I will show how to create a simple web service with JSON. Our service will get the parameters by using $_GET , therefore we will put the parameters to url. For instance http://mywebserviceurl.com?s=myparameter , so the service will answer depending on myparameter.
Lets look at service's index file:
index.php
<?php
include('connectdb.php');
$something = $_GET['s'];
$sqlcode = mysql_query("Select $something from mydb limit 5 ");
$jsonObj= array();
while($result=mysql_fetch_object($sqlcode))
{
$jsonObj[] = $result;
}
$final_res =json_encode($jsonObj) ;
echo $final_res;
?>
connectdb.php
<?php
$hostname="localhost";
$username=""; //write your username
$password=""; //write your password
$db_name=""; //write your db name
$con=mysql_connect($hostname,$username,$password);
mysql_select_db($db_name,$con) or die ("Cannot connect the Database");
mysql_query("SET NAMES 'utf8'",$con);
?>
Thats all. You will see the JSON results on the screen. You can validate the JSON results with the help of some sites. Json validator addresses:
http://jsoneditor.net/
http://jsonlint.com/
How to get results of a web service?
Your application will ask this webservice something, then the service will give response with a json result. Your application should get the results with a reader to read the webservice's output.
In PHP, you can do that with file_get_contents() function. Here is an example of my php application:
readwebservice.php
<?php
$jsonObj = file_get_contents('http://mywebserviceurl.com/?s=myparameter');
$final_res = json_decode($jsonObj, true) ;
var_dump( $final_res );
?>
In Android, you can use JSONParser.java which you can find the whole codes at the following topic below. You can simply use jsonParser.getJSONFromUrl() function to read the results. Here is example:
UserFunctions.java
import java.util.ArrayList;
import java.util.List;
import org.apache.http.NameValuePair;
import org.apache.http.message.BasicNameValuePair;
import org.json.JSONObject;
/**
* function make webservice Request
* @param myparameter
* */
public JSONObject loginUser(String myparameter){
String webserviceURL = "http://mywebserviceurl.com/";
JSONParser jsonParser = new JSONParser();
// Building Parameters
List params = new ArrayList();
params.add(new BasicNameValuePair("s", myparameter));
JSONObject json = jsonParser.getJSONFromUrl(webserviceURL, params);
// return json
// Log.e("JSON", json.toString());
return json;
}
Thats all for a simple webservice example. Lets look at an complex example now.
PHP LOGIN WEBSERVICE AND HOW TO USE IT IN ANDROID APP
If you want to create more complex webservices, I am gonna give you an example which is for "login" control. (If you want to look at my source files, you can download full "PHP Login Webservice" from https://sourceforge.net/p/phploginwebservice/)
Put the php web service codes into a directory which name is "android_login_api", so you can reach the web service via "http://mywebserviceurl.com/android_login_api/" url link. Also you should create another directory for other web service needs like "search" or "post" etc. By this way, you can seperate the service codes in a logical manner.
In web service with PHP:
index.php (Web service)
<?php
/**
* File to handle all API requests
* Accepts GET and POST
*
* Each request will be identified by TAG
* Response will be JSON data
/**
* check for POST request
*/
if (isset($_POST['tag']) && $_POST['tag'] != '') {
// get tag
$tag = $_POST['tag'];
// include db handler
require_once 'DB_Functions.php';
$db = new DB_Functions();
// response Array
$response = array("tag" => $tag, "success" => 0, "error" => 0);
// check for tag type
if ($tag == 'login') {
// Request type is check Login
$email = $_POST['email'];
$password = $_POST['password'];
// check for user
$user = $db->getUserByEmailAndPassword($email, $password);
if ($user != false) {
// user found
// echo json with success = 1
$response["success"] = 1;
$response["uid"] = $user["unique_id"];
$response["user"]["name"] = $user["name"];
$response["user"]["email"] = $user["email"];
$response["user"]["created_at"] = $user["created_at"];
$response["user"]["updated_at"] = $user["updated_at"];
echo json_encode($response);
} else {
// user not found
// echo json with error = 1
$response["error"] = 1;
$response["error_msg"] = "Incorrect email or password!";
echo json_encode($response);
}
} else if ($tag == 'register') {
// Request type is Register new user
$name = $_POST['name'];
$email = $_POST['email'];
$password = $_POST['password'];
// check if user is already existed
if ($db->isUserExisted($email)) {
// user is already existed - error response
$response["error"] = 2;
$response["error_msg"] = "User already existed";
echo json_encode($response);
} else {
// store user
$user = $db->storeUser($name, $email, $password);
if ($user) {
// user stored successfully
$response["success"] = 1;
$response["uid"] = $user["unique_id"];
$response["user"]["name"] = $user["name"];
$response["user"]["email"] = $user["email"];
$response["user"]["created_at"] = $user["created_at"];
$response["user"]["updated_at"] = $user["updated_at"];
echo json_encode($response);
} else {
// user failed to store
$response["error"] = 1;
$response["error_msg"] = "Error occured in Registartion";
echo json_encode($response);
}
}
} else {
echo "Invalid Request";
}
} else {
echo "Access Denied";
}
?>
DB_Functions.php (Web service)
<?php
class DB_Functions {
private $db;
//put your code here
// constructor
function __construct() {
require_once 'DB_Connect.php';
// connecting to database
$this->db = new DB_Connect();
$this->db->connect();
}
// destructor
function __destruct() {
}
/**
* Storing new user
* returns user details
*/
public function storeUser($name, $email, $password) {
$uuid = uniqid('', true);
$hash = $this->hashSSHA($password);
$encrypted_password = $hash["encrypted"]; // encrypted password
$salt = $hash["salt"]; // salt
$result = mysql_query("INSERT INTO users(unique_id, name, email, encrypted_password, salt, created_at) VALUES('$uuid', '$name', '$email', '$encrypted_password', '$salt', NOW())");
// check for successful store
if ($result) {
// get user details
$uid = mysql_insert_id(); // last inserted id
$result = mysql_query("SELECT * FROM users WHERE uid = $uid");
// return user details
return mysql_fetch_array($result);
} else {
return false;
}
}
/**
* Get user by email and password
*/
public function getUserByEmailAndPassword($email, $password) {
$result = mysql_query("SELECT * FROM users WHERE email = '$email'") or die(mysql_error());
// check for result
$no_of_rows = mysql_num_rows($result);
if ($no_of_rows > 0) {
$result = mysql_fetch_array($result);
$salt = $result['salt'];
$encrypted_password = $result['encrypted_password'];
$hash = $this->checkhashSSHA($salt, $password);
// check for password equality
if ($encrypted_password == $hash) {
// user authentication details are correct
return $result;
}
} else {
// user not found
return false;
}
}
/**
* Check user is existed or not
*/
public function isUserExisted($email) {
$result = mysql_query("SELECT email from users WHERE email = '$email'");
$no_of_rows = mysql_num_rows($result);
if ($no_of_rows > 0) {
// user existed
return true;
} else {
// user not existed
return false;
}
}
/**
* Encrypting password
* @param password
* returns salt and encrypted password
*/
public function hashSSHA($password) {
$salt = sha1(rand());
$salt = substr($salt, 0, 10);
$encrypted = base64_encode(sha1($password . $salt, true) . $salt);
$hash = array("salt" => $salt, "encrypted" => $encrypted);
return $hash;
}
/**
* Decrypting password
* @param salt, password
* returns hash string
*/
public function checkhashSSHA($salt, $password) {
$hash = base64_encode(sha1($password . $salt, true) . $salt);
return $hash;
}
}
?>
DB_Connect.php (Web service)
<?php
class DB_Connect {
// constructor
function __construct() {
}
// destructor
function __destruct() {
// $this->close();
}
// Connecting to database
public function connect() {
/**
* Database config variables
*/
define("DB_HOST", "localhost");
define("DB_USER", "my_db_user");
define("DB_PASSWORD", "my_db_pass");
define("DB_DATABASE", "my_db_name");
// connecting to mysql
$con = mysql_connect(DB_HOST, DB_USER, DB_PASSWORD);
// selecting database
mysql_select_db(DB_DATABASE);
// return database handler
return $con;
}
// Closing database connection
public function close() {
mysql_close();
}
}
?>
This is all for web service. Now you can go to Android app source codes. In Android:
JSONParser.java (Android)
package com.myapp.library;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.UnsupportedEncodingException;
import java.util.List;
import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.NameValuePair;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.entity.UrlEncodedFormEntity;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.impl.client.DefaultHttpClient;
import org.json.JSONException;
import org.json.JSONObject;
import android.util.Log;
public class JSONParser {
static InputStream is = null;
static JSONObject jObj = null;
static String json = "";
// constructor
public JSONParser() {
}
public JSONObject getJSONFromUrl(String url, List params) {
// Making HTTP request
try {
// defaultHttpClient
DefaultHttpClient httpClient = new DefaultHttpClient();
HttpPost httpPost = new HttpPost(url);
httpPost.setEntity(new UrlEncodedFormEntity(params));
HttpResponse httpResponse = httpClient.execute(httpPost);
HttpEntity httpEntity = httpResponse.getEntity();
is = httpEntity.getContent();
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
} catch (ClientProtocolException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
try {
BufferedReader reader = new BufferedReader(new InputStreamReader(
is, "iso-8859-1"), 8);
StringBuilder sb = new StringBuilder();
String line = null;
while ((line = reader.readLine()) != null) {
sb.append(line + "\n");
}
is.close();
json = sb.toString();
Log.e("JSON", json);
} catch (Exception e) {
Log.e("Buffer Error", "Error converting result " + e.toString());
}
// try parse the string to a JSON object
try {
jObj = new JSONObject(json);
} catch (JSONException e) {
Log.e("JSON Parser", "Error parsing data " + e.toString());
}
// return JSON String
return jObj;
}
}
UserFunctions.java (Android)
package com.myapp.library;
import java.util.ArrayList;
import java.util.List;
import org.apache.http.NameValuePair;
import org.apache.http.message.BasicNameValuePair;
import org.json.JSONObject;
import android.content.Context;
public class UserFunctions {
private JSONParser jsonParser;
private static String loginURL = "http://mywebserviceurl.com/android_login_api/";
private static String registerURL = "http://mywebserviceurl.com/android_login_api/";
private static String login_tag = "login";
private static String register_tag = "register";
// constructor
public UserFunctions(){
jsonParser = new JSONParser();
}
/**
* function make Login Request
* @param email
* @param password
* */
public JSONObject loginUser(String email, String password){
// Building Parameters
List params = new ArrayList();
params.add(new BasicNameValuePair("tag", login_tag));
params.add(new BasicNameValuePair("email", email));
params.add(new BasicNameValuePair("password", password));
JSONObject json = jsonParser.getJSONFromUrl(loginURL, params);
// return json
// Log.e("JSON", json.toString());
return json;
}
/**
* function make Login Request
* @param name
* @param email
* @param password
* */
public JSONObject registerUser(String name, String email, String password){
// Building Parameters
List params = new ArrayList();
params.add(new BasicNameValuePair("tag", register_tag));
params.add(new BasicNameValuePair("name", name));
params.add(new BasicNameValuePair("email", email));
params.add(new BasicNameValuePair("password", password));
// getting JSON Object
JSONObject json = jsonParser.getJSONFromUrl(registerURL, params);
// return json
return json;
}
/**
* Function get Login status
* */
public boolean isUserLoggedIn(Context context){
DatabaseHandler db = new DatabaseHandler(context);
int count = db.getRowCount();
if(count > 0){
// user logged in
return true;
}
return false;
}
/**
* Function to logout user
* Reset Database
* */
public boolean logoutUser(Context context){
DatabaseHandler db = new DatabaseHandler(context);
db.resetTables();
return true;
}
}
In your application, you can use this UserFunctions.java like that:
import com.myapp.library.UserFunctions;
Lets say our response JSON of webservice will be like that:
{ "success": 1,
"user": {
"name":"Seval",
"email":"hello@hotmail.com"
}
}
You can call parse the results in a function, for example "loginUser":
JSONObject json = userFunction.loginUser(email, password);
// check for login response
String res = json.getString("success");
if(Integer.parseInt(res) == 1){
JSONObject json_user = json.getJSONObject("user");
String name = json_user.getString("name");
String email = json_user.getString("email");
}
