Differences between a HttpURLConnection and a browser connection

Question

I'm trying to connect to a web page through a HttpURLConnection but it's not responding the same as a regular browser (firefox, chrome). I'm getting an error 500.

With the same code I can get "anyother" page (google, for example). My code is posted below, but I'm pretty sure it is ok.

Using "Live HTTP Headers" firefox addon I sent the same request and received a valid response.

//...
String urlConsulta = "myURL";
URL url = new URL(urlConsulta);
HttpURLConnection uConsulta = (HttpURLConnection)consulta.openConnection();
uConsulta.setDoOutput(true);
uConsulta.setRequestMethod("POST");
uConsulta.addRequestProperty("Content-Type", "application/x-www-form-urlencoded");
uConsulta.addRequestProperty("Host", "host");
//...

Answer 1

This can be caused by everything. The server may rely on the presence of certain request parameters. The server may rely on a valid session. The server may sniff the user agent. Etc..etc.. Read the server logs for the cause of the error. Or if you don't have access to server logs, read the body of the error response by HttpURLConnection#getErrorStream(), it may contain the error details.

See also:

• How to use URLConnection to fire and handle HTTP requests