Module | JSON |
In: |
lib/json.rb
lib/json/pure.rb lib/json/version.rb lib/json/generic_object.rb lib/json/ext.rb lib/json/common.rb lib/json/pure/generator.rb lib/json/pure/parser.rb |
JSON is a lightweight data-interchange format. It is easy for us humans to read and write. Plus, equally simple for machines to generate or parse. JSON is completely language agnostic, making it the ideal interchange format.
Built on two universally available structures:
1. A collection of name/value pairs. Often referred to as an _object_, hash table, record, struct, keyed list, or associative array. 2. An ordered list of values. More commonly called an _array_, vector, sequence or list.
To read more about JSON visit: json.org
To parse a JSON string received by another application or generated within your existing application:
require 'json' my_hash = JSON.parse('{"hello": "goodbye"}') puts my_hash["hello"] => "goodbye"
Notice the extra quotes ’’ around the hash notation. Ruby expects the argument to be a string and can‘t convert objects like a hash or array.
Ruby converts your string into a hash
Creating a JSON string for communication or serialization is just as simple.
require 'json' my_hash = {:hello => "goodbye"} puts JSON.generate(my_hash) => "{\"hello\":\"goodbye\"}"
Or an alternative way:
require 'json' puts {:hello => "goodbye"}.to_json => "{\"hello\":\"goodbye\"}"
JSON.generate only allows objects or arrays to be converted to JSON syntax. to_json, however, accepts many Ruby classes even though it acts only as a method for serialization:
require 'json' 1.to_json => "1"
JSON_LOADED | = | true unless defined?(::JSON::JSON_LOADED) | ||
VERSION | = | '1.7.7' | JSON version | |
JSON_LOADED | = | true unless defined?(::JSON::JSON_LOADED) | ||
NaN | = | 0.0/0 | ||
Infinity | = | 1.0/0 | ||
MinusInfinity | = | -Infinity | ||
UnparserError | = | GeneratorError | For backwards compatibility |
create_id | [RW] | This is create identifier, which is used to decide if the json_create hook of a class should be called. It defaults to ‘json_class’. |
dump_default_options | [RW] |
The global default options for the JSON.dump method:
:max_nesting: false :allow_nan: true :quirks_mode: true |
generator | [R] | Returns the JSON generator module that is used by JSON. This is either JSON::Ext::Generator or JSON::Pure::Generator. |
load_default_options | [RW] |
The global default options for the JSON.load method:
:max_nesting: false :allow_nan: true :quirks_mode: true |
parser | [R] | Returns the JSON parser class that is used by JSON. This is either JSON::Ext::Parser or JSON::Pure::Parser. |
state | [RW] | Returns the JSON generator state class that is used by JSON. This is either JSON::Ext::Generator::State or JSON::Pure::Generator::State. |
Dumps obj as a JSON string, i.e. calls generate on the object and returns the result.
If anIO (an IO-like object or an object that responds to the write method) was given, the resulting JSON is written to it.
If the number of nested arrays or objects exceeds limit, an ArgumentError exception is raised. This argument is similar (but not exactly the same!) to the limit argument in Marshal.dump.
The default options for the generator can be changed via the dump_default_options method.
This method is part of the implementation of the load/dump interface of Marshal and YAML.
Generate a JSON document from the Ruby data structure obj and return it. state is * a JSON::State object,
that is used as or to configure a State object.
It defaults to a state object, that creates the shortest possible JSON text in one line, checks for circular data structures and doesn‘t allow NaN, Infinity, and -Infinity.
A state hash can have the following keys:
See also the fast_generate for the fastest creation method with the least amount of sanity checks, and the pretty_generate method for some defaults for pretty output.
Load a ruby data structure from a JSON source and return it. A source can either be a string-like object, an IO-like object, or an object responding to the read method. If proc was given, it will be called with any nested Ruby object as an argument recursively in depth first order. To modify the default options pass in the optional options argument as well.
BEWARE: This method is meant to serialise data from trusted user input, like from your own database server or clients under your control, it could be dangerous to allow untrusted users to pass JSON sources into it. The default options for the parser can be changed via the load_default_options method.
This method is part of the implementation of the load/dump interface of Marshal and YAML.
Parse the JSON document source into a Ruby data structure and return it.
opts can have the following keys:
Parse the JSON document source into a Ruby data structure and return it. The bang version of the parse method defaults to the more dangerous values for the opts hash, so be sure only to parse trusted source documents.
opts can have the following keys: