How to send XML using UTL_HTTP

Question

I am trying to workout how to send XML data to a webserver using UTL_HTTP but am not getting any reply
I need to submit the following XML document to a server "http://api.fastsms.co.uk/api/xmlapi.php"  Their instructions are "The XML Document should be posted unencoded, with a UTF-8 character set as parameter 'xml'"
If I submit the following XML on their test form
<?xml version="1.0"?>
<apirequest version="1">
<user>
  <username>**USER**</username>
  <password>**PASSWORD**</password>
</user>
<application>
  <name>Example Application</name>
  <version>1.0</version>
</application>
<inboundcheck lastid="10711399"/>
</apirequest>
I get an XML response back with the messages in my inbox. 
This is the code I am trying to use to accomplish the same from PL/SQL : I know a response is coming back as there is header information - just no content.  What am I doing wrong ?
  l_xml VARCHAR2(5000);
  req utl_http.req;
  resp utl_http.resp;
  header_name VARCHAR2(256); -- Response header name
  header_value VARCHAR2(1024); -- Response header value
  response_text VARCHAR2(4000); -- Response body
  l_url VARCHAR2(100);
BEGIN
  l_xml := 'xml=<?xml version="1.0"?>';
  l_xml := '<apirequest version="1">';
  l_xml := '<user>';
  l_xml := '<username>**USER**</username>';
  l_xml := '<password>**PASSWORD**</password>';
  l_xml := '</user>';
  l_xml := '<application>';
  l_xml := '<name>Example Application</name>';
  l_xml := '<version>1.0</version>';
  l_xml := '</application>';
  l_xml := '<inboundcheck lastid="10711399"/>';
  l_xml := '</apirequest>';
  -- Open HTTP connection
  l_url := 'http://api.fastsms.co.uk/api/xmlapi.php';
  req := utl_http.begin_request(l_url,'POST',utl_http.HTTP_VERSION_1_1);
  -- Set headers for type and length
  utl_http.set_header(req,'Content-Type','application/x-www-form-urlencoded');
  utl_http.set_header(req,'Content-Length',to_char(length(l_xml)));
  -- Write parameter
  utl_http.write_text(req,l_xml);
  -- Read response file
  resp := utl_http.get_response(req);
  -- Print out the response headers
  FOR i IN 1 .. utl_http.get_header_count(resp) LOOP
    utl_http.get_header(resp,i,header_name,header_value);
    logging_pkg.info(header_name || ': ' || header_value);
  END LOOP;
  -- Print out the response body
  BEGIN
    LOOP
      utl_http.read_text(resp,response_text);
      logging_pkg.info(response_text);
    END LOOP;
  EXCEPTION
    WHEN utl_http.end_of_body THEN
      logging_pkg.info('End of body');
  END;
  -- close http connection
  utl_http.end_response(resp);
  EXCEPTION
    WHEN utl_http.end_of_body THEN
      utl_http.end_response(resp);
END;
Cheers,
Brent

Answer 1

Hi Billy
Yikes - how embarassing !  Thanks for pointing out my beginners mistake there.  I've fixed my code - and also implemented the substitutions of parameters like you suggested - I like that approach.
Unfortunately the end result is no better - the line
utl_http.read_text(resp,response_text);
Still returns nothing back
The headers that are coming back are
Date: Thu, 04 Jul 2013 08:31:56 GMT
Server: Apache/2.2.16 (Ubuntu)
X-Powered-By: PHP/5.3.3-1ubuntu9.3
Expires: Thu, 19 Nov 1981 08:52:00 GMT
Cache-Control: no-store, no-cache, must-revalidate, post-check=0, pre-check=0
Pragma: no-cache
Vary: Accept-Encoding
Content-Length: 0
Content-Type: text/html; charset=UTF-8
Connection: close
I guess I will need to try chasing it with the fastsms vendor so see if they can check my incoming request and see if there are any glaring problems. I know the xml is correct as I am now logging the xml string just before I send it and when I take that string and put it in their test form it works perfectly - something else in the puzzle is missing. I've had no experience using utl_http before - perhaps it's no possible to read the xml repsonse using this ?
Anyway, thanks for your help Billy.
ps - How do you paste your code into your message to get that formatting ?
Cheers,
Brent