class Nokogiri::XML::Reader

The Reader parser allows you to effectively pull parse an XML document. Once instantiated, call Nokogiri::XML::Reader#each to iterate over each node.

Nokogiri::XML::Reader parses an XML document similar to the way a cursor would move. The Reader is given an XML document, and yields nodes to an each block.

The Reader parser might be good for when you need the speed and low memory usage of a SAX parser, but do not want to write a SAX::Document handler.

Here is an example of usage:

reader = Nokogiri::XML::Reader.new <<~XML
  <x xmlns:tenderlove='http://tenderlovemaking.com/'>
    <tenderlove:foo awesome='true'>snuggles!</tenderlove:foo>
  </x>
XML

reader.each do |node|
  # node is an instance of Nokogiri::XML::Reader
  puts node.name
end

⚠ Nokogiri::XML::Reader#each can only be called once! Once the cursor moves through the entire document, you must parse the document again. It may be better to capture all information you need during a single iteration.

⚠ libxml2 does not support error recovery in the Reader parser. The RECOVER ParseOption is ignored. If a syntax error is encountered during parsing, an exception will be raised.

Constants

TYPE_ATTRIBUTE: Attribute node type
TYPE_CDATA: CDATA node type
TYPE_COMMENT: Comment node type
TYPE_DOCUMENT: Document node type
TYPE_DOCUMENT_FRAGMENT: Document Fragment node type
TYPE_DOCUMENT_TYPE: Document Type node type
TYPE_ELEMENT: Element node type
TYPE_END_ELEMENT: Element end node type
TYPE_END_ENTITY: Entity end node type
TYPE_ENTITY: Entity node type
TYPE_ENTITY_REFERENCE: Entity Reference node type
TYPE_NONE
TYPE_NOTATION: Notation node type
TYPE_PROCESSING_INSTRUCTION: PI node type
TYPE_SIGNIFICANT_WHITESPACE: Significant Whitespace node type
TYPE_TEXT: Text node type
TYPE_WHITESPACE: Whitespace node type
TYPE_XML_DECLARATION: XML Declaration node type

Attributes

errors [RW]

A list of errors encountered while parsing

source [R]

The XML source

Public Class Methods

new(input) { |options| ... } → Reader

new(input, url:, encoding:, options:) { |options| ... } → Reader

Source

# File lib/nokogiri/xml/reader.rb, line 99
def self.new(
  string_or_io,
  url_ = nil, encoding_ = nil, options_ = ParseOptions::STRICT,
  url: url_, encoding: encoding_, options: options_
)
  options = Nokogiri::XML::ParseOptions.new(options) if Integer === options
  yield options if block_given?

  if string_or_io.respond_to?(:read)
    return Reader.from_io(string_or_io, url, encoding, options.to_i)
  end

  Reader.from_memory(string_or_io, url, encoding, options.to_i)
end

Create a new Reader to parse an XML document.

Required Parameters

input (String | IO): The XML document to parse.

Optional Parameters

url: (String) The base URL of the document.
encoding: (String) The name of the encoding of the document.
options: (Integer | ParseOptions) Options to control the parser behavior. Defaults to ParseOptions::STRICT.

Yields: If present, the block will be passed a Nokogiri::XML::ParseOptions object to modify before the fragment is parsed. See Nokogiri::XML::ParseOptions for more information.

Public Instance Methods

attributes ()

Source

# File lib/nokogiri/xml/reader.rb, line 126
def attributes
  attribute_hash.merge(namespaces)
end

Get the attributes and namespaces of the current node as a Hash.

This is the union of Reader#attribute_hash and Reader#namespaces

Returns: (Hash<String, String>) Attribute names and values, and namespace prefixes and hrefs.

each () { |cursor| ... }

Source

# File lib/nokogiri/xml/reader.rb, line 132
def each
  while (cursor = read)
    yield cursor
  end
end

Move the cursor through the document yielding the cursor to the block