java - Http Requests POST vs GET

Question

I am using a lot of HTTP Requests in an application that I am writing which uses OAuth. Currently, I am sending my GET and POST requests the same way:

HttpConnection connection = (HttpConnection) Connector.open(url
                    + connectionParameters);

            connection.setRequestMethod(method);
            connection.setRequestProperty("WWW-Authenticate",
                    "OAuth realm=api.netflix.com");

            int responseCode = connection.getResponseCode();

And this is working fine. I am successfully POSTing and GETing. However, I am worried that I am not doing POST the right way. Do I need to include in the above code the following if-statement?

if (method.equals("POST") && postData != null) {
                    connection.setRequestProperty("Content-type",
                            "application/x-www-form-urlencoded");
                    connection.setRequestProperty("Content-Length", Integer
                            .toString(postData.length));
                    OutputStream requestOutput = connection.openOutputStream();
                    requestOutput.write(postData);
                    requestOutput.close();
                }

If so, why? What's the difference? I would appreciate any feedback.

Thanks!

Answer 1

connection.setRequestProperty("Content-type", "application/x-www-form-urlencoded");

The content type must match the actual format of the postData. A content type of application/x-www-form-urlencoded is only necessary if the content type is actually url encoded. E.g. you're encoding POST data as follows:

String data = "param1=" + URLEncoder.encode(param1, "UTF-8")
           + "&param2=" + URLEncoder.encode(param2, "UTF-8");

This way the other side will be able to parse the data according the specified format without breaking it.

And,

connection.setRequestProperty("Content-Length", Integer.toString(postData.length));

This is preferable to ensure a robust data transfer. If you omit this and the connection somehow get broken, then the other side will never be able to determine if the content is fully streamed in or not.

That said, the cast to HttpUrlConnection is unnecessary if you know the fact that the request method will "automatically" be set to POST if you do:

connection.setDoOutput(true);

or in your case more suitable:

connection.setDoOutput("POST".equals(method));