[Dovecot] API problem (noob)

[Lars Stavholm]

I'm a bit of a newbie, especially when it comes to dovecot
internals, but nevertheless, I need some help:

I'm working on a dovecot plugin, and I would like to copy
a mail message from the mail store out to a temporary file,
less a few headers:

  static const char *const exclude_headers[] = {
    "X-DSPAM-Signature"
  }
  strcpy(fname, mktemp(fname));
  fd = creat(fname, 0600);
  mail_get_stream(mail, NULL, NULL, &input);
  output = o_stream_create_fd_file(fd, 0, TRUE);
  input = i_stream_create_header_filter(input,
        HEADER_FILTER_EXCLUDE | HEADER_FILTER_NO_CR,
        exclude_headers, N_ELEMENTS(exclude_headers),
        null_header_filter_callback, NULL);
  o_stream_send_istream(output, input);


But all I get in the temp file is the message body,
i.e. no headers at all. What am I doing wrong here?

My understanding (or hope:) of what the function
i_stream_create_header_filter() is supposed to do
might not be accurate: I was hoping that it would
exclude the aforementioned headers, but leave the
rest of the headers as is.

Any help appreciated
/Lars