##// END OF EJS Templates
Provide a more useful error for invalid use case....
Provide a more useful error for invalid use case. The previous help statement was not very usefull for users who don't know how to use nbconvert (ironically, the exact set of users who would encounter the error).

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storemagic.py
227 lines | 7.7 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.StoreMagic.autorestore = True
"""
#-----------------------------------------------------------------------------
# Copyright (c) 2012, The IPython Development Team.
#
# Distributed under the terms of the Modified BSD License.
#
# The full license is in the file COPYING.txt, distributed with this software.
#-----------------------------------------------------------------------------
#-----------------------------------------------------------------------------
# Imports
#-----------------------------------------------------------------------------
# Stdlib
import inspect, os, sys, textwrap
# Our own
from IPython.core.error import UsageError
from IPython.core.fakemodule import FakeModule
from IPython.core.magic import Magics, magics_class, line_magic
from IPython.testing.skipdoctest import skip_doctest
#-----------------------------------------------------------------------------
# Functions and classes
#-----------------------------------------------------------------------------
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."""
@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
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, basestring):
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
# This needs to be refactored to use the new AliasManager stuff.
if args[0] in ip.alias_manager:
name = args[0]
nargs, cmd = ip.alias_manager.alias_table[ name ]
staliases = db.get('stored_aliases',{})
staliases[ name ] = cmd
db['stored_aliases'] = staliases
print "Alias stored: %s (%s)" % (name, cmd)
return
else:
raise UsageError("Unknown variable '%s'" % args[0])
else:
if isinstance(inspect.getmodule(obj), FakeModule):
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)