1"""Utilities to manipulate JSON objects."""
2
3# Copyright (c) IPython Development Team.
4# Distributed under the terms of the Modified BSD License.
5
6import math
7import numbers
8import re
9import types
10from binascii import b2a_base64
11from datetime import date, datetime
12
13from jupyter_client._version import version_info as jupyter_client_version
14
15next_attr_name = "__next__"
16
17# -----------------------------------------------------------------------------
18# Globals and constants
19# -----------------------------------------------------------------------------
20
21# timestamp formats
22ISO8601 = "%Y-%m-%dT%H:%M:%S.%f"
23ISO8601_PAT = re.compile(
24 r"^(\d{4}-\d{2}-\d{2}T\d{2}:\d{2}:\d{2})(\.\d{1,6})?Z?([\+\-]\d{2}:?\d{2})?$"
25)
26
27# holy crap, strptime is not threadsafe.
28# Calling it once at import seems to help.
29datetime.strptime("2000-01-01", "%Y-%m-%d")
30
31# -----------------------------------------------------------------------------
32# Classes and functions
33# -----------------------------------------------------------------------------
34
35
36# constants for identifying png/jpeg data
37PNG = b"\x89PNG\r\n\x1a\n"
38# front of PNG base64-encoded
39PNG64 = b"iVBORw0KG"
40JPEG = b"\xff\xd8"
41# front of JPEG base64-encoded
42JPEG64 = b"/9"
43# constants for identifying gif data
44GIF_64 = b"R0lGODdh"
45GIF89_64 = b"R0lGODlh"
46# front of PDF base64-encoded
47PDF64 = b"JVBER"
48
49JUPYTER_CLIENT_MAJOR_VERSION = jupyter_client_version[0]
50
51
52def encode_images(format_dict):
53 """b64-encodes images in a displaypub format dict
54
55 Perhaps this should be handled in json_clean itself?
56
57 Parameters
58 ----------
59 format_dict : dict
60 A dictionary of display data keyed by mime-type
61
62 Returns
63 -------
64 format_dict : dict
65 A copy of the same dictionary,
66 but binary image data ('image/png', 'image/jpeg' or 'application/pdf')
67 is base64-encoded.
68
69 """
70
71 # no need for handling of ambiguous bytestrings on Python 3,
72 # where bytes objects always represent binary data and thus
73 # base64-encoded.
74 return format_dict
75
76
77def json_clean(obj): # pragma: no cover
78 """Deprecated, this is a no-op for jupyter-client>=7.
79
80 Clean an object to ensure it's safe to encode in JSON.
81
82 Atomic, immutable objects are returned unmodified. Sets and tuples are
83 converted to lists, lists are copied and dicts are also copied.
84
85 Note: dicts whose keys could cause collisions upon encoding (such as a dict
86 with both the number 1 and the string '1' as keys) will cause a ValueError
87 to be raised.
88
89 Parameters
90 ----------
91 obj : any python object
92
93 Returns
94 -------
95 out : object
96 A version of the input which will not cause an encoding error when
97 encoded as JSON. Note that this function does not *encode* its inputs,
98 it simply sanitizes it so that there will be no encoding errors later.
99
100 """
101 if int(JUPYTER_CLIENT_MAJOR_VERSION) >= 7:
102 return obj
103
104 # types that are 'atomic' and ok in json as-is.
105 atomic_ok = (str, type(None))
106
107 # containers that we need to convert into lists
108 container_to_list = (tuple, set, types.GeneratorType)
109
110 # Since bools are a subtype of Integrals, which are a subtype of Reals,
111 # we have to check them in that order.
112
113 if isinstance(obj, bool):
114 return obj
115
116 if isinstance(obj, numbers.Integral):
117 # cast int to int, in case subclasses override __str__ (e.g. boost enum, #4598)
118 return int(obj)
119
120 if isinstance(obj, numbers.Real):
121 # cast out-of-range floats to their reprs
122 if math.isnan(obj) or math.isinf(obj):
123 return repr(obj)
124 return float(obj)
125
126 if isinstance(obj, atomic_ok):
127 return obj
128
129 if isinstance(obj, bytes):
130 # unanmbiguous binary data is base64-encoded
131 # (this probably should have happened upstream)
132 return b2a_base64(obj).decode("ascii")
133
134 if isinstance(obj, container_to_list) or (
135 hasattr(obj, "__iter__") and hasattr(obj, next_attr_name)
136 ):
137 obj = list(obj)
138
139 if isinstance(obj, list):
140 return [json_clean(x) for x in obj]
141
142 if isinstance(obj, dict):
143 # First, validate that the dict won't lose data in conversion due to
144 # key collisions after stringification. This can happen with keys like
145 # True and 'true' or 1 and '1', which collide in JSON.
146 nkeys = len(obj)
147 nkeys_collapsed = len(set(map(str, obj)))
148 if nkeys != nkeys_collapsed:
149 msg = (
150 "dict cannot be safely converted to JSON: "
151 "key collision would lead to dropped values"
152 )
153 raise ValueError(msg)
154 # If all OK, proceed by making the new dict that will be json-safe
155 out = {}
156 for k, v in obj.items():
157 out[str(k)] = json_clean(v)
158 return out
159 if isinstance(obj, (datetime, date)):
160 return obj.strftime(ISO8601)
161
162 # we don't understand it, it's probably an unserializable object
163 raise ValueError("Can't clean for JSON: %r" % obj)