# class XML::Reader

- XML::Reader
- Reference
- Object

##
Overview

`XML::Reader` is a parser for XML that iterates a XML document.

    require "xml"

    reader = XML::Reader.new(<<-XML)
      <message>Hello XML!</message>
      XML
    reader.read
    reader.name # => "message"
    reader.read
    reader.value # => "Hello XML!"

This is an alternative approach to `XML.parse` which parses an entire document into an XML data structure. `XML::Reader` offers more control and does not need to store the XML document in memory entirely. The latter is especially useful for large documents with the `IO`-based constructor.

WARNING This type is not concurrency-safe.

##
Defined in:

xml/reader.cr
xml/reader/type.cr

##
Constructors

- .new(str : String, options : XML::ParserOptions = XML::ParserOptions.default)

  Creates a new reader from a string.

- .new(io : IO, options : XML::ParserOptions = XML::ParserOptions.default)

  Creates a new reader from an IO.

##
Instance Method Summary

- #[](attribute : String) : String

  Gets the attribute content for the attribute given by name.

- #[]?(attribute : String) : String | Nil

  Gets the attribute content for the attribute given by name.

- #attributes_count : Int32

  Returns attribute count of the node.

- #depth : Int32

  Returns the current nesting depth of the reader.

- #empty_element? : Bool

  Checks if the node is an empty element.

- #errors : Array(XML::Error)

  Returns the errors reported while parsing.

- #expand : XML::Node

  Expands the node to a `XML::Node` that can be searched with XPath etc.

- #expand? : XML::Node | Nil

  Expands the node to a `XML::Node` that can be searched with XPath etc.

- #has_attributes? : Bool

  Checks if the node has any attributes.

- #move_to_attribute(name : String) : Bool

  Moves to the `XML::Reader::Type::ATTRIBUTE` with the specified name.

- #move_to_element : Bool

  Moves from the `XML::Reader::Type::ATTRIBUTE` to its containing `XML::Reader::Type::ELEMENT`.

- #move_to_first_attribute : Bool

  Moves to the first `XML::Reader::Type::ATTRIBUTE` of the node.

- #move_to_next_attribute : Bool

  Moves to the next `XML::Reader::Type::ATTRIBUTE` of the node.

- #name : String

  Returns the name of the node.

- #next : Bool

  Moves the reader to the next node while skipping subtrees.

- #next_sibling : Bool

  Moves the reader to the next sibling node while skipping subtrees.

- #node_type : XML::Reader::Type

  Returns the `XML::Reader::Type` of the node.

- #read : Bool

  Moves the reader to the next node.

- #read_inner_xml : String

  Returns the node's XML content including subtrees.

- #read_outer_xml : String

  Returns the XML for the node and its content including subtrees.

- #to_unsafe : LibXML::XMLTextReader

  Returns a reference to the underlying `LibXML::XMLTextReader`.

- #value : String

  Returns the text content of the node.

### Instance methods inherited from class `Reference`

==(other : self)
==(other : JSON::Any)
==(other : YAML::Any)
==(other) ==, dup dup, hash(hasher) hash, initialize initialize, inspect(io : IO) : Nil inspect, object_id : UInt64 object_id, pretty_print(pp) : Nil pretty_print, same?(other : Reference) : Bool
same?(other : Nil) same?, to_s(io : IO) : Nil to_s

### Constructor methods inherited from class `Reference`

new new, unsafe_construct(address : Pointer, *args, **opts) : self unsafe_construct

### Class methods inherited from class `Reference`

pre_initialize(address : Pointer) pre_initialize

### Instance methods inherited from class `Object`

! : Bool !, !=(other) !=, !~(other) !~, ==(other) ==, ===(other : JSON::Any)
===(other : YAML::Any)
===(other) ===, =~(other) =~, as(type : Class) as, as?(type : Class) as?, class class, dup dup, hash(hasher)
hash hash, in?(collection : Object) : Bool
in?(*values : Object) : Bool in?, inspect(io : IO) : Nil
inspect : String inspect, is_a?(type : Class) : Bool is_a?, itself itself, nil? : Bool nil?, not_nil!(message)
not_nil! not_nil!, pretty_inspect(width = 79, newline = "\n", indent = 0) : String pretty_inspect, pretty_print(pp : PrettyPrint) : Nil pretty_print, responds_to?(name : Symbol) : Bool responds_to?, tap(&) tap, to_json(io : IO) : Nil
to_json : String to_json, to_pretty_json(indent : String = " ") : String
to_pretty_json(io : IO, indent : String = " ") : Nil to_pretty_json, to_s(io : IO) : Nil
to_s : String to_s, to_yaml(io : IO) : Nil
to_yaml : String to_yaml, try(&) try, unsafe_as(type : T.class) forall T unsafe_as

### Class methods inherited from class `Object`

from_json(string_or_io, root : String)
from_json(string_or_io) from_json, from_yaml(string_or_io : String | IO) from_yaml

### Macros inherited from class `Object`

class_getter(*names, &block) class_getter, class_getter!(*names) class_getter!, class_getter?(*names, &block) class_getter?, class_property(*names, &block) class_property, class_property!(*names) class_property!, class_property?(*names, &block) class_property?, class_setter(*names) class_setter, def_clone def_clone, def_equals(*fields) def_equals, def_equals_and_hash(*fields) def_equals_and_hash, def_hash(*fields) def_hash, delegate(*methods, to object) delegate, forward_missing_to(delegate) forward_missing_to, getter(*names, &block) getter, getter!(*names) getter!, getter?(*names, &block) getter?, property(*names, &block) property, property!(*names) property!, property?(*names, &block) property?, setter(*names) setter

##
Constructor Detail

def self.new(str : String, options : XML::ParserOptions = XML::ParserOptions.default) #

Creates a new reader from a string.

See `XML::ParserOptions.default` for default options.

def self.new(io : IO, options : XML::ParserOptions = XML::ParserOptions.default) #

Creates a new reader from an IO.

See `XML::ParserOptions.default` for default options.

##
Instance Method Detail

def [](attribute : String) : String #

Gets the attribute content for the attribute given by name. Raises `KeyError` if attribute is not found.

def []?(attribute : String) : String | Nil #

Gets the attribute content for the attribute given by name. Returns `nil` if attribute is not found.

def attributes_count : Int32 #

Returns attribute count of the node.

def depth : Int32 #

Returns the current nesting depth of the reader.

def empty_element? : Bool #

Checks if the node is an empty element.

def errors : Array(XML::Error) #

Returns the errors reported while parsing.

def expand : XML::Node #

Expands the node to a `XML::Node` that can be searched with XPath etc. The returned `XML::Node` is only valid until the next call to `#read`.

Raises a `XML::Error` if the node could not be expanded.

def expand? : XML::Node | Nil #

Expands the node to a `XML::Node` that can be searched with XPath etc. The returned `XML::Node` is only valid until the next call to `#read`.

Returns `nil` if the node could not be expanded.

def has_attributes? : Bool #

Checks if the node has any attributes.

def move_to_attribute(name : String) : Bool #

Moves to the `XML::Reader::Type::ATTRIBUTE` with the specified name.

def move_to_element : Bool #

Moves from the `XML::Reader::Type::ATTRIBUTE` to its containing `XML::Reader::Type::ELEMENT`.

def move_to_first_attribute : Bool #

Moves to the first `XML::Reader::Type::ATTRIBUTE` of the node.

def move_to_next_attribute : Bool #

Moves to the next `XML::Reader::Type::ATTRIBUTE` of the node.

def name : String #

Returns the name of the node.

def next : Bool #

Moves the reader to the next node while skipping subtrees.

def next_sibling : Bool #

Moves the reader to the next sibling node while skipping subtrees.

def node_type : XML::Reader::Type #

Returns the `XML::Reader::Type` of the node.

def read : Bool #

Moves the reader to the next node.

def read_inner_xml : String #

Returns the node's XML content including subtrees.

def read_outer_xml : String #

Returns the XML for the node and its content including subtrees.

def to_unsafe : LibXML::XMLTextReader #

Returns a reference to the underlying `LibXML::XMLTextReader`.

def value : String #

Returns the text content of the node.