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2Checkout Documentation

Python Payment API Tutorial

In this tutorial we will walk through integrating the 2Checkout Payment API to securely tokenize and charge a credit card and using the 2Checkout Python library. You will need a 2Checkout sandbox account to complete the tutorial so if you have not already, signup for an account and generate your Payment API keys.


Application Setup

For our example application, we will be using python 2.7 and the flask framework.

pip install Flask

We will also need to install the 2Checkout Python library. 2Checkout’s Python library provides us with a simple bindings to the API, INS and Checkout process so that we can integrate each feature with only a few lines of code. In this example, we will only be using the Payment API functionality of the library.

git clone https://github.com/2Checkout/2checkout-python.git
cd 2checkout-python
python setup.py install

To start off, lets setup the file structure for our example application.

└── payment-api
    ├── app.py
    └── templates
        └── index.html

Here we created a new directory for our application named ‘payment-api’ with a new file ‘app.py’ for our python script. We also created a sub-directory ‘templates’ with and ‘index.html’ file to display our credit card form.


Create a Token

Open the ‘index.html’ file under the templates directory and create a basic HTML skeleton.

<!DOCTYPE html>
<html>
    <head>
        <title>Python Example</title>
    </head>
    <body>

    </body>
</html>

Next add a basic credit card form that allows our buyer to enter in their card number, expiration month and year and CVC.

<form id="myCCForm" action="/order" method="post">
    <input id="token" name="token" type="hidden" value="">
    <div>
        <label>
            <span>Card Number</span>
        </label>
        <input id="ccNo" type="text" size="20" value="" autocomplete="off" required />
    </div>
    <div>
        <label>
            <span>Expiration Date (MM/YYYY)</span>
        </label>
        <input type="text" size="2" id="expMonth" required />
        <span> / </span>
        <input type="text" size="2" id="expYear" required />
    </div>
    <div>
        <label>
            <span>CVC</span>
        </label>
        <input id="cvv" size="4" type="text" value="" autocomplete="off" required />
    </div>
    <input type="submit" value="Submit Payment">
</form>

Notice that we have a no ‘name’ attributes on the input elements that collect the credit card information. This will ensure that no sensitive card data touches your server when the form is submitted. Also, we include a hidden input element for the token which we will submit to our server to make the authorization request.

Now we can add our JavaScript to make the token request call. Replace ‘sandbox-seller-id’ and ‘sandbox-publishable-key’ with your credentials.

<script src="//ajax.googleapis.com/ajax/libs/jquery/1.11.0/jquery.min.js"></script>
<script src="https://www.2checkout.com/checkout/api/2co.min.js"></script>

<script>
    // Called when token created successfully.
    var successCallback = function(data) {
        var myForm = document.getElementById('myCCForm');

        // Set the token as the value for the token input
        myForm.token.value = data.response.token.token;

        // IMPORTANT: Here we call `submit()` on the form element directly instead of using jQuery to prevent and infinite token request loop.
        myForm.submit();
    };

    // Called when token creation fails.
    var errorCallback = function(data) {
        if (data.errorCode === 200) {
            tokenRequest();
        } else {
            alert(data.errorMsg);
        }
    };

    var tokenRequest = function() {
        // Setup token request arguments
        var args = {
            sellerId: "sandbox-seller-id",
            publishableKey: "sandbox-publishable-key",
            ccNo: $("#ccNo").val(),
            cvv: $("#cvv").val(),
            expMonth: $("#expMonth").val(),
            expYear: $("#expYear").val()
        };

        // Make the token request
        TCO.requestToken(successCallback, errorCallback, args);
    };

    $(function() {
        // Pull in the public encryption key for our environment
        TCO.loadPubKey('sandbox');

        $("#myCCForm").submit(function(e) {
            // Call our token request function
            tokenRequest();

            // Prevent form from submitting
            return false;
        });
    });
</script>

Let’s take a second to look at what we did here. First we pulled in a jQuery library to help us with manipulating the document. (The 2co.js library does NOT require jQuery.)

Next we pulled in the 2co.js library so that we can make our token request with the card details.

<script src="https://www.2checkout.com/checkout/api/2co.min.js"></script>

This library provides us with 2 functions, one to load the public encryption key, and one to make the token request.

The ‘TCO.loadPubKey(String environment, Function callback)’’ function must be used to asynchronously load the public encryption key for the ‘production’ or ‘sandbox’ environment. In this example, we are going to call this as soon as the document is ready so it is not necessary to provide a callback.

TCO.loadPubKey('sandbox');

The the ‘TCO.requestToken(Function callback, Function callback, Object arguments)’ function is used to make the token request. This function takes 3 arguments:

  • Your success callback function which accepts one argument and will be called when the request is successful.
  • Your error callback function which accepts one argument and will be called when the request results in an error.
  • An object containing the credit card details and your credentials.
  • sellerId : 2Checkout account number
  • publishableKey : Payment API publishable key
  • ccNo : Credit Card Number
  • expMonth : Card Expiration Month
  • expYear : Card Expiration Year
  • cvv : Card Verification Code
TCO.requestToken(successCallback, errorCallback, args);

In our example we created ‘tokenRequest’ function to setup our arguments by pulling the values entered on the credit card form and we make the token request.

var tokenRequest = function() {
    // Setup token request arguments
    var args = {
        sellerId: "sandbox-seller-id",
        publishableKey: "sandbox-publishable-key",
        ccNo: $("#ccNo").val(),
        cvv: $("#cvv").val(),
        expMonth: $("#expMonth").val(),
        expYear: $("#expYear").val()
    };

    // Make the token request
    TCO.requestToken(successCallback, errorCallback, args);
};

We then call this function from a submit handler function that we setup on the form.

$("#myCCForm").submit(function(e) {
    // Call our token request function
    tokenRequest();

    // Prevent form from submitting
    return false;
});

The ‘successCallback’ function is called if the token request is successful. In this function we set the token as the value for our ‘token’ hidden input element and we submit the form to our server.

var successCallback = function(data) {
    var myForm = document.getElementById('myCCForm');

    // Set the token as the value for the token input
    myForm.token.value = data.response.token.token;

    // IMPORTANT: Here we call `submit()` on the form element directly instead of using jQuery to prevent and infinite token request loop.
    myForm.submit();
};

The ‘errorCallback’ function is called if the token request fails. In our example function, we check for error code 200, which indicates that the ajax call has failed. If the error code was 200, we automatically re-attempt the tokenization, otherwise, we alert with the error message.

var errorCallback = function(data) {
    if (data.errorCode === 200) {
        tokenRequest();
    } else {
        alert(data.errorMsg);
    }
};

Create the Sale

Open ‘app.py’ and add the imports we need for Flask and Twocheckout.

from flask import Flask
from flask import render_template
from flask import request
import twocheckout
from twocheckout import TwocheckoutError

Next lets create and instance of the Flask class, define routes for ‘index’ and ‘order’ and call the run() function to start the web server.

app = Flask(__name__)

# Routes will be declared here

if __name__ == '__main__':
    app.run()

In the index route, we will use ‘render_template’ to return our ‘index.html’ and display it to the buyer.

@app.route('/')
@app.route('/index')
def index():
    return render_template("index.html")

In the order route, we will use the token passed from our credit card form to submit the authorization request and display the response. Replace ‘sandbox-seller-id’ and ‘sandbox-private-key’ with your credentials.

@app.route('/order', methods=['POST'])
def order():
    # Setup credentials and environment
    twocheckout.Api.auth_credentials({
        'private_key': 'sandbox-private-key',
        'seller_id': 'sandbox-seller_id',
        'mode': 'sandbox'
    })

    # Setup arguments for authorization request
    args = {
        'merchantOrderId': '123',
        'token': request.form["token"],
        'currency': 'USD',
        'total': '1.00',
        'billingAddr': {
            'name': 'Testing Tester',
            'addrLine1': '123 Test St',
            'city': 'Columbus',
            'state': 'OH',
            'zipCode': '43123',
            'country': 'USA',
            'email': 'example@2co.com',
            'phoneNumber': '555-555-5555'
        }
    }

    # Make authorization request
    try:
        result = twocheckout.Charge.authorize(args)
        return result.responseMsg
    except TwocheckoutError as error:
        return error.msg

Lets break down this function a bit and explain what were doing here.

First we setup our credentials and the environment using the ‘twocheckout.Api.auth_credentials(dictionary)’ function. This function accepts a dictionary as the argument containing the following keys. private_key: Your Payment API private key seller_id: 2Checkout account number * mode: ‘sandbox’ or ‘production’ (defaults to production)

Next we create a dictionary with our authorization attributes. In our example we are using hard coded strings for each required attribute except for the token which is passed in from the credit card form.

Important Note: A token can only be used for one authorization call, and will expire after 30 minutes if not used.

args = {
    'merchantOrderId': '123',
    'token': request.form["token"],
    'currency': 'USD',
    'total': '1.00',
    'billingAddr': {
        'name': 'Testing Tester',
        'addrLine1': '123 Test St',
        'city': 'Columbus',
        'state': 'OH',
        'zipCode': '43123',
        'country': 'USA',
        'email': 'example@2co.com',
        'phoneNumber': '555-555-5555'
    }
}

Finally we submit the charge using the ‘twocheckout.Charge.authorize(dictionary)’ function and display the result to the buyer. It is important to wrap this in a try/catch block so that you can handle the response and catch the ‘TwocheckoutError’ exception that will be thrown if the card fails to authorize.

try:
    result = twocheckout.Charge.authorize(args)
    return result.responseMsg
except TwocheckoutError as error:
    return error.msg

Run the example application

In your console, navigate to the ‘payment-api’ directory and startup the application.

python app.py

In your browser, navigate to ‘http://localhost:5000’, and you should see a payment form where you can enter credit card information.

For your testing, you can use these values for a successful authorization

Credit Card Number: 4000000000000002

Expiration date: 10/2020

cvv: 123

And these values for a failed authorization:

Credit Card Number: 4333433343334333

Expiration date: 10/2020

cvv:123

The complete example application for this tutorial can be accessed on our public Github repository.

If you have any questions, feel free to send them to techsupport@2co.com