struct JSON::Any

Overview

JSON::Any is a convenient wrapper around all possible JSON types (JSON::Type) and can be used for traversing dynamic or unknown JSON structures.

obj = JSON.parse(%({"access": [{"name": "mapping", "speed": "fast"}, {"name": "any", "speed": "slow"}]}))
obj["access"][1]["name"].as_s  # => "any"
obj["access"][1]["speed"].as_s # => "slow"

Note that methods used to traverse a JSON structure, #[], #[]? and #each, always return a JSON::Any to allow further traversal. To convert them to String, Int32, etc., use the "as_" methods, such as #as_s, #as_i, which perform a type check against the raw underlying value. This means that invoking #as_s when the underlying value is not a String will raise: the value won't automatically be converted (parsed) to a String.

Defined in:

json/any.cr

Class Method Summary

Instance Method Summary

Instance methods inherited from struct Struct

==(other : self) : Bool ==, hash : Int32 hash, inspect(io : IO) : Nil inspect, to_s(io) to_s

Instance methods inherited from struct Value

! !, ==(other) ==, nil? nil?

Instance methods inherited from class Object

! !, !=(other) !=, !~(other) !~, ==(other) ==, ===(other) ===, =~(other) =~, class class, clone clone, crystal_type_id crystal_type_id, dup dup, hash hash, inspect
inspect(io : IO)
inspect
, itself itself, not_nil! not_nil!, tap(&block) tap, to_json to_json, to_pretty_json(io : IO)
to_pretty_json
to_pretty_json
, to_s
to_s(io : IO)
to_s
, to_yaml(io : IO)
to_yaml
to_yaml
, try(&block) try

Class methods inherited from class Object

==(other : Class) ==, ===(other) ===, cast(other) : self cast, from_json(string_or_io) from_json, from_yaml(string : String) from_yaml, hash hash, inspect(io) inspect, name : String name, to_s(io) to_s

Class Method Detail

def self.new(pull : JSON::PullParser) #

Reads a JSON::Any value from the given pull parser.


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def self.new(raw : JSON::Type) #

Creates a JSON::Any that wraps the given JSON::Type.


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Instance Method Detail

def ==(other : JSON::Any) #

Returns true if both self and other's raw object are equal.


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def ==(other) #

Returns true if the raw object is equal to other.


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def [](key : String) : JSON::Any #

Assumes the underlying value is a Hash and returns the element with the given key. Raises if the underlying value is not a Hash.


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def [](index : Int) : JSON::Any #

Assumes the underlying value is an Array and returns the element at the given index. Raises if the underlying value is not an Array.


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def []?(key : String) : JSON::Any | Nil #

Assumes the underlying value is a Hash and returns the element with the given key, or nil if the key is not present. Raises if the underlying value is not a Hash.


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def []?(index : Int) : JSON::Any | Nil #

Assumes the underlying value is an Array and returns the element at the given index, or nil if out of bounds. Raises if the underlying value is not an Array.


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def as_a : Array(Type) #

Checks that the underlying value is Array, and returns its value. Raises otherwise.


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def as_bool : Bool #

Checks that the underlying value is Bool, and returns its value. Raises otherwise.


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def as_f : Float64 #

Checks that the underlying value is Float, and returns its value as an Float64. Raises otherwise.


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def as_f32 : Float32 #

Checks that the underlying value is Float, and returns its value as an Float32. Raises otherwise.


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def as_h : Hash(String, Type) #

Checks that the underlying value is Hash, and returns its value. Raises otherwise.


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def as_i : Int32 #

Checks that the underlying value is Int, and returns its value as an Int32. Raises otherwise.


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def as_i64 : Int64 #

Checks that the underlying value is Int, and returns its value as an Int64. Raises otherwise.


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def as_nil : Nil #

Checks that the underlying value is Nil, and returns nil. Raises otherwise.


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def as_s : String #

Checks that the underlying value is String, and returns its value. Raises otherwise.


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def each(&block) #

Assumes the underlying value is an Array or Hash and yields each of the elements or key/values, always as JSON::Any. Raises if the underlying value is not an Array or Hash.


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def raw #

Returns the raw underlying value, a JSON::Type.


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def size : Int #

Assumes the underlying value is an Array or Hash and returns its size. Raises if the underlying value is not an Array or Hash.


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