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

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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

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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

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Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Instance Attribute Details

#encoding ⇒ Object (readonly)

The encoding for the document



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# File 'lib/nokogiri/xml/reader.rb', line 73

def encoding
  @encoding
end

#errors ⇒ Object

A list of errors encountered while parsing



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# File 'lib/nokogiri/xml/reader.rb', line 70

def errors
  @errors
end

#source ⇒ Object (readonly)

The XML source



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# File 'lib/nokogiri/xml/reader.rb', line 76

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 581

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 = StringValuePtr(rb_url);
  if (RTEST(encoding)) c_encoding = StringValuePtr(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) ⇒ Object

Create a new reader that parses string



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# File 'ext/nokogiri/xml_reader.c', line 537

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 = StringValuePtr(rb_url);
  if (RTEST(encoding)) c_encoding = StringValuePtr(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 210

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*)StringValuePtr(name));
  if(value == NULL) {
    /* this section is an attempt to workaround older versions of libxml that
       don't handle namespaces properly in all attribute-and-friends functions */
    xmlChar *prefix = NULL ;
    xmlChar *localname = xmlSplitQName2((xmlChar*)StringValuePtr(name), &prefix);
    if (localname != NULL) {
      value = xmlTextReaderLookupNamespace(reader, localname);
      xmlFree(localname) ;
    } else {
      value = xmlTextReaderLookupNamespace(reader, prefix);
    }
    xmlFree(prefix);
  }
  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 182

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 ⇒ Object

Get the number of attributes for the current node



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# File 'ext/nokogiri/xml_reader.c', line 248

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 ⇒ Object

Get a list of attributes for the current node



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# 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 ⇒ Object

Get a list of attributes for the current node.



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# File 'lib/nokogiri/xml/reader.rb', line 89

def attributes
  Hash[attribute_nodes.map { |node|
    [node.name, node.to_s]
  }].merge(namespaces || {})
end

#attributes? ⇒ Boolean

Does this node have attributes?

Returns:

  • (Boolean) 


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# File 'ext/nokogiri/xml_reader.c', line 109

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 ⇒ Object

base_uri

Get the xml:base of the node



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# File 'ext/nokogiri/xml_reader.c', line 410

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? ⇒ 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 71

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 ⇒ Object

Get the depth of the node



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# File 'ext/nokogiri/xml_reader.c', line 266

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 ⇒ Object

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



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# File 'lib/nokogiri/xml/reader.rb', line 105

def each
  while cursor = self.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 626

static VALUE empty_element_p(VALUE self)
{
  xmlTextReaderPtr reader;

  Data_Get_Struct(self, xmlTextReader, reader);

  if(xmlTextReaderIsEmptyElement(reader))
    return Qtrue;

  return Qfalse;
}

#inner_xml ⇒ Object

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 488

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 ⇒ Object

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



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# File 'ext/nokogiri/xml_reader.c', line 302

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 ⇒ Object

Get the local name of the node



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# File 'ext/nokogiri/xml_reader.c', line 374

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 ⇒ Object

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



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# File 'ext/nokogiri/xml_reader.c', line 392

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 ⇒ Object

Get the URI defining the namespace associated with the node



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# File 'ext/nokogiri/xml_reader.c', line 356

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 ⇒ Object

Get a hash of namespaces for this Node



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# File 'ext/nokogiri/xml_reader.c', line 128

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 ⇒ Object

Get the type of readers current node



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# File 'ext/nokogiri/xml_reader.c', line 441

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

#outer_xml ⇒ Object

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 514

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 ⇒ Object

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



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# File 'ext/nokogiri/xml_reader.c', line 338

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 ⇒ Object

Move the Reader forward through the XML document.



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# File 'ext/nokogiri/xml_reader.c', line 454

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((VALUE)NULL, error));
  else
    rb_raise(rb_eRuntimeError, "Error pulling: %d", ret);

  return Qnil;
}

#state ⇒ Object

Get the state of the reader



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# File 'ext/nokogiri/xml_reader.c', line 428

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

#value ⇒ Object

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 320

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 90

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 ⇒ Object

Get the XML version of the document being read



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# File 'ext/nokogiri/xml_reader.c', line 284

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);
}