W3cubDocs

/Crystal 0.31

struct JSON::Any

Overview

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

require "json"

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 #[]?, 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

Constructors

Instance Method Summary

Constructor Detail

def self.new(raw : Type)Source

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

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

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

Instance Method Detail

def ==(other)Source

Returns true if the raw object is equal to other.

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

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

def [](index : Int) : JSON::AnySource

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

def [](key : String) : JSON::AnySource

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

def []?(index : Int) : JSON::Any?Source

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.

def []?(key : String) : JSON::Any?Source

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.

def as_a : Array(Any)Source

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

def as_a? : Array(Any)?Source

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

def as_bool : BoolSource

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

def as_bool? : Bool?Source

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

def as_f : Float64Source

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

def as_f32 : Float32Source

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

def as_f32? : Float32?Source

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

def as_f? : Float64?Source

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

def as_h : Hash(String, Any)Source

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

def as_h? : Hash(String, Any)?Source

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

def as_i : Int32Source

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

def as_i64 : Int64Source

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

def as_i64? : Int64?Source

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

def as_i? : Int32?Source

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

def as_nil : NilSource

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

def as_s : StringSource

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

def as_s? : String?Source

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

def cloneSource

Returns a new JSON::Any instance with the #raw value #cloneed.

def dig(key : String | Int, *subkeys)Source

Traverses the depth of a structure and returns the value, otherwise raises.

def dig?(key : String | Int, *subkeys)Source

Traverses the depth of a structure and returns the value. Returns nil if not found.

def dupSource

Returns a new JSON::Any instance with the #raw value #duped.

def hash(hasher)Source

def raw : TypeSource

Returns the raw underlying value.

def size : IntSource

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

def to_yaml(yaml : YAML::Nodes::Builder)Source

© 2012–2019 Manas Technology Solutions.
Licensed under the Apache License, Version 2.0.
https://crystal-lang.org/api/0.31.1/JSON/Any.html