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 21 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 122 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 98 def self.key_format(*args) @@key_formatter = KeyFormatter.new(*args) end
# File lib/jbuilder.rb, line 11 def initialize(options = {}) @attributes = {} @key_formatter = options.fetch(:key_formatter){ @@key_formatter ? @@key_formatter.clone : nil} @ignore_nil = options.fetch(:ignore_nil, @@ignore_nil) yield self if ::Kernel.block_given? 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 177 def array!(collection = [], *attributes) array = if collection.nil? [] elsif ::Kernel.block_given? _map_collection(collection, &::Proc.new) 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 232 def attributes! @attributes end
# File lib/jbuilder.rb, line 216 def call(object, *attributes) if ::Kernel.block_given? array! object, &::Proc.new 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 142 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 208 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 117 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 93 def key_format!(*args) @key_formatter = KeyFormatter.new(*args) end
Merges hash or array into current builder.
# File lib/jbuilder.rb, line 237 def merge!(hash_or_array) @attributes = _merge_values(@attributes, hash_or_array) end
Returns the nil JSON.
# File lib/jbuilder.rb, line 225 def nil! @attributes = nil end
# File lib/jbuilder.rb, line 27 def set!(key, value = BLANK, *args) result = if ::Kernel.block_given? if !_blank?(value) # json.comments @post.comments { |comment| ... } # { "comments": [ { ... }, { ... } ] } _scope{ array! value, &::Proc.new } 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 242 def target! ::MultiJson.dump(@attributes) end
Private Instance Methods
# File lib/jbuilder.rb, line 308 def _blank?(value=@attributes) BLANK == value end
# File lib/jbuilder.rb, line 248 def _extract_hash_values(object, attributes) attributes.each{ |key| _set_value key, object.fetch(key) } end
# File lib/jbuilder.rb, line 252 def _extract_method_values(object, attributes) attributes.each{ |key| _set_value key, object.public_send(key) } end
# File lib/jbuilder.rb, line 277 def _key(key) @key_formatter ? @key_formatter.format(key) : key.to_s end
# File lib/jbuilder.rb, line 289 def _map_collection(collection) collection.map do |element| _scope{ yield element } end - [BLANK] end
# File lib/jbuilder.rb, line 304 def _mapable_arguments?(value, *args) value.respond_to?(:map) end
# File lib/jbuilder.rb, line 256 def _merge_block(key) 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 263 def _merge_values(current_value, updates) if _blank?(updates) current_value elsif _blank?(current_value) || updates.nil? updates elsif ::Array === updates ::Array === current_value ? current_value + updates : updates elsif ::Hash === current_value current_value.merge(updates) else raise "Can't merge #{updates.inspect} with #{current_value.inspect}" end end
# File lib/jbuilder.rb, line 295 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 281 def _set_value(key, value) raise NullError.build(key) if @attributes.nil? raise ArrayError.build(key) if ::Array === @attributes return if @ignore_nil && value.nil? or _blank?(value) @attributes = {} if _blank? @attributes[_key(key)] = value end