Simple HTTPS Request Gone Wrong

[roryfynn]

I've developed a frontend java midlet to collect data and send it to an already established backend. The backend takes its input via the URL eg www.backend.org/input.do?var1=x+var2=y

Is this possible to do? Do I still have to use bitstreams if I am simple calling or "opening" a URL?

I've tried many ways with variable rates of success. Like using http with bitstreams sent the data but then the midlet froze. This is probably a silly and simple query but please can someone help a novice J2ME programmer.

Here is my communication to the backend (the simple non bitstream https method)

public void run()
{
String urlT1 = "https://www.backend.org/input.do";
String urlInfo = _patient.getPatientInfo(); // input variables

String url = urlT1 + "" + urlInfo;

try {
// Query the server and retrieve the response.
HttpsConnection hc = (HttpsConnection) Connector.open(url);
hc.close();
} catch (IOException ioe) {
Alert a = new Alert("Exception", ioe.toString(), null, null);
a.setTimeout(Alert.FOREVER);
_controller.newAlert(a);
}
}

[dcrocha]

Hi,

In order to get your application to "call" a URL with the GET method, you need to open an InputStream, so that the HttpsConnection class will flush all buffers and perform the request. You don't need to use the InputStream's methods such as read() if there's nothing to read. Just open it and then close it.

Daniel

[roryfynn]

Thanks for the help but I'm still not having any luck sending the variables to the server and my program goes to a plain white screen once the "connection" is complete.

Below is my updated code. Is there a difference if I use GET or POST or HEAD? I have an idea of the basic underlying difference between these methods, however none give me the desired results.

public static String backendComms(String url) {

HttpsConnection httpsConn = null;
DataInputStream dis = null;
StringBuffer messagebuffer = new StringBuffer();

try {
// open HTTP connection with Web server
httpsConn = (HttpsConnection) Connector.open(url, Connector.READ_WRITE);

// set request method to GET
httpsConn.setRequestMethod(HttpConnection.GET);

// retrieve the response from web Server
dis = new DataInputStream(httpsConn.openInputStream());

int ch;
// Check the Content-Length first
long len = httpsConn.getLength();
if (len != -1) {
for (int i = 0; i < len; i++) {
if ((ch = dis.read()) != -1) {
messagebuffer.append((char) ch);
}
}
} else {
// if the content-length is not available
while ((ch = dis.read()) != -1) {
messagebuffer.append((char) ch);
}
}
dis.close();

} catch (IOException ioe) {
messagebuffer = new StringBuffer("ERROR!");
} finally {
try {
if (httpsConn != null) httpsConn.close();
if (dis != null) dis.close();
} catch (IOException ignored) {}
}
return messagebuffer.toString();
}

[Shaikuny]

Do not create a new dataInputStream instance but use the HttpConnection's input srteam.

// Example
HttpConnection hc = Connector.open( url, Connector.READ_WRITE);

InputStream is = hc.openDataInputStream();

// End of example.