.onerror is a function which gets called with one argument (the name of the package which was being imported) if any exception occurs while trying to import a package. If no onerror function is supplied,
ImportError
s are caught and ignored, while all other exceptions are propagated, terminating the search.Exemplos:
# list all modules python can access walk_packages() # list all submodules of ctypes walk_packages(ctypes.__path__, ctypes.__name__ + '.')
Nota
Only works for a finder which defines an
iter_modules()
method. This interface is non-standard, so the module also provides implementations forimportlib.machinery.FileFinder
andzipimport.zipimporter
.
- pkgutil.get_data(package, resource)¶
Get a resource from a package.
This is a wrapper for the loader
get_data
API. The package argument should be the name of a package, in standard module format (foo.bar
). The resource argument should be in the form of a relative filename, using/
as the path separator. The parent directory name..
is not allowed, and nor is a rooted name (starting with a/
).The function returns a binary string that is the contents of the specified resource.
For packages located in the filesystem, which have already been imported, this is the rough equivalent of:
d = os.path.dirname(sys.modules[package].__file__) data = open(os.path.join(d, resource), 'rb').read()
If the package cannot be located or loaded, or it uses a loader which does not support
get_data
, thenNone
is returned. In particular, the loader for namespace packages does not supportget_data
.
- pkgutil.resolve_name(name)¶
Resolve a name to an object.
This functionality is used in numerous places in the standard library (see bpo-12915) - and equivalent functionality is also in widely used third-party packages such as setuptools, Django and Pyramid.
It is expected that name will be a string in one of the following formats, where W is shorthand for a valid Python identifier and dot stands for a literal period in these pseudo-regexes:
W(.W)*
W(.W)*:(W(.W)*)?
The first form is intended for backward compatibility only. It assumes that some part of the dotted name is a package, and the rest is an object somewhere within that package, possibly nested inside other objects. Because the place where the package stops and the object hierarchy starts can’t be inferred by inspection, repeated attempts to import must be done with this form.
In the second form, the caller makes the division point clear through the provision of a single colon: the dotted name to the left of the colon is a package to be imported, and the dotted name to the right is the object hierarchy within that package. Only one import is needed in this form. If it ends with the colon, then a module object is returned.
The function will return an object (which might be a module), or raise one of the following exceptions:
ValueError
– if name isn’t in a recognised format.ImportError
– if an import failed when it shouldn’t have.AttributeError
– If a failure occurred when traversing the object hierarchy within the imported package to get to the desired object.Adicionado na versão 3.9.