gluon.storage 源代码

#!/usr/bin/env python
# -*- coding: utf-8 -*-

"""
| This file is part of the web2py Web Framework
| Copyrighted by Massimo Di Pierro <mdipierro@cs.depaul.edu>
| License: LGPLv3 (http://www.gnu.org/licenses/lgpl.html)

Provides:

- List; like list but returns None instead of IndexOutOfBounds
- Storage; like dictionary allowing also for `obj.foo` for `obj['foo']`
"""

from pydal.contrib import portalocker
from gluon._compat import copyreg, pickle, PY2

__all__ = ['List', 'Storage', 'Settings', 'Messages',
           'StorageList', 'load_storage', 'save_storage']

DEFAULT = lambda: 0


[文档]class Storage(dict): """ A Storage object is like a dictionary except `obj.foo` can be used in addition to `obj['foo']`, and setting obj.foo = None deletes item foo. Example:: >>> o = Storage(a=1) >>> print o.a 1 >>> o['a'] 1 >>> o.a = 2 >>> print o['a'] 2 >>> del o.a >>> print o.a None """ __slots__ = () __setattr__ = dict.__setitem__ __delattr__ = dict.__delitem__ __getitem__ = dict.get __getattr__ = dict.get __getnewargs__ = lambda self: getattr(dict,self).__getnewargs__(self) __repr__ = lambda self: '<Storage %s>' % dict.__repr__(self) # http://stackoverflow.com/questions/5247250/why-does-pickle-getstate-accept-as-a-return-value-the-very-instance-it-requi __getstate__ = lambda self: None __copy__ = lambda self: Storage(self)
[文档] def getlist(self, key): """ Returns a Storage value as a list. If the value is a list it will be returned as-is. If object is None, an empty list will be returned. Otherwise, `[value]` will be returned. Example output for a query string of `?x=abc&y=abc&y=def`:: >>> request = Storage() >>> request.vars = Storage() >>> request.vars.x = 'abc' >>> request.vars.y = ['abc', 'def'] >>> request.vars.getlist('x') ['abc'] >>> request.vars.getlist('y') ['abc', 'def'] >>> request.vars.getlist('z') [] """ value = self.get(key, []) if value is None or isinstance(value, (list, tuple)): return value else: return [value]
[文档] def getfirst(self, key, default=None): """ Returns the first value of a list or the value itself when given a `request.vars` style key. If the value is a list, its first item will be returned; otherwise, the value will be returned as-is. Example output for a query string of `?x=abc&y=abc&y=def`:: >>> request = Storage() >>> request.vars = Storage() >>> request.vars.x = 'abc' >>> request.vars.y = ['abc', 'def'] >>> request.vars.getfirst('x') 'abc' >>> request.vars.getfirst('y') 'abc' >>> request.vars.getfirst('z') """ values = self.getlist(key) return values[0] if values else default
[文档] def getlast(self, key, default=None): """ Returns the last value of a list or value itself when given a `request.vars` style key. If the value is a list, the last item will be returned; otherwise, the value will be returned as-is. Simulated output with a query string of `?x=abc&y=abc&y=def`:: >>> request = Storage() >>> request.vars = Storage() >>> request.vars.x = 'abc' >>> request.vars.y = ['abc', 'def'] >>> request.vars.getlast('x') 'abc' >>> request.vars.getlast('y') 'def' >>> request.vars.getlast('z') """ values = self.getlist(key) return values[-1] if values else default
def pickle_storage(s): return Storage, (dict(s),) copyreg.pickle(Storage, pickle_storage) if PY2: PICKABLE = (str, int, long, float, bool, list, dict, tuple, set) else: PICKABLE = (str, int, float, bool, list, dict, tuple, set)
[文档]class StorageList(Storage): """ Behaves like Storage but missing elements defaults to [] instead of None """ def __getitem__(self, key): return self.__getattr__(key) def __getattr__(self, key): if key in self: return self.get(key) else: r = [] self[key] = r return r
[文档]def load_storage(filename): fp = None try: fp = portalocker.LockedFile(filename, 'rb') storage = pickle.load(fp) finally: if fp: fp.close() return Storage(storage)
[文档]def save_storage(storage, filename): fp = None try: fp = portalocker.LockedFile(filename, 'wb') pickle.dump(dict(storage), fp) finally: if fp: fp.close()
[文档]class Settings(Storage): def __setattr__(self, key, value): if key != 'lock_keys' and self['lock_keys'] and key not in self: raise SyntaxError('setting key \'%s\' does not exist' % key) if key != 'lock_values' and self['lock_values']: raise SyntaxError('setting value cannot be changed: %s' % key) self[key] = value
[文档]class Messages(Settings): def __init__(self, T): Storage.__init__(self, T=T) def __getattr__(self, key): value = self[key] if isinstance(value, str): return self.T(value) return value
class FastStorage(dict): """ Eventually this should replace class Storage but causes memory leak because of http://bugs.python.org/issue1469629 >>> s = FastStorage() >>> s.a = 1 >>> s.a 1 >>> s['a'] 1 >>> s.b >>> s['b'] >>> s['b']=2 >>> s['b'] 2 >>> s.b 2 >>> isinstance(s,dict) True >>> dict(s) {'a': 1, 'b': 2} >>> dict(FastStorage(s)) {'a': 1, 'b': 2} >>> import pickle >>> s = pickle.loads(pickle.dumps(s)) >>> dict(s) {'a': 1, 'b': 2} >>> del s.b >>> del s.a >>> s.a >>> s.b >>> s['a'] >>> s['b'] """ def __init__(self, *args, **kwargs): dict.__init__(self, *args, **kwargs) self.__dict__ = self def __getattr__(self, key): return getattr(self, key) if key in self else None def __getitem__(self, key): return dict.get(self, key, None) def copy(self): self.__dict__ = {} s = FastStorage(self) self.__dict__ = self return s def __repr__(self): return '<Storage %s>' % dict.__repr__(self) def __getstate__(self): return dict(self) def __setstate__(self, sdict): dict.__init__(self, sdict) self.__dict__ = self def update(self, *args, **kwargs): dict.__init__(self, *args, **kwargs) self.__dict__ = self
[文档]class List(list): """ Like a regular python list but callable. When a(i) is called if i is out of bounds returns None instead of `IndexError`. """ def __call__(self, i, default=DEFAULT, cast=None, otherwise=None): """Allows to use a special syntax for fast-check of `request.args()` validity. :params: i: index default: use this value if arg not found cast: type cast otherwise: will be executed when: - casts fail - value not found, dont have default and otherwise is especified can be: - None: results in a 404 - str: redirect to this address - callable: calls the function (nothing is passed) Example: You can use:: request.args(0,default=0,cast=int,otherwise='http://error_url') request.args(0,default=0,cast=int,otherwise=lambda:...) """ n = len(self) if 0 <= i < n or -n <= i < 0: value = self[i] elif default is DEFAULT: value = None else: value, cast, otherwise = default, False, False try: if cast: value = cast(value) if not value and otherwise: raise ValueError('Otherwise will raised.') except (ValueError, TypeError): from gluon.http import HTTP, redirect if otherwise is None: raise HTTP(404) elif isinstance(otherwise, str): redirect(otherwise) elif callable(otherwise): return otherwise() else: raise RuntimeError("invalid otherwise") return value
if __name__ == '__main__': import doctest doctest.testmod()