Class: LibXML::XML::Dtd

Inherits:

Object

• Object
• LibXML::XML::Dtd

Defined in:

ext/libxml/ruby_xml_dtd.c,
ext/libxml/ruby_xml_dtd.c

Overview

The XML::Dtd class is used to prepare DTD’s for validation of xml documents.

DTDs can be created from a string or a pair of public and system identifiers. Once a Dtd object is instantiated, an XML document can be validated by the XML::Document#validate method providing the XML::Dtd object as parameeter. The method will raise an exception if the document is not valid.

Basic usage:

# parse DTD
dtd = XML::Dtd.new("<!ELEMENT root (item*) >\n<!ELEMENT item (#PCDATA) >\n")

# parse xml document to be validated
instance = XML::Document.file('instance.xml')

# validate
instance.validate(dtd)

Instance Method Summary

• #external_id ⇒ Object

  Obtain this dtd’s external identifer (for a PUBLIC DTD).

• #initialize(*args) ⇒ Object constructor

  Create a new Dtd from the specified public and system identifiers.

• #name ⇒ Object

  Obtain this dtd’s name.

• #uri ⇒ Object (also: #system_id)

  Obtain this dtd’s URI (for a SYSTEM or PUBLIC DTD).

Constructor Details

#XML::Dtd.new("DTD string") ⇒ Object #XML::Dtd.new("public", "system") ⇒ Object #XML::Dtd.new("name", "public", "system", document) ⇒ Object #XML::Dtd.new("name", "public", "system", document, false) ⇒ Object #XML::Dtd.new("name", "public", "system", document, true) ⇒ Object

Create a new Dtd from the specified public and system identifiers.

# File 'ext/libxml/ruby_xml_dtd.c', line 144

static VALUE rxml_dtd_initialize(int argc, VALUE *argv, VALUE self)
{
  VALUE external, system, dtd_string;
  xmlParserInputBufferPtr buffer;
  xmlCharEncoding enc = XML_CHAR_ENCODING_NONE;
  xmlChar *new_string;
  xmlDtdPtr xdtd;

  // 1 argument -- string                            --> parsujeme jako dtd
  // 2 arguments -- public, system                   --> bude se hledat
  // 3 arguments -- public, system, name             --> creates an external subset (any parameter may be nil)
  // 4 arguments -- public, system, name, doc        --> creates an external subset (any parameter may be nil)
  // 5 arguments -- public, system, name, doc, true  --> creates an internal subset (all but last parameter may be nil)
  switch (argc)
  {
  case 3:
  case 4:
  case 5: {
      VALUE name, doc, internal;
      const xmlChar *xname = NULL, *xpublic = NULL, *xsystem = NULL;
      xmlDocPtr xdoc = NULL;

      rb_scan_args(argc, argv, "32", &external, &system, &name, &doc, &internal);

      if (external != Qnil) {
        Check_Type(external, T_STRING);
        xpublic = (const xmlChar*) StringValuePtr(external);
      }
      if (system != Qnil) {
        Check_Type(system, T_STRING);
        xsystem = (const xmlChar*) StringValuePtr(system);
      }
      if (name != Qnil) {
        Check_Type(name, T_STRING);
        xname = (const xmlChar*) StringValuePtr(name);
      }
      if (doc != Qnil) {
        if (rb_obj_is_kind_of(doc, cXMLDocument) == Qfalse)
          rb_raise(rb_eTypeError, "Must pass an XML::Document object");
        Data_Get_Struct(doc, xmlDoc, xdoc);
      }

      if (internal == Qnil || internal == Qfalse)
        xdtd = xmlNewDtd(xdoc, xname, xpublic, xsystem);
      else
        xdtd = xmlCreateIntSubset(xdoc, xname, xpublic, xsystem);

      if (xdtd == NULL)
        rxml_raise(&xmlLastError);

      /* Document will free this dtd now. */
      RDATA(self)->dfree = NULL;
      DATA_PTR(self) = xdtd;

      xmlSetTreeDoc((xmlNodePtr) xdtd, xdoc);
    }
    break;

  case 2:
    rb_scan_args(argc, argv, "20", &external, &system);

    Check_Type(external, T_STRING);
    Check_Type(system, T_STRING);

    xdtd = xmlParseDTD((xmlChar*) StringValuePtr(external),
        (xmlChar*) StringValuePtr(system));

    if (xdtd == NULL)
      rxml_raise(&xmlLastError);

    DATA_PTR(self) = xdtd;

    xmlSetTreeDoc((xmlNodePtr) xdtd, NULL);
    break;

  case 1:
    rb_scan_args(argc, argv, "10", &dtd_string);
    Check_Type(dtd_string, T_STRING);

    /* Note that buffer is freed by xmlParserInputBufferPush*/
    buffer = xmlAllocParserInputBuffer(enc);
    new_string = xmlStrdup((xmlChar*) StringValuePtr(dtd_string));
    xmlParserInputBufferPush(buffer, xmlStrlen(new_string),
        (const char*) new_string);

    xdtd = xmlIOParseDTD(NULL, buffer, enc);

    if (xdtd == NULL)
      rxml_raise(&xmlLastError);

    xmlFree(new_string);

    DATA_PTR(self) = xdtd;
    break;

  default:
    rb_raise(rb_eArgError, "wrong number of arguments");
  }

  return self;
}

Instance Method Details

#external_id ⇒ Object

Obtain this dtd’s external identifer (for a PUBLIC DTD).

# File 'ext/libxml/ruby_xml_dtd.c', line 84

static VALUE rxml_dtd_external_id_get(VALUE self)
{
  xmlDtdPtr xdtd;
  Data_Get_Struct(self, xmlDtd, xdtd);


  if (xdtd->ExternalID == NULL)
    return (Qnil);
  else
    return (rb_str_new2((const char*) xdtd->ExternalID));
}

#name ⇒ Object

Obtain this dtd’s name.

# File 'ext/libxml/ruby_xml_dtd.c', line 102

static VALUE rxml_dtd_name_get(VALUE self)
{
  xmlDtdPtr xdtd;
  Data_Get_Struct(self, xmlDtd, xdtd);


  if (xdtd->name == NULL)
    return (Qnil);
  else
    return (rb_str_new2((const char*) xdtd->name));
}

#uri ⇒ Object Also known as: system_id

Obtain this dtd’s URI (for a SYSTEM or PUBLIC DTD).

# File 'ext/libxml/ruby_xml_dtd.c', line 121

static VALUE rxml_dtd_uri_get(VALUE self)
{
  xmlDtdPtr xdtd;
  Data_Get_Struct(self, xmlDtd, xdtd);


  if (xdtd->SystemID == NULL)
    return (Qnil);
  else
    return (rb_str_new2((const char*) xdtd->SystemID));
}