Error when header origin is not send: attempt to index field 'origin' (a nil value)

[Skoucail]

When the frontend receives a request without an origin header the script craches on line 100 (local origin = headers["origin"][0]).
Because headers["origin"] = nil so asking an index from nil.

I fixed my script with:

function cors_request(txn, allowed_methods, allowed_origins, allowed_headers)
  local headers = txn.http:req_get_headers()
  local transaction_data = {}
  
  if headers["origin"] ~= nil and headers["origin"][0] ~= nil then
    core.Debug("CORS: Got 'Origin' header: " .. headers["origin"][0])
    transaction_data["origin"] = headers["origin"][0]
  end

  transaction_data["allowed_methods"] = allowed_methods
  transaction_data["allowed_origins"] = allowed_origins
  transaction_data["allowed_headers"] = allowed_headers

  txn:set_priv(transaction_data)

  local method = txn.sf:method()
  transaction_data["method"] = method

  if method == "OPTIONS" and txn.reply ~= nil then
    preflight_request_ver2(txn, origin, allowed_methods, allowed_origins, allowed_headers)
  end
end

[Skoucail]

I made a PR to fix the issue: #19