oga/lib/oga/xml/element.rb

374 lines
8.6 KiB
Ruby

module Oga
module XML
##
# Class that contains information about an XML element such as the name,
# attributes and child nodes.
#
# @!attribute [rw] name
# The name of the element.
# @return [String]
#
# @!attribute [ww] namespace_name
# The name of the namespace.
# @return [String]
#
# @!attribute [rw] attributes
# The attributes of the element.
# @return [Array<Oga::XML::Attribute>]
#
# @!attribute [rw] namespaces
# The registered namespaces.
# @return [Hash]
#
class Element < Node
include Querying
attr_accessor :name, :namespace_name, :attributes, :namespaces
##
# The attribute prefix/namespace used for registering element namespaces.
#
# @return [String]
#
XMLNS_PREFIX = 'xmlns'.freeze
##
# @param [Hash] options
#
# @option options [String] :name The name of the element.
#
# @option options [String] :namespace_name The name of the namespace.
#
# @option options [Array<Oga::XML::Attribute>] :attributes The attributes
# of the element as an Array.
#
def initialize(options = {})
super
@name = options[:name]
@namespace_name = options[:namespace_name]
@attributes = options[:attributes] || []
@namespaces = options[:namespaces] || {}
link_attributes
register_namespaces_from_attributes
end
##
# Returns an attribute matching the given name (with or without the
# namespace).
#
# @example
# # find an attribute that only has the name "foo"
# attribute('foo')
#
# # find an attribute with namespace "foo" and name bar"
# attribute('foo:bar')
#
# @param [String|Symbol] name The name (with or without the namespace)
# of the attribute.
#
# @return [Oga::XML::Attribute]
#
def attribute(name)
name, ns = split_name(name)
attributes.each do |attr|
return attr if attribute_matches?(attr, ns, name)
end
return
end
alias_method :attr, :attribute
##
# Returns the value of the given attribute.
#
# @example
# element.get('class') # => "container"
#
# @see [#attribute]
#
def get(name)
found = attribute(name)
return found ? found.value : nil
end
##
# Adds a new attribute to the element.
#
# @param [Oga::XML::Attribute] attribute
#
def add_attribute(attribute)
attribute.element = self
attributes << attribute
end
##
# Sets the value of an attribute to the given value. If the attribute does
# not exist it is created automatically.
#
# @param [String] name The name of the attribute, optionally including the
# namespace.
#
# @param [String] value The new value of the attribute.
#
def set(name, value)
found = attribute(name)
if found
found.value = value
else
if name.include?(':')
ns, name = name.split(':')
else
ns = nil
end
attr = Attribute.new(
:name => name,
:namespace_name => ns,
:value => value
)
add_attribute(attr)
end
end
##
# Removes an attribute from the element.
#
# @param [String] name The name (optionally including namespace prefix)
# of the attribute to remove.
#
# @return [Oga::XML::Attribute]
#
def unset(name)
found = attribute(name)
return attributes.delete(found) if found
end
##
# Returns the namespace of the element.
#
# @return [Oga::XML::Namespace]
#
def namespace
unless @namespace
available = available_namespaces
@namespace = available[namespace_name] || available[XMLNS_PREFIX]
end
return @namespace
end
##
# Returns the text of all child nodes joined together.
#
# @return [String]
#
def text
return children.text
end
##
# Returns the text of the current element only.
#
# @return [String]
#
def inner_text
text = ''
text_nodes.each do |node|
text << node.text
end
return text
end
##
# Returns any {Oga::XML::Text} nodes that are a direct child of this
# element.
#
# @return [Oga::XML::NodeSet]
#
def text_nodes
nodes = NodeSet.new
children.each do |child|
nodes << child if child.is_a?(Text)
end
return nodes
end
##
# Sets the inner text of the current element to the given String.
#
# @param [String] text
#
def inner_text=(text)
text_node = XML::Text.new(:text => text)
@children = NodeSet.new([text_node], self)
end
##
# Converts the element and its child elements to XML.
#
# @return [String]
#
def to_xml
if namespace_name
full_name = "#{namespace_name}:#{name}"
else
full_name = name
end
body = children.map(&:to_xml).join('')
attrs = ''
attributes.each do |attr|
attrs << " #{attr.to_xml}"
end
if self_closing?
return "<#{full_name}#{attrs} />"
else
return "<#{full_name}#{attrs}>#{body}</#{full_name}>"
end
end
##
# @return [String]
#
def inspect
segments = []
[:name, :namespace, :attributes, :children].each do |attr|
value = send(attr)
if !value or (value.respond_to?(:empty?) and value.empty?)
next
end
segments << "#{attr}: #{value.inspect}"
end
return "Element(#{segments.join(' ')})"
end
##
# Registers a new namespace for the current element and its child
# elements.
#
# @param [String] name
# @param [String] uri
# @see [Oga::XML::Namespace#initialize]
#
def register_namespace(name, uri)
if namespaces[name]
raise ArgumentError, "The namespace #{name.inspect} already exists"
end
namespaces[name] = Namespace.new(:name => name, :uri => uri)
end
##
# Returns a Hash containing all the namespaces available to the current
# element.
#
# @return [Hash]
#
def available_namespaces
merged = namespaces.dup
node = parent
while node && node.respond_to?(:namespaces)
node.namespaces.each do |prefix, ns|
merged[prefix] = ns unless merged[prefix]
end
node = node.parent
end
return merged
end
##
# Returns `true` if the element is a self-closing element.
#
# @return [TrueClass|FalseClass]
#
def self_closing?
self_closing = children.empty?
root = root_node
if root.is_a?(Document) and root.html? \
and !HTML_VOID_ELEMENTS.include?(name)
self_closing = false
end
return self_closing
end
private
##
# Registers namespaces based on any "xmlns" attributes.
#
def register_namespaces_from_attributes
attributes.each do |attr|
# We're using `namespace_name` opposed to `namespace.name` as "xmlns"
# is not a registered namespace.
if attr.name == XMLNS_PREFIX or attr.namespace_name == XMLNS_PREFIX
register_namespace(attr.name, attr.value)
end
end
end
##
# Links all attributes to the current element.
#
def link_attributes
attributes.each do |attr|
attr.element = self
end
end
##
# @param [String] name
# @return [Array]
#
def split_name(name)
segments = name.to_s.split(':')
return segments.pop, segments.pop
end
##
# @param [Oga::XML::Attribute] attr
# @param [String] ns
# @param [String] name
# @return [TrueClass|FalseClass]
#
def attribute_matches?(attr, ns, name)
name_matches = attr.name == name
ns_matches = false
if ns
ns_matches = attr.namespace.to_s == ns
elsif name_matches and !attr.namespace
ns_matches = true
end
return name_matches && ns_matches
end
end # Element
end # XML
end # Oga