Question

I’m using a pdf package for oracle pl/sql called pl_fpdf to create pdfs on the fly (this is what I have to use at the moment). It works on one database, but doesn’t work on the other. I believe I’ve narrowed down the issue to a difference in character set and the behavior of utl_raw.cast_to_varchar2 when trying to convert image binary to ascii (base64).

The working character set is WE8MSWIN1252, and the other is AL32UTF8 (seems to be much more common these days)

My question is, how do I make utl_raw.cast_to_varchar2 behave the same with AL32UTF8 as it does with WE8MSWIN1252 so that the resulting base64 image data is correct?

Here’s the code where I think the issue is. If I’m completely wrong here, then please let me know.

procedure p_putstream(pData in out NOCOPY blob) is
    offset integer := 1;
    lv_content_length number := dbms_lob.getlength(pdata);
    buf_size integer := 2000;
    buf raw(2000);
begin
    p_out('stream');
    -- read the blob and put it in small pieces in a varchar
    while offset < lv_content_length loop
      dbms_lob.read(pData,buf_size,offset,buf);
      p_out(utl_raw.cast_to_varchar2(buf), false);
      offset := offset + buf_size;
    end loop;
    -- put a CRLF at te end of the blob
    p_out(chr(10), false);
    p_out('endstream');
exception
  when others then
   error('p_putstream : '||sqlerrm);
end p_putstream;

Answer 1

What is p_out ? A wrapper around dbms_output.put_line ?

Could this be a client character set issue ? According to the utl_raw.cast_to_varchar2 documentation:

“When casting to a VARCHAR2, the current Globalization Support character set is used for the characters within that VARCHAR2.”

E.g.

$ export NLS_LANG=AMERICAN_AMERICA.UTF8
$ sqlplus
SQL> select utl_raw.cast_to_varchar2('80') from dual;

UTL_RAW.CAST_TO_VARCHAR2('80')
--------------------------------------------------------------------------------
€

SQL>

But

$ unset NLS_LANG
$ sqlplus
SQL> select utl_raw.cast_to_varchar2('80') from dual;

UTL_RAW.CAST_TO_VARCHAR2('80')
--------------------------------------------------------------------------------
?

SQL>

When database character set is

SQL> select * from nls_database_parameters where parameter like '%CHARACTERSET';

PARAMETER                      VALUE
------------------------------ ----------------------------------------
NLS_CHARACTERSET               WE8MSWIN1252
NLS_NCHAR_CHARACTERSET         AL16UTF16