A Guide to Enable Stripe Subscription Payment Integration in CodeIgniter

codeigniter_stripe_subscription_payment_integration/
├── application/
│   ├── config/
│   │   └── stripe.php
│   ├── controllers/
│   │   └── Subscription.php
│   ├── libraries/
│   │   └── Stripe_lib.php
│   ├── models/
│   │   └── User.php
│   ├── third_party/
│   │   └── stripe-php/
│   ├── views/
│   │   └── subscription/
│   │       ├── index.php
│   │       └── payment-status.php
└── assets/
    └── css/
        └── style.css

CREATE TABLE `plans` (
 `id` int(11) NOT NULL AUTO_INCREMENT,
 `name` varchar(255) COLLATE utf8_unicode_ci NOT NULL,
 `price` float(10,2) NOT NULL,
 `currency` varchar(10) COLLATE utf8_unicode_ci NOT NULL DEFAULT 'USD',
 `interval` enum('week','month','year') COLLATE utf8_unicode_ci NOT NULL,
 PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci;

CREATE TABLE `users` (
 `id` int(11) NOT NULL AUTO_INCREMENT,
 `subscription_id` int(11) NOT NULL DEFAULT 0,
 `first_name` varchar(25) COLLATE utf8_unicode_ci NOT NULL,
 `last_name` varchar(25) COLLATE utf8_unicode_ci NOT NULL,
 `email` varchar(50) COLLATE utf8_unicode_ci NOT NULL,
 `password` varchar(255) COLLATE utf8_unicode_ci NOT NULL,
 `gender` enum('Male','Female') COLLATE utf8_unicode_ci NOT NULL,
 `phone` varchar(15) COLLATE utf8_unicode_ci NOT NULL,
 `created` datetime NOT NULL,
 `modified` datetime NOT NULL,
 `status` enum('1','0') COLLATE utf8_unicode_ci NOT NULL DEFAULT '1',
 PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci;

CREATE TABLE `user_subscriptions` (
 `id` int(11) NOT NULL AUTO_INCREMENT,
 `user_id` int(11) NOT NULL DEFAULT 0,
 `plan_id` int(11) NOT NULL,
 `payment_method` enum('stripe') COLLATE utf8_unicode_ci NOT NULL DEFAULT 'stripe',
 `stripe_subscription_id` varchar(50) COLLATE utf8_unicode_ci NOT NULL,
 `stripe_customer_id` varchar(50) COLLATE utf8_unicode_ci NOT NULL,
 `stripe_plan_id` varchar(50) COLLATE utf8_unicode_ci NOT NULL,
 `plan_amount` float(10,2) NOT NULL,
 `plan_amount_currency` varchar(10) COLLATE utf8_unicode_ci NOT NULL,
 `plan_interval` varchar(10) COLLATE utf8_unicode_ci NOT NULL,
 `plan_interval_count` tinyint(2) NOT NULL,
 `plan_period_start` datetime NOT NULL,
 `plan_period_end` datetime NOT NULL,
 `payer_email` varchar(50) COLLATE utf8_unicode_ci NOT NULL,
 `created` datetime NOT NULL,
 `status` varchar(50) COLLATE utf8_unicode_ci NOT NULL,
 PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci;

<?php 
defined('BASEPATH') OR exit('No direct script access allowed'); 
/* 
| ------------------------------------------------------------------- 
|  Stripe API Configuration 
| ------------------------------------------------------------------- 
| 
| You will get the API keys from Developers panel of the Stripe account 
| Login to Stripe account (https://dashboard.stripe.com/) 
| and navigate to the Developers » API keys page 
| Remember to switch to your live publishable and secret key in production! 
| 
|  stripe_api_key            string   Your Stripe API Secret key. 
|  stripe_publishable_key    string   Your Stripe API Publishable key. 
|  stripe_currency           string   Currency code. 
*/ 
$config['stripe_api_key']         = 'Your_API_Secret_key'; 
$config['stripe_publishable_key'] = 'Your_API_Publishable_key'; 
$config['stripe_currency']        = 'usd';

<?php 
defined('BASEPATH') OR exit('No direct script access allowed'); 
 
/** 
 * Stripe Library for CodeIgniter 3.x 
 * 
 * Library for Stripe payment gateway. It helps to integrate Stripe payment gateway 
 * in CodeIgniter application. 
 * 
 * This library requires the Stripe PHP bindings and it should be placed in the third_party folder. 
 * It also requires Stripe API configuration file and it should be placed in the config directory. 
 * 
 * @package     CodeIgniter 
 * @category    Libraries 
 * @author      PHPStackoverflow
 * @version     3.0 
 */ 
 
class Stripe_lib{ 
    var $CI; 
    var $api_error; 
     
    function __construct(){ 
        $this->api_error = ''; 
        $this->CI =& get_instance(); 
        $this->CI->load->config('stripe'); 
         
        // Include the Stripe PHP bindings library 
        require APPPATH .'third_party/stripe-php/init.php'; 
         
        // Set API key 
        \Stripe\Stripe::setApiKey($this->CI->config->item('stripe_api_key')); 
    } 
 
    function addCustomer($name, $email, $token){ 
        try { 
            // Add customer to stripe 
            $customer = \Stripe\Customer::create(array( 
                'name' => $name, 
                'email' => $email, 
                'source'  => $token 
            )); 
            return $customer; 
        }catch(Exception $e) { 
            $this->api_error = $e->getMessage(); 
            return false; 
        } 
    } 
     
    function createPlan($planName, $planPrice, $planInterval){ 
        // Convert price to cents 
        $priceCents = ($planPrice*100); 
        $currency = $this->CI->config->item('stripe_currency'); 
         
        try { 
            // Create a plan 
            $plan = \Stripe\Plan::create(array( 
                "product" => [ 
                    "name" => $planName 
                ], 
                "amount" => $priceCents, 
                "currency" => $currency, 
                "interval" => $planInterval, 
                "interval_count" => 1 
            )); 
            return $plan; 
        }catch(Exception $e) { 
            $this->api_error = $e->getMessage(); 
            return false; 
        } 
    } 
     
    function createSubscription($customerID, $planID){ 
        try { 
            // Creates a new subscription 
            $subscription = \Stripe\Subscription::create(array( 
                "customer" => $customerID, 
                "items" => array( 
                    array( 
                        "plan" => $planID 
                    ), 
                ), 
            )); 
             
            // Retrieve charge details 
            $subsData = $subscription->jsonSerialize(); 
            return $subsData; 
        }catch(Exception $e) { 
            $this->api_error = $e->getMessage(); 
            return false; 
        } 
    } 
}

<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed'); 
 
class Subscription extends CI_Controller { 
     
    function __construct() { 
        parent::__construct(); 
         
        // Load Stripe library 
        $this->load->library('stripe_lib'); 
         
        // Load product model 
        $this->load->model('user'); 
         
        // Get user ID from current SESSION 
        $this->userID = isset($_SESSION['loggedInUserID'])?$_SESSION['loggedInUserID']:1; 
    } 
     
    public function index(){ 
        $data = array(); 
         
        // If payment form is submitted with token 
        if($this->input->post('stripeToken')){ 
            // Retrieve stripe token and user info from the posted form data 
            $postData = $this->input->post(); 
             
            // Make payment 
            $paymentID = $this->payment($postData); 
             
            // If payment successful 
            if($paymentID){ 
                redirect('subscription/payment_status/'.$paymentID); 
            }else{ 
                $apiError = !empty($this->stripe_lib->api_error)?' ('.$this->stripe_lib->api_error.')':''; 
                $data['error_msg'] = 'Transaction has been failed!'.$apiError; 
            } 
        } 
         
        // Get plans from the database 
        $data['plans'] = $this->user->getPlans(); 
         
        // Pass plans data to the list view 
        $this->load->view('subscription/index', $data); 
    } 
     
    function payment($postData){ 
         
        // If post data is not empty 
        if(!empty($postData)){ 
            // Retrieve stripe token and user info from the submitted form data 
            $token  = $postData['stripeToken']; 
            $name = $postData['name']; 
            $email = $postData['email']; 
             
            // Plan info 
            $planID = $_POST['subscr_plan']; 
            $planInfo = $this->user->getPlans($planID); 
            $planName = $planInfo['name']; 
            $planPrice = $planInfo['price']; 
            $planInterval = $planInfo['interval']; 
             
            // Add customer to stripe 
            $customer = $this->stripe_lib->addCustomer($name, $email, $token); 
             
            if($customer){ 
                // Create a plan 
                $plan = $this->stripe_lib->createPlan($planName, $planPrice, $planInterval); 
                 
                if($plan){ 
                    // Creates a new subscription 
                    $subscription = $this->stripe_lib->createSubscription($customer->id, $plan->id); 
                     
                    if($subscription){ 
                        // Check whether the subscription activation is successful 
                        if($subscription['status'] == 'active'){ 
                            // Subscription info 
                            $subscrID = $subscription['id']; 
                            $custID = $subscription['customer']; 
                            $planID = $subscription['plan']['id']; 
                            $planAmount = ($subscription['plan']['amount']/100); 
                            $planCurrency = $subscription['plan']['currency']; 
                            $planInterval = $subscription['plan']['interval']; 
                            $planIntervalCount = $subscription['plan']['interval_count']; 
                            $created = date("Y-m-d H:i:s", $subscription['created']); 
                            $current_period_start = date("Y-m-d H:i:s", $subscription['current_period_start']); 
                            $current_period_end = date("Y-m-d H:i:s", $subscription['current_period_end']); 
                            $status = $subscription['status']; 
                             
                            // Insert tansaction data into the database 
                            $subscripData = array( 
                                'user_id' => $this->userID, 
                                'plan_id' => $planInfo['id'], 
                                'stripe_subscription_id' => $subscrID, 
                                'stripe_customer_id' => $custID, 
                                'stripe_plan_id' => $planID, 
                                'plan_amount' => $planAmount, 
                                'plan_amount_currency' => $planCurrency, 
                                'plan_interval' => $planInterval, 
                                'plan_interval_count' => $planIntervalCount, 
                                'plan_period_start' => $current_period_start, 
                                'plan_period_end' => $current_period_end, 
                                'payer_email' => $email, 
                                'created' => $created, 
                                'status' => $status 
                            ); 
                            $subscription_id = $this->user->insertSubscription($subscripData); 
                             
                            // Update subscription id in the users table  
                            if($subscription_id && !empty($this->userID)){ 
                                $data = array('subscription_id' => $subscription_id); 
                                $update = $this->user->updateUser($data, $this->userID); 
                            } 
                             
                            return $subscription_id; 
                        } 
                    } 
                } 
            } 
        } 
        return false; 
    } 
     
    function payment_status($id){ 
        $data = array(); 
         
        // Get subscription data from the database 
        $subscription = $this->user->getSubscription($id); 
         
        // Pass subscription data to the view 
        $data['subscription'] = $subscription; 
        $this->load->view('subscription/payment-status', $data); 
    } 
}

<?php 
if ( ! defined('BASEPATH')) exit('No direct script access allowed'); 
 
class User extends CI_Model { 
    function __construct(){ 
        $this->userTbl        = 'users'; 
        $this->planTbl    = 'plans'; 
        $this->subscripTbl    = 'user_subscriptions'; 
    } 
     
    /* 
     * Update user data to the database 
     * @param data array 
     * @param id specific user 
     */ 
    public function updateUser($data, $id){ 
        $update = $this->db->update($this->userTbl, $data, array('id' => $id)); 
        return $update?true:false; 
    } 
     
    /* 
     * Fetch order data from the database 
     * @param id returns a single record 
     */ 
    public function getSubscription($id){ 
        $this->db->select('s.*, p.name as plan_name, p.price as plan_price, p.currency as plan_price_currency, p.interval'); 
        $this->db->from($this->subscripTbl.' as s'); 
        $this->db->join($this->planTbl.' as p', 'p.id = s.plan_id', 'left'); 
        $this->db->where('s.id', $id); 
        $query  = $this->db->get(); 
        return ($query->num_rows() > 0)?$query->row_array():false; 
    } 
     
    /* 
     * Insert subscription data in the database 
     * @param data array 
     */ 
    public function insertSubscription($data){ 
        $insert = $this->db->insert($this->subscripTbl,$data); 
        return $insert?$this->db->insert_id():false; 
    } 
     
    /* 
     * Fetch plans data from the database 
     * @param id returns a single record if specified, otherwise all records 
     */ 
    public function getPlans($id = ''){ 
        $this->db->select('*'); 
        $this->db->from($this->planTbl); 
        if($id){ 
            $this->db->where('id', $id); 
            $query  = $this->db->get(); 
            $result = ($query->num_rows() > 0)?$query->row_array():array(); 
        }else{ 
            $this->db->order_by('id', 'asc'); 
            $query  = $this->db->get(); 
            $result = ($query->num_rows() > 0)?$query->result_array():array(); 
        } 
         
        // return fetched data 
        return !empty($result)?$result:false; 
    } 
}

<div class="panel">
    <form action="" method="POST" id="paymentFrm">
        <div class="panel-heading">
            <h3 class="panel-title">Plan Subscription with Stripe</h3>
            <!-- Plan Info -->
            <p>
                <b>Select Plan:</b>
                <select name="subscr_plan" id="subscr_plan">
                    <?php foreach($plans as $plan){ ?>
                    <option value="<?php echo $plan['id']; ?>"><?php echo $plan['name'].' [$'.$plan['price'].'/'.$plan['interval'].']'; ?></option>
                    <?php } ?>
                </select>
            </p>
        </div>
        <div class="panel-body">
            <!-- Display errors returned by createToken -->
            <div id="paymentResponse"></div>
			
            <!-- Payment form -->
            <div class="form-group">
                <label>NAME</label>
                <input type="text" name="name" id="name" class="field" placeholder="Enter name" required="" autofocus="">
            </div>
            <div class="form-group">
                <label>EMAIL</label>
                <input type="email" name="email" id="email" class="field" placeholder="Enter email" required="">
            </div>
            <div class="form-group">
                <label>CARD NUMBER</label>
                <div id="card_number" class="field"></div>
            </div>
            <div class="row">
                <div class="left">
                    <div class="form-group">
                        <label>EXPIRY DATE</label>
                        <div id="card_expiry" class="field"></div>
                    </div>
                </div>
                <div class="right">
                    <div class="form-group">
                        <label>CVC CODE</label>
                        <div id="card_cvc" class="field"></div>
                    </div>
                </div>
            </div>
            <button type="submit" class="btn btn-success" id="payBtn">Submit Payment</button>
        </div>
    </form>
</div>

<script src="https://js.stripe.com/v3/"></script>

<script>
// Create an instance of the Stripe object
// Set your publishable API key
var stripe = Stripe('<?php echo $this->config->item('stripe_publishable_key'); ?>');

// Create an instance of elements
var elements = stripe.elements();

var style = {
    base: {
        fontWeight: 400,
        fontFamily: 'Roboto, Open Sans, Segoe UI, sans-serif',
        fontSize: '16px',
        lineHeight: '1.4',
        color: '#555',
        backgroundColor: '#fff',
        '::placeholder': {
            color: '#888',
        },
    },
    invalid: {
        color: '#eb1c26',
    }
};

var cardElement = elements.create('cardNumber', {
    style: style
});
cardElement.mount('#card_number');

var exp = elements.create('cardExpiry', {
    'style': style
});
exp.mount('#card_expiry');

var cvc = elements.create('cardCvc', {
    'style': style
});
cvc.mount('#card_cvc');

// Validate input of the card elements
var resultContainer = document.getElementById('paymentResponse');
cardElement.addEventListener('change', function(event) {
    if (event.error) {
        resultContainer.innerHTML = '<p>'+event.error.message+'</p>';
    } else {
        resultContainer.innerHTML = '';
    }
});

// Get payment form element
var form = document.getElementById('paymentFrm');

// Create a token when the form is submitted.
form.addEventListener('submit', function(e) {
    e.preventDefault();
    createToken();
});

// Create single-use token to charge the user
function createToken() {
    stripe.createToken(cardElement).then(function(result) {
        if (result.error) {
            // Inform the user if there was an error
            resultContainer.innerHTML = '<p>'+result.error.message+'</p>';
        } else {
            // Send the token to your server
            stripeTokenHandler(result.token);
        }
    });
}

// Callback to handle the response from stripe
function stripeTokenHandler(token) {
    // Insert the token ID into the form so it gets submitted to the server
    var hiddenInput = document.createElement('input');
    hiddenInput.setAttribute('type', 'hidden');
    hiddenInput.setAttribute('name', 'stripeToken');
    hiddenInput.setAttribute('value', token.id);
    form.appendChild(hiddenInput);
	
    // Submit the form
    form.submit();
}
</script>

<?php if(!empty($subscription)){ ?>
    <?php if($subscription['status'] == 'active'){ ?>
    <h1 class="success">Your Subscription Payment has been Successful!</h1>
    <?php }else{ ?>
    <h1 class="error">Subscription activation failed!</h1>
    <?php } ?>

    <h4>Payment Information</h4>
    <p><b>Reference Number:</b> <?php echo $subscription['id']; ?></p>
    <p><b>Transaction ID:</b> <?php echo $subscription['stripe_subscription_id']; ?></p>
    <p><b>Amount:</b> <?php echo $subscription['plan_amount'].' '.$subscription['plan_amount_currency']; ?></p>
    
    <h4>Subscription Information</h4>
    <p><b>Plan Name:</b> <?php echo $subscription['plan_name']; ?></p>
    <p><b>Amount:</b> <?php echo $subscription['plan_price'].' '.$subscription['plan_price_currency']; ?></p>
    <p><b>Plan Interval:</b> <?php echo $subscription['plan_interval']; ?></p>
    <p><b>Period Start:</b> <?php echo $subscription['plan_period_start']; ?></p>
    <p><b>Period End:</b> <?php echo $subscription['plan_period_end']; ?></p>
    <p><b>Status:</b> <?php echo $subscription['status']; ?></p>
<?php }else{ ?>
    <h1 class="error">The transaction has been failed!</h1>
<?php } ?>