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1 | """Utilities to manipulate JSON objects. |
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1 | """Utilities to manipulate JSON objects. | |
2 | """ |
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2 | """ | |
3 | #----------------------------------------------------------------------------- |
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3 | #----------------------------------------------------------------------------- | |
4 | # Copyright (C) 2010 The IPython Development Team |
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4 | # Copyright (C) 2010 The IPython Development Team | |
5 | # |
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5 | # | |
6 | # Distributed under the terms of the BSD License. The full license is in |
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6 | # Distributed under the terms of the BSD License. The full license is in | |
7 | # the file COPYING.txt, distributed as part of this software. |
|
7 | # the file COPYING.txt, distributed as part of this software. | |
8 | #----------------------------------------------------------------------------- |
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8 | #----------------------------------------------------------------------------- | |
9 |
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9 | |||
10 | #----------------------------------------------------------------------------- |
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10 | #----------------------------------------------------------------------------- | |
11 | # Imports |
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11 | # Imports | |
12 | #----------------------------------------------------------------------------- |
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12 | #----------------------------------------------------------------------------- | |
13 | # stdlib |
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13 | # stdlib | |
14 | import re |
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14 | import re | |
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15 | import sys | |||
15 | import types |
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16 | import types | |
16 | from datetime import datetime |
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17 | from datetime import datetime | |
17 |
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18 | |||
18 | #----------------------------------------------------------------------------- |
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19 | #----------------------------------------------------------------------------- | |
19 | # Globals and constants |
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20 | # Globals and constants | |
20 | #----------------------------------------------------------------------------- |
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21 | #----------------------------------------------------------------------------- | |
21 |
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22 | |||
22 | # timestamp formats |
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23 | # timestamp formats | |
23 | ISO8601="%Y-%m-%dT%H:%M:%S.%f" |
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24 | ISO8601="%Y-%m-%dT%H:%M:%S.%f" | |
24 | ISO8601_PAT=re.compile(r"^\d{4}-\d{2}-\d{2}T\d{2}:\d{2}:\d{2}\.\d+$") |
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25 | ISO8601_PAT=re.compile(r"^\d{4}-\d{2}-\d{2}T\d{2}:\d{2}:\d{2}\.\d+$") | |
25 |
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26 | |||
26 | #----------------------------------------------------------------------------- |
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27 | #----------------------------------------------------------------------------- | |
27 | # Classes and functions |
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28 | # Classes and functions | |
28 | #----------------------------------------------------------------------------- |
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29 | #----------------------------------------------------------------------------- | |
29 |
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30 | |||
30 | def rekey(dikt): |
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31 | def rekey(dikt): | |
31 | """Rekey a dict that has been forced to use str keys where there should be |
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32 | """Rekey a dict that has been forced to use str keys where there should be | |
32 | ints by json.""" |
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33 | ints by json.""" | |
33 | for k in dikt.iterkeys(): |
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34 | for k in dikt.iterkeys(): | |
34 | if isinstance(k, basestring): |
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35 | if isinstance(k, basestring): | |
35 | ik=fk=None |
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36 | ik=fk=None | |
36 | try: |
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37 | try: | |
37 | ik = int(k) |
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38 | ik = int(k) | |
38 | except ValueError: |
|
39 | except ValueError: | |
39 | try: |
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40 | try: | |
40 | fk = float(k) |
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41 | fk = float(k) | |
41 | except ValueError: |
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42 | except ValueError: | |
42 | continue |
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43 | continue | |
43 | if ik is not None: |
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44 | if ik is not None: | |
44 | nk = ik |
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45 | nk = ik | |
45 | else: |
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46 | else: | |
46 | nk = fk |
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47 | nk = fk | |
47 | if nk in dikt: |
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48 | if nk in dikt: | |
48 | raise KeyError("already have key %r"%nk) |
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49 | raise KeyError("already have key %r"%nk) | |
49 | dikt[nk] = dikt.pop(k) |
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50 | dikt[nk] = dikt.pop(k) | |
50 | return dikt |
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51 | return dikt | |
51 |
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52 | |||
52 |
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53 | |||
53 | def extract_dates(obj): |
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54 | def extract_dates(obj): | |
54 | """extract ISO8601 dates from unpacked JSON""" |
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55 | """extract ISO8601 dates from unpacked JSON""" | |
55 | if isinstance(obj, dict): |
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56 | if isinstance(obj, dict): | |
56 | obj = dict(obj) # don't clobber |
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57 | obj = dict(obj) # don't clobber | |
57 | for k,v in obj.iteritems(): |
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58 | for k,v in obj.iteritems(): | |
58 | obj[k] = extract_dates(v) |
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59 | obj[k] = extract_dates(v) | |
59 | elif isinstance(obj, (list, tuple)): |
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60 | elif isinstance(obj, (list, tuple)): | |
60 | obj = [ extract_dates(o) for o in obj ] |
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61 | obj = [ extract_dates(o) for o in obj ] | |
61 | elif isinstance(obj, basestring): |
|
62 | elif isinstance(obj, basestring): | |
62 | if ISO8601_PAT.match(obj): |
|
63 | if ISO8601_PAT.match(obj): | |
63 | obj = datetime.strptime(obj, ISO8601) |
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64 | obj = datetime.strptime(obj, ISO8601) | |
64 | return obj |
|
65 | return obj | |
65 |
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66 | |||
66 | def squash_dates(obj): |
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67 | def squash_dates(obj): | |
67 | """squash datetime objects into ISO8601 strings""" |
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68 | """squash datetime objects into ISO8601 strings""" | |
68 | if isinstance(obj, dict): |
|
69 | if isinstance(obj, dict): | |
69 | obj = dict(obj) # don't clobber |
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70 | obj = dict(obj) # don't clobber | |
70 | for k,v in obj.iteritems(): |
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71 | for k,v in obj.iteritems(): | |
71 | obj[k] = squash_dates(v) |
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72 | obj[k] = squash_dates(v) | |
72 | elif isinstance(obj, (list, tuple)): |
|
73 | elif isinstance(obj, (list, tuple)): | |
73 | obj = [ squash_dates(o) for o in obj ] |
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74 | obj = [ squash_dates(o) for o in obj ] | |
74 | elif isinstance(obj, datetime): |
|
75 | elif isinstance(obj, datetime): | |
75 | obj = obj.strftime(ISO8601) |
|
76 | obj = obj.strftime(ISO8601) | |
76 | return obj |
|
77 | return obj | |
77 |
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78 | |||
78 | def date_default(obj): |
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79 | def date_default(obj): | |
79 | """default function for packing datetime objects in JSON.""" |
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80 | """default function for packing datetime objects in JSON.""" | |
80 | if isinstance(obj, datetime): |
|
81 | if isinstance(obj, datetime): | |
81 | return obj.strftime(ISO8601) |
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82 | return obj.strftime(ISO8601) | |
82 | else: |
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83 | else: | |
83 | raise TypeError("%r is not JSON serializable"%obj) |
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84 | raise TypeError("%r is not JSON serializable"%obj) | |
84 |
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85 | |||
85 |
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86 | |||
86 |
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87 | |||
87 | def json_clean(obj): |
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88 | def json_clean(obj): | |
88 | """Clean an object to ensure it's safe to encode in JSON. |
|
89 | """Clean an object to ensure it's safe to encode in JSON. | |
89 |
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90 | |||
90 | Atomic, immutable objects are returned unmodified. Sets and tuples are |
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91 | Atomic, immutable objects are returned unmodified. Sets and tuples are | |
91 | converted to lists, lists are copied and dicts are also copied. |
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92 | converted to lists, lists are copied and dicts are also copied. | |
92 |
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93 | |||
93 | Note: dicts whose keys could cause collisions upon encoding (such as a dict |
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94 | Note: dicts whose keys could cause collisions upon encoding (such as a dict | |
94 | with both the number 1 and the string '1' as keys) will cause a ValueError |
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95 | with both the number 1 and the string '1' as keys) will cause a ValueError | |
95 | to be raised. |
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96 | to be raised. | |
96 |
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97 | |||
97 | Parameters |
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98 | Parameters | |
98 | ---------- |
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99 | ---------- | |
99 | obj : any python object |
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100 | obj : any python object | |
100 |
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101 | |||
101 | Returns |
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102 | Returns | |
102 | ------- |
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103 | ------- | |
103 | out : object |
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104 | out : object | |
104 |
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105 | |||
105 | A version of the input which will not cause an encoding error when |
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106 | A version of the input which will not cause an encoding error when | |
106 | encoded as JSON. Note that this function does not *encode* its inputs, |
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107 | encoded as JSON. Note that this function does not *encode* its inputs, | |
107 | it simply sanitizes it so that there will be no encoding errors later. |
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108 | it simply sanitizes it so that there will be no encoding errors later. | |
108 |
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109 | |||
109 | Examples |
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110 | Examples | |
110 | -------- |
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111 | -------- | |
111 | >>> json_clean(4) |
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112 | >>> json_clean(4) | |
112 | 4 |
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113 | 4 | |
113 | >>> json_clean(range(10)) |
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114 | >>> json_clean(range(10)) | |
114 | [0, 1, 2, 3, 4, 5, 6, 7, 8, 9] |
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115 | [0, 1, 2, 3, 4, 5, 6, 7, 8, 9] | |
115 | >>> json_clean(dict(x=1, y=2)) |
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116 | >>> json_clean(dict(x=1, y=2)) | |
116 | {'y': 2, 'x': 1} |
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117 | {'y': 2, 'x': 1} | |
117 | >>> json_clean(dict(x=1, y=2, z=[1,2,3])) |
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118 | >>> json_clean(dict(x=1, y=2, z=[1,2,3])) | |
118 | {'y': 2, 'x': 1, 'z': [1, 2, 3]} |
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119 | {'y': 2, 'x': 1, 'z': [1, 2, 3]} | |
119 | >>> json_clean(True) |
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120 | >>> json_clean(True) | |
120 | True |
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121 | True | |
121 | """ |
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122 | """ | |
122 | # types that are 'atomic' and ok in json as-is. bool doesn't need to be |
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123 | # types that are 'atomic' and ok in json as-is. bool doesn't need to be | |
123 | # listed explicitly because bools pass as int instances |
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124 | # listed explicitly because bools pass as int instances | |
124 |
atomic_ok = ( |
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125 | atomic_ok = (unicode, int, float, types.NoneType) | |
125 |
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126 | |||
126 | # containers that we need to convert into lists |
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127 | # containers that we need to convert into lists | |
127 | container_to_list = (tuple, set, types.GeneratorType) |
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128 | container_to_list = (tuple, set, types.GeneratorType) | |
128 |
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129 | |||
129 | if isinstance(obj, atomic_ok): |
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130 | if isinstance(obj, atomic_ok): | |
130 | return obj |
|
131 | return obj | |
131 |
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132 | |||
|
133 | if isinstance(obj, bytes): | |||
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134 | return obj.decode(sys.getdefaultencoding(), 'replace') | |||
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135 | ||||
132 | if isinstance(obj, container_to_list) or ( |
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136 | if isinstance(obj, container_to_list) or ( | |
133 | hasattr(obj, '__iter__') and hasattr(obj, 'next')): |
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137 | hasattr(obj, '__iter__') and hasattr(obj, 'next')): | |
134 | obj = list(obj) |
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138 | obj = list(obj) | |
135 |
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139 | |||
136 | if isinstance(obj, list): |
|
140 | if isinstance(obj, list): | |
137 | return [json_clean(x) for x in obj] |
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141 | return [json_clean(x) for x in obj] | |
138 |
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142 | |||
139 | if isinstance(obj, dict): |
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143 | if isinstance(obj, dict): | |
140 | # First, validate that the dict won't lose data in conversion due to |
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144 | # First, validate that the dict won't lose data in conversion due to | |
141 | # key collisions after stringification. This can happen with keys like |
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145 | # key collisions after stringification. This can happen with keys like | |
142 | # True and 'true' or 1 and '1', which collide in JSON. |
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146 | # True and 'true' or 1 and '1', which collide in JSON. | |
143 | nkeys = len(obj) |
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147 | nkeys = len(obj) | |
144 | nkeys_collapsed = len(set(map(str, obj))) |
|
148 | nkeys_collapsed = len(set(map(str, obj))) | |
145 | if nkeys != nkeys_collapsed: |
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149 | if nkeys != nkeys_collapsed: | |
146 | raise ValueError('dict can not be safely converted to JSON: ' |
|
150 | raise ValueError('dict can not be safely converted to JSON: ' | |
147 | 'key collision would lead to dropped values') |
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151 | 'key collision would lead to dropped values') | |
148 | # If all OK, proceed by making the new dict that will be json-safe |
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152 | # If all OK, proceed by making the new dict that will be json-safe | |
149 | out = {} |
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153 | out = {} | |
150 | for k,v in obj.iteritems(): |
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154 | for k,v in obj.iteritems(): | |
151 | out[str(k)] = json_clean(v) |
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155 | out[str(k)] = json_clean(v) | |
152 | return out |
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156 | return out | |
153 |
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157 | |||
154 | # If we get here, we don't know how to handle the object, so we just get |
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158 | # If we get here, we don't know how to handle the object, so we just get | |
155 | # its repr and return that. This will catch lambdas, open sockets, class |
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159 | # its repr and return that. This will catch lambdas, open sockets, class | |
156 | # objects, and any other complicated contraption that json can't encode |
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160 | # objects, and any other complicated contraption that json can't encode | |
157 | return repr(obj) |
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161 | return repr(obj) |
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