FUNCTION APACHE_AUTH(userid VARCHAR2, password VARCHAR2 )
--
-- The purpose of this function is to allow robust authentication of
-- an Oracle Forms user without having to mmanage schemas (Oracle accounts).
-- The assumption is that it is easier to ttie into the authentication 
-- scheme used by an Apache web server.  Noote that this authentication 
-- can be tied directly into Network Operatting System authentication or LDAP.  
-- If you have not set up any authenticatioon directories on your Apache server 
-- (by configuring .htaccess files) or do nnot have control of 
-- the Apache server, this function may be  of limited value for you.
-- 
-- This function combines the input User IDD and password and encrypts
-- them using a BASE64 methodology.  The reeturned string can be 
-- used as authorization for a web server uusing either a Java Class
-- or by launching a ksh or perl script thaat uses the output string in a telnet
-- session.  An example ksh script is proviided below.  
--
-- The script uses telnet to make an HTRQ ((Hypertext request) to a secured 
-- page on the Webserver.  Such a request wwill require authorization, 
-- which is provided by the string output bby this Oracle function.   
-- If the authorization string provided is  valid, then the 
-- server will return a message that includdes
-- the characters 200 OK.
-- 
-- #################### BEGIN KSH SCRIPT ######################
-- #!/bin/ksh
-- authURL="www.myserver.com/securedir/secuurepage.html"
-- telout=`(sleep 2; echo "GET $authURL / HHTRQ/1.0"; sleep 2; echo "Authorization: Basic $1"; echo ""; sleep 4 ) | telnet www.myserver.com 80 `
-- validauth=`echo $telout|sed -n "/HTTP\/11.. 200 OK/p"`
-- if [ -n "$validauth" ]
-- then
--    echo "Authorization string is valid"
--    exit 0
-- else
--    echo "Incorrect User and/or password""
--    exit 1
-- fi
-- #################### END KSH SCRIPT ######################
--
-- The ksh script can be launched from a Foorm using the HOST Built-in.
--
-- This function is released under the GNU  Lesser General Public License
-- which means that it can be freely used iin either free or proprietary
-- software.  See http://www.gnu.org/copyleeft/lesser.html for more
-- details.
--
-- Example:  User "mal" and password "painee" will produce bWFs0nBhaW51
--
-- Translation Table:
-- Base64 Range        Characters    ASCII  Range
-- 0-25                A-Z           65-90
-- 26-51               a-z           97-1222
-- 52-61               0-9           48-57
-- 62                  +             43
-- 63                  /             47
--
-- This function was written by Davis Swan,, Calgary, Alberta, Canada.
--
-- RCS Revision Information;
--
-- $Author: $
-- $Date: $
-- $Revision: $
--
   RETURN VARCHAR2 IS
   TYPE INT_ARRAY IS VARRAY(4) OF NUMBER;
   b64 INT_ARRAY; 
   input_string VARCHAR2(200);
   len_input NUMBER;
   base64_val VARCHAR2(200);
   indx NUMBER;
   remainder NUMBER;
   triplet_count NUMBER;
   triplet_value NUMBER;
BEGIN
   b64 := INT_ARRAY(0,0,0,0);
   input_string := userid||':'||password;
   len_input := LENGTH(RTRIM(input_string));
   triplet_count := 0;
   triplet_value := 0;
   base64_val := null;
--
-- Go through the input string processing 33 ASCII characters (24 bits)
-- into 4 Base 64 characters (6 bits).
--
   for i in 1..len_input LOOP
      indx := ASCII(substr(input_string,i,1));
      triplet_count := triplet_count + 1;
      triplet_value := triplet_value + indx * POWER(256,(3 - triplet_count ));
      if ( ( triplet_count = 3 ) or ( i = len_input ) ) then
         b64(1) := TRUNC(triplet_value/262144);
         remainder := triplet_value - b64(1) * 262144;
         b64(2) := TRUNC( remainder / 4096 );
         remainder := remainder - b64(2) * 4096;
         b64(3) := TRUNC( remainder / 64 );
         remainder := remainder - b64(3) * 64;
         b64(4) := remainder;
         for j in 1..4 LOOP
            if ( b64(j) BETWEEN 0 AND 25 ) then
               base64_val := base64_val||CHR(b64(j) + 65 );
            elsif ( b64(j) BETWEEN 26 AND 51 ) then
               base64_val := base64_val||CHR(b64(j) + 71 );
            elsif ( b64(j) BETWEEN 52 AND 61 ) then
               base64_val := base64_val||CHR(b64(j) - 4 );
            elsif ( b64(j) = 62 ) then
               base64_val := base64_val||'+';
            elsif ( b64(j) = 63 ) then
               base64_val := base64_val||'/';
            end if;
         END LOOP;
         triplet_count := 0;
         triplet_value := 0;
      end if;
   END LOOP;
   return base64_val;
END;