API PHP MySQL

Creating Database

• We need to following database table.

• So first you create a new database in your PhpMyAdmin (localhost/phpmyadmin).
• Inside the database we create the above shown table. And for this you can use the following query.

PgSQL

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-- created by belal -- website www.simplifiedcoding.net -- Table: users CREATE TABLE users (     id int NOT NULL AUTO_INCREMENT,     username varchar(200) NOT NULL,     email varchar(200) NOT NULL,     password text NOT NULL,     gender varchar(6) NOT NULL,     CONSTRAINT users_pk PRIMARY KEY (id) ); -- End of file.

• When you will execute the above given query in your database you will get the following table.

Database Table

• Now we have our database table where we will store the user data. Now lets create a PHP Project for our Web Services.

Creating a new PHP Project

• Go to the htdocs folder, and create a new folder there. (This folder is actually our project). You can use an IDE like PHP Storm to create a new project but remember create it inside htdocs only (c:/xampp/htdocs). Here I am using Sublime Text.
• Now the first step is the database connection.

Connecting to the Database

• So inside your project folder create a new php file named DbConnect.php. We will use this file to connect to the database. So write the following code inside.

DbConnect.php

PHP

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<? //these are the server details //the username is root by default in case of xampp //password is nothing by default //and lastly we have the database named android. if your database name is different you have to change it $servername = "localhost"; $username = "root"; $password = ""; $database = "android";     //creating a new connection object using mysqli $conn = new mysqli($servername, $username, $password, $database);   //if there is some error connecting to the database //with die we will stop the further execution by displaying a message causing the error if ($conn->connect_error) {     die("Connection failed: " . $conn->connect_error); }

• To confirm that the above script is working, you should open it in your browser (localhost/YourProjectFolder/DbConnect.php). If you are seeing nothing in the browser that means it is working fine.

Building Web Services

• Now here comes the main part. For the current application we need Web Services for two operation, the first one is User Registration and the second one is User Login.
• So for this create a new php file named Api.php. Inside this file we will handle all the API calls. Currently we have only two the User Registration and User Login.
• So write the following code inside Api.php.

Api.php

PHP

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<?php         //getting the database connection require_once 'DbConnect.php'; //an array to display response $response = array(); //if it is an api call //that means a get parameter named api call is set in the URL //and with this parameter we are concluding that it is an api call if(isset($_GET['apicall'])){ switch($_GET['apicall']){ case 'signup': //in this part we will handle the registration break; case 'login': //this part will handle the login break; default: $response['error'] = true; $response['message'] = 'Invalid Operation Called'; } }else{ //if it is not api call //pushing appropriate values to response array $response['error'] = true; $response['message'] = 'Invalid API Call'; } //displaying the response in json structure echo json_encode($response);

Parameter Validations

• We also need to validate that the required parameters are available or not. For this at the bottom in the same file (Api.php), create the following function.

PHP

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//function validating all the paramters are available //we will pass the required parameters to this function function isTheseParametersAvailable($params){ //traversing through all the parameters foreach($params as $param){ //if the paramter is not available if(!isset($_POST[$param])){ //return false return false; } } //return true if every param is available return true; }

User Registration

• Now lets complete the user registration. So inside switch where we need to perform the registration write the following code.

PHP

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case 'signup': //checking the parameters required are available or not if(isTheseParametersAvailable(array('username','email','password','gender'))){ //getting the values $username = $_POST['username']; $email = $_POST['email']; $password = md5($_POST['password']); $gender = $_POST['gender']; //checking if the user is already exist with this username or email //as the email and username should be unique for every user $stmt = $conn->prepare("SELECT id FROM users WHERE username = ? OR email = ?"); $stmt->bind_param("ss", $username, $email); $stmt->execute(); $stmt->store_result(); //if the user already exist in the database if($stmt->num_rows > 0){ $response['error'] = true; $response['message'] = 'User already registered'; $stmt->close(); }else{ //if user is new creating an insert query $stmt = $conn->prepare("INSERT INTO users (username, email, password, gender) VALUES (?, ?, ?, ?)"); $stmt->bind_param("ssss", $username, $email, $password, $gender); //if the user is successfully added to the database if($stmt->execute()){ //fetching the user back $stmt = $conn->prepare("SELECT id, id, username, email, gender FROM users WHERE username = ?"); $stmt->bind_param("s",$username); $stmt->execute(); $stmt->bind_result($userid, $id, $username, $email, $gender); $stmt->fetch(); $user = array( 'id'=>$id, 'username'=>$username, 'email'=>$email, 'gender'=>$gender ); $stmt->close(); //adding the user data in response $response['error'] = false; $response['message'] = 'User registered successfully'; $response['user'] = $user; } } }else{ $response['error'] = true; $response['message'] = 'required parameters are not available'; } break;

• Now you can test the registration using a REST Client (I am here using POSTMAN).

• You see the user registration is working fine. Now lets create the User Login API.

User Login

• After registration user will login to the application. So again inside switch where we need to define the login write the following code.

PHP

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case 'login': //for login we need the username and password if(isTheseParametersAvailable(array('username', 'password'))){ //getting values $username = $_POST['username']; $password = md5($_POST['password']); //creating the query $stmt = $conn->prepare("SELECT id, username, email, gender FROM users WHERE username = ? AND password = ?"); $stmt->bind_param("ss",$username, $password); $stmt->execute(); $stmt->store_result(); //if the user exist with given credentials if($stmt->num_rows > 0){ $stmt->bind_result($id, $username, $email, $gender); $stmt->fetch(); $user = array( 'id'=>$id, 'username'=>$username, 'email'=>$email, 'gender'=>$gender ); $response['error'] = false; $response['message'] = 'Login successfull'; $response['user'] = $user; }else{ //if the user not found $response['error'] = false; $response['message'] = 'Invalid username or password'; } } break;

• Now you can test the login part as well.

The Complete Api Code

• This is the complete code of my Api.php file.

Api.php

PHP

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<?php   require_once 'DbConnect.php'; $response = array(); if(isset($_GET['apicall'])){ switch($_GET['apicall']){ case 'signup': if(isTheseParametersAvailable(array('username','email','password','gender'))){ $username = $_POST['username']; $email = $_POST['email']; $password = md5($_POST['password']); $gender = $_POST['gender']; $stmt = $conn->prepare("SELECT id FROM users WHERE username = ? OR email = ?"); $stmt->bind_param("ss", $username, $email); $stmt->execute(); $stmt->store_result(); if($stmt->num_rows > 0){ $response['error'] = true; $response['message'] = 'User already registered'; $stmt->close(); }else{ $stmt = $conn->prepare("INSERT INTO users (username, email, password, gender) VALUES (?, ?, ?, ?)"); $stmt->bind_param("ssss", $username, $email, $password, $gender);   if($stmt->execute()){ $stmt = $conn->prepare("SELECT id, id, username, email, gender FROM users WHERE username = ?"); $stmt->bind_param("s",$username); $stmt->execute(); $stmt->bind_result($userid, $id, $username, $email, $gender); $stmt->fetch(); $user = array( 'id'=>$id, 'username'=>$username, 'email'=>$email, 'gender'=>$gender ); $stmt->close(); $response['error'] = false; $response['message'] = 'User registered successfully'; $response['user'] = $user; } } }else{ $response['error'] = true; $response['message'] = 'required parameters are not available'; } break; case 'login': if(isTheseParametersAvailable(array('username', 'password'))){ $username = $_POST['username']; $password = md5($_POST['password']); $stmt = $conn->prepare("SELECT id, username, email, gender FROM users WHERE username = ? AND password = ?"); $stmt->bind_param("ss",$username, $password); $stmt->execute(); $stmt->store_result(); if($stmt->num_rows > 0){ $stmt->bind_result($id, $username, $email, $gender); $stmt->fetch(); $user = array( 'id'=>$id, 'username'=>$username, 'email'=>$email, 'gender'=>$gender ); $response['error'] = false; $response['message'] = 'Login successfull'; $response['user'] = $user; }else{ $response['error'] = false; $response['message'] = 'Invalid username or password'; } } break; default: $response['error'] = true; $response['message'] = 'Invalid Operation Called'; } }else{ $response['error'] = true; $response['message'] = 'Invalid API Call'; } echo json_encode($response); function isTheseParametersAvailable($params){ foreach($params as $param){ if(!isset($_POST[$param])){ return false; } } return true; }

• So we are finished creating with APIs. Now lets move to android side. But before moving ahead if you need you can download my API code.