site
— 特定站点配置挂钩
¶
源代码： Lib/site.py
此模块在初始化期间自动导入。
The automatic import can be suppressed using the interpreter’s
-S
选项。
Importing this module will append site-specific paths to the module search path and add a few builtins, unless
-S
was used. In that case, 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
site.main()
函数。
3.3 版改变：
Importing the module used to trigger paths manipulation even when using
-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
/site-packages
(on Unix and Macintosh). 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.
3.5 版改变： Support for the “site-python” directory has been removed.
If a file named “pyvenv.cfg” exists one directory above sys.executable, sys.prefix and sys.exec_prefix are set to that directory and it is also checked for site-packages (sys.base_prefix and sys.base_exec_prefix will always be the “real” prefixes of the Python installation). If “pyvenv.cfg” (a bootstrap configuration file) contains the key “include-system-site-packages” set to anything other than “false” (case-insensitive), the system-level prefixes will still also be searched for site-packages; otherwise they won’t.
A path configuration file is a file whose name has the form
name
.pth
and exists in one of the four directories mentioned above; its contents are additional items (one per line) to be added to
sys.path
. Non-existing items 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. Lines starting with
import
(followed by space or tab) are executed.
For example, suppose
sys.prefix
and
sys.exec_prefix
被设为
/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 subsubdirectories,
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
and
bar.pth
contains:
# bar package configuration
bar
Then the following version-specific directories are added to
sys.path
, in this order:
/usr/local/lib/pythonX.Y/site-packages/bar
/usr/local/lib/pythonX.Y/site-packages/foo
注意，
bletch
is omitted because it doesn’t exist; the
bar
directory precedes the
foo
directory because
bar.pth
comes alphabetically before
foo.pth
; and
spam
is omitted because it is not mentioned in either path configuration file.
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
exception, 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 exception other than
ImportError
causes a silent and perhaps mysterious failure of the process.
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
. An
ImportError
will be 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.
当系统支持
readline
, this module will also import and configure the
rlcompleter
module, if Python is started in
交互模式
and without the
-S
option. The default behavior is 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
文件。
3.4 版改变： Activation of rlcompleter and history was made automatic.
site.
PREFIXES
¶
A list of prefixes for site-packages directories.
site.
ENABLE_USER_SITE
¶
Flag showing the status of the user site-packages directory.
True
means that it is enabled and was added to
sys.path
.
False
means that it was disabled by user request (with
-s
or
PYTHONNOUSERSITE
).
None
means it was disabled for security reasons (mismatch between user or group id and effective id) or by an administrator.
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
/site-packages
for UNIX and non-framework Mac OS X builds,
~/Library/Python/
X.Y
/lib/python/site-packages
for Mac framework builds, and
%APPDATA%
\Python\Python
XY
\site-packages
on Windows. 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 Mac OS X non-framework builds,
~/Library/Python/
X.Y
for Mac framework builds, and
%APPDATA%
\Python
for Windows. This value is used by Distutils to compute the installation directories for scripts, data files, Python modules, etc. for the
user installation scheme
。另请参阅
PYTHONUSERBASE
.
site.
main
(
)
¶
Adds all the standard site-specific directories to the module search path. This function is called automatically when this module is imported, unless the Python interpreter was started with the
-S
标志。
3.3 版改变： This function used to be called unconditionally.
site.
addsitedir
(
sitedir
,
known_paths=None
)
¶
Add a directory to sys.path and process its
.pth
files. Typically used in
sitecustomize
or
usercustomize
(see above).
site.
getsitepackages
(
)
¶
Return a list containing all global site-packages directories.
3.2 版新增。
site.
getuserbase
(
)
¶
Return the path of the user base directory,
USER_BASE
. If it is not initialized yet, this function will also set it, respecting
PYTHONUSERBASE
.
3.2 版新增。
site.
getusersitepackages
(
)
¶
Return the path of the user-specific site-packages directory,
USER_SITE
. If it is not initialized yet, this function will also set it, respecting
PYTHONNOUSERSITE
and
USER_BASE
.
3.2 版新增。
site
module also provides a way to get the user directories from the command line:
$ python3 -m site --user-site
/home/user/.local/lib/python3.3/site-packages
If it is called without arguments, it will print the contents of
sys.path
on the standard output, followed by the value of
USER_BASE
and whether the directory exists, then the same thing for
USER_SITE
, and finally the value of
ENABLE_USER_SITE
.
--user-base
Print the path to the user base directory.
--user-site
Print the path to the user site-packages directory.
If both options are given, user base and user site will be printed (always in this order), separated by
os.pathsep
.
If any option is given, the script will exit with one of these values:
0
if the user site-packages directory is enabled,
1
if it was disabled by the user,
2
if it is disabled for security reasons or by an administrator, and a value greater than 2 if there is an error.
另请参阅
PEP 370 – 每用户站点包目录