class Jbuilder
Constants
- BLANK
- DependencyTracker
Public Class Methods
Yields a builder and automatically turns the result into a JSON string
# File lib/jbuilder.rb, line 20 def self.encode(*args, &block) new(*args, &block).target! end
Same as instance method ::ignore_nil! except sets the default.
# File lib/jbuilder.rb, line 121 def self.ignore_nil(value = true) @@ignore_nil = value end
Same as the instance method ::key_format! except sets the default.
# File lib/jbuilder.rb, line 97 def self.key_format(*args) @@key_formatter = KeyFormatter.new(*args) end
# File lib/jbuilder.rb, line 10 def initialize(options = {}, &block) @attributes = {} @key_formatter = options.fetch(:key_formatter){ @@key_formatter.clone } @ignore_nil = options.fetch(:ignore_nil, @@ignore_nil) yield self if block end
Public Instance Methods
Turns the current element into an array and iterates over the passed collection, adding each iteration as an element of the resulting array.
Example:
json.array!(@people) do |person| json.name person.name json.age calculate_age(person.birthday) end [ { "name": David", "age": 32 }, { "name": Jamie", "age": 31 } ]
If you are using Ruby 1.9+, you can use the call syntax instead of an explicit extract! call:
json.(@people) { |person| ... }
It's generally only needed to use this method for top-level arrays. If you have named arrays, you can do:
json.people(@people) do |person| json.name person.name json.age calculate_age(person.birthday) end { "people": [ { "name": David", "age": 32 }, { "name": Jamie", "age": 31 } ] }
If you omit the block then you can set the top level array directly:
json.array! [1, 2, 3] [1,2,3]
# File lib/jbuilder.rb, line 176 def array!(collection = [], *attributes, &block) array = if collection.nil? [] elsif block _map_collection(collection, &block) elsif attributes.any? _map_collection(collection) { |element| extract! element, *attributes } else collection.to_a end merge! array end
Returns the attributes of the current builder.
# File lib/jbuilder.rb, line 231 def attributes! @attributes end
# File lib/jbuilder.rb, line 215 def call(object, *attributes, &block) if block array! object, &block else extract! object, *attributes end end
Turns the current element into an array and yields a builder to add a hash.
Example:
json.comments do json.child! { json.content "hello" } json.child! { json.content "world" } end { "comments": [ { "content": "hello" }, { "content": "world" } ]}
More commonly, you'd use the combined iterator, though:
json.comments(@post.comments) do |comment| json.content comment.formatted_content end
# File lib/jbuilder.rb, line 141 def child! @attributes = [] unless ::Array === @attributes @attributes << _scope{ yield self } end
Extracts the mentioned attributes or hash elements from the passed object and turns them into attributes of the JSON.
Example:
@person = Struct.new(:name, :age).new('David', 32) or you can utilize a Hash @person = { name: 'David', age: 32 } json.extract! @person, :name, :age { "name": David", "age": 32 }, { "name": Jamie", "age": 31 }
You can also use the call syntax instead of an explicit extract! call:
json.(@person, :name, :age)
# File lib/jbuilder.rb, line 207 def extract!(object, *attributes) if ::Hash === object _extract_hash_values(object, *attributes) else _extract_method_values(object, *attributes) end end
If you want to skip adding nil values to your JSON hash. This is useful for JSON clients that don't deal well with nil values, and would prefer not to receive keys which have null values.
Example:
json.ignore_nil! false json.id User.new.id { "id": null } json.ignore_nil! json.id User.new.id {}
# File lib/jbuilder.rb, line 116 def ignore_nil!(value = true) @ignore_nil = value end
Specifies formatting to be applied to the key. Passing in a name of a function will cause that function to be called on the key. So :upcase will upper case the key. You can also pass in lambdas for more complex transformations.
Example:
json.key_format! :upcase json.author do json.name "David" json.age 32 end { "AUTHOR": { "NAME": "David", "AGE": 32 } }
You can pass parameters to the method using a hash pair.
json.key_format! camelize: :lower json.first_name "David" { "firstName": "David" }
Lambdas can also be used.
json.key_format! ->(key){ "_" + key } json.first_name "David" { "_first_name": "David" }
# File lib/jbuilder.rb, line 92 def key_format!(*args) @key_formatter = KeyFormatter.new(*args) end
Merges hash or array into current builder.
# File lib/jbuilder.rb, line 236 def merge!(hash_or_array) @attributes = _merge_values(@attributes, hash_or_array) end
Returns the nil JSON.
# File lib/jbuilder.rb, line 224 def nil! @attributes = nil end
# File lib/jbuilder.rb, line 26 def set!(key, value = BLANK, *args, &block) result = if block if !_blank?(value) # json.comments @post.comments { |comment| ... } # { "comments": [ { ... }, { ... } ] } _scope{ array! value, &block } else # json.comments { ... } # { "comments": ... } _merge_block(key){ yield self } end elsif args.empty? if ::Jbuilder === value # json.age 32 # json.person another_jbuilder # { "age": 32, "person": { ... } value.attributes! else # json.age 32 # { "age": 32 } value end elsif _mapable_arguments?(value, *args) # json.comments @post.comments, :content, :created_at # { "comments": [ { "content": "hello", "created_at": "..." }, { "content": "world", "created_at": "..." } ] } _scope{ array! value, *args } else # json.author @post.creator, :name, :email_address # { "author": { "name": "David", "email_address": "david@loudthinking.com" } } _merge_block(key){ extract! value, *args } end _set_value key, result end
Encodes the current builder as JSON.
# File lib/jbuilder.rb, line 241 def target! ::MultiJson.dump(@attributes) end
Private Instance Methods
# File lib/jbuilder.rb, line 312 def _blank?(value=@attributes) BLANK == value end
# File lib/jbuilder.rb, line 247 def _extract_hash_values(object, *attributes) attributes.each{ |key| _set_value key, object.fetch(key) } end
# File lib/jbuilder.rb, line 251 def _extract_method_values(object, *attributes) attributes.each{ |key| _set_value key, object.public_send(key) } end
# File lib/jbuilder.rb, line 282 def _key(key) @key_formatter.format(key) end
# File lib/jbuilder.rb, line 293 def _map_collection(collection) collection.map do |element| _scope{ yield element } end - [BLANK] end
# File lib/jbuilder.rb, line 308 def _mapable_arguments?(value, *args) value.respond_to?(:map) end
# File lib/jbuilder.rb, line 255 def _merge_block(key, &block) current_value = _blank? ? BLANK : @attributes.fetch(_key(key), BLANK) raise NullError.build(key) if current_value.nil? new_value = _scope{ yield self } _merge_values(current_value, new_value) end
# File lib/jbuilder.rb, line 262 def _merge_values(current_value, updates) if _blank?(updates) current_value elsif _blank?(current_value) || updates.nil? updates elsif ::Array === updates current_value = ::Array === current_value ? current_value.dup : [] current_value.concat updates else current_value = current_value.dup current_value.update updates end end
# File lib/jbuilder.rb, line 299 def _scope parent_attributes, parent_formatter = @attributes, @key_formatter @attributes = BLANK yield @attributes ensure @attributes, @key_formatter = parent_attributes, parent_formatter end
# File lib/jbuilder.rb, line 286 def _set_value(key, value) raise NullError.build(key) if @attributes.nil? return if @ignore_nil && value.nil? return if _blank?(value) _write key, value end
# File lib/jbuilder.rb, line 277 def _write(key, value) @attributes = {} if _blank? @attributes[_key(key)] = value end