summaryrefslogtreecommitdiffstats
path: root/doc/src/corelib/json.qdoc
blob: 91a89761e3d5a26daeab87c1c3bdb809756ad11d (plain)
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
/****************************************************************************
**
** Copyright (C) 2012 Nokia Corporation and/or its subsidiary(-ies).
** Contact: http://www.qt-project.org/
**
** This file is part of the documentation of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:FDL$
** GNU Free Documentation License
** Alternatively, this file may be used under the terms of the GNU Free
** Documentation License version 1.3 as published by the Free Software
** Foundation and appearing in the file included in the packaging of
** this file.
**
** Other Usage
** Alternatively, this file may be used in accordance with the terms
** and conditions contained in a signed written agreement between you
** and Nokia.
**
**
**
**
**
** $QT_END_LICENSE$
**
****************************************************************************/

/*!
    \group json
    \title JSON Classes
*/

/*!
    \page json.html
    \title JSON Support in Qt
    \ingroup qt-basic-concepts
    \brief An overview over the JSON support in Qt.

    \ingroup frameworks-technologies

    \keyword JSON

    Qt provides support for dealing with JSON data. JSON is a
    format to encode object data derived from Javascript, but
    now widely used as a data exchange format on the internet.

    The JSON support in Qt provides an easy to use C++ API to parse,
    modify and save JSON data. It also contains support for saving this
    data in a binary format that is directly mmap'able and very fast to
    access.

    More details about the JSON data format can be found at \link json.org
    and in \l{http://tools.ietf.org/html/rfc4627}{RFC-4627}.

    \tableofcontents

    \section1 Overview

    JSON is a format to store structured data. It has 6 basic data types:

    \list
    \o bool
    \o double
    \o string
    \o array
    \o object
    \o null
    \endlist

    Any value can be any of the above type. A boolean value is represented by the
    strings true or false in JSON. JSON doesn't explicitly specify the valid range
    for numbers, but the support in Qt is limited to the valid range and precision of
    doubles. A string can be any valid unicode string. An array is a list of values, and an
    object is a dictionary of key/value pairs. All keys in an object are strings, and
    an object cannot contain any duplicated keys.

    The text representation, of JSON encloses arrays in square brackets ([ ... ]) and
    objects in curly brackets ({ ... }). The different entries in arrays and objects
    are separated by commas. The separator between keys and values in an object is a
    colon (:).

    A simple JSON document encoding a person, its age, address and phone numbers could
    look like:

    \code
    {
        "FirstName": "John",
        "LastName": "Doe",
        "Age": 43,
        "Address": {
            "Street": "Downing Street 10",
            "City": "London",
            "Country": "Great Britain"
        },
        "Phone numbers": [
            "+44 1234567",
            "+44 2345678"
        ]
    }
    \endcode

    The above example consists of an object with 5 key/value pairs. Two of the values are strings,
    one is a number, one is another object and the last one an array.

    A valid JSON document is either an array or an object, so a document always starts
    with a square or curly bracket.

    The JSON support in Qt consists of a set of 4 classes.


    \section1 The JSON Classes

    The JSON support in Qt consists of these classes:

    \annotatedlist json

    All JSON classes are value based, implicitly shared classes.
*/