Class: Nokogiri::XML::Reader

Inherits:
Object
  • Object
show all
Includes:
Enumerable
Defined in:
lib/nokogiri/xml/reader.rb,
ext/nokogiri/xml_reader.c

Overview

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(<<-eoxml)
  <x xmlns:tenderlove='http://tenderlovemaking.com/'>
    <tenderlove:foo awesome='true'>snuggles!</tenderlove:foo>
  </x>
eoxml

reader.each do |node|

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

end

Note that Nokogiri::XML::Reader#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.

Constant Summary collapse

TYPE_NONE =
0
TYPE_ELEMENT =

Element node type

1
TYPE_ATTRIBUTE =

Attribute node type

2
TYPE_TEXT =

Text node type

3
TYPE_CDATA =

CDATA node type

4
TYPE_ENTITY_REFERENCE =

Entity Reference node type

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TYPE_ENTITY =

Entity node type

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TYPE_PROCESSING_INSTRUCTION =

PI node type

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TYPE_COMMENT =

Comment node type

8
TYPE_DOCUMENT =

Document node type

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TYPE_DOCUMENT_TYPE =

Document Type node type

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TYPE_DOCUMENT_FRAGMENT =

Document Fragment node type

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TYPE_NOTATION =

Notation node type

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TYPE_WHITESPACE =

Whitespace node type

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TYPE_SIGNIFICANT_WHITESPACE =

Significant Whitespace node type

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TYPE_END_ELEMENT =

Element end node type

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TYPE_END_ENTITY =

Entity end node type

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TYPE_XML_DECLARATION =

XML Declaration node type

17

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Instance Attribute Details

#errorsObject

A list of errors encountered while parsing


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# File 'lib/nokogiri/xml/reader.rb', line 72

def errors
  @errors
end

#sourceObject (readonly)

The XML source


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# File 'lib/nokogiri/xml/reader.rb', line 75

def source
  @source
end

Class Method Details

.from_io(io, url = nil, encoding = nil, options = 0) ⇒ Object

Create a new reader that parses io


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# File 'ext/nokogiri/xml_reader.c', line 650

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)noko_io_read,
             (xmlInputCloseCallback)noko_io_close,
             (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) ⇒ Object

Create a new reader that parses string


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# File 'ext/nokogiri/xml_reader.c', line 605

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;
}

Instance Method Details

#attribute(name) ⇒ Object

Get the value of attribute named name


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# File 'ext/nokogiri/xml_reader.c', line 267

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) ⇒ Object

Get the value of attribute at index


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# File 'ext/nokogiri/xml_reader.c', line 238

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_countObject

Get the number of attributes for the current node


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# File 'ext/nokogiri/xml_reader.c', line 293

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(count);
}

#attribute_hashObject

:call-seq: attribute_hash() → Hash<String ⇒ String>

Get the attributes of the current node as a Hash of names and values.

See related: #attributes and #namespaces


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# File 'ext/nokogiri/xml_reader.c', line 198

static VALUE
rb_xml_reader_attribute_hash(VALUE rb_reader)
{
  VALUE rb_attributes = rb_hash_new();
  xmlTextReaderPtr c_reader;
  xmlNodePtr c_node;
  xmlAttrPtr c_property;

  Data_Get_Struct(rb_reader, xmlTextReader, c_reader);

  if (!has_attributes(c_reader)) {
    return rb_attributes;
  }

  c_node = xmlTextReaderExpand(c_reader);
  c_property = c_node->properties;
  while (c_property != NULL) {
    VALUE rb_name = NOKOGIRI_STR_NEW2(c_property->name);
    VALUE rb_value = Qnil;
    xmlChar *c_value = xmlNodeGetContent((xmlNode *)c_property);

    if (c_value) {
      rb_value = NOKOGIRI_STR_NEW2(c_value);
      xmlFree(c_value);
    }

    rb_hash_aset(rb_attributes, rb_name, rb_value);

    c_property = c_property->next;
  }

  return rb_attributes;
}

#attribute_nodesObject

:call-seq: attribute_nodes() → Array<Nokogiri::XML::Attr>

Get the attributes of the current node as an Array of XML:Attr

⚠ This method is deprecated and unsafe to use. It will be removed in a future version of Nokogiri.

See related: #attribute_hash, #attributes


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# File 'ext/nokogiri/xml_reader.c', line 158

static VALUE
rb_xml_reader_attribute_nodes(VALUE rb_reader)
{
  xmlTextReaderPtr c_reader;
  xmlNodePtr c_node;
  VALUE attr_nodes;
  int j;

  // TODO: deprecated, remove in Nokogiri v1.15, see https://github.com/sparklemotion/nokogiri/issues/2598
  // After removal, we can also remove all the "node_has_a_document" special handling from xml_node.c
  NOKO_WARN_DEPRECATION("Reader#attribute_nodes is deprecated and will be removed in a future version of Nokogiri. Please use Reader#attribute_hash instead.");

  Data_Get_Struct(rb_reader, xmlTextReader, c_reader);

  if (! has_attributes(c_reader)) {
    return rb_ary_new() ;
  }

  c_node = xmlTextReaderExpand(c_reader);
  if (c_node == NULL) {
    return Qnil;
  }

  attr_nodes = noko_xml_node_attrs(c_node);

  /* ensure that the Reader won't be GCed as long as a node is referenced */
  for (j = 0 ; j < RARRAY_LEN(attr_nodes) ; j++) {
    rb_iv_set(rb_ary_entry(attr_nodes, j), "@reader", rb_reader);
  }

  return attr_nodes;
}

#attributesObject

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.


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# File 'lib/nokogiri/xml/reader.rb', line 92

def attributes
  attribute_hash.merge(namespaces)
end

#attributes?Boolean

Does this node have attributes?

Returns:

  • (Boolean)

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# File 'ext/nokogiri/xml_reader.c', line 106

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_uriObject

base_uri

Get the xml:base of the node


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# File 'ext/nokogiri/xml_reader.c', line 464

static VALUE
rb_xml_reader_base_uri(VALUE rb_reader)
{
  VALUE rb_base_uri;
  xmlTextReaderPtr c_reader;
  xmlChar *c_base_uri;

  Data_Get_Struct(rb_reader, xmlTextReader, c_reader);

  c_base_uri = xmlTextReaderBaseUri(c_reader);
  if (c_base_uri == NULL) {
    return Qnil;
  }

  rb_base_uri = NOKOGIRI_STR_NEW2(c_base_uri);
  xmlFree(c_base_uri);

  return rb_base_uri;
}

#default?Boolean

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

Returns:

  • (Boolean)

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# File 'ext/nokogiri/xml_reader.c', line 66

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;
}

#depthObject

Get the depth of the node


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# File 'ext/nokogiri/xml_reader.c', line 312

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(depth);
}

#eachObject

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


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# File 'lib/nokogiri/xml/reader.rb', line 98

def each
  while (cursor = read)
    yield cursor
  end
end

#empty_element?(#) ⇒ Boolean Also known as: self_closing?

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

Returns:

  • (Boolean)

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# File 'ext/nokogiri/xml_reader.c', line 696

static VALUE
empty_element_p(VALUE self)
{
  xmlTextReaderPtr reader;

  Data_Get_Struct(self, xmlTextReader, reader);

  if (xmlTextReaderIsEmptyElement(reader)) {
    return Qtrue;
  }

  return Qfalse;
}

#encodingObject


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# File 'ext/nokogiri/xml_reader.c', line 710

static VALUE
rb_xml_reader_encoding(VALUE rb_reader)
{
  xmlTextReaderPtr c_reader;
  const char *parser_encoding;
  VALUE constructor_encoding;

  constructor_encoding = rb_iv_get(rb_reader, "@encoding");
  if (RTEST(constructor_encoding)) {
    return constructor_encoding;
  }

  Data_Get_Struct(rb_reader, xmlTextReader, c_reader);
  parser_encoding = (const char *)xmlTextReaderConstEncoding(c_reader);
  if (parser_encoding == NULL) { return Qnil; }
  return NOKOGIRI_STR_NEW2(parser_encoding);
}

#inner_xmlObject

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


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# File 'ext/nokogiri/xml_reader.c', line 554

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;
}

#langObject

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


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# File 'ext/nokogiri/xml_reader.c', line 350

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_nameObject

Get the local name of the node


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# File 'ext/nokogiri/xml_reader.c', line 426

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);
}

#nameObject

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


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# File 'ext/nokogiri/xml_reader.c', line 445

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_uriObject

Get the URI defining the namespace associated with the node


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# File 'ext/nokogiri/xml_reader.c', line 407

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);
}

#namespacesObject

Get a hash of namespaces for this Node


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# File 'ext/nokogiri/xml_reader.c', line 126

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_typeObject

Get the type of readers current node


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# File 'ext/nokogiri/xml_reader.c', line 504

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

#outer_xmlObject

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


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# File 'ext/nokogiri/xml_reader.c', line 581

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;
}

#prefixObject

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


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# File 'ext/nokogiri/xml_reader.c', line 388

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);
}

#readObject

Move the Reader forward through the XML document.


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# File 'ext/nokogiri/xml_reader.c', line 518

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;
}

#stateObject

Get the state of the reader


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# File 'ext/nokogiri/xml_reader.c', line 490

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

#valueObject

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


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# File 'ext/nokogiri/xml_reader.c', line 369

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?Boolean

Does this node have a text value?

Returns:

  • (Boolean)

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# File 'ext/nokogiri/xml_reader.c', line 86

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_versionObject

Get the XML version of the document being read


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# File 'ext/nokogiri/xml_reader.c', line 331

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);
}