Sending a response from PHP to an Android/Java mobile app?

I currently have a piece of code in my Android application that picks up the devices IMEI and sends that IMEI as a parameter to a PHP script that is hosted on the Internet.

The PHP script then takes the IMEI parameter and checks a file to see if the IMEI exists in the file, if it does I want to be able to let my Android application know that the IMEI exists. So essentially I just want to be able to return True to my application.

Is this possible using PHP?

Here is my code so far:

Android/Java

//Test HTTP Get for PHP

        public void executeHttpGet() throws Exception {
            BufferedReader in = null;
            try {
                HttpClient client = new DefaultHttpClient开发者_开发问答();
                HttpGet request = new HttpGet();
                request.setURI(new URI("http://testsite.com/" +
                        "imei_script.php?imei=" + telManager.getDeviceId()
                        ));
                HttpResponse response = client.execute(request);
                in = new BufferedReader
                (new InputStreamReader(response.getEntity().getContent()));
                StringBuffer sb = new StringBuffer("");
                String line = "";
                String NL = System.getProperty("line.separator");
                while ((line = in.readLine()) != null) {
                    sb.append(line + NL);
                }
                in.close();
                String page = sb.toString();
                System.out.println(page);
                } finally {
                if (in != null) {
                    try {
                        in.close();
                        } catch (IOException e) {
                        e.printStackTrace();
                    }
                }
            }
        }

The above sends the IMEI as a parameter to the PHP script which picks it up successfully and runs a check against the file successfully, however I neeed to then be able to send a positive response back from the PHP script if the IMEI matches one in the file.

Here is the PHP:

<?php
    // to return plain text
    header("Content-Type: plain/text"); 
    $imei = $_GET["imei"];

    $file=fopen("imei.txt","r") or exit("Unable to open file!");

    while(!feof($file))
     {
    if ($imei==chop(fgets($file)))
     echo "True";
     }

    fclose($file);

?>

So instead of echo True I want to be able to let my application know that the IMEI was found, is this possible and if so what should I be using to achieve it?

this is good stuff! actually, you're nearly there. your php shouldn't change, your java should! you just need to check the result of the response inside your java code. redeclare your java method as

public String executeHttpGet() {

then, let this method return the variable page.

now you can create a helper method somewhere. if you put it in the same class as executeHttpGet, it will look like this:

public boolean imeiIsKnown(){
    return executeHttpGet().equals("True");
}

now you can call this method to find out if your imei is known in your php backend.

I'm not sure is it good for you or not - but you can use headers. If the IMEI was found you can send header("Status: HTTP/1.1 200 OK") otherwise send header("Status: 404 Not Found").

And then you should check response status in your application.

your code is basically sound, all you need to do is tweak it up a bit. i mixed and matched the answers above, because i needed to accomplish exactly what you were trying to. i created a database, instead of checking txt files.

CREATE TABLE IF NOT EXISTS `user_device` (
  `Id_User_Device` int(11) NOT NULL auto_increment,
  `Nr_User_Device` varchar(60) collate utf8_bin NOT NULL,
  `Ic_User_Device_Satus` int(11) NOT NULL default '1',
  PRIMARY KEY  (`Id_User_Device`),
  KEY `Nr_User_Device` (`Nr_User_Device`,`Ic_User_Device_Satus`)
) 
ENGINE=InnoDB  DEFAULT CHARSET=utf8 COLLATE=utf8_bin AUTO_INCREMENT=20 ;

the java android code would be (dont forget to create the proper adjustements in the main.xml layout file, inserting 2 elements to a classical helloworld screen:

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.net.URI;
import org.apache.http.HttpResponse;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.DefaultHttpClient;
import android.app.Activity;
import android.os.Bundle;
import android.util.Log;
import android.widget.TextView;

public class ZdeltestEMEIActivity extends Activity {
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        DeviceUuidFactory deviceUuidFactory = new DeviceUuidFactory(this);
        String deviceUuid = deviceUuidFactory.getDeviceUuid().toString();
        Log.d("tgpost",deviceUuid);
        try {
            String webPostAnswer = deviceIdCheck(deviceUuid);
            if (webPostAnswer != null) {
                TextView tv1 = (TextView) findViewById(R.id.textdisplay01);
                TextView tv2 = (TextView) findViewById(R.id.textdisplay02);
                tv1.setText(webPostAnswer);
                tv2.setText(deviceUuid);
                Log.d("tgpost", "okok "+webPostAnswer);
            } else {
                Log.d("tgpost", "nono empty");
            }
        } catch (Exception e) {
            // TODO Auto-generated catch block
            Log.i("tgpost", "exc  " + e.getMessage());
            Log.i("tgpost", e.toString());
            Log.e("tgpost", e.getStackTrace().toString());
            e.printStackTrace();
        }        
    }
    public String deviceIdCheck(String deviceUuidIn) throws Exception {
        boolean flagOK = false;
        BufferedReader in = null;
        try {
            HttpClient client = new DefaultHttpClient();
            HttpGet request = new HttpGet();
            Log.v("tgpost", "okok");
            //"imei_script.php?deviceId="; + telManager.getDeviceId()
            request.setURI(new URI("http://www.you.net/" +
                    "deviceIdCheck.php?deviceId=" + deviceUuidIn
                    ));
            HttpResponse response = client.execute(request);
            Log.d("tgpost", "php answered> "+response);
            in = new BufferedReader
            (new InputStreamReader(response.getEntity().getContent()));
            StringBuffer sb = new StringBuffer("");
            String line = "";
            String NL = System.getProperty("line.separator");
            while ((line = in.readLine()) != null) {
                sb.append(line + NL);
            }
            in.close();
            String page = sb.toString();
            Log.d("tgpost", "php answered HUMAN> "+page);
            return page;

        } catch (Exception e) {
            return "problems with connection "+e.getMessage();
        }  
    }
}

with an addtional class

import android.content.Context;
import android.content.SharedPreferences;
import android.provider.Settings.Secure;
import android.telephony.TelephonyManager;
import java.io.UnsupportedEncodingException;
import java.util.UUID;

public class DeviceUuidFactory {
    protected static final String PREFS_FILE = "device_id.xml";
    protected static final String PREFS_DEVICE_ID = "device_id";    
    protected static UUID uuid;
    public DeviceUuidFactory(Context context) { 
        if( uuid ==null ) {
            synchronized (DeviceUuidFactory.class) {
                if( uuid == null) {
                    final SharedPreferences prefs = context.getSharedPreferences( PREFS_FILE, 0);
                    final String id = prefs.getString(PREFS_DEVICE_ID, null );
                    if (id != null) {
                        // Use the ids previously computed and stored in the prefs file
                        uuid = UUID.fromString(id);
                    } else {
                        final String androidId = Secure.getString(context.getContentResolver(), Secure.ANDROID_ID);

                        // Use the Android ID unless it's broken, in which case fallback on deviceId,
                        // unless it's not available, then fallback on a random number which we store
                        // to a prefs file
                        try {
                            if (!"9774d56d682e549c".equals(androidId)) {
                                uuid = UUID.nameUUIDFromBytes(androidId.getBytes("utf8"));
                            } else {
                                final String deviceId = ((TelephonyManager) context.getSystemService( Context.TELEPHONY_SERVICE )).getDeviceId();
                                uuid = deviceId!=null ? UUID.nameUUIDFromBytes(deviceId.getBytes("utf8")) : UUID.randomUUID();
                            }
                        } catch (UnsupportedEncodingException e) {
                            throw new RuntimeException(e);
                        }

                        // Write the value out to the prefs file
                        prefs.edit().putString(PREFS_DEVICE_ID, uuid.toString() ).commit();

                    }

                }
            }
        }

    }


    /**
     * Returns a unique UUID for the current android device.  As with all UUIDs, this unique ID is "very highly likely"
     * to be unique across all Android devices.  Much more so than ANDROID_ID is.
     *
     * The UUID is generated by using ANDROID_ID as the base key if appropriate, falling back on
     * TelephonyManager.getDeviceID() if ANDROID_ID is known to be incorrect, and finally falling back
     * on a random UUID that's persisted to SharedPreferences if getDeviceID() does not return a
     * usable value.
     *
     * In some rare circumstances, this ID may change.  In particular, if the device is factory reset a new device ID
     * may be generated.  In addition, if a user upgrades their phone from certain buggy implementations of Android 2.2
     * to a newer, non-buggy version of Android, the device ID may change.  Or, if a user uninstalls your app on
     * a device that has neither a proper Android ID nor a Device ID, this ID may change on reinstallation.
     *
     * Note that if the code falls back on using TelephonyManager.getDeviceId(), the resulting ID will NOT
     * change after a factory reset.  Something to be aware of.
     *
     * Works around a bug in Android 2.2 for many devices when using ANDROID_ID directly.
     *
     * @see http://code.google.com/p/android/issues/detail?id=10603
     *
     * @return a UUID that may be used to uniquely identify your device for most purposes.
     */
    public UUID getDeviceUuid() {
        return uuid;
    }
}

on the php side:

<?php
// to return plain text
// header("Content-Type: plain/text"); 
include('/home/public_html/ConnStrDB.php');
$deviceId = $_GET["deviceId"];
$sql = "SELECT Nr_User_Device FROM user_device WHERE Nr_User_Device = '".$deviceId."'";
$result = mysql_query($sql);
if ($result) {
    $row = mysql_fetch_array($result);
    if ($row[0]) {$deviceIdFile = $row[0];} else {$deviceIdFile = "device not found";}
} else {
    $deviceIdFile = "no check was made, empty set";
}
echo $_GET["deviceId"]."  ".$deviceIdFile;
?>

and (so that you dont have to insert the numbers manually (just change the php fileName in the submit):

<?php
// to return plain text
// header("Content-Type: plain/text"); 
include('/home/public_html/ConnStrDB.php');
$deviceId = $_GET["deviceId"];
$sql = "SELECT Nr_User_Device, Ic_User_Device_Status FROM user_device WHERE Nr_User_Device = ".$deviceId;

$sql = "INSERT INTO user_device (Nr_User_Device) VALUES ('".$deviceId."')";
$result = mysql_query($sql);
if ($result) {
    $deviceIdFile = "device inserted";
} else {
    $deviceIdFile = "not inserted";
}
echo $_GET["deviceId"]."  ".$deviceIdFile;
?>

if succesful, your mobile screen will display the imei 3 times (the one on the device, the one received in php and the one retrieved on the database).

ConnStrDB.php is a file that contains your complete connection to MySQL database.

if you reply with long text, the android application will receive it, as well as the verbose version of any php warning. if you dont need json, you can answer any xml thru a php echo. thanx for your question, very useful! and thanx for the EXCELLENT answers!