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class Nokogiri::XML::Reader

Parent:: Object
Included modules:

The Reader parser allows you to effectively pull parse an XML document. Once instantiated, call #each to iterate over each node. Note that you may only iterate over the document once!

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.

Here is an example of usage:

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

reader.each do |node|

  # node is an instance of Nokogiri::XML::Reader
  puts node.name

end

Note that #each can only be called once!! Once the cursor moves through the entire document, you must parse the document again. So make sure that you capture any information you need during the first iteration.

The Reader parser is good for when you need the speed of a SAX parser, but do not want to write a Document handler.

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

encoding[R]

The encoding for the document

errors[RW]

A list of errors encountered while parsing

source[R]

The XML source

Public Class Methods

from_io(io, url = nil, encoding = nil, options = 0) Show source

Create a new reader that parses io

static VALUE from_io(int argc, VALUE *argv, VALUE klass)
{
  VALUE rb_io, rb_url, encoding, rb_options;
  xmlTextReaderPtr reader;
  const char * c_url      = NULL;
  const char * c_encoding = NULL;
  int c_options           = 0;
  VALUE rb_reader, args[3];

  rb_scan_args(argc, argv, "13", &rb_io, &rb_url, &encoding, &rb_options);

  if (!RTEST(rb_io)) rb_raise(rb_eArgError, "io cannot be nil");
  if (RTEST(rb_url)) c_url = StringValueCStr(rb_url);
  if (RTEST(encoding)) c_encoding = StringValueCStr(encoding);
  if (RTEST(rb_options)) c_options = (int)NUM2INT(rb_options);

  reader = xmlReaderForIO(
      (xmlInputReadCallback)io_read_callback,
      (xmlInputCloseCallback)io_close_callback,
      (void *)rb_io,
      c_url,
      c_encoding,
      c_options
  );

  if(reader == NULL) {
    xmlFreeTextReader(reader);
    rb_raise(rb_eRuntimeError, "couldn't create a parser");
  }

  rb_reader = Data_Wrap_Struct(klass, NULL, dealloc, reader);
  args[0] = rb_io;
  args[1] = rb_url;
  args[2] = encoding;
  rb_obj_call_init(rb_reader, 3, args);

  return rb_reader;
}

from_memory(string, url = nil, encoding = nil, options = 0) Show source

Create a new reader that parses string

static VALUE from_memory(int argc, VALUE *argv, VALUE klass)
{
  VALUE rb_buffer, rb_url, encoding, rb_options;
  xmlTextReaderPtr reader;
  const char * c_url      = NULL;
  const char * c_encoding = NULL;
  int c_options           = 0;
  VALUE rb_reader, args[3];

  rb_scan_args(argc, argv, "13", &rb_buffer, &rb_url, &encoding, &rb_options);

  if (!RTEST(rb_buffer)) rb_raise(rb_eArgError, "string cannot be nil");
  if (RTEST(rb_url)) c_url = StringValueCStr(rb_url);
  if (RTEST(encoding)) c_encoding = StringValueCStr(encoding);
  if (RTEST(rb_options)) c_options = (int)NUM2INT(rb_options);

  reader = xmlReaderForMemory(
      StringValuePtr(rb_buffer),
      (int)RSTRING_LEN(rb_buffer),
      c_url,
      c_encoding,
      c_options
  );

  if(reader == NULL) {
    xmlFreeTextReader(reader);
    rb_raise(rb_eRuntimeError, "couldn't create a parser");
  }

  rb_reader = Data_Wrap_Struct(klass, NULL, dealloc, reader);
  args[0] = rb_buffer;
  args[1] = rb_url;
  args[2] = encoding;
  rb_obj_call_init(rb_reader, 3, args);

  return rb_reader;
}

Public Instance Methods

attribute(name) Show source

Get the value of attribute named name

static VALUE reader_attribute(VALUE self, VALUE name)
{
  xmlTextReaderPtr reader;
  xmlChar *value ;
  VALUE rb_value;

  Data_Get_Struct(self, xmlTextReader, reader);

  if(NIL_P(name)) return Qnil;
  name = StringValue(name) ;

  value = xmlTextReaderGetAttribute(reader, (xmlChar*)StringValueCStr(name));
  if(value == NULL) return Qnil;

  rb_value = NOKOGIRI_STR_NEW2(value);
  xmlFree(value);
  return rb_value;
}

attribute_at(index) Show source

Get the value of attribute at index

static VALUE attribute_at(VALUE self, VALUE index)
{
  xmlTextReaderPtr reader;
  xmlChar *value;
  VALUE rb_value;

  Data_Get_Struct(self, xmlTextReader, reader);

  if(NIL_P(index)) return Qnil;
  index = rb_Integer(index);

  value = xmlTextReaderGetAttributeNo(
      reader,
      (int)NUM2INT(index)
  );
  if(value == NULL) return Qnil;

  rb_value = NOKOGIRI_STR_NEW2(value);
  xmlFree(value);
  return rb_value;
}

attribute_count Show source

Get the number of attributes for the current node

static VALUE attribute_count(VALUE self)
{
  xmlTextReaderPtr reader;
  int count;

  Data_Get_Struct(self, xmlTextReader, reader);
  count = xmlTextReaderAttributeCount(reader);
  if(count == -1) return Qnil;

  return INT2NUM((long)count);
}

attribute_nodes() Show source

Get a list of attributes for the current node

# File lib/nokogiri/xml/reader.rb, line 97
def attribute_nodes
  nodes = attr_nodes
  nodes.each { |v| v.instance_variable_set(:@_r, self) }
  nodes
end

attributes() Show source

Get a list of attributes for the current node.

# File lib/nokogiri/xml/reader.rb, line 89
def attributes
  Hash[attribute_nodes.map { |node|
    [node.name, node.to_s]
  }].merge(namespaces || {})
end

attributes? Show source

Does this node have attributes?

static VALUE attributes_eh(VALUE self)
{
  xmlTextReaderPtr reader;
  int eh;

  Data_Get_Struct(self, xmlTextReader, reader);
  eh = has_attributes(reader);
  if(eh == 0) return Qfalse;
  if(eh == 1) return Qtrue;

  return Qnil;
}

base_uri Show source

Get the xml:base of the node

static VALUE base_uri(VALUE self)
{
  xmlTextReaderPtr reader;
  const char * base_uri;

  Data_Get_Struct(self, xmlTextReader, reader);
  base_uri = (const char *)xmlTextReaderBaseUri(reader);
  if (base_uri == NULL) return Qnil;

  return NOKOGIRI_STR_NEW2(base_uri);
}

default? Show source

Was an attribute generated from the default value in the DTD or schema?

static VALUE default_eh(VALUE self)
{
  xmlTextReaderPtr reader;
  int eh;

  Data_Get_Struct(self, xmlTextReader, reader);
  eh = xmlTextReaderIsDefault(reader);
  if(eh == 0) return Qfalse;
  if(eh == 1) return Qtrue;

  return Qnil;
}

depth Show source

Get the depth of the node

static VALUE depth(VALUE self)
{
  xmlTextReaderPtr reader;
  int depth;

  Data_Get_Struct(self, xmlTextReader, reader);
  depth = xmlTextReaderDepth(reader);
  if(depth == -1) return Qnil;

  return INT2NUM((long)depth);
}

each() { |cursor| ... } Show source

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

# File lib/nokogiri/xml/reader.rb, line 105
def each
  while cursor = self.read
    yield cursor
  end
end

empty_element? # → true or false Show source

Returns true if the current node is empty, otherwise false.

static VALUE empty_element_p(VALUE self)
{
  xmlTextReaderPtr reader;

  Data_Get_Struct(self, xmlTextReader, reader);

  if(xmlTextReaderIsEmptyElement(reader))
    return Qtrue;

  return Qfalse;
}

Also aliased as: self_closing?

inner_xml Show source

Read the contents of the current node, including child nodes and markup. Returns a utf-8 encoded string.

static VALUE inner_xml(VALUE self)
{
  xmlTextReaderPtr reader;
  xmlChar* value;
  VALUE str;

  Data_Get_Struct(self, xmlTextReader, reader);

  value = xmlTextReaderReadInnerXml(reader);

  str = Qnil;
  if(value) {
    str = NOKOGIRI_STR_NEW2((char*)value);
    xmlFree(value);
  }

  return str;
}

lang Show source

Get the xml:lang scope within which the node resides.

static VALUE lang(VALUE self)
{
  xmlTextReaderPtr reader;
  const char *lang;

  Data_Get_Struct(self, xmlTextReader, reader);
  lang = (const char *)xmlTextReaderConstXmlLang(reader);
  if(lang == NULL) return Qnil;

  return NOKOGIRI_STR_NEW2(lang);
}

local_name Show source

Get the local name of the node

static VALUE local_name(VALUE self)
{
  xmlTextReaderPtr reader;
  const char *name;

  Data_Get_Struct(self, xmlTextReader, reader);
  name = (const char *)xmlTextReaderConstLocalName(reader);
  if(name == NULL) return Qnil;

  return NOKOGIRI_STR_NEW2(name);
}

name Show source

Get the name of the node. Returns a utf-8 encoded string.

static VALUE name(VALUE self)
{
  xmlTextReaderPtr reader;
  const char *name;

  Data_Get_Struct(self, xmlTextReader, reader);
  name = (const char *)xmlTextReaderConstName(reader);
  if(name == NULL) return Qnil;

  return NOKOGIRI_STR_NEW2(name);
}

namespace_uri Show source

Get the URI defining the namespace associated with the node

static VALUE namespace_uri(VALUE self)
{
  xmlTextReaderPtr reader;
  const char *uri;

  Data_Get_Struct(self, xmlTextReader, reader);
  uri = (const char *)xmlTextReaderConstNamespaceUri(reader);
  if(uri == NULL) return Qnil;

  return NOKOGIRI_STR_NEW2(uri);
}

namespaces Show source

Get a hash of namespaces for this Node

static VALUE namespaces(VALUE self)
{
  xmlTextReaderPtr reader;
  xmlNodePtr ptr;
  VALUE attr ;

  Data_Get_Struct(self, xmlTextReader, reader);

  attr = rb_hash_new() ;

  if (! has_attributes(reader))
    return attr ;

  ptr = xmlTextReaderExpand(reader);
  if(ptr == NULL) return Qnil;

  Nokogiri_xml_node_namespaces(ptr, attr);

  return attr ;
}

node_type Show source

Get the type of readers current node

static VALUE node_type(VALUE self)
{
  xmlTextReaderPtr reader;
  Data_Get_Struct(self, xmlTextReader, reader);
  return INT2NUM((long)xmlTextReaderNodeType(reader));
}

outer_xml Show source

Read the current node and its contents, including child nodes and markup. Returns a utf-8 encoded string.

static VALUE outer_xml(VALUE self)
{
  xmlTextReaderPtr reader;
  xmlChar *value;
  VALUE str = Qnil;

  Data_Get_Struct(self, xmlTextReader, reader);

  value = xmlTextReaderReadOuterXml(reader);

  if(value) {
    str = NOKOGIRI_STR_NEW2((char*)value);
    xmlFree(value);
  }
  return str;
}

prefix Show source

Get the shorthand reference to the namespace associated with the node.

static VALUE prefix(VALUE self)
{
  xmlTextReaderPtr reader;
  const char *prefix;

  Data_Get_Struct(self, xmlTextReader, reader);
  prefix = (const char *)xmlTextReaderConstPrefix(reader);
  if(prefix == NULL) return Qnil;

  return NOKOGIRI_STR_NEW2(prefix);
}

read Show source

Move the Reader forward through the XML document.

static VALUE read_more(VALUE self)
{
  xmlTextReaderPtr reader;
  xmlErrorPtr error;
  VALUE error_list;
  int ret;

  Data_Get_Struct(self, xmlTextReader, reader);

  error_list = rb_funcall(self, rb_intern("errors"), 0);

  xmlSetStructuredErrorFunc((void *)error_list, Nokogiri_error_array_pusher);
  ret = xmlTextReaderRead(reader);
  xmlSetStructuredErrorFunc(NULL, NULL);

  if(ret == 1) return self;
  if(ret == 0) return Qnil;

  error = xmlGetLastError();
  if(error)
    rb_exc_raise(Nokogiri_wrap_xml_syntax_error(error));
  else
    rb_raise(rb_eRuntimeError, "Error pulling: %d", ret);

  return Qnil;
}

self_closing?()

Alias for: empty_element?

state Show source

Get the state of the reader

static VALUE state(VALUE self)
{
  xmlTextReaderPtr reader;
  Data_Get_Struct(self, xmlTextReader, reader);
  return INT2NUM((long)xmlTextReaderReadState(reader));
}

value Show source

Get the text value of the node if present. Returns a utf-8 encoded string.

static VALUE value(VALUE self)
{
  xmlTextReaderPtr reader;
  const char *value;

  Data_Get_Struct(self, xmlTextReader, reader);
  value = (const char *)xmlTextReaderConstValue(reader);
  if(value == NULL) return Qnil;

  return NOKOGIRI_STR_NEW2(value);
}

value? Show source

Does this node have a text value?

static VALUE value_eh(VALUE self)
{
  xmlTextReaderPtr reader;
  int eh;

  Data_Get_Struct(self, xmlTextReader, reader);
  eh = xmlTextReaderHasValue(reader);
  if(eh == 0) return Qfalse;
  if(eh == 1) return Qtrue;

  return Qnil;
}

xml_version Show source

Get the XML version of the document being read

static VALUE xml_version(VALUE self)
{
  xmlTextReaderPtr reader;
  const char *version;

  Data_Get_Struct(self, xmlTextReader, reader);
  version = (const char *)xmlTextReaderConstXmlVersion(reader);
  if(version == NULL) return Qnil;

  return NOKOGIRI_STR_NEW2(version);
}

© 2008–2017 Aaron Patterson, Mike Dalessio, Charles Nutter, Sergio Arbeo
Patrick Mahoney, Yoko Harada, Akinori Musha, John Shahid
Licensed under the MIT License.