"site" --- Site-specific configuration hook
*******************************************

**Código Fuente:** Lib/site.py

======================================================================

**Este módulo se importa automáticamente durante la inicialización.**
La importación automática se puede suprimir utilizando la opción del
intérprete opción "-S" .

Importing this module normally appends site-specific paths to the
module search path and adds callables, including "help()" to the
built-in namespace. However, Python startup option "-S" blocks this,
and this module can be safely imported with no automatic modifications
to the module search path or additions to the builtins.  To explicitly
trigger the usual site-specific additions, call the "main()" function.

Distinto en la versión 3.3: Importar el módulo utilizado para activar
la manipulación de rutas incluso cuando se utiliza "-S".

It starts by constructing up to four directories from a head and a
tail part. For the head part, it uses "sys.prefix" and
"sys.exec_prefix"; empty heads are skipped.  For the tail part, it
uses the empty string and then "lib/site-packages" (on Windows) or
"lib/python*X.Y[t]*/site-packages" (on Unix and macOS). (The optional
suffix "t" indicates the *free-threaded build*, and is appended if
""t"" is present in the "sys.abiflags" constant.) For each of the
distinct head-tail combinations, it sees if it refers to an existing
directory, and if so, adds it to "sys.path" and also inspects the
newly added path for configuration files.

Distinto en la versión 3.5: Se ha eliminado la compatibilidad con el
directorio "site-python".

Distinto en la versión 3.13: On Unix, *Free threading* Python
installations are identified by the "t" suffix in the version-specific
directory name, such as "lib/python3.13t/".

Distinto en la versión 3.14: "site" is no longer responsible for
updating "sys.prefix" and "sys.exec_prefix" on Virtual Environments.
This is now done during the path initialization. As a result, under
Virtual Environments, "sys.prefix" and "sys.exec_prefix" no longer
depend on the "site" initialization, and are therefore unaffected by
"-S".

When running under a virtual environment, the "pyvenv.cfg" file in
"sys.prefix" is checked for site-specific configurations. If the
"include-system-site-packages" key exists and is set to "true" (case-
insensitive), the system-level prefixes will be searched for site-
packages, otherwise they won't.  If the system-level prefixes are not
searched then the user site prefixes are also implicitly not searched
for site-packages.

The "site" module recognizes two startup configuration files of the
form "*name*.pth" for path configurations, and "*name*.start" for pre-
first-line code execution.  Both files can exist in one of the four
directories mentioned above.  Within each directory, these files are
sorted alphabetically by filename, then parsed in sorted order.


Path extensions (".pth" files)
==============================

"*name*.pth" contains additional items (one per line) to be appended
to "sys.path".  Items that name non-existing directories are never
added to "sys.path", and no check is made that the item refers to a
directory rather than a file.  No item is added to "sys.path" more
than once.  Blank lines and lines beginning with "#" are skipped.

For backward compatibility, lines starting with "import" (followed by
space or tab) are executed with "exec()".

Distinto en la versión 3.13: The ".pth" files are now decoded by UTF-8
at first and then by the *locale encoding* if it fails.

Distinto en la versión 3.15: ".pth" file lines starting with "import"
are deprecated.  During the deprecation period, such lines are still
executed (except in the case below), but a diagnostic message is
emitted only when the "-v" flag is given."import" lines in
"*name*.pth" are silently ignored when a matching "*name*.start" file
exists.Errors on individual lines no longer abort processing of the
rest of the file.  Each error is reported and the remaining lines
continue to be processed.

Deprecated since version 3.15, will be removed in version 3.20:
Decoding "*name*.pth" files in any encoding other than "utf-8-sig" is
deprecated in Python 3.15, and support for decoding from the locale
encoding will be removed in Python 3.20."import" lines in "*name*.pth"
files are deprecated and will be silently ignored in Python 3.18 and
3.19.  In Python 3.20 a warning will be produced for "import" lines in
"*name*.pth" files.


Startup entry points (".start" files)
=====================================

Added in version 3.15.

A startup entry point file is a file whose name has the form
"*name*.start" and exists in one of the site-packages directories
described above.  Each file specifies entry points to be called during
interpreter startup, using the "pkg.mod:callable" syntax understood by
"pkgutil.resolve_name()".

Each non-blank line that does not begin with "#" must contain an entry
point reference in the form "pkg.mod:callable".  The colon and
callable portion are mandatory.  Each callable is invoked with no
arguments, and any return value is discarded.

".start" files are processed after all ".pth" path extensions have
been applied to "sys.path", ensuring that paths are available before
any startup code runs.

Unlike "sys.path" extensions from ".pth" files, duplicate entry points
are **not** de-duplicated --- if an entry point appears more than
once, it will be called more than once.

If an exception occurs during resolution or invocation of an entry
point, a traceback is printed to "sys.stderr" and processing continues
with the remaining entry points.

".start" files must be encoded in UTF-8.

**PEP 829** defined the original specification for these features.

Nota:

  If a "*name*.start" file exists alongside a "*name*.pth" file with
  the same base name, any "import" lines in the ".pth" file are
  ignored in favor of the entry points in the ".start" file.

Nota:

  Executable lines ("import" lines in "*name*.pth" files and
  "*name*.start" file entry points) are always run at Python startup
  (unless "-S" is given to disable the "site.py" module entirely),
  regardless of whether a particular module is actually going to be
  used.

Nota:

  "*name*.start" files invoke "pkgutil.resolve_name()" with
  "strict=True", which requires the full "pkg.mod:callable" form.


Startup file examples
=====================

For example, suppose "sys.prefix" and "sys.exec_prefix" are set to
"/usr/local".  The Python X.Y library is then installed in
"/usr/local/lib/python*X.Y*".  Suppose this has a subdirectory
"/usr/local/lib/python*X.Y*/site-packages" with three sub-
subdirectories, "foo", "bar" and "spam", and two path configuration
files, "foo.pth" and "bar.pth".  Assume "foo.pth" contains the
following:

   # foo package configuration

   foo
   bar
   bletch

y "bar.pth" contiene:

   # bar package configuration

   bar

Luego, los siguientes directorios específicos de la versión se agregan
a "sys.path", en este orden:

   /usr/local/lib/pythonX.Y/site-packages/bar
   /usr/local/lib/pythonX.Y/site-packages/foo

Tenga en cuenta que "bletch" se omite porque no existe; el directorio
"bar" precede al directorio "foo" porque "bar.pth" viene
alfabéticamente antes de "foo.pth"; y "spam" se omite porque no se
menciona en ninguno de los archivos de configuración de ruta.

Let's say that there is also a "foo.start" file containing the
following:

   # foo package startup code

   foo.submod:initialize

Now, after "sys.path" has been extended as above, and before Python
turns control over to user code, the "foo.submod" module is imported
and the "initialize()" function from that module is called.


Migrating from "import" lines in ".pth" files to ".start" files
===============================================================

If your package currently ships a "*name*.pth" file, you can keep all
"sys.path" extension lines unchanged.  Only "import" lines need to be
migrated.

To migrate, create a callable (taking zero arguments) within an
importable module in your package.  Reference it as a
"pkg.mod:callable" entry point in a matching "*name*.start" file.
Move everything on your "import" line after the first semi-colon into
the "callable()" function.

If your package must straddle older Pythons that do not support **PEP
829** and newer Pythons that do, change the "import" lines in your
"*name*.pth" to use the following form:

   import pkg.mod; pkg.mod.callable()

Older Pythons will execute these "import" lines, while newer Pythons
will ignore them in favor of the "*name*.start" file.  After the
straddling period, remove all "import" lines from your ".pth" files.


"sitecustomize"
===============

After these path manipulations, an attempt is made to import a module
named "sitecustomize", which can perform arbitrary site-specific
customizations. It is typically created by a system administrator in
the site-packages directory.  If this import fails with an
"ImportError" or its subclass exception, and the exception's "name"
attribute equals "'sitecustomize'", it is silently ignored.  If Python
is started without output streams available, as with "pythonw.exe" on
Windows (which is used by default to start IDLE), attempted output
from "sitecustomize" is ignored.  Any other exception causes a silent
and perhaps mysterious failure of the process.


"usercustomize"
===============

After this, an attempt is made to import a module named
"usercustomize", which can perform arbitrary user-specific
customizations, if "ENABLE_USER_SITE" is true.  This file is intended
to be created in the user site-packages directory (see below), which
is part of "sys.path" unless disabled by "-s".  If this import fails
with an "ImportError" or its subclass exception, and the exception's
"name" attribute equals "'usercustomize'", it is silently ignored.

Note that for some non-Unix systems, "sys.prefix" and
"sys.exec_prefix" are empty, and the path manipulations are skipped;
however the import of "sitecustomize" and "usercustomize" is still
attempted.


Configuración de *Readline*
===========================

On systems that support "readline", this module will also import and
configure the "rlcompleter" module, if Python is started in
interactive mode and without the "-S" option. The default behavior is
to enable tab completion and to use "~/.python_history" as the history
save file.  To disable it, delete (or override) the
"sys.__interactivehook__" attribute in your "sitecustomize" or
"usercustomize" module or your "PYTHONSTARTUP" file.

Distinto en la versión 3.4: La activación de *rlcompleter* y el
historial se hizo automática.


Contenido del módulo
====================

site.PREFIXES

   Una lista de prefijos para directorios de site-packages.

site.ENABLE_USER_SITE

   Flag que muestra el estado del directorio site-packages del
   usuario. "True" significa que está habilitado y se agregó a
   "sys.path". "False" significa que fue deshabilitado por solicitud
   del usuario (con "-s" o "PYTHONNOUSERSITE"). "None" significa que
   fue deshabilitado por razones de seguridad (falta de coincidencia
   entre la identificación de usuario o grupo y la identificación
   efectiva) o por un administrador.

site.USER_SITE

   Path to the user site-packages for the running Python.  Can be
   "None" if "getusersitepackages()" hasn't been called yet.  Default
   value is "~/.local/lib/python*X.Y*[t]/site-packages" for UNIX and
   non-framework macOS builds, "~/Library/Python/*X.Y*/lib/python
   /site-packages" for macOS framework builds, and
   "*%APPDATA%*\Python\Python*XY*\site-packages" on Windows.  The
   optional "t" indicates the free-threaded build.  This directory is
   a site directory, which means that ".pth" files in it will be
   processed.

site.USER_BASE

   Path to the base directory for the user site-packages.  Can be
   "None" if "getuserbase()" hasn't been called yet.  Default value is
   "~/.local" for UNIX and macOS non-framework builds,
   "~/Library/Python/*X.Y*" for macOS framework builds, and
   "*%APPDATA%*\Python" for Windows.  This value is used to compute
   the installation directories for scripts, data files, Python
   modules, etc. for the user installation scheme. See also
   "PYTHONUSERBASE".

site.main()

   Agrega todos los directorios estándar específicos del sitio a la
   ruta de búsqueda del módulo. Esta función se llama automáticamente
   cuando se importa este módulo, a menos que el intérprete de Python
   se haya iniciado con la opción "-S".

   Distinto en la versión 3.3: Esta función solía llamarse
   incondicionalmente.

site.makepath(*paths)

   Join *paths* with "os.path.join()", attempt to make the result
   absolute with "os.path.abspath()", and return a 2-tuple containing
   the absolute path and its case-normalized form as produced by
   "os.path.normcase()".  If "os.path.abspath()" raises "OSError", the
   joined path is used unchanged for the case-normalization step.

   The second element of the returned tuple is the form used
   throughout the "site" module to compare paths on case-insensitive
   file systems, and is what populates the "known_paths" sets that
   prevent duplicate "sys.path" entries in various APIs within this
   module.

class site.StartupState(known_paths=None)

   Instances of this class accumulate interpreter startup
   configuration data from one or more site directories.  They are the
   preferred interface for batching the processing of ".pth" and
   ".start" files across multiple site directories, so that every
   "sys.path" extension is visible before any startup code runs.

   The optional *known_paths* argument is a set of case-normalized
   paths (which can be produced by "makepath()") used to prevent
   duplicate "sys.path" entries.  When "None" (the default), the set
   is built from the current "sys.path".  "main()" implicitly uses an
   instance of this class.

   Typical use:

      state = site.StartupState()
      for sitedir in site_dirs:
          state.addsitedir(sitedir)
      state.process()

   Added in version 3.15.

   addsitedir(sitedir)

      Read the ".pth" and ".start" files in *sitedir* and record their
      "sys.path" extensions, deprecated ".pth" "import" lines, and
      ".start" entry points on this state. The recorded data is not
      applied until "process()" is called.

   addusersitepackages()

      Add the per-user site-packages directory, if enabled and if it
      exists. The directory's startup data is accumulated for later
      processing by "process()".

   addsitepackages(prefixes=None)

      Add global site-packages directories, computed from *prefixes*
      or from the global "PREFIXES" when *prefixes* is "None".  Each
      directory's startup data is accumulated for later processing by
      "process()".

   process()

      Apply the accumulated state by first adding the path extensions
      to "sys.path", then executing the ".start" file entry points and
      ".pth" file "import" lines (deprecated).

      This method is not idempotent and must not be called more than
      once on the same instance.  Doing so will apply the accumulated
      state more than once, re-running entry points and "import"
      lines.

site.addsitedir(sitedir, known_paths=None)

   Add a directory to sys.path and parse the ".pth" and ".start" files
   found in that directory.  Typically used in "sitecustomize" or
   "usercustomize" (see above).

   The *known_paths* argument is an optional set of case-normalized
   paths used to prevent duplicate "sys.path" entries.  When "None"
   (the default), the set is built from the current "sys.path".

   For batched processing across multiple site directories, build a
   "StartupState" explicitly and call "StartupState.addsitedir()" on
   it; that defers ".pth" and ".start" processing until a single
   "StartupState.process()" call, ensuring every "sys.path" extension
   is visible before any startup code runs.

   Distinto en la versión 3.15: Also processes ".start" files.  See
   Startup entry points (.start files).

site.getsitepackages()

   Retorna una lista que contiene todos los directorios *site-
   packages* globales.

   Added in version 3.2.

site.getuserbase()

   Retorna la ruta del directorio base del usuario "USER_BASE". Si
   este aún no fue inicializado, esta función también lo configurará,
   respetando "PYTHONUSERBASE".

   Added in version 3.2.

site.getusersitepackages()

   Retorna la ruta del directorio base del usuario "USER_SITE". Si
   este aún no fue inicializado, esta función también lo configurará,
   respetando "USER_BASE". Para determinar si los paquetes específicos
   del sitio de usuario fueron añadidos a "sys.path" debe usarse
   "ENABLE_USER_SITE".

   Added in version 3.2.


Command-line interface
======================

The "site" module also provides a way to get the user directories from
the command line:

   $ python -m site --user-site
   /home/user/.local/lib/python3.11/site-packages

Si se llama sin argumentos, imprimirá el contenido de "sys.path" en la
salida estándar, seguido del valor de "USER_BASE" y si el directorio
existe, entonces lo mismo para "USER_SITE", y finalmente el valor de
"ENABLE_USER_SITE".

--user-base

   Imprime la ruta al directorio base del usuario.

--user-site

   Imprime la ruta al directorio *site-packages* del usuario.

Si se dan ambas opciones, la ruta del directorio base y la del
directorio *site-packages* del usuario se imprimirán (siempre en este
orden), separados por "os.pathsep".

Si se da alguna opción, el script saldrá con uno de estos valores: "0"
si el directorio *site-packages* del usuario está habilitado, "1" si
fue deshabilitado por el usuario, "2" si está deshabilitado por
razones de seguridad o por un administrador, y un valor mayor que 2 si
hay un error.

Ver también:

  * **PEP 370** - Directorio *site-packages* de cada usuario

  * **PEP 829** -- Startup entry points and the deprecation of import
    lines in ".pth" files

  * La inicialización de la ruta de búsqueda de módulo de sys.path --
    Inicialización de "sys.path".
