/**
* Copyright (c) 2012-2013 Nokia Corporation. All rights reserved.
* Nokia and Nokia Connecting People are registered trademarks of Nokia Corporation.
* Oracle and Java are trademarks or registered trademarks of Oracle and/or its
* affiliates. Other product and company names mentioned herein may be trademarks
* or trade names of their respective owners.
* See LICENSE.TXT for license information.
*/
package com.nokia.example.weatherapp.network;
import java.io.ByteArrayOutputStream;
import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.IOException;
import javax.microedition.io.Connector;
import javax.microedition.io.HttpConnection;
/**
* Provides asynchronous HTTP GET and POST operations.
*/
public class Network
implements Runnable {
private NetworkListener listener;
private String url = null;
private String request = null;
private String contentType = null;
private static boolean allowed = false;
private static boolean prompted = false;
public Network(NetworkListener listener) {
this.listener = listener;
}
/**
* Sends a GET request synchronously.
* @param url Target of the request.
* @return Data received
* @throws NetworkError
*/
private String sendHttpGet(String url) throws NetworkError {
HttpConnection hcon = null;
DataInputStream dis = null;
ByteArrayOutputStream response = new ByteArrayOutputStream();
try {
// A standard HttpConnection with READ access
hcon = (HttpConnection) Connector.open(urlEncode(url));
if (hcon == null) {
throw new NetworkError("No network access");
}
// Obtain a DataInputStream from the HttpConnection
dis = new DataInputStream(hcon.openInputStream());
// Retrieve the response from the server
int ch;
while ((ch = dis.read()) != -1) {
response.write((byte) ch);
}
}
catch (Exception e) {
if (e instanceof SecurityException) {
prompted = true;
allowed = false;
}
throw new NetworkError(e.getMessage());
}
finally {
try {
if (hcon != null) {
hcon.close();
}
if (dis != null) {
dis.close();
}
}
catch (IOException ioe) {
ioe.printStackTrace();
}
}
return response.toString();
}
/**
* Sends a POST request synchronously.
* @param url Target for the request.
* @param request Request body
* @throws NetworkError
*/
private String sendHttpPost(String url, String request) throws NetworkError {
HttpConnection hcon = null;
DataInputStream dis = null;
DataOutputStream dos = null;
StringBuffer responseMessage = new StringBuffer();
try {
// An HttpConnection with both read and write access
hcon = (HttpConnection) Connector.open(urlEncode(url), Connector.READ_WRITE);
if (hcon == null) {
throw new NetworkError("No network access");
}
// Set the request method to POST
hcon.setRequestMethod(HttpConnection.POST);
// Content-Type is must to pass parameters in POST Request
hcon.setRequestProperty("Content-Type", contentType);
// Obtain DataOutputStream for sending the request string
dos = hcon.openDataOutputStream();
byte[] request_body = request.getBytes();
// Send request string to server
for (int i = 0; i < request_body.length; i++) {
dos.writeByte(request_body[i]);
}
// Obtain DataInputStream for receiving server response
dis = new DataInputStream(hcon.openInputStream());
// Retrieve the response from server
int ch;
while ((ch = dis.read()) != -1) {
responseMessage.append((char) ch);
}
}
catch (Exception e) {
if (e instanceof SecurityException) {
prompted = true;
allowed = false;
}
throw new NetworkError(e.getMessage());
}
finally {
// Free up i/o streams and http connection
try {
if (hcon != null) {
hcon.close();
}
if (dis != null) {
dis.close();
}
if (dos != null) {
dos.close();
}
}
catch (IOException ioe) {
ioe.printStackTrace();
}
}
return responseMessage.toString();
}
/**
* Thread entry point. Network operation is run in a separate thread.
*/
public void run() {
try {
if (!isAllowed()) {
throw new NetworkError("Network connection not allowed");
}
if (request == null) {
String response = sendHttpGet(url);
listener.networkHttpGetResponse(response);
}
else {
String response = sendHttpPost(url, request);
listener.networkHttpPostResponse(response);
}
}
catch (NetworkError e) {
if (request == null) {
listener.networkHttpGetResponse(null);
}
else {
listener.networkHttpPostResponse(null);
}
}
catch (Exception e) {
}
}
/**
* Sends a HTTP POST request asynchronously, returns immediately and
* reports later using the listener.
* @param url Target url
* @param request Body
* @param contentType Content type
*/
void startHttpPost(String url, String request, String contentType) {
this.url = url;
this.request = request;
this.contentType = contentType;
Thread thread = new Thread(this);
thread.start();
}
/**
* Sends a HTTP POST request asynchronously, returns immediately and
* reports later using the listener.
* @param url Target url
* @param request Body
* @param contentType Content type
*/
void startHttpPost(String url, String request) {
startHttpPost(url, request, "application/x-www-form-urlencoded");
}
/**
* Sends a HTTP POST request asynchronously, returns immediately and
* reports later using the listener.
* @param url Target url
*/
void startHttpPost(String url) {
startHttpPost(url, "");
}
/**
* Sends a HTTP GET request asynchronously, returns immediately and
* reports later using the listener.
* @param url Target url
*/
public void startHttpGet(String url) {
this.url = url;
Thread thread = new Thread(this);
thread.start();
}
/**
* Simple url encoder
* @param url
* @return Encoded string
*/
public static String urlEncode(String url) {
StringBuffer encoded = new StringBuffer();
for (int i = 0; i < url.length(); i++) {
char ch = url.charAt(i);
if (ch == '<') {
encoded.append("%3C");
}
else if (ch == '>') {
encoded.append("%3E");
}
else if (ch == ' ') {
encoded.append("%20");
}
else if (ch == '-') {
encoded.append("%2D");
}
else {
encoded.append(ch);
}
}
return encoded.toString();
}
public static boolean isAllowed() {
if (!prompted) {
prompted = true;
promptNetworkAccess();
}
return allowed;
}
/**
* Opens a network connection just to trigger the network prompt
*/
private static void promptNetworkAccess() {
HttpConnection stimulus = null;
try {
stimulus = (HttpConnection) Connector.open("http://promptNetworkAccess.com");
}
catch (SecurityException se) {
allowed = false;
return;
}
catch (Exception e) {
// Catch all the other exceptions
}
finally {
try {
if (stimulus != null) {
stimulus.close();
}
}
catch (IOException ioe) {
}
}
allowed = true;
}
}