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web::json::value Class Reference

A JSON value represented as a C++ class. More...

#include <json.h>

Public Types

enum   value_type {
  Number, Boolean, String, Object,
  Array, Null
}
  This enumeration represents the various kinds of JSON values. More...
 

Public Member Functions

_ASYNCRTIMP  value ()
  Constructor creating a null value More...
 
_ASYNCRTIMP  value (int32_t value)
  Constructor creating a JSON number value More...
 
_ASYNCRTIMP  value (uint32_t value)
  Constructor creating a JSON number value More...
 
_ASYNCRTIMP  value (int64_t value)
  Constructor creating a JSON number value More...
 
_ASYNCRTIMP  value (uint64_t value)
  Constructor creating a JSON number value More...
 
_ASYNCRTIMP  value (double value)
  Constructor creating a JSON number value More...
 
_ASYNCRTIMP  value (bool value)
  Constructor creating a JSON Boolean value More...
 
_ASYNCRTIMP  value (utility::string_t value)
  Constructor creating a JSON string value More...
 
_ASYNCRTIMP  value (utility::string_t value, bool has_escape_chars)
  Constructor creating a JSON string value specifying if the string contains characters to escape More...
 
_ASYNCRTIMP  value (const utility::char_t *value)
  Constructor creating a JSON string value More...
 
_ASYNCRTIMP  value (const utility::char_t *value, bool has_escape_chars)
  Constructor creating a JSON string value More...
 
_ASYNCRTIMP  value (const value &)
  Copy constructor More...
 
_ASYNCRTIMP  value (value &&) CPPREST_NOEXCEPT
  Move constructor More...
 
_ASYNCRTIMP value &  operator= (const value &)
  Assignment operator. More...
 
_ASYNCRTIMP value &  operator= (value &&) CPPREST_NOEXCEPT
  Move assignment operator. More...
 
_ASYNCRTIMP json::value::value_type  type () const
  Accesses the type of JSON value the current value instance is More...
 
bool  is_null () const
  Is the current value a null value? More...
 
bool  is_number () const
  Is the current value a number value? More...
 
_ASYNCRTIMP bool  is_integer () const
  Is the current value represented as an integer number value? More...
 
_ASYNCRTIMP bool  is_double () const
  Is the current value represented as an double number value? More...
 
bool  is_boolean () const
  Is the current value a Boolean value? More...
 
bool  is_string () const
  Is the current value a string value? More...
 
bool  is_array () const
  Is the current value an array? More...
 
bool  is_object () const
  Is the current value an object? More...
 
size_t  size () const
  Gets the number of children of the value. More...
 
_ASYNCRTIMP utility::string_t  serialize () const
  Serializes the current JSON value to a C++ string. More...
 
_ASYNCRTIMP void  serialize (utility::ostream_t &stream) const
  Writes the current JSON value to a stream with the native platform character width. More...
 
_ASYNCRTIMP double  as_double () const
  Converts the JSON value to a C++ double, if and only if it is a number value. Throws json_exception if the value is not a number More...
 
_ASYNCRTIMP int  as_integer () const
  Converts the JSON value to a C++ integer, if and only if it is a number value. Throws json_exception if the value is not a number More...
 
_ASYNCRTIMP const json::number &  as_number () const
  Converts the JSON value to a number class, if and only if it is a number value. Throws json_exception if the value is not a number More...
 
_ASYNCRTIMP bool  as_bool () const
  Converts the JSON value to a C++ bool, if and only if it is a Boolean value. More...
 
_ASYNCRTIMP json::array &  as_array ()
  Converts the JSON value to a json array, if and only if it is an array value. More...
 
_ASYNCRTIMP const json::array &  as_array () const
  Converts the JSON value to a json array, if and only if it is an array value. More...
 
_ASYNCRTIMP json::object &  as_object ()
  Converts the JSON value to a json object, if and only if it is an object value. More...
 
_ASYNCRTIMP const json::object &  as_object () const
  Converts the JSON value to a json object, if and only if it is an object value. More...
 
_ASYNCRTIMP const utility::string_t &  as_string () const
  Converts the JSON value to a C++ STL string, if and only if it is a string value. More...
 
_ASYNCRTIMP bool  operator== (const value &other) const
  Compares two JSON values for equality. More...
 
bool  operator!= (const value &other) const
  Compares two JSON values for inequality. More...
 
bool  has_field (const utility::string_t &key) const
  Tests for the presence of a field. More...
 
value  get (const utility::string_t &key) const
  Accesses a field of a JSON object. More...
 
_ASYNCRTIMP void  erase (size_t index)
  Erases an element of a JSON array. Throws if index is out of bounds. More...
 
_ASYNCRTIMP void  erase (const utility::string_t &key)
  Erases an element of a JSON object. Throws if the key doesn't exist. More...
 
_ASYNCRTIMP json::value &  at (size_t index)
  Accesses an element of a JSON array. Throws when index out of bounds. More...
 
_ASYNCRTIMP const json::value &  at (size_t index) const
  Accesses an element of a JSON array. Throws when index out of bounds. More...
 
_ASYNCRTIMP json::value &  at (const utility::string_t &key)
  Accesses an element of a JSON object. If the key doesn't exist, this method throws. More...
 
_ASYNCRTIMP const json::value &  at (const utility::string_t &key) const
  Accesses an element of a JSON object. If the key doesn't exist, this method throws. More...
 
_ASYNCRTIMP value &  operator[] (const utility::string_t &key)
  Accesses a field of a JSON object. More...
 
value  get (size_t index) const
  Accesses an element of a JSON array. More...
 
_ASYNCRTIMP value &  operator[] (size_t index)
  Accesses an element of a JSON array. More...
 

Static Public Member Functions

static _ASYNCRTIMP value __cdecl  null ()
  Creates a null value More...
 
static _ASYNCRTIMP value __cdecl  number (double value)
  Creates a number value More...
 
static _ASYNCRTIMP value __cdecl  number (int32_t value)
  Creates a number value More...
 
static _ASYNCRTIMP value __cdecl  number (uint32_t value)
  Creates a number value More...
 
static _ASYNCRTIMP value __cdecl  number (int64_t value)
  Creates a number value More...
 
static _ASYNCRTIMP value __cdecl  number (uint64_t value)
  Creates a number value More...
 
static _ASYNCRTIMP value __cdecl  boolean (bool value)
  Creates a Boolean value More...
 
static _ASYNCRTIMP value __cdecl  string (utility::string_t value)
  Creates a string value More...
 
static _ASYNCRTIMP value __cdecl  string (utility::string_t value, bool has_escape_chars)
  Creates a string value specifying if the string contains characters to escape More...
 
static _ASYNCRTIMP json::value __cdecl  object (bool keep_order=false)
  Creates an object value More...
 
static _ASYNCRTIMP json::value __cdecl  object (std::vector< std::pair<::utility::string_t, value >> fields, bool keep_order=false)
  Creates an object value from a collection of field/values More...
 
static _ASYNCRTIMP json::value __cdecl  array ()
  Creates an empty JSON array More...
 
static _ASYNCRTIMP json::value __cdecl  array (size_t size)
  Creates a JSON array More...
 
static _ASYNCRTIMP json::value __cdecl  array (std::vector< value > elements)
  Creates a JSON array More...
 
static _ASYNCRTIMP value __cdecl  parse (const utility::string_t &value)
  Parses a string and construct a JSON value. More...
 
static _ASYNCRTIMP value __cdecl  parse (const utility::string_t &value, std::error_code &errorCode)
  Attempts to parse a string and construct a JSON value. More...
 
CASABLANCA_DEPRECATED("This API is deprecated and has been renamed to avoid confusion with as_string(), use ::web::json::value::serialize() instead.") _ASYNCRTIMP utility static _ASYNCRTIMP value __cdecl  parse (utility::istream_t &input)
  Serializes the current JSON value to a C++ string. More...
 
static _ASYNCRTIMP value __cdecl  parse (utility::istream_t &input, std::error_code &errorCode)
  Parses a JSON value from the contents of an input stream using the native platform character width. More...
 

Friends

class  web::json::details::_Object
 
class  web::json::details::_Array
 
template<typename CharType >
class  web::json::details::JSON_Parser
 

Detailed Description

A JSON value represented as a C++ class.

Member Enumeration Documentation

enum web::json::value::value_type

This enumeration represents the various kinds of JSON values.

Enumerator
Number 

Number value.

Boolean 

Boolean value.

String 

String value.

Object 

Object value.

Array 

Array value.

Null 

Null value.

Constructor & Destructor Documentation

_ASYNCRTIMP web::json::value::value ( )

Constructor creating a null value

_ASYNCRTIMP web::json::value::value ( int32_t  value )

Constructor creating a JSON number value

Parameters
value The C++ value to create a JSON value from
_ASYNCRTIMP web::json::value::value ( uint32_t  value )

Constructor creating a JSON number value

Parameters
value The C++ value to create a JSON value from
_ASYNCRTIMP web::json::value::value ( int64_t  value )

Constructor creating a JSON number value

Parameters
value The C++ value to create a JSON value from
_ASYNCRTIMP web::json::value::value ( uint64_t  value )

Constructor creating a JSON number value

Parameters
value The C++ value to create a JSON value from
_ASYNCRTIMP web::json::value::value ( double  value )

Constructor creating a JSON number value

Parameters
value The C++ value to create a JSON value from
_ASYNCRTIMP web::json::value::value ( bool  value )
explicit

Constructor creating a JSON Boolean value

Parameters
value The C++ value to create a JSON value from
_ASYNCRTIMP web::json::value::value ( utility::string_t  value )
explicit

Constructor creating a JSON string value

Parameters
value The C++ value to create a JSON value from, a C++ STL string of the platform-native character width

This constructor has O(n) performance because it tries to determine if specified string has characters that should be properly escaped in JSON.

_ASYNCRTIMP web::json::value::value ( utility::string_t  value,
bool  has_escape_chars 
)
explicit

Constructor creating a JSON string value specifying if the string contains characters to escape

Parameters
value The C++ value to create a JSON value from, a C++ STL string of the platform-native character width
has_escape_chars Whether value contains characters that should be escaped in JSON value

This constructor has O(1) performance.

_ASYNCRTIMP web::json::value::value ( const utility::char_t *  value )
explicit

Constructor creating a JSON string value

Parameters
value The C++ value to create a JSON value from, a C++ STL string of the platform-native character width

This constructor has O(n) performance because it tries to determine if specified string has characters that should be properly escaped in JSON.

This constructor exists in order to avoid string literals matching another constructor, as is very likely. For example, conversion to bool does not require a user-defined conversion, and will therefore match first, which means that the JSON value turns up as a boolean.

_ASYNCRTIMP web::json::value::value ( const utility::char_t *  value,
bool  has_escape_chars 
)
explicit

Constructor creating a JSON string value

Parameters
value The C++ value to create a JSON value from, a C++ STL string of the platform-native character width
has_escape_chars Whether value contains characters

This overload has O(1) performance.

This constructor exists in order to avoid string literals matching another constructor, as is very likely. For example, conversion to bool does not require a user-defined conversion, and will therefore match first, which means that the JSON value turns up as a boolean.

_ASYNCRTIMP web::json::value::value ( const value &  )

Copy constructor

_ASYNCRTIMP web::json::value::value ( value &&  )

Move constructor

Member Function Documentation

static _ASYNCRTIMP json::value __cdecl web::json::value::array ( )
static

Creates an empty JSON array

Returns
An empty JSON array value
static _ASYNCRTIMP json::value __cdecl web::json::value::array ( size_t  size )
static

Creates a JSON array

Parameters
size The initial number of elements of the JSON value
Returns
A JSON array value
static _ASYNCRTIMP json::value __cdecl web::json::value::array ( std::vector< value >  elements )
static

Creates a JSON array

Parameters
elements A vector of JSON values
Returns
A JSON array value
_ASYNCRTIMP json::array& web::json::value::as_array ( )

Converts the JSON value to a json array, if and only if it is an array value.

The returned json::array should have the same or shorter lifetime as this

Returns
An array representation of the value
_ASYNCRTIMP const json::array& web::json::value::as_array ( ) const

Converts the JSON value to a json array, if and only if it is an array value.

The returned json::array should have the same or shorter lifetime as this

Returns
An array representation of the value
_ASYNCRTIMP bool web::json::value::as_bool ( ) const

Converts the JSON value to a C++ bool, if and only if it is a Boolean value.

Returns
A C++ bool representation of the value
_ASYNCRTIMP double web::json::value::as_double ( ) const

Converts the JSON value to a C++ double, if and only if it is a number value. Throws json_exception if the value is not a number

Returns
A double representation of the value
_ASYNCRTIMP int web::json::value::as_integer ( ) const

Converts the JSON value to a C++ integer, if and only if it is a number value. Throws json_exception if the value is not a number

Returns
An integer representation of the value
_ASYNCRTIMP const json::number& web::json::value::as_number ( ) const

Converts the JSON value to a number class, if and only if it is a number value. Throws json_exception if the value is not a number

Returns
An instance of number class
_ASYNCRTIMP json::object& web::json::value::as_object ( )

Converts the JSON value to a json object, if and only if it is an object value.

Returns
An object representation of the value
_ASYNCRTIMP const json::object& web::json::value::as_object ( ) const

Converts the JSON value to a json object, if and only if it is an object value.

Returns
An object representation of the value
_ASYNCRTIMP const utility::string_t& web::json::value::as_string ( ) const

Converts the JSON value to a C++ STL string, if and only if it is a string value.

Returns
A C++ STL string representation of the value
_ASYNCRTIMP json::value& web::json::value::at ( size_t  index )

Accesses an element of a JSON array. Throws when index out of bounds.

Parameters
index The index of an element in the JSON array.
Returns
A reference to the value.
_ASYNCRTIMP const json::value& web::json::value::at ( size_t  index ) const

Accesses an element of a JSON array. Throws when index out of bounds.

Parameters
index The index of an element in the JSON array.
Returns
A reference to the value.
_ASYNCRTIMP json::value& web::json::value::at ( const utility::string_t &  key )

Accesses an element of a JSON object. If the key doesn't exist, this method throws.

Parameters
key The key of an element in the JSON object.
Returns
If the key exists, a reference to the value.
_ASYNCRTIMP const json::value& web::json::value::at ( const utility::string_t &  key ) const

Accesses an element of a JSON object. If the key doesn't exist, this method throws.

Parameters
key The key of an element in the JSON object.
Returns
If the key exists, a reference to the value.
static _ASYNCRTIMP value __cdecl web::json::value::boolean ( bool  value )
static

Creates a Boolean value

Parameters
value The C++ value to create a JSON value from
Returns
A JSON Boolean value
_ASYNCRTIMP void web::json::value::erase ( size_t  index )

Erases an element of a JSON array. Throws if index is out of bounds.

Parameters
index The index of the element to erase in the JSON array.
_ASYNCRTIMP void web::json::value::erase ( const utility::string_t &  key )

Erases an element of a JSON object. Throws if the key doesn't exist.

Parameters
key The key of the element to erase in the JSON object.
value web::json::value::get ( const utility::string_t &  key ) const

Accesses a field of a JSON object.

Parameters
key The name of the field
Returns
The value kept in the field; null if the field does not exist
value web::json::value::get ( size_t  index ) const

Accesses an element of a JSON array.

Parameters
index The index of an element in the JSON array
Returns
The value kept at the array index; null if outside the boundaries of the array
bool web::json::json::value::has_field ( const utility::string_t &  key ) const
inline

Tests for the presence of a field.

Test for the presence of a field.

Parameters
key The name of the field
Returns
True if the field exists, false otherwise.
bool web::json::value::is_array ( ) const
inline

Is the current value an array?

Returns
true if the value is an array, false otherwise
bool web::json::value::is_boolean ( ) const
inline

Is the current value a Boolean value?

Returns
true if the value is a Boolean value, false otherwise
_ASYNCRTIMP bool web::json::value::is_double ( ) const

Is the current value represented as an double number value?

Note that if a json value is a number but represented as a int it can still be retrieved as a double using as_double().

Returns
true if the value is an double value, false otherwise.
_ASYNCRTIMP bool web::json::value::is_integer ( ) const

Is the current value represented as an integer number value?

Note that if a json value is a number but represented as a double it can still be retrieved as a integer using as_integer(), however the value will be truncated.

Returns
true if the value is an integer value, false otherwise.
bool web::json::value::is_null ( ) const
inline

Is the current value a null value?

Returns
true if the value is a null value, false otherwise
bool web::json::value::is_number ( ) const
inline

Is the current value a number value?

Returns
true if the value is a number value, false otherwise
bool web::json::value::is_object ( ) const
inline

Is the current value an object?

Returns
true if the value is an object, false otherwise
bool web::json::value::is_string ( ) const
inline

Is the current value a string value?

Returns
true if the value is a string value, false otherwise
static _ASYNCRTIMP value __cdecl web::json::value::null ( )
static

Creates a null value

Returns
A JSON null value
static _ASYNCRTIMP value __cdecl web::json::value::number ( double  value )
static

Creates a number value

Parameters
value The C++ value to create a JSON value from
Returns
A JSON number value
static _ASYNCRTIMP value __cdecl web::json::value::number ( int32_t  value )
static

Creates a number value

Parameters
value The C++ value to create a JSON value from
Returns
A JSON number value
static _ASYNCRTIMP value __cdecl web::json::value::number ( uint32_t  value )
static

Creates a number value

Parameters
value The C++ value to create a JSON value from
Returns
A JSON number value
static _ASYNCRTIMP value __cdecl web::json::value::number ( int64_t  value )
static

Creates a number value

Parameters
value The C++ value to create a JSON value from
Returns
A JSON number value
static _ASYNCRTIMP value __cdecl web::json::value::number ( uint64_t  value )
static

Creates a number value

Parameters
value The C++ value to create a JSON value from
Returns
A JSON number value
static _ASYNCRTIMP json::value __cdecl web::json::value::object ( bool  keep_order = false )
static

Creates an object value

Parameters
keep_order Whether to preserve the original order of the fields
Returns
An empty JSON object value
static _ASYNCRTIMP json::value __cdecl web::json::value::object ( std::vector< std::pair<::utility::string_t, value >>  fields,
bool  keep_order = false 
)
static

Creates an object value from a collection of field/values

Parameters
fields Field names associated with JSON values
keep_order Whether to preserve the original order of the fields
Returns
A non-empty JSON object value
bool web::json::value::operator!= ( const value &  other ) const
inline

Compares two JSON values for inequality.

Parameters
other The JSON value to compare with.
Returns
True iff the values are unequal.
_ASYNCRTIMP value& web::json::value::operator= ( const value &  )

Assignment operator.

Returns
The JSON value object that contains the result of the assignment.
_ASYNCRTIMP value& web::json::value::operator= ( value &&  )

Move assignment operator.

Returns
The JSON value object that contains the result of the assignment.
_ASYNCRTIMP bool web::json::value::operator== ( const value &  other ) const

Compares two JSON values for equality.

Parameters
other The JSON value to compare with.
Returns
True iff the values are equal.
_ASYNCRTIMP value& web::json::value::operator[] ( const utility::string_t &  key )

Accesses a field of a JSON object.

Parameters
key The name of the field
Returns
A reference to the value kept in the field.
_ASYNCRTIMP value& web::json::value::operator[] ( size_t  index )

Accesses an element of a JSON array.

Parameters
index The index of an element in the JSON array.
Returns
A reference to the value kept in the field.
static _ASYNCRTIMP value __cdecl web::json::value::parse ( const utility::string_t &  value )
static

Parses a string and construct a JSON value.

Parameters
value The C++ value to create a JSON value from, a C++ STL double-byte string
static _ASYNCRTIMP value __cdecl web::json::value::parse ( const utility::string_t &  value,
std::error_code &  errorCode 
)
static

Attempts to parse a string and construct a JSON value.

Parameters
value The C++ value to create a JSON value from, a C++ STL double-byte string
errorCode If parsing fails, the error code is greater than 0
Returns
The parsed object. Returns web::json::value::null if failed
CASABLANCA_DEPRECATED ("This API is deprecated and has been renamed to avoid confusion with as_string(), use ::web::json::value::serialize() instead.") _ASYNCRTIMP utility static _ASYNCRTIMP value __cdecl web::json::value::parse ( utility::istream_t &  input )
static

Serializes the current JSON value to a C++ string.

Returns
A string representation of the value

Parses a JSON value from the contents of an input stream using the native platform character width.

Parameters
input The stream to read the JSON value from
Returns
The JSON value object created from the input stream.
static _ASYNCRTIMP value __cdecl web::json::value::parse ( utility::istream_t &  input,
std::error_code &  errorCode 
)
static

Parses a JSON value from the contents of an input stream using the native platform character width.

Parameters
input The stream to read the JSON value from
errorCode If parsing fails, the error code is greater than 0
Returns
The parsed object. Returns web::json::value::null if failed
_ASYNCRTIMP utility::string_t web::json::value::serialize ( ) const

Serializes the current JSON value to a C++ string.

Returns
A string representation of the value
_ASYNCRTIMP void web::json::value::serialize ( utility::ostream_t &  stream ) const

Writes the current JSON value to a stream with the native platform character width.

Parameters
stream The stream that the JSON string representation should be written to.
size_t web::json::json::value::size ( ) const
inline

Gets the number of children of the value.

Returns
The number of children. 0 for all non-composites.
static _ASYNCRTIMP value __cdecl web::json::value::string ( utility::string_t  value )
static

Creates a string value

Parameters
value The C++ value to create a JSON value from
Returns
A JSON string value

This overload has O(n) performance because it tries to determine if specified string has characters that should be properly escaped in JSON.

static _ASYNCRTIMP value __cdecl web::json::value::string ( utility::string_t  value,
bool  has_escape_chars 
)
static

Creates a string value specifying if the string contains characters to escape

Parameters
value The C++ value to create a JSON value from
has_escape_chars Whether value contains characters that should be escaped in JSON value
Returns
A JSON string value

This overload has O(1) performance.

_ASYNCRTIMP json::value::value_type web::json::value::type ( ) const

Accesses the type of JSON value the current value instance is

Returns
The value's type
The documentation for this class was generated from the following file:
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