class Jbuilder

Constants

BLANK

Public Class Methods

encode(*args, &block) click to toggle source

Yields a builder and automatically turns the result into a JSON string

# File lib/jbuilder.rb, line 54
def self.encode(*args, &block)
  new(*args, &block).target!
end
ignore_nil(value = true) click to toggle source

Same as instance method ::ignore_nil! except sets the default.

# File lib/jbuilder.rb, line 169
def self.ignore_nil(value = true)
  @@ignore_nil = value
end
key_format(*args) click to toggle source

Same as the instance method ::key_format! except sets the default.

# File lib/jbuilder.rb, line 145
def self.key_format(*args)
  @@key_formatter = KeyFormatter.new(*args)
end
new(*args) { |self| ... } click to toggle source
# File lib/jbuilder.rb, line 61
def initialize(*args, &block)
  @attributes = ::ActiveSupport::OrderedHash.new

  options = args.extract_options!
  @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

array!(collection, *attributes, &block) click to toggle source

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 224
def array!(collection, *attributes, &block)
  @attributes = if block && block.arity == 2
    _two_arguments_map_collection(collection, &block)
  elsif block
    _map_collection(collection, &block)
  elsif attributes.any?
    _map_collection(collection) { |element| extract! element, *attributes }
  else
    collection
  end
end
attributes!() click to toggle source

Returns the attributes of the current builder.

# File lib/jbuilder.rb, line 277
def attributes!
  @attributes
end
call(object, *attributes, &block) click to toggle source
# File lib/jbuilder.rb, line 261
def call(object, *attributes, &block)
  if block
    array! object, &block
  else
    extract! object, *attributes
  end
end
child!() { |self| ... } click to toggle source

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 189
def child!
  @attributes = [] unless ::Array === @attributes
  @attributes << _scope { yield self }
end
extract!(object, *attributes) click to toggle source

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 }

If you are using Ruby 1.9+, you can use the call syntax instead of an explicit extract! call:

json.(@person, :name, :age)
# File lib/jbuilder.rb, line 253
def extract!(object, *attributes)
  if ::Hash === object
    _extract_hash_values(object, *attributes)
  else
    _extract_method_values(object, *attributes)
  end
end
ignore_nil!(value = true) click to toggle source

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 164
def ignore_nil!(value = true)
  @ignore_nil = value
end
key_format!(*args) click to toggle source

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 140
def key_format!(*args)
  @key_formatter = KeyFormatter.new(*args)
end
nil!() click to toggle source

Returns the nil JSON.

# File lib/jbuilder.rb, line 270
def nil!
  @attributes = nil
end
Also aliased as: null!
null!()
Alias for: nil!
set!(key, value = BLANK, *args) { |self| ... } click to toggle source
# File lib/jbuilder.rb, line 72
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": ... }
      _scope { 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 value.respond_to?(:map)
    # 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" } }
    _scope { extract! value, *args }
  end

  _set_value key, result
end
Also aliased as: method_missing
target!() click to toggle source

Encodes the current builder as JSON.

# File lib/jbuilder.rb, line 282
def target!
  ::MultiJson.dump @attributes
end

Private Instance Methods

_extract_hash_values(object, *attributes) click to toggle source
# File lib/jbuilder.rb, line 288
def  _extract_hash_values(object, *attributes)
  attributes.each{ |key| _set_value key, object.fetch(key) }
end
_extract_method_values(object, *attributes) click to toggle source
# File lib/jbuilder.rb, line 292
def _extract_method_values(object, *attributes)
  attributes.each do |method_name|
    unless object.respond_to?(method_name)
      message = "Private method #{method_name.inspect} was used to " +
        'extract value. This will be an error in future versions of Jbuilder'
    end

    _set_value method_name, object.send(method_name)
    ::ActiveSupport::Deprecation.warn message if message
  end
end
_map_collection(collection) { |element| ... } click to toggle source
# File lib/jbuilder.rb, line 311
def _map_collection(collection)
  return [] if collection.nil?

  collection.map do |element|
    _scope { yield element }
  end
end
_merge(hash_or_array) click to toggle source
# File lib/jbuilder.rb, line 328
def _merge(hash_or_array)
  if ::Array === hash_or_array
    @attributes = [] unless ::Array === @attributes
    @attributes.concat hash_or_array
  else
    @attributes.update hash_or_array
  end
end
_scope() { || ... } click to toggle source
# File lib/jbuilder.rb, line 319
def _scope
  parent_attributes, parent_formatter = @attributes, @key_formatter
  @attributes = ::ActiveSupport::OrderedHash.new
  yield
  @attributes
ensure
  @attributes, @key_formatter = parent_attributes, parent_formatter
end
_set_value(key, value) click to toggle source
# File lib/jbuilder.rb, line 304
def _set_value(key, value)
  raise NullError, key if @attributes.nil?
  unless @ignore_nil && value.nil?
    @attributes[@key_formatter.format(key)] = value
  end
end
_two_arguments_map_collection(collection, &block) click to toggle source
# File lib/jbuilder.rb, line 337
def _two_arguments_map_collection(collection, &block)
  message = "Passing jbuilder object to block is "          "deprecated and will be removed soon."

  if block.respond_to?(:parameters)
    arguments  = block.parameters.map(&:last)
    actual     = "|#{arguments.drop(1) * ', '}|"
    deprecated = "|#{arguments * ', '}|"
    message   += "\nUse #{actual} instead of #{deprecated} as block arguments"
  end

  ::ActiveSupport::Deprecation.warn message, ::Kernel.caller(5)

  _map_collection(collection){ |element| block[self, element] }
end
method_missing(key, value = BLANK, *args, &block)
Alias for: set!