Upload BLOB files using PL/SQL HTTP - http

Question

Usually, I use the following structure to send POST request with contents of varchar2 and numbers .. etc.
content := '{"Original File Name":"'||V_HOMEBANNER_1_EN_NAME(indx)||'"}';
url := 'https://api.appery.io/rest/1/db/Names';
req := utl_http.begin_request(url, 'POST',' HTTP/1.1');
UTL_HTTP.set_header(req, 'X-Appery-Database-Id', '5f2dac54b02cc6402dbe');
utl_http.set_header(req, 'content-type', 'application/json');
UTL_HTTP.set_header(req, 'X-Appery-Session-Token', sessionToken);
utl_http.set_header(req, 'Content-Length', LENGTH(content));
utl_http.write_text(req, content);
res := utl_http.get_response(req);
BEGIN
LOOP
utl_http.read_line(res, buffer);
END LOOP;
utl_http.end_response(res);
EXCEPTION
WHEN utl_http.end_of_body THEN
utl_http.end_response(res);
END;
And It works just fine. However, now I want to send/upload a blob files (images of jpg) into some MongoDB collection called 'Files' (so url := ttps://api.appery.io/rest/1/db/Files). The collection guide has the following cURL as a general advice :
curl -X POST \
-H "X-Appery-Database-Id: 5f2dac54b02cc6402dbe" \
-H "X-Appery-Session-Token: <session_token>" \
-H "Content-Type: <content_type>" \
--data-binary '<file_content>' \
https://api.appery.io/rest/1/db/files/<file_name>
But I could not translate this cURL into PL/SQL request. Specifically, the part (--data-binary '')
I have these BLOB files in Oracle table and they are stored with their names as follows:
+-----------+--------------+
| File_Name | File_content |
+-----------+--------------+
| PIC_1.jpg | BLOB |
| PIC_2.jpg | BLOB |
| PIC_3.jpg | BLOB |
+-----------+--------------+
My question, how to upload these images into the targeted URL?

Answer 1

Inspired by this blog advised by #JeffreyKemp, I go it working by only replacing write_text() with write_raw() in order to send content body as BLOB (Requested by the API).
The following code is the critical part of my function with the changes needed:
content := V_HOMEBANNER_1_EN(indx);
file_name := 'test.jpg';
url := 'https://api.appery.io/rest/1/db/files/'||file_name;
req := utl_http.begin_request(url, 'POST',' HTTP/1.1');
UTL_HTTP.set_header(req, 'X-Appery-Database-Id', '53fae4b02cc4021dbe');
UTL_HTTP.set_header(req, 'X-Appery-Session-Token', sessionToken);
utl_http.set_header(req, 'content-type', 'image/jpeg');
req_length := DBMS_LOB.getlength(CONTENT);
DBMS_OUTPUT.PUT_LINE(req_length);
--IF MSG DATA UNDER 32KB LIMIT:
IF req_length <= 32767
THEN
begin
utl_http.set_header(req, 'Content-Length', req_length);
utl_http.write_raw(req, content);
exception
when others then
DBMS_OUTPUT.PUT_LINE(sqlerrm);
end;
--IF MSG DATA MORE THAN 32KB
ELSIF req_length >32767
THEN
BEGIN
DBMS_OUTPUT.PUT_LINE(req_length);
utl_http.set_header(req, 'Transfer-Encoding', 'Chunked');
WHILE (offset < req_length)
LOOP
DBMS_LOB.read(content, amount, offset, buffer);
utl_http.write_raw(req, buffer);
offset := offset + amount;
END LOOP;
exception
when others then
DBMS_OUTPUT.PUT_LINE(sqlerrm);
end;
END IF;
l_http_response := UTL_HTTP.get_response(req);
UTL_HTTP.read_text(l_http_response, response_body, 32767);
UTL_HTTP.end_response(l_http_response);
Tried and tested for both greater and smaller than 32KB images/jpg.