the __future__ is now.
the __future__ is now.

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storemagic.py
227 lines | 7.3 KiB | text/x-python | PythonLexer
# -*- coding: utf-8 -*-
"""
%store magic for lightweight persistence.
Stores variables, aliases and macros in IPython's database.
To automatically restore stored variables at startup, add this to your
:file:`ipython_config.py` file::
c.StoreMagics.autorestore = True
"""
# Copyright (c) IPython Development Team.
# Distributed under the terms of the Modified BSD License.
import inspect, os, sys, textwrap
from IPython.core.error import UsageError
from IPython.core.magic import Magics, magics_class, line_magic
from traitlets import Bool
from IPython.utils.py3compat import string_types
def restore_aliases(ip):
staliases = ip.db.get('stored_aliases', {})
for k,v in staliases.items():
#print "restore alias",k,v # dbg
#self.alias_table[k] = v
ip.alias_manager.define_alias(k,v)
def refresh_variables(ip):
db = ip.db
for key in db.keys('autorestore/*'):
# strip autorestore
justkey = os.path.basename(key)
try:
obj = db[key]
except KeyError:
print("Unable to restore variable '%s', ignoring (use %%store -d to forget!)" % justkey)
print("The error was:", sys.exc_info()[0])
else:
#print "restored",justkey,"=",obj #dbg
ip.user_ns[justkey] = obj
def restore_dhist(ip):
ip.user_ns['_dh'] = ip.db.get('dhist',[])
def restore_data(ip):
refresh_variables(ip)
restore_aliases(ip)
restore_dhist(ip)
@magics_class
class StoreMagics(Magics):
"""Lightweight persistence for python variables.
Provides the %store magic."""
autorestore = Bool(False, help=
"""If True, any %store-d variables will be automatically restored
when IPython starts.
"""
).tag(config=True)
def __init__(self, shell):
super(StoreMagics, self).__init__(shell=shell)
self.shell.configurables.append(self)
if self.autorestore:
restore_data(self.shell)
@line_magic
def store(self, parameter_s=''):
"""Lightweight persistence for python variables.
Example::
In [1]: l = ['hello',10,'world']
In [2]: %store l
In [3]: exit
(IPython session is closed and started again...)
ville@badger:~$ ipython
In [1]: l
NameError: name 'l' is not defined
In [2]: %store -r
In [3]: l
Out[3]: ['hello', 10, 'world']
Usage:
* ``%store`` - Show list of all variables and their current
values
* ``%store spam`` - Store the *current* value of the variable spam
to disk
* ``%store -d spam`` - Remove the variable and its value from storage
* ``%store -z`` - Remove all variables from storage
* ``%store -r`` - Refresh all variables from store (overwrite
current vals)
* ``%store -r spam bar`` - Refresh specified variables from store
(delete current val)
* ``%store foo >a.txt`` - Store value of foo to new file a.txt
* ``%store foo >>a.txt`` - Append value of foo to file a.txt
It should be noted that if you change the value of a variable, you
need to %store it again if you want to persist the new value.
Note also that the variables will need to be pickleable; most basic
python types can be safely %store'd.
Also aliases can be %store'd across sessions.
"""
opts,argsl = self.parse_options(parameter_s,'drz',mode='string')
args = argsl.split(None,1)
ip = self.shell
db = ip.db
# delete
if 'd' in opts:
try:
todel = args[0]
except IndexError:
raise UsageError('You must provide the variable to forget')
else:
try:
del db['autorestore/' + todel]
except:
raise UsageError("Can't delete variable '%s'" % todel)
# reset
elif 'z' in opts:
for k in db.keys('autorestore/*'):
del db[k]
elif 'r' in opts:
if args:
for arg in args:
try:
obj = db['autorestore/' + arg]
except KeyError:
print("no stored variable %s" % arg)
else:
ip.user_ns[arg] = obj
else:
restore_data(ip)
# run without arguments -> list variables & values
elif not args:
vars = db.keys('autorestore/*')
vars.sort()
if vars:
size = max(map(len, vars))
else:
size = 0
print('Stored variables and their in-db values:')
fmt = '%-'+str(size)+'s -> %s'
get = db.get
for var in vars:
justkey = os.path.basename(var)
# print 30 first characters from every var
print(fmt % (justkey, repr(get(var, '<unavailable>'))[:50]))
# default action - store the variable
else:
# %store foo >file.txt or >>file.txt
if len(args) > 1 and args[1].startswith('>'):
fnam = os.path.expanduser(args[1].lstrip('>').lstrip())
if args[1].startswith('>>'):
fil = open(fnam, 'a')
else:
fil = open(fnam, 'w')
obj = ip.ev(args[0])
print("Writing '%s' (%s) to file '%s'." % (args[0],
obj.__class__.__name__, fnam))
if not isinstance (obj, string_types):
from pprint import pprint
pprint(obj, fil)
else:
fil.write(obj)
if not obj.endswith('\n'):
fil.write('\n')
fil.close()
return
# %store foo
try:
obj = ip.user_ns[args[0]]
except KeyError:
# it might be an alias
name = args[0]
try:
cmd = ip.alias_manager.retrieve_alias(name)
except ValueError:
raise UsageError("Unknown variable '%s'" % name)
staliases = db.get('stored_aliases',{})
staliases[name] = cmd
db['stored_aliases'] = staliases
print("Alias stored: %s (%s)" % (name, cmd))
return
else:
modname = getattr(inspect.getmodule(obj), '__name__', '')
if modname == '__main__':
print(textwrap.dedent("""\
Warning:%s is %s
Proper storage of interactively declared classes (or instances
of those classes) is not possible! Only instances
of classes in real modules on file system can be %%store'd.
""" % (args[0], obj) ))
return
#pickled = pickle.dumps(obj)
db[ 'autorestore/' + args[0] ] = obj
print("Stored '%s' (%s)" % (args[0], obj.__class__.__name__))
def load_ipython_extension(ip):
"""Load the extension in IPython."""
ip.register_magics(StoreMagics)