Integrate Cashfree Payment Gateway in Flutter

Payment Gateway:

A payment gateway is a merchant service provided by an e-commerce application service provider that authorizes credit card or direct payments processing for e-businesses, online retailers, bricks and clicks, or traditional brick and mortar.^[1] The payment gateway may be provided by a bank to its customers, but can be provided by a specialised financial service provider as a separate service, such as a payment service provider.

A payment gateway facilitates a payment transaction by the transfer of information between a payment portal (such as a website, mobile phone or interactive voice response service) and the front end processor or acquiring bank.

Payment gateways are a service that helps merchants initiate ecommerce, in-app, and point of sale payments for a broad variety of payment methods. The gateway is not directly involved in the money flow; typically it is a web server to which a merchant's website or POS system is connected. A payment gateway often connects several acquiring banks and payment methods under one system.

To Integrate cashfree Payment Gateway into your flutter project follow these step only (For Android) :

Step 1.

install this dependancy after runing this command in terminal:

flutter pub get flutter_cashfree_pg_sdk

Step 2.

// Please put cursor on every import where it is break the line

// and make it one liner

import 'dart:convert';

import 'dart:math';

import 'package:flutter/material.dart';

import 'package:flutter_cashfree_pg_sdk/api/cferrorresponse

/cferrorresponse.dart';

import 'package:flutter_cashfree_pg_sdk/api/cfpayment

/cfdropcheckoutpayment.dart';

import 'package:flutter_cashfree_pg_sdk/api/cfpaymentcomponents

/cfpaymentcomponent.dart';

import 'package:flutter_cashfree_pg_sdk/api/cfpaymentgateway

/cfpaymentgatewayservice.dart';

import 'package:flutter_cashfree_pg_sdk/api/cfsession

/cfsession.dart';

import 'package:flutter_cashfree_pg_sdk/api/cftheme

/cftheme.dart';

import 'package:flutter_cashfree_pg_sdk/utils

/cfenums.dart';

import 'package:flutter_cashfree_pg_sdk/utils

/cfexceptions.dart';

import 'package:get/get.dart';

import 'package:http/http.dart' as http;

class PaymentMethodScreen extends StatefulWidget {

  const PaymentMethodScreen({super.key});

  @override

  State<PaymentMethodScreen> createState() =>

_PaymentMethodScreenState();

}

class _PaymentMethodScreenState extends

State<PaymentMethodScreen> {

 

  CFPaymentGatewayService cfPaymentGatewayService =

      CFPaymentGatewayService(); // Cashfree Payment Instance

  bool? isSuccess;

  @override

  void initState() {

    super.initState();

    // Attach events when payment is success and

// when error occured

    cfPaymentGatewayService.setCallback(verifyPayment, onError);

  }

  @override

  Widget build(BuildContext context) {

    return Scaffold(

      appBar: AppBar(

        title: const Text('Payment Method'),

      ),

      body: Column(

        mainAxisAlignment: MainAxisAlignment.start,

        children: [

          ListTile(

            onTap: () {

              pay();

            },

            title: Text("Online Pay"),

          ),

        ],

      ),

    );

  } // When payment is done successfully

  void verifyPayment(String orderId) {

    // Here we will only print the statement

    // to check payment is done or not

    isSuccess = true;

    setState(() {});

// redirect to final screen from here

 

    print("Verify Payment $orderId");

  }

// If some error occur during payment this will trigger

  void onError(CFErrorResponse errorResponse, String orderId) {

    // printing the error message so that we can show

    // it to user or checkourselves for testing

    isSuccess = false;

    setState(() {});

    print(errorResponse.getMessage());

    print("Error while making payment");

  }

  String orderId = new DateTime.now()

    .millisecondsSinceEpoch

    .toString();

  Future<CFSession?> createSession() async {

    try {

     
final mySessionIDData = await createSessionID(

          orderId);

// This will create session id from flutter itself

     

      print(mySessionIDData);

      // Now we will se some parameter like orderID ,

        //environment,payment sessionID

      // after that we wil create the checkout session

      // which will launch through which user can pay.

      var session = CFSessionBuilder()

          .setEnvironment(CFEnvironment.SANDBOX)

          .setOrderId(mySessionIDData["order_id"])

          .setPaymentSessionId(

            mySessionIDData["payment_session_id"])

          .build();

      return session;

    } on CFException catch (e) {

      print(e.message);

    }

    return null;

  }

  pay() async {

    try {

      var session = await createSession();

      List<CFPaymentModes> components = <CFPaymentModes>[];

      // If you want to set paument mode to be shown

// to customer

      var paymentComponent =

          CFPaymentComponentBuilder()

        .setComponents(components)

        .build();

      // We will set theme of checkout session page like

        //fonts, color

      var theme = CFThemeBuilder()

          .setNavigationBarBackgroundColorColor("#FF0000")

          .setPrimaryFont("Menlo")

          .setSecondaryFont("Futura")

          .build();

      // Create checkout with all the settings

//we have set earlier

      var cfDropCheckoutPayment =

     CFDropCheckoutPaymentBuilder()

          .setSession(session!)

          .setPaymentComponent(paymentComponent)

          .setTheme(theme)

          .build();

      // Launching the payment page

      cfPaymentGatewayService.doPayment(cfDropCheckoutPayment);

    } on CFException catch (e) {

      print(e.message);

    }

  }

}

createSessionID(String orderID) async {

  var headers = {

    'Content-Type': 'application/json',

    'x-client-id': "Your app id of cashfree account" ?? "",

    'x-client-secret': "your app secret of cashfree account" ?? "",

    'x-api-version': '2022-09-01',

    // This is latest version for API

    'x-request-id': 'fluterwings'

  };

  print(headers);

  var request =

      http.Request('POST',

Uri.parse('https://sandbox.cashfree.com/pg/orders'));

  request.body = json.encode({

    "order_amount": 1,

// Order Amount in Rupees

    "order_id": orderID,

// OrderiD created by you it must be unique

    "order_currency": "INR",

// Currency of order like INR,USD

    "customer_details": {

      "customer_id": "customer_id",

// Customer id

      "customer_name": "customer_name",

// Name of customer

      "customer_email": "customer_email@gmail.com",

// Email id of customer

      "customer_phone": "+91 customer_mobile_number"

// Phone Number of customer

    },

    "order_meta": {"notify_url": "https://test.cashfree.com"},

    "order_note": "some order note here"

// If you want to store something extra

  });

  request.headers.addAll(headers);

  http.StreamedResponse response = await request.send();

  if (response.statusCode == 200) {

    // If All the details is correct it will return the

    // response and you can get sessionid for checkout

    return jsonDecode(await response.stream.bytesToString());

  } else {

    print(await response.stream.bytesToString());

    print(response.reasonPhrase);

  }

}