Connectng to remote database in Adobe AIR - actionscript-3

Question

I am developing an AIR mobile application. I am using Sqlite as my local database. Now I have to maintain some datas in a centralised database which has located in remote server ie., i have to push some data to remote database from my mobile application as well as retreieve.
My questions are
Can I use sqlite as centralised database?
How can I connect to the database located in server.
Thanks in Advance.

Answer 1

I'll try to sum up the answer for this question. SQLite is not designed to be a service and therefore can not be used as a remote database, unless you only need to read from it.
If you only need it for reading data you can download it from the server, save as a file and then use it as a local database. This method is better explained here: Link
But if you want to use it for writing as well as reading you'll have a lot of problems with concurrency and data usage, so using a SQLite database is not an option here. Better explained here: Link
The correct way of doing this is having a backend (server script or server program), which listens to your requests and acts according to them.
For example if you want to authenticate user you can send something like this to the server:
username: "Gio"
password: "123"
action: "login"
In Actionscript 3 call would look like this:
import flash.net.URLVariables;
import flash.net.URLRequest;
import flash.net.URLLoader;
import flash.events.IOErrorEvent;
import flash.events.Event;
import flash.net.URLRequestMethod;
// create a URLLoader to POST data to the server
var loader:URLLoader = new URLLoader();
// server address where your script is listening
var request:URLRequest = new URLRequest("http://example.com");
// create and set the variables passed to the server script
var params:URLVariables = new URLVariables();
params.username = "Gio";
params.password = "123";
params.action = "login";
request.data = params;
// set the request type to POST as it's more secure and can hold more data
request.method = URLRequestMethod.POST;
loader.addEventListener(Event.COMPLETE, onPostComplete);
loader.addEventListener(IOErrorEvent.IO_ERROR, onPostFailed);
loader.load(request);
function onPostFailed(e:Event):void
{
// happens if the server is unreachable
trace("I/O Error when sending a POST request");
}
function onPostComplete(e:Event):void
{
// loader.data will hold the response received from the server
trace(e.target.data);
}
On the server side I'd recommend using PHP as it's easier to learn, simple and works great with MySQL.
In PHP you'd have something like this to handle the request:
<?php
$host="localhost"; // Host name
$username=""; // Mysql username
$password=""; // Mysql password
$db_name="test"; // Database name
$tbl_name="members"; // Table name
// Connect to server and select databse.
mysql_connect("$host", "$username", "$password")or die("cannot connect");
mysql_select_db("$db_name")or die("cannot select DB");
// username and password sent from form
if($_POST['action'] == "login")
{
$receivedUsername=$_POST['username'];
$receivedPassword=$_POST['password'];
$sql="SELECT * FROM $tbl_name WHERE username='$receivedUsername' and password='$receivedPassword'";
$result=mysql_query($sql);
// Mysql_num_row is counting table row
$count=mysql_num_rows($result);
// If result matched $receivedUsername and $receivedPassword, table row must be 1 row
if($count==1){
echo "Authentication success";
}
else {
echo "Wrong Username or Password";
}
}
?>
This will seem a little complicated at first, but it's not of a big deal actually. You'll have to read more on PHP and how to setup it as I can't fit all the details in this post.

Answer 2

I using AMFPHP in serverside.
In Flash You call service on server:
_net_connection = new NetConnection();
_net_connection.addEventListener(NetStatusEvent.NET_STATUS, connectionStatusHandler);
_net_connection.connect(_server_url);
_responder = new Responder(loginResult, null);
_net_connection.call("userSerivce2/login", _responder, _user_login, _user_passwword);
private function loginResult(result_object:Object):void {
save_log('loginResult (' + result_object.status + ")");
//rest of code
}
responder - is function in AS3 you will execute after call
userSerivce2/login - class userSerivce2, method login
you add responder (_responder) and additional arguments like _user_login, _user_passwword, in this case.
server PHP:
public function login($user_name, $user_password) {
//SELECT blablabla
try {
if ($logged) {
$this->call_result['status'] = 0;
throw new mysqli_sql_exception("Pomyślnie zalogowano.");
} else {
$this->call_result['status'] = 3;
throw new mysqli_sql_exception("Błąd logowania. Wprowadź poprawny login, oraz hasło.");
}
} catch(Exception $e) {
$this->call_result['error_message'] = $e->getMessage();
return $this->call_result;
}
return $this->call_result; //method will return object
}