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Flutter Integration Guide

This integration allows you to integrate with a Telr Flutter SDK in your app. You can view the integration video on Youtube.

The Flutter SDK is hosted on https://pub.dev/ you can get the sdk here. The example app is located here.

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Setting Up SDK

Our Flutter SDK supports Android SDK version 19 and above and iOS minimum deployment target of 11 and above. Open your project’s pubspec.yaml and add the following under dependencies: flutter_cashfree_pg_sdk: 2.2.5+43

iOS

Add this to your application’s info.plist file.

<key>LSApplicationQueriesSchemes</key>
<array>
<string>phonepe</string>
<string>tez</string>
<string>paytmmp</string>
<string>bhim</string>
<string>credpay</string>
</array>

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Step 1: Creating an Order

The first step in the Telr Payment Gateway integration is to create an Order. You need to do this before any payment can be processed. You can add an endpoint to your server which creates this order and is used for communication with your frontend.

API Request for Creating an Order

Here’s a sample request for creating an order using your desired backend language. Telr offers backend SDKs to simplify the integration process.

You can find the SDKs here.

import { Cashfree } from "cashfree-pg";

Cashfree.XClientId = {Client ID};
Cashfree.XClientSecret = {Client Secret Key};
Cashfree.XEnvironment = Cashfree.Environment.PRODUCTION;

function createOrder() {
  var request = {
    "order_amount": "1",
    "order_currency": "INR",
    "customer_details": {
      "customer_id": "node_sdk_test",
      "customer_name": "",
      "customer_email": "example@gmail.com",
      "customer_phone": "9999999999"
    },
    "order_meta": {
      "return_url": "https://test.cashfree.com/pgappsdemos/return.php?order_id=order_123"
    },
    "order_note": ""
  }

	Cashfree.PGCreateOrder("2023-08-01", request).then((response) => {
    var a = response.data;
    console.log(a)
  })
    .catch((error) => {
      console.error('Error setting up order request:', error.response.data);
    });
}

After successfully creating an order, you will receive a unique order_id and payment_session_id that you need for subsequent steps.

You can view all the complete api request and response for /orders here.

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Step 2: Opening the payment page

Web Checkout is a streamlined payment solution that integrates Telr’s payment gateway into your iOS app through our SDK. This implementation uses a WebView to provide a secure, feature-rich payment experience.

Your customers are presented with a familiar web interface where they can enter their payment details and complete their transaction seamlessly. All payment logic, UI components, and security measures are managed by our SDK, eliminating the need for complex custom implementation.

To complete the payment, we can follow the following steps:

  1. Create a CFSession object.
  2. Create a Web Checkout Payment object.
  3. Set payment callback.
  4. Initiate the payment using the payment object created

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Create a session

This object contains essential information about the order, including the payment session ID (payment_session_id) and order ID (order_id) obtained from Step 1. It also specifies the environment (sandbox or production).

try {
    var session = CFSessionBuilder().setEnvironment(environment).setOrderId(orderId).setPaymentSessionId(paymentSessionId).build();
    return session;
} on CFException catch (e) {
    print(e.message);
}

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Create a Web Checkout Payment object

Use CFWebCheckoutPaymentBuilder to create the payment object. This object acceps a CFSession, like the one created in the previous step.

var cfWebCheckout = CFWebCheckoutPaymentBuilder()
  .setSession(session!)
  .build();

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Setup callback

You need to set up callback handlers to handle events after payment processing.

void verifyPayment(String orderId) {
    print("Verify Payment");
  }

  void onError(CFErrorResponse errorResponse, String orderId) {
    print(errorResponse.getMessage());
    print("Error while making payment");
  }

var cfPaymentGatewayService = CFPaymentGatewayService();

  @override
  void initState() {
    super.initState();
    cfPaymentGatewayService.setCallback(verifyPayment, onError);
}

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Step 3: Sample Code

class _MyAppState extends State<MyApp> {

  var cfPaymentGatewayService = CFPaymentGatewayService();

  @override
  void initState() {
    super.initState();
    cfPaymentGatewayService.setCallback(verifyPayment, onError);
  }

  void verifyPayment(String orderId) {
    print("Verify Payment");
  }

  void onError(CFErrorResponse errorResponse, String orderId) {
    print(errorResponse.getMessage());
    print("Error while making payment");
  }

  webCheckout() async {
    try {
      var session = createSession();
      var cfWebCheckout = CFWebCheckoutPaymentBuilder().setSession(session!).build();
      cfPaymentGatewayService.doPayment(cfWebCheckout);
    } on CFException catch (e) {
      print(e.message);
    }

  }

  CFSession? createSession() {
    try {
      var session = CFSessionBuilder().setEnvironment(environment).setOrderId(orderId).setPaymentSessionId(paymentSessionId).build();
      return session;
    } on CFException catch (e) {
      print(e.message);
    }
    return null;
  }
}

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Step 4: Confirming the Payment

Once the payment is completed, you need to confirm whether the payment was successful by checking the order status. Once the payment finishes, the user will be redirected back to your activity.

Ensure you check the order status from your server endpoint.

To verify an order you can call our /pg/orders endpoint from your backend. You can also use our SDK to achieve the same.

version := "2023-08-01"
response, httpResponse, err := cashfree.PGFetchOrder(&version, "<order_id>", nil, nil, nil)
if err != nil {
	fmt.Println(err.Error())
} else {
	fmt.Println(httpResponse.StatusCode)
	fmt.Println(response)
}

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Testing

You should now have a working checkout button that redirects your customer to Telr payment page. If your integration isn’t working:

  1. Open the Network tab in your browser’s developer tools.
  2. Click the button and check the console logs.
  3. Use console.log(session) inside your button click listener to confirm the correct error returned.

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Error Codes

To confirm the error returned in your application, you can view the error codes that are exposed by the SDK.