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Working with Webservices

Nilanjan Banerjee

Mobile Systems Programming

University of ArkansasFayetteville, AR

nilanjan.banerjee@gmail.com

Some of the simple web based services you would use!

Writing data to a database

Querying data from a database

Map queries (extracting maps, geocoding, reverse geocoding)

Other advanced webservices?

Optical Character Recognition System (OCR)

Relay services and Rendezvous Services

Speech to Text Service

General architecture for accessing databases

Mobile Phone

Intermediary Script (php, perl etc)

Backend database

Sending simple text data from a Mobile phone (Server side)– Adding userinfo --- username and password

$firstname = $_REQUEST["firstname"];$lastname = $_REQUEST["lastname"];$username = $_REQUEST["username"];$fpassword = $_REQUEST["fpassword"];

require_once('db.inc.php');

$insertquery="INSERT INTO table_name (first_name, last_name, user_name, fpassword) VALUES ('$firstname', '$lastname', '$username', '$fpassword’)";

$result = mysql_query($insertquery);mysql_close();

<?$user=”XXX";$password=”YYY";$database="weedidapp";$host="mpss.csce.uark.edu";mysql_connect($host,$user,$password);@mysql_select_db($database) or die( "Unable to select database");?>

- db.inc.php

Authenticating userinfo (server side)

<?php

foreach ($_GET as $key => $value) { eval("\$" . $key . " = \"" . $value . "\";");}

$username = $_REQUEST["username"];$fpassword = $_REQUEST["fpassword"];require_once('db.inc.php');$query="SELECT * from table where user_name='$username' AND fpassword='$fpassword'";$result = mysql_query($query);if($result && mysql_numrows($result)>0) echo "y”;else echo "n”;mysql_close();?>

– Check that the username password is present in the database– Note that this is all in plaintext. Ideally you would create a MD5

hash of the password and store the hash

Adding text to a mysql database

$latitude = $_REQUEST[”latitude"];$longitude = $_REQUEST[”longitude"];

require_once('db.inc.php');

$insertquery="INSERT INTO table_name (latitude, longitude) VALUES (’$latitude', '$longitude’)";

$result = mysql_query($insertquery);mysql_close();

– Send the data encoded in the url• For e.g., http://www.csce.uark.edu/~nilanb/insertdb.php?latitude=“-

31.5”;longitude=“-94.6”– The url is parsed by the php script and a hashtable with <key,

value> pairs are extraced• _REQUEST[“latitude”] = -31.5• _REQUEST[“longitude”] = -94.6

Retrieving text from a mysql server and sending it backmysql_select_db("locationgame",$con);$list = mysql_list_tables("locationgame");$i = 0;$idarray = array();$latarray = array();$longarray = array();$count = 0;while($i < mysql_num_rows($list)){ $tb_names[$i] = mysql_tablename($list,$i); $sql = "SELECT * FROM $tb_names[$i] order by Date desc limit 1"; $result = mysql_query($sql, $con); $num = mysql_numrows($result); $j = 0; while($j < $num) { $fielddate=mysql_result($result,$j,"Date"); $fieldlatitude = mysql_result($result, $j, "Latitude"); $fieldlongitude = mysql_result($result, $j, "Longitude"); $phpdate = strtotime($fielddate); $dist = distance($fieldlatitude, $fieldlongitude, $latitude, $longitude); $idarray[] = $tb_names[$i]; $latarray[] = $fieldlatitude; $longarray[] = $fieldlongitude; $count ++; $j++; } $i++;}for ($i = 0; $i < $count; $i++){print "$idarray[$i] ”; print "$latarray[$i] ”; print "$longarray[$i] ”; print "\n”;}mysql_close($con);

Code on the phone

  httpclient = new DefaultHttpClient();91                     httppost = new HttpPost(php_script);92                     // Add your data93                     nameValuePairs = new ArrayList<NameValuePair>(2);94                    nameValuePairs.add(new BasicNameValuePair("UserEmail", name.trim()));95                     nameValuePairs.add(new BasicNameValuePair("Password", pass.trim()));96                     httppost.setEntity(new UrlEncodedFormEntity(nameValuePairs));97  98                     // Execute HTTP Post Request99                     response = httpclient.execute(httppost);100                     inputStream = response.getEntity().getContent();101  102                     data = new byte[256];103  104                     buffer = new StringBuffer();105                     int len = 0;106                     while (-1 != (len = inputStream.read(data)) )107                     {108                         buffer.append(new String(data, 0, len));109                     }110  111                     inputStream.close();

Uploading images to a mysql server

php script

Phone

database

folderName of image and attributes

enter where image is stored and itsCharacteristics (size etc)

Send actual images

storeImage in a folder

Schematic for upload of images

Image

Bitmap

ByteArrayOutputStream

byte

String (Base64 encoded) String

binary (Base64 decoded)

image

Android Server

Uploading images to the server

<?php$base=$_REQUEST['image'];echo $base;// base64 encoded utf-8 string$binary=base64_decode($base);// binary, utf-8 bytesheader('Content-Type: bitmap; charset=utf-8’);$file = fopen('test.jpg', 'wb');fwrite($file, $binary);fclose($file);echo '<img src=test.jpg>';?>

Sending images from the phone

29             byte [] byte_arr = stream.toByteArray();30             String image_str = Base64.encodeBytes(byte_arr);31             ArrayList<NameValuePair> nameValuePairs = new  ArrayList<NameValuePair>();32  33             nameValuePairs.add(new BasicNameValuePair("image",image_str));34  35             try{36                 HttpClient httpclient = new DefaultHttpClient();37                 HttpPost httppost = new HttpPost(php_script);38                 httppost.setEntity(new UrlEncodedFormEntity(nameValuePairs));39                 HttpResponse response = httpclient.execute(httppost);40                  String the_string_response = convertResponseToString(response);42              }catch(Exception e){ }                                

Sending images from the phone (Response)               String res = "";

          StringBuffer buffer = new StringBuffer();               inputStream = response.getEntity().getContent();

53               int contentLength = (int) response.getEntity().getContentLength(); 55               if (contentLength < 0){56              }57              else{58                     byte[] data = new byte[512];59                     int len = 0;60                     try61                     {62                         while (-1 != (len = inputStream.read(data)) )63                         {64                             buffer.append(new String(data, 0, len)); 65                         }66                     }67                     catch (IOException e)68                     {}71                     try72                     {73                         inputStream.close(); 74                     }75                     catch (IOException e)76                     {}79                      res = buffer.toString();   .83              }84              return res;85         }                           

SMS Sending• STEP 1

– In the AndroidManifest.xml file, add the two permissions - SEND_SMS and RECEIVE_SMS.

• STEP 2– In the main.xml, add Text

view to display "Enter the phone number of recipient“ and "Message"

– EditText with id txtPhoneNo and txtMessage

– Add the button ID "Send SMS“

SMS Sending

• Step 3 Import Classes and Interfacesimport android.app.Activity;import android.app.PendingIntent;import android.content.Intent;import android.os.Bundle;import android.telephony.SmsManager;import android.view.View;import android.widget.Button;import android.widget.EditText;import android.widget.Toast;

SMS Sending

Step 4 Write the SMS class public class SMS extends Activity { Button btnSendSMS; EditText txtPhoneNo; EditText txtMessage; /** Called when the activity is first created. */ @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); btnSendSMS = (Button) findViewById(R.id.btnSendSMS); txtPhoneNo = (EditText) findViewById(R.id.txtPhoneNo); txtMessage = (EditText) findViewById(R.id.txtMessage); btnSendSMS.setOnClickListener(new View.OnClickListener() { public void onClick(View v) { String phoneNo = txtPhoneNo.getText().toString(); String message = txtMessage.getText().toString();

if (phoneNo.length()>0 && message.length()>0) sendSMS(phoneNo, message); else Toast.makeText(getBaseContext(), "Please enter both phone number and message.", Toast.LENGTH_SHORT).show(); } }); } }

Input from the user (i.e., the phone no, text message and

sendSMS is implemented).

SMS Sending

Step 5◦ To send an SMS message, you use the SmsManager class.

And to instantiate this class call getDefault() static method.

◦ The sendTextMessage() method sends the SMS message with a PendingIntent.

◦ The PendingIntent object is used to identify a target to invoke at a later time.

private void sendSMS(String phoneNumber, String message) { PendingIntent pi = PendingIntent.getActivity(this, 0, new Intent(this, SMS.class), 0); SmsManager sms = SmsManager.getDefault(); sms.sendTextMessage(phoneNumber, null, message, pi, null);}

SMS Sending

Receiving SMS

• Step 1

Receiving SMS

• Step 2– In the AndroidManifest.xml file add the <receiver> element so

that incoming SMS messages can be intercepted by the SmsReceiver class.

<receiver android:name=".SmsReceiver"> <intent-filter> <action android:name= "android.provider.Telephony.SMS_RECEIVED" /> </intent-filter> </receiver>

Receiving SMS

• Step 3import android.content.BroadcastReceiver;import android.content.Context;import android.content.Intent;import android.telephony.SmsMessage;import android.widget.Toast;

Receiving SMS

Step 4public class SmsReceiver extends BroadcastReceiver { @Override public void onReceive(Context context, Intent intent) { //---get the SMS message passed in--- Bundle bundle = intent.getExtras(); SmsMessage[] msgs = null; String str = ""; if (bundle != null){ //---retrieve the SMS message received--- Object[] pdus = (Object[]) bundle.get("pdus"); msgs = new SmsMessage[pdus.length]; for (int i=0; i<msgs.length; i++) { msgs[i] = SmsMessage.createFromPdu((byte[])pdus[i]); str += "SMS from " + msgs[i].getOriginatingAddress(); str += " :"; str += msgs[i].getMessageBody().toString(); str += "\n"; } //---display the new SMS message--- Toast.makeText(context, str, Toast.LENGTH_SHORT).show(); } }}

In the SmsReceiver class, extend the

BroadcastReceiver class and override the

onReceive() method. The message is attached to

the Intent

The messages are stored in a object array PDU format. To extract each message, you use the static createFromPdu() method from the SmsMessage class. The SMS message is then displayed using the Toast class

Receiving SMS