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Extend the shim pickleshare library and fix the store magic to use .get...
Extend the shim pickleshare library and fix the store magic to use .get This should make it more obvious what is happening.

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storemagic.py
236 lines | 8.0 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 IPython.testing.skipdoctest import skip_doctest
from traitlets import Bool
def restore_aliases(ip, alias=None):
staliases = ip.db.get('stored_aliases', {})
if alias is None:
for k,v in staliases.items():
#print "restore alias",k,v # dbg
#self.alias_table[k] = v
ip.alias_manager.define_alias(k,v)
else:
ip.alias_manager.define_alias(alias, staliases[alias])
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)
@skip_doctest
@line_magic
def store(self, parameter_s=''):
"""Lightweight persistence for python variables.
Example::
In [1]: l = ['hello',10,'world']
In [2]: %store l
Stored 'l' (list)
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 bar`` - Store the *current* value of the variables spam
and bar 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, aliases and directory history
from store (overwrite current vals)
* ``%store -r spam bar`` - Refresh specified variables and aliases 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.
To remove an alias from the storage, use the %unalias magic.
"""
opts,argsl = self.parse_options(parameter_s,'drz',mode='string')
args = argsl.split()
ip = self.shell
db = ip.db
# delete
if 'd' in opts:
try:
todel = args[0]
except IndexError as e:
raise UsageError('You must provide the variable to forget') from e
else:
try:
del db['autorestore/' + todel]
except BaseException as e:
raise UsageError("Can't delete variable '%s'" % todel) from e
# 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:
try:
restore_aliases(ip, alias=arg)
except KeyError:
print("no stored variable or alias %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", encoding="utf-8")
else:
fil = open(fnam, "w", encoding="utf-8")
with fil:
obj = ip.ev(args[0])
print("Writing '%s' (%s) to file '%s'." % (args[0],
obj.__class__.__name__, fnam))
if not isinstance (obj, str):
from pprint import pprint
pprint(obj, fil)
else:
fil.write(obj)
if not obj.endswith('\n'):
fil.write('\n')
return
# %store foo
for arg in args:
try:
obj = ip.user_ns[arg]
except KeyError:
# it might be an alias
name = arg
try:
cmd = ip.alias_manager.retrieve_alias(name)
except ValueError as e:
raise UsageError("Unknown variable '%s'" % name) from e
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.
""" % (arg, obj) ))
return
#pickled = pickle.dumps(obj)
db[ 'autorestore/' + arg ] = obj
print("Stored '%s' (%s)" % (arg, obj.__class__.__name__))
def load_ipython_extension(ip):
"""Load the extension in IPython."""
ip.register_magics(StoreMagics)