title: lua: http post dynamic
body: <p>I am trying to consume a web service using Lua programming language. When I run my script, I receive a http error 500. My API is written in Python Flask and this is my Lua script.</p>
  
  <pre><code>http = require("socket.http");
  ltn12 = require("ltn12");
  param_1 = argv[1];
  param_2 = argv[2];
  path = "http://www.url.com:8080/api/"
  body = [[ {"number_id":"b8ce37fb-2061-4aea-975b-57a8e2d355ce","caller_number":param_1,"called_number":param_2} ]]
  response_body = { }
  res, code, response_headers, status = http.request
  {
      url = path,
      method = "POST",
      headers =
      {
            ["X-Access-Key"] = "xxxxxxxxxxxxx",
            ["Content-Type"] = "application/json",
            ["Content-Length"] = body:len()
      },
      source = ltn12.source.string(body),
  }
  </code></pre>
  
  <p>I have received the following python traceback: </p>
  
  <pre><code>Expecting value: line 1 column 70 (char 69)(185.22                                                                                                             2.62.80)
  Traceback (most recent call last):
  File "/root/TVS/tokens-via-sva/app/controllers/api/codes.py", line 31, in crea                                                                                                             te_code
      data = json.loads(request.data)
  File "/usr/lib/python3.6/json/__init__.py", line 354, in loads
       return _default_decoder.decode(s)
  File "/usr/lib/python3.6/json/decoder.py", line 339, in decode
       obj, end = self.raw_decode(s, idx=_w(s, 0).end())
  File "/usr/lib/python3.6/json/decoder.py", line 357, in raw_decode
       raise JSONDecodeError("Expecting value", s, err.value) from None
      json.decoder.JSONDecodeError: Expecting value: line 1 column 70 (char 69)
  </code></pre>
  
  <p>what could the origin of the problem?</p>