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
|
"""Implementation of the JSON adaptation objects
This module exists to avoid a circular import problem: pyscopg2.extras depends
on psycopg2.extension, so I can't create the default JSON typecasters in
extensions importing register_json from extras.
"""
# psycopg/_json.py - Implementation of the JSON adaptation objects
#
# Copyright (C) 2012-2019 Daniele Varrazzo <daniele.varrazzo@gmail.com>
# Copyright (C) 2020-2021 The Psycopg Team
#
# psycopg2 is free software: you can redistribute it and/or modify it
# under the terms of the GNU Lesser General Public License as published
# by the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# In addition, as a special exception, the copyright holders give
# permission to link this program with the OpenSSL library (or with
# modified versions of OpenSSL that use the same license as OpenSSL),
# and distribute linked combinations including the two.
#
# You must obey the GNU Lesser General Public License in all respects for
# all of the code used other than OpenSSL.
#
# psycopg2 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 Lesser General Public
# License for more details.
import json
from psycopg2._psycopg import ISQLQuote, QuotedString
from psycopg2._psycopg import new_type, new_array_type, register_type
# oids from PostgreSQL 9.2
JSON_OID = 114
JSONARRAY_OID = 199
# oids from PostgreSQL 9.4
JSONB_OID = 3802
JSONBARRAY_OID = 3807
class Json:
"""
An `~psycopg2.extensions.ISQLQuote` wrapper to adapt a Python object to
:sql:`json` data type.
`!Json` can be used to wrap any object supported by the provided *dumps*
function. If none is provided, the standard :py:func:`json.dumps()` is
used.
"""
def __init__(self, adapted, dumps=None):
self.adapted = adapted
self._conn = None
self._dumps = dumps or json.dumps
def __conform__(self, proto):
if proto is ISQLQuote:
return self
def dumps(self, obj):
"""Serialize *obj* in JSON format.
The default is to call `!json.dumps()` or the *dumps* function
provided in the constructor. You can override this method to create a
customized JSON wrapper.
"""
return self._dumps(obj)
def prepare(self, conn):
self._conn = conn
def getquoted(self):
s = self.dumps(self.adapted)
qs = QuotedString(s)
if self._conn is not None:
qs.prepare(self._conn)
return qs.getquoted()
def __str__(self):
# getquoted is binary
return self.getquoted().decode('ascii', 'replace')
def register_json(conn_or_curs=None, globally=False, loads=None,
oid=None, array_oid=None, name='json'):
"""Create and register typecasters converting :sql:`json` type to Python objects.
:param conn_or_curs: a connection or cursor used to find the :sql:`json`
and :sql:`json[]` oids; the typecasters are registered in a scope
limited to this object, unless *globally* is set to `!True`. It can be
`!None` if the oids are provided
:param globally: if `!False` register the typecasters only on
*conn_or_curs*, otherwise register them globally
:param loads: the function used to parse the data into a Python object. If
`!None` use `!json.loads()`, where `!json` is the module chosen
according to the Python version (see above)
:param oid: the OID of the :sql:`json` type if known; If not, it will be
queried on *conn_or_curs*
:param array_oid: the OID of the :sql:`json[]` array type if known;
if not, it will be queried on *conn_or_curs*
:param name: the name of the data type to look for in *conn_or_curs*
The connection or cursor passed to the function will be used to query the
database and look for the OID of the :sql:`json` type (or an alternative
type if *name* if provided). No query is performed if *oid* and *array_oid*
are provided. Raise `~psycopg2.ProgrammingError` if the type is not found.
"""
if oid is None:
oid, array_oid = _get_json_oids(conn_or_curs, name)
JSON, JSONARRAY = _create_json_typecasters(
oid, array_oid, loads=loads, name=name.upper())
register_type(JSON, not globally and conn_or_curs or None)
if JSONARRAY is not None:
register_type(JSONARRAY, not globally and conn_or_curs or None)
return JSON, JSONARRAY
def register_default_json(conn_or_curs=None, globally=False, loads=None):
"""
Create and register :sql:`json` typecasters for PostgreSQL 9.2 and following.
Since PostgreSQL 9.2 :sql:`json` is a builtin type, hence its oid is known
and fixed. This function allows specifying a customized *loads* function
for the default :sql:`json` type without querying the database.
All the parameters have the same meaning of `register_json()`.
"""
return register_json(conn_or_curs=conn_or_curs, globally=globally,
loads=loads, oid=JSON_OID, array_oid=JSONARRAY_OID)
def register_default_jsonb(conn_or_curs=None, globally=False, loads=None):
"""
Create and register :sql:`jsonb` typecasters for PostgreSQL 9.4 and following.
As in `register_default_json()`, the function allows to register a
customized *loads* function for the :sql:`jsonb` type at its known oid for
PostgreSQL 9.4 and following versions. All the parameters have the same
meaning of `register_json()`.
"""
return register_json(conn_or_curs=conn_or_curs, globally=globally,
loads=loads, oid=JSONB_OID, array_oid=JSONBARRAY_OID, name='jsonb')
def _create_json_typecasters(oid, array_oid, loads=None, name='JSON'):
"""Create typecasters for json data type."""
if loads is None:
loads = json.loads
def typecast_json(s, cur):
if s is None:
return None
return loads(s)
JSON = new_type((oid, ), name, typecast_json)
if array_oid is not None:
JSONARRAY = new_array_type((array_oid, ), f"{name}ARRAY", JSON)
else:
JSONARRAY = None
return JSON, JSONARRAY
def _get_json_oids(conn_or_curs, name='json'):
# lazy imports
from psycopg2.extensions import STATUS_IN_TRANSACTION
from psycopg2.extras import _solve_conn_curs
conn, curs = _solve_conn_curs(conn_or_curs)
# Store the transaction status of the connection to revert it after use
conn_status = conn.status
# column typarray not available before PG 8.3
typarray = conn.info.server_version >= 80300 and "typarray" or "NULL"
# get the oid for the hstore
curs.execute(
"SELECT t.oid, %s FROM pg_type t WHERE t.typname = %%s;"
% typarray, (name,))
r = curs.fetchone()
# revert the status of the connection as before the command
if conn_status != STATUS_IN_TRANSACTION and not conn.autocommit:
conn.rollback()
if not r:
raise conn.ProgrammingError(f"{name} data type not found")
return r
|
