vsp_calculate_digest — calculate on server-side a digest to perform a HTTP digest authentication


vsp_calculate_digest ( in username varchar ,
in password varchar ,
in credentials any );


The vsp_calculate_digest() function is used to calculate on server-side a digest to perform a HTTP digest authentication. When the authentication type is 'digest' the function will return a md5 checksum based on credentials, user name and password. The checksum calculation will be made as required for HTTP Digest authentication to compare against 'response' element of credentials. If the authentication is basic a NULL will be returned.



A string with name of the user account name


A string with a plain text password from the users table (can be from external LDAP server etc.)


A vector of name/value pairs (the keyword and value are strings) of:

Table24.114.Valid values

Name Description
authtype 'digest' or 'basic'
realm from HTTP Authorization request header
method from HTTP request line
uri from HTTP Authorization request header
nonce from HTTP Authorization request header
nc from HTTP Authorization request header
cnonce from HTTP Authorization request header
qop from HTTP Authorization request header
response the client-side calculated digest

Return Types

A string containing md5 digest, if 'authtype' option is 'digest'. Otherwise returns null.


Example24.446.A VSP page performing digest authentication

The following page check for digest authentication and returns OK if authentication succeeds, otherwise it asks for authentication again.

          declare auth any;
          declare cs varchar;
          auth := app_auth_vec (lines);
          if (not isarray (auth))
            app_get_auth ();
          cs := vsp_calculate_digest ('u1', 'secret', auth);
          if (cs is not null and cs = get_keyword ('response',auth))
             http ('OK');
            app_get_auth ();

      -- making the HTTP Digest authentication header
      create procedure app_get_auth ()
         http_request_status ('HTTP/1.1 401 Unauthorized');
         http_header (sprintf ('WWW-Authenticate: Digest realm="%s", domain="%s", nonce="%s", opaque="%s", stale="%s", qop="auth", algorithm="MD5"\r\n', 'my_realm', http_path(), md5 (datestring (now ())), md5 ('some string for hash'), 'false'));

      -- returns an array suitable for vsp_calculate_digest
      create procedure app_auth_vec (in lines any)
          declare ahdr, arr, authvec any;
          ahdr := http_request_header (lines, 'Authorization');
          if (isstring (ahdr) and ahdr like 'Digest%')
              ahdr := subseq (ahdr, 6, length (ahdr));
              arr := split_and_decode (ahdr, 0, '\0\0,=');
              authvec := vector ('authtype', 'Digest', 'method', http_request_get ('REQUEST_METHOD'));
              foreach (varchar elm in arr) do
                  declare elm1 varchar;
                  elm1 := trim (elm, '" ');
                  authvec := vector_concat (authvec, vector (elm1));
           return authvec;

See Also