I am trying to use reverse proxy to connect to a restful webservice which requires https. Since I am consuming the service from inside an Oracle XE DB, which has issues with newer versions of https, I am trying to a use reverse proxy, so that oracle can connect using http. I decided to go with apache and tried to follow this guide. My httpd.conf contains the following entries:
Listen 8086
RewriteEngine On
ProxyVia On
ProxyRequests Off
SSLProxyEngine On
SSLProxyVerify none
SSLProxyCheckPeerCN off
SSLProxyCheckPeerName off
SSLProxyCheckPeerExpire off
<proxy *="">
Order deny,allow
Allow from all
</proxy>
ProxyPass /earthquakes_allday/ https://earthquake.usgs.gov/earthquakes/feed/v1.0/summary/all_day.geojson
ProxyPassReverse /earthquakes_allday/ https://earthquake.usgs.gov/earthquakes/feed/v1.0/summary/all_day.geojson
ProxyRemote https://earthquake.usgs.gov/earthquakes/feed/v1.0/summary/all_day.geojson http://revprox-ip.here:8086
With this entry I was able to issue a request from Firefox using a rest client extension to http://revprox-ip:8086/earthquakes_allday/ and it worked without flaws.
Status Code: 200 OK
Access-Control-Allow-Headers: accept,origin,authorization,content-type
Access-Control-Allow-Methods: *
...
Inside oracle I created the following function to make requests:
FUNCTION make_request (
p_url VARCHAR2,
p_request_type VARCHAR2,
p_request_body CLOB
) RETURN CLOB IS
utl_req utl_http.req;
utl_resp utl_http.resp;
req_length BINARY_INTEGER;
response_body CLOB;
resp_length BINARY_INTEGER;
buffer VARCHAR2(2000);
amount PLS_INTEGER := 2000;
offset PLS_INTEGER := 1;
ret_code INTEGER;
res_clob CLOB;
BEGIN
DBMS_LOB.CREATETEMPORARY(RES_CLOB,TRUE);
utl_req := utl_http.begin_request(p_url,p_request_type,'http/1.1');
utl_http.set_cookie_support(true);
utl_http.set_header(utl_req,'user-agent',user_agent);
utl_http.set_header(utl_req,'content-type',content_type);
req_length := dbms_lob.getlength(p_request_body);
IF
req_length <= 32767
THEN
utl_http.set_header(utl_req,'Content-Length',req_length);
utl_http.write_text(utl_req,p_request_body);
-- If Message data more than 32kb
ELSIF req_length > 32767 THEN
utl_http.set_header(utl_req,'transfer-encoding','chunked');
WHILE ( offset < req_length ) LOOP
dbms_lob.read(p_request_body,amount,offset,buffer);
utl_http.write_text(utl_req,buffer);
offset := offset + amount;
END LOOP;
END IF;
utl_resp := utl_http.get_response(utl_req);
BEGIN
LOOP
utl_http.read_text(utl_resp,buffer);
dbms_lob.writeappend(res_clob,length(buffer),buffer);
dbms_output.put_line(buffer);
END LOOP;
utl_http.end_response(utl_resp);
EXCEPTION
WHEN utl_http.end_of_body THEN
utl_http.end_response(utl_resp);
WHEN OTHERS THEN
utl_http.end_response(utl_resp);
--utl_tcp.close_all_connection();
RAISE;
ret_code := utl_resp.status_code;
utl_http.end_response(utl_resp);
--analyze_response_code(ret_code);
END;
RETURN res_clob;
END;
When I called the function like this:
DECLARE
my_clob clob;
BEGIN
MY_CLOB := make_request('http://revprox-ip.here:8086/earthquakes_allday/', 'GET', NULL);
END;
This gives me only the following output:
<html>
<head><title>400 Bad Request</title></head>
<body bgcolor="white">
<center><h1>400 Bad Request</h1></center>
<hr><center>nginx/1.13.9</center>
</body>
</html>
Then I tried to use Fiddler in between by adding adding the following to fiddler's rules:
if (oSession.host == "fiddlerhost:8888") {
oSession.host ="http://revprox-ip.here:8086";
}
Adding fiddler to the chain causes that calling the webservice from oracle works (reminds me of the observer effect). So how can I resolve this? In the productive environment I won't be able to install fiddler in addition to the reverse proxy.
