1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
|
# Authors:
# Pavel Zuna <pzuna@redhat.com>
#
# Copyright (C) 2009 Red Hat
# see file 'COPYING' for use and warranty information
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/>.
"""
Encoding capabilities.
"""
from decimal import Decimal
class EncoderSettings(object):
"""
Container for encoder settings.
"""
encode_to = 'utf-8'
encode_none = False
encode_dict_keys = False
encode_dict_keys_postprocess = True
encode_dict_vals = True
encode_dict_vals_postprocess = True
encode_postprocessor = staticmethod(lambda x: x)
decode_from = 'utf-8'
decode_none = False
decode_dict_keys = False
decode_dict_keys_postprocess = True
decode_dict_vals = True
decode_dict_vals_postprocess = True
decode_dict_vals_table = dict()
decode_dict_vals_table_keygen = staticmethod(lambda x, y: x)
decode_postprocessor = staticmethod(lambda x: x)
class Encoder(object):
"""
Base class implementing encoding of python scalar types to strings
and vise-versa.
"""
encoder_settings = EncoderSettings()
def __init__(self):
# each instance should have its own settings
self.encoder_settings = EncoderSettings()
def _decode_dict_val(self, key, val):
f = self.encoder_settings.decode_dict_vals_table.get(
self.encoder_settings.decode_dict_vals_table_keygen(key, val)
)
if f:
return val
return self.decode(val)
def encode(self, var):
"""
Encode any python built-in python type variable into `self.encode_to`.
Compound types have their individual members encoded.
Returns an encoded copy of 'var'.
"""
if isinstance(var, str):
return var
elif isinstance(var, unicode):
return self.encoder_settings.encode_postprocessor(
var.encode(self.encoder_settings.encode_to)
)
elif isinstance(var, (bool, float, Decimal, int, long)):
return self.encoder_settings.encode_postprocessor(
str(var).encode(self.encoder_settings.encode_to)
)
elif isinstance(var, list):
return [self.encode(m) for m in var]
elif isinstance(var, tuple):
return tuple(self.encode(m) for m in var)
elif isinstance(var, dict):
if self.encoder_settings.encode_dict_keys:
dct = dict()
if not self.encoder_settings.encode_dict_keys_postprocess:
tmp = self.encoder_settings.encode_postprocessor
self.encoder_settings.encode_postprocessor = lambda x: x
for (k, v) in var.iteritems():
dct[self.encode(k)] = v
if not self.encoder_settings.encode_dict_keys_postprocess:
self.encoder_settings.encode_postprocessor = tmp
else:
dct = dict(var)
if self.encoder_settings.encode_dict_vals:
if not self.encoder_settings.encode_dict_vals_postprocess:
tmp = self.encoder_settings.encode_postprocessor
self.encoder_settings.encode_postprocessor = lambda x: x
for (k, v) in dct.iteritems():
dct[k] = self.encode(v)
if not self.encoder_settings.encode_dict_vals_postprocess:
self.encoder_settings.encode_postprocessor = tmp
return dct
elif var is None:
if self.encoder_settings.encode_none:
return self.encoder_settings.encode_postprocessor(
str(var).encode(self.encoder_settings.encode_to)
)
return None
raise TypeError('python built-in type expected, got \'%s\'', type(var))
def decode(self, var):
"""
Decode strings in `self.decode_from` into python strings.
Compound types have their individual members decoded.
Dictionaries can have their values decoded into other types
by looking up keys in `self.decode_dict_vals_table`.
Returns a decoded copy of 'var'.
"""
if isinstance(var, unicode):
return var
elif isinstance(var, str):
return self.encoder_settings.decode_postprocessor(
var.decode(self.encoder_settings.decode_from)
)
elif isinstance(var, (bool, float, Decimal, int, long)):
return var
elif isinstance(var, list):
return [self.decode(m) for m in var]
elif isinstance(var, tuple):
return tuple(self.decode(m) for m in var)
elif isinstance(var, dict):
if self.encoder_settings.decode_dict_keys:
dct = dict()
if not self.encoder_settings.decode_dict_keys_postprocess:
tmp = self.encoder_settings.decode_postprocessor
self.encoder_settings.decode_postprocessor = lambda x: x
for (k, v) in var.iteritems():
dct[self.decode(k)] = v
if not self.encoder_settings.decode_dict_keys_postprocess:
self.encoder_settings.decode_postprocessor = tmp
else:
dct = dict(var)
if self.encoder_settings.decode_dict_vals:
if not self.encoder_settings.decode_dict_vals_postprocess:
tmp = self.encoder_settings.decode_postprocessor
self.encoder_settings.decode_postprocessor = lambda x: x
for (k, v) in dct.iteritems():
dct[k] = self._decode_dict_val(k, v)
if not self.encoder_settings.decode_dict_vals_postprocess:
self.encoder_settings.decode_postprocessor = tmp
return dct
elif var is None:
if self.encoder_settings.decode_none:
return self.encoder_settings.decode_postprocessor(
str(var).decode(self.encoder_settings.decode_from)
)
return None
raise TypeError('python built-in type expected, got \'%s\'', type(var))
## ENCODER METHOD DECORATORS
def encode_args(*outer_args):
def decorate(f):
def new_f(*args, **kwargs):
assert isinstance(args[0], Encoder), \
'first argument not Encoder instance'
new_args = list(args)
for a in outer_args:
if isinstance(a, int):
if a < len(args):
new_args[a] = args[0].encode(args[a])
elif isinstance(a, basestring):
if a in kwargs:
kwargs[a] = args[0].encode(kwargs[a])
else:
raise TypeError(
'encode_args takes a list of ints and basestrings'
)
return f(*new_args, **kwargs)
new_f.func_name = f.func_name
return new_f
return decorate
def decode_retval():
def decorate(f):
def new_f(*args, **kwargs):
assert isinstance(args[0], Encoder), \
'first argument not Encoder instance'
return args[0].decode(f(*args, **kwargs))
new_f.func_name = f.func_name
return new_f
return decorate
|
