How validate HTML using PL/SQL

Question

Hi,
I try validate HTML using PL/SQL that user inputs.
I did create below function for that purpose
CREATE OR REPLACE
FUNCTION validate_html(
  p_html IN VARCHAR2
) RETURN BOOLEAN
AS
  l_comment  XMLTYPE;
  xml_parse_err EXCEPTION;
  PRAGMA EXCEPTION_INIT (xml_parse_err , -31011);
BEGIN
  l_comment := xmlType.createXML('<root><row>' || p_html || '</row></root>');
  RETURN TRUE;
EXCEPTION WHEN xml_parse_err THEN
  RETURN FALSE;
END;
Function works ok and return true if I run e.g.
BEGIN
  IF validate_html('<p>Hello</p>') THEN
    dbms_output.put_line('OK');
  ELSE
    dbms_output.put_line('Not valid HTML');
  END IF;
END;
And return false if I enter not valid HTML like
BEGIN
  IF validate_html('<p>Hello') THEN
    dbms_output.put_line('OK');
  ELSE
    dbms_output.put_line('Not valid HTML');
  END IF;
END;
But it return false also if I run below
BEGIN
  IF validate_html('<p>Hello &nbsp</p>') THEN
    dbms_output.put_line('OK');
  ELSE
    dbms_output.put_line('Not valid HTML');
  END IF;
END;
Problem seems to be that &nbsp (there is ; in end but do not know how post it without forum convert that to space) witch is valid HTML for me.
I know that HTML is not XML, but can I use Oracle database XML functions for validating HTML?
How I should validate user inputted HTML?
I'm currently developing this using Oracle XE 11G database.
Regards,
Jari

Answer 1

Not an elegant way:
But try this.........
CREATE OR REPLACE FUNCTION validate_html (p_html IN VARCHAR2)
   RETURN BOOLEAN AS
   l_comment       XMLTYPE;
   xml_parse_err   EXCEPTION;
   PRAGMA EXCEPTION_INIT (xml_parse_err, -31011);
BEGIN
   l_comment :=
      xmlType.createXML (
         '<root><row>'
         || CASE
               WHEN INSTR (p_html, '&') > 0 THEN
                  UTL_I18N.escape_reference (p_html)
               ELSE
                  p_html
            END
         || '</row></root>');
   RETURN TRUE;
EXCEPTION
   WHEN xml_parse_err THEN
      RETURN FALSE;
END;
SET DEFINE OFF
SET SERVEROUTPUT ON
BEGIN
   IF validate_html ('<p>Hello') THEN
      DBMS_OUTPUT.put_line ('OK');
   ELSE
      DBMS_OUTPUT.put_line ('Not valid HTML');
   END IF;
END;
SET DEFINE OFF
SET SERVEROUTPUT ON
BEGIN
   IF validate_html ('<p>Hello &nbsp</p>') THEN
      DBMS_OUTPUT.put_line ('OK');
   ELSE
      DBMS_OUTPUT.put_line ('Not valid HTML');
   END IF;
END;
Cheers,
Manik.