/
extensions.py
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/
extensions.py
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# encoding: utf-8
"""A class for managing IPython extensions."""
# Copyright (c) IPython Development Team.
# Distributed under the terms of the Modified BSD License.
import os
from shutil import copyfile
import sys
from traitlets.config.configurable import Configurable
from IPython.utils.path import ensure_dir_exists
from traitlets import Instance
try:
from importlib import reload
except ImportError :
## deprecated since 3.4
from imp import reload
#-----------------------------------------------------------------------------
# Main class
#-----------------------------------------------------------------------------
class ExtensionManager(Configurable):
"""A class to manage IPython extensions.
An IPython extension is an importable Python module that has
a function with the signature::
def load_ipython_extension(ipython):
# Do things with ipython
This function is called after your extension is imported and the
currently active :class:`InteractiveShell` instance is passed as
the only argument. You can do anything you want with IPython at
that point, including defining new magic and aliases, adding new
components, etc.
You can also optionally define an :func:`unload_ipython_extension(ipython)`
function, which will be called if the user unloads or reloads the extension.
The extension manager will only call :func:`load_ipython_extension` again
if the extension is reloaded.
You can put your extension modules anywhere you want, as long as
they can be imported by Python's standard import mechanism. However,
to make it easy to write extensions, you can also put your extensions
in ``os.path.join(self.ipython_dir, 'extensions')``. This directory
is added to ``sys.path`` automatically.
"""
shell = Instance('IPython.core.interactiveshell.InteractiveShellABC',
allow_none=True)
def __init__(self, shell=None, **kwargs):
super(ExtensionManager, self).__init__(shell=shell, **kwargs)
self.shell.on_trait_change(
self._on_ipython_dir_changed, 'ipython_dir'
)
self.loaded = set()
@property
def ipython_extension_dir(self):
return os.path.join(self.shell.ipython_dir, u'extensions')
def _on_ipython_dir_changed(self):
ensure_dir_exists(self.ipython_extension_dir)
def load_extension(self, module_str):
"""Load an IPython extension by its module name.
Returns the string "already loaded" if the extension is already loaded,
"no load function" if the module doesn't have a load_ipython_extension
function, or None if it succeeded.
"""
if module_str in self.loaded:
return "already loaded"
from IPython.utils.syspathcontext import prepended_to_syspath
with self.shell.builtin_trap:
if module_str not in sys.modules:
with prepended_to_syspath(self.ipython_extension_dir):
__import__(module_str)
mod = sys.modules[module_str]
if self._call_load_ipython_extension(mod):
self.loaded.add(module_str)
else:
return "no load function"
def unload_extension(self, module_str):
"""Unload an IPython extension by its module name.
This function looks up the extension's name in ``sys.modules`` and
simply calls ``mod.unload_ipython_extension(self)``.
Returns the string "no unload function" if the extension doesn't define
a function to unload itself, "not loaded" if the extension isn't loaded,
otherwise None.
"""
if module_str not in self.loaded:
return "not loaded"
if module_str in sys.modules:
mod = sys.modules[module_str]
if self._call_unload_ipython_extension(mod):
self.loaded.discard(module_str)
else:
return "no unload function"
def reload_extension(self, module_str):
"""Reload an IPython extension by calling reload.
If the module has not been loaded before,
:meth:`InteractiveShell.load_extension` is called. Otherwise
:func:`reload` is called and then the :func:`load_ipython_extension`
function of the module, if it exists is called.
"""
from IPython.utils.syspathcontext import prepended_to_syspath
if (module_str in self.loaded) and (module_str in sys.modules):
self.unload_extension(module_str)
mod = sys.modules[module_str]
with prepended_to_syspath(self.ipython_extension_dir):
reload(mod)
if self._call_load_ipython_extension(mod):
self.loaded.add(module_str)
else:
self.load_extension(module_str)
def _call_load_ipython_extension(self, mod):
if hasattr(mod, 'load_ipython_extension'):
mod.load_ipython_extension(self.shell)
return True
def _call_unload_ipython_extension(self, mod):
if hasattr(mod, 'unload_ipython_extension'):
mod.unload_ipython_extension(self.shell)
return True
def install_extension(self, url, filename=None):
"""Download and install an IPython extension.
If filename is given, the file will be so named (inside the extension
directory). Otherwise, the name from the URL will be used. The file must
have a .py or .zip extension; otherwise, a ValueError will be raised.
Returns the full path to the installed file.
"""
# Ensure the extension directory exists
ensure_dir_exists(self.ipython_extension_dir)
if os.path.isfile(url):
src_filename = os.path.basename(url)
copy = copyfile
else:
# Deferred imports
try:
from urllib.parse import urlparse # Py3
from urllib.request import urlretrieve
except ImportError:
from urlparse import urlparse
from urllib import urlretrieve
src_filename = urlparse(url).path.split('/')[-1]
copy = urlretrieve
if filename is None:
filename = src_filename
if os.path.splitext(filename)[1] not in ('.py', '.zip'):
raise ValueError("The file must have a .py or .zip extension", filename)
filename = os.path.join(self.ipython_extension_dir, filename)
copy(url, filename)
return filename