Oracle APEX - An unexpected error with the following message occurred: application/pdf - sql

Question

I have a pl/sql procedure that that downloads a blob file in pdf format from Jasper Server. In this procedure I have the following code which prompts the browser to download the file to my local drive.
begin
v_param_val (1) := 1;
owa.init_cgi_env (v_param_val);
htp.flush;
-- clear the output buffer and reset response state
htp.init;
owa_util.mime_header ('application/pdf', false);--,'UTF-8'
htp.p('Content-length: ' || v_lob_length);
htp.p('Content-Disposition: attachement; filename="'||v_file||'"' );
owa_util.http_header_close;
htp.showpage ();
wpg_docload.download_file(v_blobref);
exception
when timeout_on_resource then
raise_application_error (-00051,'No response from the server.');
when others then
htp.p('other error : ' || sqlerrm);
end;
The problem is, I have an oracle apex page that I use to call my procedure. The page passes through the values to be used as parameters in the call of the procedure. I have a an apex process that makes this happen...
declare
v_report_name reports_data.report_name%type;
begin
v_report_name := s_reports_data.get_report_name(:P31_AVAILABLE_REPORTS);
s_reports_data.generate_jasper_report(v_report_name, :P31_DATE_TO,
:P31_RESEARCH_STATION, :P31_DATE_FROM);
end;
No the following error comes up when I try to call the procedure.
An unexpected error with the following message occurred: application/pdf
It seems like the following line is the cause of the error.
owa_util.mime_header ('application/pdf', false);--,'UTF-8'
Or the following line.
wpg_docload.download_file(v_blobref);

Answer 1

Looking in the docs, the function seems to need 3 parameters. Have you tried
owa_util.mime_header('application/pdf', false, 'UTF-8')

Answer 2

I finally got rid of the problem I had. This is how my code looks like now and it works perfectly fine.
begin
sys.htp.init;
sys.owa_util.mime_header (nvl(v_mime,'application/octet'), false, 'UTF-8');
sys.htp.p('Content-length: ' || v_lob_length);
sys.htp.p('Content-Disposition: attachement; filename="'||v_file||'"' );
sys.owa_util.http_header_close;
sys.wpg_docload.download_file(v_blobref);
apex_application.stop_apex_engine;
exception when others then
sys.htp.prn('error: '||sqlerrm);
apex_application.stop_apex_engine;
end;