BlackBerry Connection Utility

HttpConnectionHelper.java

import java.io.InputStream;
import java.util.Hashtable;

import javax.microedition.io.HttpConnection;
import javax.microedition.io.InputConnection;

import net.rim.device.api.io.IOUtilities;
import net.rim.device.api.io.http.HttpProtocolConstants;
import net.rim.device.api.io.transport.ConnectionDescriptor;
import net.rim.device.api.io.transport.ConnectionFactory;
import net.rim.device.api.io.transport.TransportDescriptor;
import net.rim.device.api.io.transport.TransportInfo;
import net.rim.device.api.system.Bitmap;
import net.rim.device.api.system.EncodedImage;
import net.rim.device.api.system.RadioInfo;
import net.rim.device.api.system.WLANInfo;

import com.idnoodle.controller.Settings;

public class HttpConnectionHelper {

	private String url = null;
	private ConnectionFactory connectionFactory = null;
	private HttpConnection connection = null;

	// keys to access response hashtable
	public static final String RESULT_ETAG = "etag";
	public static final String RESULT_DATA = "result";

	public HttpConnectionHelper() {
	}

	public void setURL(String url) {
		this.url = url;
	}
	
	/**
	 * GETs the helper's set URL and returns a hash table with RESULT_ETAG and RESULT_DATA indexes, where result is a string of the response data.
	 * 
	 * Optionally an etag can be set, which may change the return hash to contain an etag, with a null result, if the server's data has not changed.
	 * 
	 * @param etag
	 * @return
	 */
	public Hashtable getURLAsString(String etag) {
		Hashtable responseHash = new Hashtable(2);
		
		if (etag == null) {
			etag = "";
		}
		responseHash.put(RESULT_ETAG, etag);
		responseHash.put(RESULT_DATA, "");

		System.out.println("### Getting url as string: " + this.url + " etag: " + etag);
		
		if (this.url == null) {
			throw new IllegalStateException("No URL set. Call setURL(String url) first");
		}
		
		try {
			this.connectionFactory = new ConnectionFactory();
			this.connectionFactory.setPreferredTransportTypes(Settings.kPreferredTransports);
			this.connectionFactory.setAttemptsLimit(5);
			this.connectionFactory.setConnectionTimeout(5000);
			ConnectionDescriptor cd = this.connectionFactory.getConnection(this.url);
			this.connection = (HttpConnection) cd.getConnection();
			this.connection.setRequestMethod(HttpConnection.GET);
			if (etag != null && !etag.equalsIgnoreCase("")) {
				this.connection.setRequestProperty(HttpProtocolConstants.HEADER_IF_NONE_MATCH, etag);
			}

			int responseCode = this.connection.getResponseCode();
			String responseEtag = this.connection.getHeaderField(HttpProtocolConstants.HEADER_ETAG);
			System.out.println("### Response code is: " + responseCode + " ETAG: " + responseEtag);

			if (responseCode == HttpConnection.HTTP_NOT_MODIFIED) {
				System.out.println("### Response was cached: " + responseCode + " etag: " + etag);
				this.connection.close();
				return responseHash;
			}
			
			if (responseCode == HttpConnection.HTTP_OK) {
				InputConnection inputConnection = (InputConnection) this.connection;
				InputStream is = inputConnection.openInputStream();

				byte[] data = net.rim.device.api.io.IOUtilities.streamToBytes(is);
				String httpResult = new String(data);

				//System.out.println("### url result: " + httpResult);
				if (responseEtag == null) {
					responseHash.put(RESULT_ETAG, "");
				}
				else {
					responseHash.put(RESULT_ETAG, responseEtag);
				}
				
				responseHash.put(RESULT_DATA, httpResult);
			}
			else {
				// TODO Properly handle 500's
				System.out.println("### Response was a failure: " + etag);
				responseHash.put(RESULT_ETAG, etag);
			}

		} catch (Exception e) {
			System.out.println("### An exception occured: " + e.getMessage());
			e.printStackTrace();
		}

		return responseHash;
	}

	/**
	 * Grab the image from the network
	 * @param imageUrl URL for the image
	 * @return a Bitmap object for the image.
	 */
	public static Bitmap getURLAsImage(String imageUrl) {
		System.out.println("### Getting image from url:" + imageUrl);
		Bitmap bitmap = null;
		
		if (quickCheckConnection() == false) {
			return bitmap;
		}
		
		try {
			ConnectionFactory connectionFactory = new ConnectionFactory();
			connectionFactory.setPreferredTransportTypes(Settings.kPreferredTransports);
			connectionFactory.setAttemptsLimit(5);
			connectionFactory.setConnectionTimeout(2000);
			ConnectionDescriptor connectionDescriptor = connectionFactory.getConnection(imageUrl);
			if(connectionDescriptor != null){
				InputConnection connection = (InputConnection)connectionDescriptor.getConnection();
				InputStream inputStream = connection.openInputStream();
				byte[] data = IOUtilities.streamToBytes(inputStream);
				
				EncodedImage encodedImage = EncodedImage.createEncodedImage(data, 0, data.length);
				bitmap = encodedImage.getBitmap();
			}
        } catch (Exception e) { 
        	System.out.println("### Error downloading image for dynamic button.  url:" + imageUrl);
            e.printStackTrace();
        }
		
		return bitmap;
	}
	
	public static String buildURLTransport(String url) {
		StringBuffer returnUrl = new StringBuffer();
		returnUrl.append(url);
		
		try {
			ConnectionDescriptor connDescriptor = new ConnectionFactory().getConnection(url);
			if (connDescriptor != null) {
				TransportDescriptor transDescriptor = connDescriptor.getTransportDescriptor();
				String transUID = transDescriptor.getUid();
				int transportType = transDescriptor.getTransportType();
				if(transportType == TransportInfo.TRANSPORT_TCP_WIFI)
				{
					returnUrl.append(";deviceside=true;interface=wifi");
				}
				else if(transportType == TransportInfo.TRANSPORT_MDS)
				{
					returnUrl.append(";deviceside=false");
				}
				else if(transportType == TransportInfo.TRANSPORT_BIS_B)
				{
					returnUrl.append(";deviceside=false;connectionUID=" + transUID);
				}
				else if(transportType == TransportInfo.TRANSPORT_TCP_CELLULAR)
				{
					returnUrl.append(";deviceside=true");
				}
				else if(transportType == TransportInfo.TRANSPORT_WAP2)
				{
					returnUrl.append(";deviceside=true;ConnectionUID=" + transUID);
				}
			}
		} catch (Exception e) {
			// pass
		}
		
		return returnUrl.toString();
	}
	
	public static boolean quickCheckConnection() {
		boolean canConnect = true;
		
		if (RadioInfo.getState() == RadioInfo.STATE_OFF && WLANInfo.getWLANState() == WLANInfo.WLAN_STATE_DISCONNECTED) {
			System.out.println("### RADIO IS OFF");
			canConnect = false;
		}
		
		return canConnect;
	}
}